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To test the hypotheses that multigenerational predation risk favors clones with longer postero-lateral spines and a larger body, and that fitness consequences of selection depend on both tested fitness variables and selection intensity, we expose replicate Brachionus dorcas populations in low (LK) and high (HK) concentrations of Asplanchna kairomones. Over 60 days (23 asexual generations) of selection, LK-selected populations showed the highest equilibrium population densities, and median mictic ratios and postero-lateral spine lengths, and HK-selected populations showed the lowest equilibrium population densities, the highest mictic ratios, and the longest postero-lateral spines, among all the control and treatment populations. In the absence of Asplanchna kairomones, and compared with populations with the control selection history, populations with an LK selection history showed increased growth rates/intrinsic rates of population increase and net reproductive rates, but decreased mictic ratios, indicating three fitness gains and a fitness cost; and those with an HK selection history showed increased life expectancy at hatching and mictic ratios, but decreased growth rates, indicating two fitness gains and a fitness cost. Asplanchna kairomones might increase the heritability of higher equilibrium densities or mictic ratios, and longer postero-lateral spines, and thus enable the prey to survive predation. [ABSTRACT FROM AUTHOR]

The blister beetle Epicauta atomaria (Germar) (Coleoptera: Meloidae) is a phytophagous pest of various agricultural crops, especially in Amaranthaceae, Solanaceae, and Fabaceae. Currently, this insect is managed through the spraying of synthetic insecticides that cause serious human health and environmental damage. To reduce the use of synthetic insecticides, the integrated pest management (IPM) programs for other crop pests rely on the use of semiochemical compounds, such as pheromones, kairomones, and allomones, to manipulate the insects' behavior to prevent crop damage. However, studies on semiochemical compounds related to E. atomaria have never been carried out. For this reason, the aim of this study was to explore the chemical communication of E. atomaria. This includes the existence of (i) a sex and/or an aggregation pheromone, (ii) attractant volatile kairomones from host plants, and (iii) repellent volatile allomones from non‐host plants. Tests were carried out using olfactometers and an experimental arena. First, olfactometer tests failed to show the existence of volatile sex and/or aggregation pheromones of these insects. Second, olfactometer and experimental arena tests failed to demonstrate attraction of E. atomaria via volatile kairomonal compounds from host plants (chard, bell pepper, and cock's‐eggs). However, olfactometer tests showed that non‐host plants of E. atomaria (thyme and lavender) emit allomonal volatile compounds with repellent activity. This work represents a first step toward the elucidation of the chemical ecology of E. atomaria and suggests that volatiles from non‐host plants help shape the host preferences of these insects. Those volatiles could be used as a “push” component in a “push–pull” strategy against this pest. [ABSTRACT FROM AUTHOR]

The behavioural responses of predator-naïve (laboratory-born), predator-experienced (laboratory-born but with short-term experience with predators), and wild-caught (with long-term experience with predators in natural settings) tadpoles of Sphaerotheca breviceps to carnivorous predatory tadpoles of Hoplobatrachus tigerinus was studied in the laboratory. The predator's stimulus solution (kairomones) was used to simulate predation threat. All S. breviceps tadpoles (i.e., predatornaïve, predator-experienced and wild-caught) exhibited behavioural antipredator responses, i.e., reduced swimming activity and time spent swimming, and had a higher burst speed in response to water-borne kairomonal cues of predators. Wildcaught tadpoles showed stronger responses than predator-naïve and predator-experienced tadpoles and the latter exhibited stronger responses than predator-naïve tadpoles. Our study thus suggests that antipredator behaviour in these tadpoles is basically innate. Furthermore, the enhanced antipredator behaviour of wild-caught tadpoles indicates that learning is involved. [ABSTRACT FROM AUTHOR]

The mere presence of predators causes prey organisms to display predation‐avoidance strategies. Predator presence is often communicated through predator‐released chemical signals. Ovipositing female mosquitoes of several species are repelled by unknown signals released from larvivorous fish.It was previously suggested that in many cases, a predator's microbiota plays an important role in the release of these signals; however, this mechanism is still poorly understood.In this study, we looked into the effects of the microbiota originating from the larvivorous Gambusia affinis (Baird and Girard) on the oviposition behaviour of gravid female mosquitoes. We used fish with altered microbiota and bacterial isolates in a set of outdoor mesocosm experiments to address this aim.We show that interference with the fish microbiota significantly reduces fish's repellent effect. We further show that the bacterium Pantoea pleuroti, isolated from the skin of the fish, repels oviposition of Culex laticinctus Edwards and Culiseta longiareolata Macquart mosquitoes similarly to the way in which live fish repel them.Our results highlight the importance of bacteria in the interspecies interactions of their hosts. Furthermore, this finding may lead to the development of an ecologically friendly mosquito repellent, that may reduce the use of larvivorous fish for mosquito control. [ABSTRACT FROM AUTHOR]

Background: The successful use of semiochemicals to attract insects to traps is based on research on the most suitable compounds and their release profiles over time. Based on the group's promising results, matrices with a more adequate release profile and more eco-friendly properties for the release of 1-hexanol were developed. To use a more suitable prototype in the field, the most promising systems were added to a capsule and evaluated in a wind tunnel. Behavioral experiments were performed using the sand fly species, Lutzomyia longipalpis, to evaluate the efficacy of the proposed system. Methods: Different delivery systems were developed by varying the polymer (gellan gum and pectin) ratio, crosslinker (aluminum chloride) concentration, and glutaraldehyde removal.The delivery systems were loaded with 1-hexanol, and their release profiles were evaluated using gravimetric analysis under ambient and high-humidity conditions. When the matrix system was placed inside a plastic container, modulations in the active release profile were observed and the system could be reused. Actid attraction behaviors of the sand fly species, Lu. longipalpis, were evaluated in a wind tunnel when exposed to 1-hexanol-loaded release systems at different times. Results: Among the four formulations evaluated, System 2 (gellan gum and pectin in a 1:1 ratio with 5% aluminum chloride) exhibited the most promising release profile, with greater uniformity and longer compound release time. The maximum 1-hexanol release uniformity was achieved over a longer time, mainly every 24 h, under both ambient and high-humidity conditions. System 2 can be reused at least once with the same structure. The wind tunnel trials exhibited efficient activation and attraction of Lu. longipalpis to 1-hexanol after 24, 48, and 72 h in System 2 placed inside the capsules. Conclusions: The polymeric matrix supplemented with 1-hexanol and introduced in plastic capsules showed promising results in attracting sand flies. This system can be used as a solution for other attractive compounds as well as in other applications where their release needs to be controlled or prolonged. [ABSTRACT FROM AUTHOR]

To test the hypothesis that non-consumptive predation pressures favor genotypes that have higher equilibrium densities or mictic ratios, we expose replicate populations of the rotifer Brachionus angularis to low (LK) and high (HK) concentrations of predator Asplanchna kairomones. Over 75 days (25 asexual generations) of selection, LK-treated populations have higher equilibrium densities and lower mictic ratios than the control populations. The opposite occurs for HK-treated populations. These results suggest that compared with the control, LK and HK select for genotypes with higher equilibrium densities and mictic ratios, respectively. Common garden bioassays reveal that in the absence of Asplanchna kairomones, populations with an LK selection history have a higher average intrinsic rate of population increase, and those with an HK selection history have a higher average mictic ratio than those with the control selection history, which suggest that adaptations to LK and HK increase average intrinsic rate of population increase and mictic ratio of prey populations, respectively. Increased intrinsic rate of population increase and mictic ratio can serve as strategies of offsetting mortality from predation and escaping the predator, and thus enable prey to survive low and high predation pressures, respectively. [ABSTRACT FROM AUTHOR]

Background: Phenotypic plasticity is a crucial adaptive mechanism that enables organisms to modify their traits in response to changes in their environment. Predator-induced defenses are an example of phenotypic plasticity observed across a wide range of organisms, from single-celled organisms to vertebrates. In addition to morphology and behavior, these responses also affect life-history traits. The crustacean Daphnia galeata is a suitable model organism for studying predator-induced defenses, as it exhibits life-history traits changes under predation risk. To get a better overview of their phenotypic plasticity under predation stress, we conducted RNA sequencing on the transcriptomes of two Korean Daphnia galeata genotypes, KE1, and KB11, collected in the same environment. Results: When exposed to fish kairomones, the two genotypes exhibited phenotypic variations related to reproduction and growth, with opposite patterns in growth-related phenotypic variation. From both genotypes, a total of 135,611 unigenes were analyzed, of which 194 differentially expressed transcripts (DETs) were shared among the two genotypes under predation stress, which showed consistent, or inconsistent expression patterns in both genotypes. Prominent DETs were related to digestion and reproduction and consistently up-regulated in both genotypes, thus associated with changes in life-history traits. Among the inconsistent DETs, transcripts encode vinculin (VINC) and protein obstructor-E (OBST-E), which are associated with growth; these may explain the differences in life-history traits between the two genotypes. In addition, genotype-specific DETs could explain the variation in growth-related life-history traits between genotypes, and could be associated with the increased body length of genotype KE1. Conclusions: The current study allows for a better understanding of the adaptation mechanisms related to reproduction and growth of two Korean D. galeata genotypes induced by predation stress. However, further research is necessary to better understand the specific mechanisms by which the uncovered DETs are related with the observed phenotypic variation in each genotype. In the future, we aim to unravel the precise adaptive mechanisms underlying predator-induced responses. [ABSTRACT FROM AUTHOR]

Organisms can exhibit plasticity in phenotypic responses to environmental stimuli but the response can vary based on the evolutionary history of a population. Numerous studies have found that prey will express adaptive responses when subjected to various predators in experimental settings. For species with a large distribution, such as Ambystoma maculatum (spotted salamander), it is not surprising that phenotypic variance can be high across their range. This variance has been hypothesized to be because of different predator regimes of populations. While A. maculatum preferentially oviposit eggs in low-risk ponds (temporary fishless) to decrease egg and larval mortality, Missouri populations still use high-risk ponds (permanent with fish) for reproduction. Using a series of experiments, we investigated how A. maculatum population risk influenced adaptive responses to both native and novel predator kairomones. For natural predators, we used larval A. opacum (marbled salamanders) and Lepomis macrochirus (bluegill) and for novel predators we used Siren intermedia (lesser siren). We found that larval salamanders generally responded with no differences in morphological traits to all three predators. However, head width was larger for low-risk populations. One hypothesized benefit of larger heads (increased foraging efficiency) was not fully supported. All larval salamanders also increased refuge use with predators but this decreased over time. Our results suggest that predation risk of a population may influence the degree of phenotypic expression in response to larval predators. Overall, local adaptation may dictate the ability of prey to respond to environmental conditions within a life stage. [ABSTRACT FROM AUTHOR]

Species that are not closely related can express similar inducible traits, but molecular mechanisms underlying the observed responses are often unknown, nor is it known if these mechanisms are shared between such species.Here, we compared transcriptional profiles of two Daphnia species (D. mitsukuri and D. sinensis) from different subgenera, at both juvenile and adult developmental stages. Both species were exposed to the same predation threat (fish kairomones), and both showed similar induced morphological changes (reduced body length).At the early developmental stage, response to predation risk resulted in similar changes in expression levels of 23 orthologues in both species. These orthologues, involved in 107 GO categories, changed in the same direction in both species (over‐ or underexpressed), in comparison to non‐exposed controls. Several of these orthologues were associated with DNA replication, structural constituents of cuticle or innate immune response. In both species, the differentially expressed (DE) genes on average had higher ω (dN/dS) values than non‐DE genes, suggesting that these genes had experienced greater positive selection or lower purifying selection than non‐DE genes.Overall, our results suggest that similar suites of genes, responding in similar ways to predation pressure, have been retained in Daphnia for many millions of years. [ABSTRACT FROM AUTHOR]

Carbon nanofibers, recently recognized pollutants, have been heavily used among the nanomaterials in many industries. Due to the poor suspension-stability, carbon nanofibers tend to sediment at the bottom of waterbodies and hence can be consumed by the bottom-dwellers. The current investigation evaluates the impact of carbon nanofibers at concentrations between 0.1 and 10 mg L−1 on the common bottom dweller spiny loach Lepidocephalichthys thermalis inhabiting Indian rivers. Carbon nanofiber exposure elevated the activities of the hepatic antioxidant enzymes superoxide dismutase, catalase, peroxidase and glutathione S-transferase, as oxidative stress markers. The fish behaviour patterns were examined by testing the effect of carbon nanofibers on predator recognition ability using kairomones, conspecific alarm cues, and dietary cues. The carbon nanofiber-exposed fish showed a loss of predator-recognition abilities. The results collectively demonstrated the carbon nanofiber driven hepatic oxidative damage and impaired predator-recognition ability in L. thermalis. The investigation, first of its kind, highlights the toxic potential of the carbon nanofibers on benthic fishes. [ABSTRACT FROM AUTHOR]

Background: The successful use of semiochemicals to attract insects to traps is based on research on the most suitable compounds and their release profiles over time. Based on the group's promising results, matrices with a more adequate release profile and more eco-friendly properties for the release of 1-hexanol were developed. To use a more suitable prototype in the field, the most promising systems were added to a capsule and evaluated in a wind tunnel. Behavioral experiments were performed using the sand fly species, Lutzomyia longipalpis, to evaluate the efficacy of the proposed system. Methods: Different delivery systems were developed by varying the polymer (gellan gum and pectin) ratio, crosslinker (aluminum chloride) concentration, and glutaraldehyde removal.The delivery systems were loaded with 1-hexanol, and their release profiles were evaluated using gravimetric analysis under ambient and high-humidity conditions. When the matrix system was placed inside a plastic container, modulations in the active release profile were observed and the system could be reused. Actid attraction behaviors of the sand fly species, Lu. longipalpis, were evaluated in a wind tunnel when exposed to 1-hexanol-loaded release systems at different times. Results: Among the four formulations evaluated, System 2 (gellan gum and pectin in a 1:1 ratio with 5% aluminum chloride) exhibited the most promising release profile, with greater uniformity and longer compound release time. The maximum 1-hexanol release uniformity was achieved over a longer time, mainly every 24 h, under both ambient and high-humidity conditions. System 2 can be reused at least once with the same structure. The wind tunnel trials exhibited efficient activation and attraction of Lu. longipalpis to 1-hexanol after 24, 48, and 72 h in System 2 placed inside the capsules. Conclusions: The polymeric matrix supplemented with 1-hexanol and introduced in plastic capsules showed promising results in attracting sand flies. This system can be used as a solution for other attractive compounds as well as in other applications where their release needs to be controlled or prolonged. [ABSTRACT FROM AUTHOR]

Context-dependency is prevalent in nature, challenging our understanding and prediction of the potential ecological impacts of non-native species (NNS). The presence of a top predator, for example, can modify the foraging behaviour of an intermediate consumer, by means of non-consumptive effects. This raises the question of whether the fear of predation might modulate consumption rates of NNS, thus shaping the magnitude of ecological impacts. Here, we quantified the functional feeding responses of three non-native crayfish species - red swamp crayfish Procambarus clarkii, rusty crayfish Faxonius rusticus and virile crayfish Faxonius virilis - compared to the native analogue signal crayfish Pacifastacus leniusculus, considering the predation risk imposed by a top fish predator, the globally invasive largemouth bass Micropterus salmoides. We applied the comparative functional response (FR) approach using snails as prey and exposing crayfish to water containing predator and dietary chemical cues or not. All crayfish species presented a destabilising Type II FR, regardless of the presence of chemical cues. Predation risk resulted in significantly longer handling times or lower attack rates in non-native crayfish; however, no significant differences were observed in signal crayfish. We estimated per capita impacts for each species using the functional response ratio (FRR; attack rate divided by handling time). The FRR metric was lower for all crayfish species when exposed to predation risk. Rusty crayfish demonstrated the highest FRR in the absence of chemical cues, followed by signal crayfish, virile crayfish and red swamp crayfish. By contrast, the FRR of signal crayfish was nearly twice that of rusty crayfish and virile crayfish and ten times greater than red swamp crayfish when chemical cues were present. The latter result agrees with the well-recognised ecological impacts of signal crayfish throughout its globally-introduced range. This study demonstrates the importance of considering the non-consumptive effects of predators when quantifying the ecological impacts of intermediate non-native consumers on prey. The direction and magnitude of the modulating effects of predators have clear implications for our understanding of NNS impacts and the prioritisation of management actions. [ABSTRACT FROM AUTHOR]

Predator–prey interactions are a key feature of ecosystems and often chemically mediated, whereby individuals detect molecules in their environment that inform whether they should attack or defend. These molecules are largely unidentified, and their discovery is important for determining their ecological role in complex trophic systems. Homarine and trigonelline are two previously identified blue crab (Callinectes sapidus) urinary metabolites that cause mud crabs (Panopeus herbstii) to seek refuge, but it was unknown whether these molecules influence other species within this oyster reef system. In the current study, homarine, trigonelline, and blue crab urine were tested on juvenile oysters (Crassostrea virginica) to ascertain if the same molecules known to alter mud crab behavior also affect juvenile oyster morphology, thus mediating interactions between a generalist predator, a mesopredator, and a basal prey species. Oyster juveniles strengthened their shells in response to blue crab urine and when exposed to homarine and trigonelline in combination, especially at higher concentrations. This study builds upon previous work to pinpoint specific molecules from a generalist predator's urine that induce defensive responses in two marine prey from different taxa and trophic levels, supporting the hypothesis that common fear molecules exist in ecological systems. [ABSTRACT FROM AUTHOR]

Cladocerans can produce dormant stages to avoid unfavorable environments, such as predation pressure and population crowding. However, only a few studies evaluated the influences of the biochemical signals of predation risk and population crowding on the termination of dormant stages of cladocerans. This study aimed to investigate the influences of predation risk signals from different predators and crowding signals from high‐density populations on the hatching of cladoceran resting eggs and the anti‐predation defensive traits of hatched offspring. We collected resting eggs of Ceriodaphnia cornuta from the surface of lake sediments and incubated them under different biochemical signals (fish kairomones, Chaoborus kairomones, alarm signals, and crowding signals) in the laboratory. In response to fish kairomones, Chaoborus kairomones, and alarm signals, the hatching time of resting eggs was delayed to a certain extent, and the body length of the offspring hatched from resting eggs increased at their birth and decreased at their first reproduction. This indicated that the offspring hatched from C. cornuta resting eggs possibly can sense predation risk signals but cannot distinguish the type of signals. In addition, the effects of crowding signals on the resting eggs were similar to those of fish kairomones, both of which can increase the body length of hatched offspring at birth, but these influences would not be further enhanced in the simultaneous presence of fish kairomones and crowding signals. This study will contribute to a better understanding of the perception of resting eggs to environmental biochemical signals and the corresponding hatching strategies of cladocerans. [ABSTRACT FROM AUTHOR]

Multisensory stimuli provide organisms with information to assess the threat present in the surroundings. Olfactory cues show dominance over other sensory modalities in the aquatic environment. The impact of chemical predator cues combined with experiences gained (learning) in species without previous contact is not fully understood. We investigated the foraging and shelter‐seeking behaviour of naïve and experienced marbled crayfish Procambarus virginalis juveniles in response to the chemical signals of pumpkinseed Lepomis gibbosus alone and in combination with alarm chemicals produced by preyed‐upon conspecifics. Naïve and experienced (previously exposed to pumpkinseed predation) juveniles were stocked in an arena with shelter and feed and exposed (1) to water from a tank containing a predator actively feeding on conspecifics, (2) water from a tank with predator only and (3) water only as control. Crayfish exposed to the combined stimuli avoided the inlet zone and gravitated to shelter zone of the arena to a greater extent than did those exposed to predator‐only cues and the control. Regardless of the treatment, experienced crayfish showed significantly reduced interest in feeding. Our findings imply that crayfish response to threat‐associated odours with the greatest potency when visual or tactile cues are present, while previous encounters with predators may make them more cautious. [ABSTRACT FROM AUTHOR]

Agricultural crop productivity relies on the application of chemical pesticides to reduce pest and pathogen damage. However, chemical pesticides also pose a range of ecological, environmental and economic penalties. This includes the development of pesticide resistance by insect pests and pathogens, rendering pesticides less effective. Alternative sustainable crop protection tools should therefore be considered. Semiochemicals are signalling molecules produced by organisms, including plants, microbes, and animals, which cause behavioural or developmental changes in receiving organisms. Manipulating semiochemicals could provide a more sustainable approach to the management of insect pests and pathogens across crops. Here, we review the role of semiochemicals in the interaction between plants, insects and microbes, including examples of how they have been applied to agricultural systems. We highlight future research priorities to be considered for semiochemicals to be credible alternatives to the application of chemical pesticides. [ABSTRACT FROM AUTHOR]

Simple Summary: Understanding insect olfactory perception can lead to more effective and specific ways to manage pests. In fact, odors have two components: (1) the quality, defined as its chemical composition, and (2) the quantity, defined by the concentration of the odor. The quantitative aspect is often missing and we aim to provide valuable information on the quantitative aspect of the odors that attract the western flower thrips, an insect that damages crops. In this study, we tested how the western flower thrips responded to different odors in an olfactometer. We measured the odor concentrations carried by the air and found that the thrips were most attracted to a pheromone at very low concentrations, much lower than the other odors we tested. Our results show that the attraction of western flower thrips to an odor depends on its quantitative aspect and could help to develop better ways of managing this pest. An understanding of insect olfaction allows for more specific alternative methods of pest control. We evaluated the responses of the western flower thrips (WFT, Frankliniella occidentalis) in a Y-olfactometer to estimate gas-phase concentrations of the aggregation pheromone neryl (S)-2-methylbutanoate and known kairomones such as methyl isonicotinate, (S)-(-)-verbenone, and p-anisaldehyde. The gas-phase concentrations of these compounds were obtained from the release rates measured in dynamic headspace cells. The compounds were collected from the headspace using dried solid-phase extraction (SPE) cartridges and analyzed with a triple quadrupole GC-MS/MS. We observed that the aggregation pheromone significantly attracted WFT females at doses of 10 and 100 µg, whereas methyl isonicotinate and p-anisaldehyde significantly attracted WFT females at the highest dose. Verbenone did not produce any significant results. A completely different picture was obtained when the gas-phase concentrations were considered. The minimal gas-phase concentrations of the pheromone required to attract WFT females was 0.027 ng/mL, at least 100 times lower than that of the other two compounds. The relevance and implications of our results are discussed in light of the insect's biology and pest management methods. [ABSTRACT FROM AUTHOR]

Drosophila suzukii is a main pest of berries on all continents. Population control relies on insecticides and a current research challenge is to develop alternative strategies. Methods based on behavior-modifying semiochemicals are widely used against other horticultural insects, and the functional characterization of chemoreceptors facilitates the identification of active compounds. Following heterologous expression of single olfactory receptors (ORs) in ab3A olfactory sensory neurons of D. melanogaster, we screened three transcript variants from the OR69a-locus (DsuzOR69aA, DsuzOR69aB, DsuzOR69aC), demonstrating binding to two possible kairomones (3-octanol and R-carvone) and to a possible fly-emitted volatile compound [(Z)-4-nonenal], although with different pharmacological qualities. By coupling Gas Chromatography to SSR (GC-SSR), these ligands enhanced ab3A-spiking at nanogram-aliquots in a complementary fashion among the different OR69a-variants, and we identified another possible kairomone, methyl salicylate, as the most active and specific ligand for the sole DsuzOR69aB. In testing headspaces collected from D. suzukii females and from the fly-associated yeast Hanseniaspora uvarum we did not observe activation from female headspaces but activation from yeast headspaces. In situ hybridization analysis on D. suzukii antennae suggests unique expression of OR69a-subunits in specific neurons, and points toward co-expression within the same neurons. The OR69a-subunits of D. suzukii constitute cation channels, which binding suggests kairomone specificity, even if effects coexist for a complementary binding of (Z)-4-nonenal. Methyl salicylate is the most active ligand and is specific to the sole DsuzOR69aB, inspiring future investigation to validate potentials of this compound for D. suzukii control strategies. [ABSTRACT FROM AUTHOR]

Quince (Cydonia oblonga Miller) is one of the common hosts of the codling moth, Cydia pomonella L. Knowledge of the chemical ecology of codling moth is based on its behaviour against apples and pears but not quince. Here, we present a laboratory study on olfactometry and oviposition behavior preference of mated females and neonate larvae of codling moth against four quince cultivars. Oviposition of mated females was evaluated on dual‐choice test, whereas olfactometry response was evaluated in a Y‐tube olfactometer. Neonate larvae were evaluated in a dual‐choice test between pieces of fruit of quince cultivars in pairwise comparisons. In the Y‐tube olfactometer assay, mated females always responded positively to the fruit‐scented arm to quince fruit volatiles. Smyrna and Champion cultivars showed significant differences in the time that mated females spent in the fruit‐scented arm. In the oviposition assay, all pairwise comparisons showed significant differences in the number of the eggs laid, with Smyrna and Champion being the cultivars most preferred. No significant differences were detected in dual choice of neonate larvae. All comparisons elicited the behaviour of contacting the fruit source. Based on the potential emission of recognized kairomones and the results found here, cultivars Smyrna and Champion are suggested as cultivars most susceptible to codling moth infestation. [ABSTRACT FROM AUTHOR]

Many organisms have evolved to produce different phenotypes in response to environmental variation. Dendropsophus ebraccatus tadpoles develop opposing shifts in morphology and coloration when they are exposed to invertebrate vs vertebrate predators. Each of these alternate phenotypes are adaptive, conferring a survival advantage against the predator with which tadpoles were reared but imposing a survival cost with the mismatched predator. Here, we measured the phenotypic response of tadpoles to graded cues and mixed cues of both fish and dragonfly nymphs. Prey species like D. ebraccatus commonly co-occur with both of these types of predators, amongst many others as well. In our first experiment, tadpoles increased investment in defensive phenotypes in response to increasing concentrations of predator cues. Whereas morphology only differed in the strongest predation cue, tail spot coloration differed even at the lowest cue concentration. In our second experiment, tadpoles reared with cues from both predators developed an intermediate yet skewed phenotype that was most similar to the fish-induced phenotype. Previous studies have shown that fish are more lethal than dragonfly larvae; thus tadpoles responded most strongly to the more dangerous predator, even though the number of prey consumed by each predator was the same. This may be due to D. ebraccatus having evolved a stronger response to fish or because fish produce more kairomones than do dragonflies for a given amount of food. We demonstrate that not only do tadpoles assess predation risk via the concentration of predation cues in the water, they produce a stronger response to a more lethal predator even when the strength of cues is presumed to be identical. [ABSTRACT FROM AUTHOR]

This study was conducted in 2013–2014 in order to determine the response of the egg parasitoid, Trissolcus semistriatus (Nees) (Hymenoptera: Scelionidae) to metathoracic scent gland (MSG) extract from Eurygaster maura (L.) (Hemiptera: Scutelleridae) in laboratory conditions. For this purpose, the MSG extracts obtained separately from males and females were diluted with hexane and six different concentrations were prepared. Naïve, mated parasitoids (2-3 days old) were used in the experiments. Hexane and distilled water were used as control treatments. In a Y-tube olfactometer, low concentrations of MSG extract from both sexes attracted the T. semistriatus but the preference for MSG extract was reduced with the increase in extract concentration and parasitoids oriented towards clean air. In order to determine the effect of MSG extract of E. maura on parasitisation and emergence rates of T. semistriatus, a single parasitoid was presented with two egg masses on blotting paper treated with MSG extract and two on blotting paper treated with hexane 4 cm apart in a Petri dish. The parasitoid was allowed 24 h for parasitisation. Parasitisation rates were higher than control at low concentrations of MSG extract of both sexes. There was no effect of MSG extracts on the emergence rates of parasitoids from eggs. According to the present results, the performance of the egg parasitoid, T. semistriatus in the control of the sunn pest, E. maura, can be enhanced by MSG extracts of the pest. [ABSTRACT FROM AUTHOR]

The redbay ambrosia beetle, Xyleborus glabratus Eichhoff (Coleoptera: Curculionidae: Scolytinae), vectors the mycopathogen that causes laurel wilt, a lethal vascular disease of trees in the Lauraceae. Since being detected in Georgia, USA in 2002, this invasive pest has become established in 11 additional states.With continued spread, X. glabratus will likely enter Mexico. In advance of this event, this study was initiated to assess the risk posed to eight native laurels and Hass avocados, the predominant cultivar grown in Mexico.Wood bolts from each species were used in (a) field tests to determine the relative attraction of female X. glabratus, (b) laboratory bioassays to evaluate boring preferences, and (c) GC–MS analyses to identify host kairomones. For comparison, tests included control bolt treatments consisting of silkbay (an attractive U.S. laurel) and Simmonds avocado (a Florida cultivar susceptible to laurel wilt).Hass avocado and two native laurels (Persea schiedeana and Ocotea heribertoi vel aff.) were highly attractive to females and elicited strong boring responses. These species were high in sesquiterpene hydrocarbons, including α‐copaene and α‐cubebene.Results of this study suggest that X. glabratus could become a serious agricultural and forest pest upon incursion into Mexico, with severe economic and ecological impacts. [ABSTRACT FROM AUTHOR]

Predators can modify population and community dynamics not only through direct predation, but also through nonconsumptive effects. Predator‐induced changes in the traits of prey species are important components of these nonconsumptive effects. While these are well studied in simplified one‐predator one‐prey settings, relatively little is known about how kairomones act on prey across heterogeneous aquatic ecosystems with diverse identities of predator and prey. Kairomones are, to some extent, predator specific, and can be classified as diet dependent or diet independent. This classification depends on whether the identity of the prey plays a role in eliciting a defense response. In an effort to elucidate how prey and predator identity determines the defense responses in water fleas, we used inducible morphology and life history traits of Daphnia mitsukuri as a model to systematically explore to what extent predator and prey identity, and species composition of the prey community determined the expression of inducible defenses, and to what extent predator‐induced responses differed among genotypes. Our results showed that the defense responses of D. mitsukuri mainly relied on diet‐dependent kairomones, which were not influenced by fish species identity but were highly dependent on the phylogenetic distances between D. mitsukuri and the prey ingested by fish. This phylogenetic signal is strong, with D. mitsukuri responding only to the kairomones of fish that feed on cladocerans. We also found that the amplitude of the responses to fish kairomones increased with the amount of cladoceran in the dietary community. We observed significant differences in defensive traits among three D. mitsukuri genotypes, but the differences were minor compared with the effects of kairomones themselves. The results of our systematic analyses point to the role of prey phylogeny in eliciting inducible defenses of D. mitsukuri, thereby enriching our understanding of nonconsumptive effects in aquatic ecosystems. [ABSTRACT FROM AUTHOR]

Prey organisms need to detect predators and respond with adequate antipredator behaviours. To recognize predators, chemosensory cues play a pivotal role, particularly in aquatic ecosystems, where sight may be restricted. However, it is less known whether the ability to use these cues, enabling appropriate antipredator behaviour, varies between subpopulations occupying different habitats with different predation risks. We examined antipredator behaviour of wild‐caught larval fire salamanders (Salamandra salamandra) from two different habitats, ponds and streams. Ponds and streams are inhabited by habitat‐specific predators, such as alpine newts (Ichthyosaura alpestris), which only occur in ponds. We confronted larvae from both habitats with either tap water (control) or tap water that had contained alpine newts (newt treatment) and investigated potential behavioural differences in activity and shelter emergence. In the activity test, pond larvae, but not stream larvae, were significantly less active when faced with chemical cues (potentially kairomones) from newts than those faced with a control stimulus, but stream larvae generally exhibited significantly lower activity than pond larvae. In the shelter‐emergence test, larvae from both habitats spent significantly less time outside a shelter in the newt treatment than in control water. This suggests that larval fire salamanders, independent of their habitat, recognize chemical cues from potential predators and alter their behaviour accordingly. Larvae of both habitats were able to detect and use chemical cues released from potential predators, but they differed slightly in their response to these chemical cues. This finding reflects varying antipredator strategies in response to the habitat‐specific differences. [ABSTRACT FROM AUTHOR]

The planktonic rotifer Brachionus calyciflorus was reported to have a behavioral response to the predatory rotifer Asplanchna , where individuals move up to a surface-film refuge. Here, I re-examine this response and also test the hypothesis that Asplanchna affects the propensity of B. calyciflorus to attach to glass surfaces. In eight experiments where B. calyciflorus was exposed to a strong Asplanchna stimulus for periods varying from 3 to 65 h, adults and juveniles showed no increase in propensity to settle at the surface film or to attach to glass surfaces. In treatments with and without Asplanchna , percentages of Brachionus free-swimming, attached to glass or settled at the surface film were 81–100%, 0–18% and 0–3%, respectively. Three types of defensive responses in planktonic rotifers are reviewed: (1) transgenerational, spine-development responses to the Asplanchna kairomone in many brachionids; (2) slow-onset (4–48 h) increases in attachment propensity due to Asplanchna , or just its kairomone, in the facultatively epizoic Brachionus rubens and Brachionus variabilis and in an attachment-prone clone of Brachionus dorcas (B. calyciflorus species complex) and (3) brief escape movements caused by disturbance immediately after contact or near-contact with various predators (Asplanchna , Daphnia , copepods) in Filinia , Keratella , Hexarthra and Polyarthra. [ABSTRACT FROM AUTHOR]

Simple Summary: Over the past two decades, researchers around the world have conducted studies to identify volatile compounds that serve as attractants for one of the most important agricultural pests, the western flower thrips (WFT). In this review, the preferred reporting items for systematic reviews and meta-analyses (PRISMA) guidelines were used to find published studies and to extract the information generated worldwide to determine the overall attraction of the reported compounds using a meta-analysis approach. This systematic review shows that the most-used compounds worldwide are those based on pyridines, which show a high attraction ratio. Methyl isonicotinate is the most studied of these compounds. Data from the meta-analysis accurately estimated the potential attraction of other novel compounds that could be used for integrated pest management strategies, such as monitoring WFT populations or mass trapping. A call for new research evaluating and developing new products with these novel compounds is made. The study of the semiochemicals of the western flower thrips (WFT), Frankliniella occidentalis, Pergande (Thysanoptera: Thripidae), is a relevant topic that spans the last two decades. Approximately a hundred articles published on this subject from 2000 to 2022 can be found in academic databases, representing approximately 5% of the research on this important pest. These topics have generated a platform for novel research with a high potential for development. However, to move on to a new research step, an effectiveness evaluation of the compounds discovered so far is necessary. This review conducted a systematic analysis of the research focused on the semiochemicals (kairomones, pheromones, and attractants) for this pest. Papers from the past three decades on WFT attraction to semiochemicals were collected from databases using the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines. The number of individuals attracted to compounds was extracted from the papers and compiled for analysis. With this information, an attraction ratio was calculated. Forty-one possible attractants were found in the literature, with methyl isonicotinate being the most-studied compound so far, with the third-highest attraction ratio. δ-Decalactone was the compound with the highest attraction ratio, but it was one of the least studied. A meta-analysis of the WFT choosing proportion was performed for the compounds with more trials found in the literature. The predicted mean choice percentages for methyl isonicotinate (MIN) and Lurem-TR, the MIN's commercial product, were 76.6% and 66.6%, respectively. There was a convergence among the analyzed studies showing a high degree of research focus on the same group of nitrogen-containing compounds (mainly the pyridine structure). These findings call for future research to diversify the discovery and evaluation of attractive compounds in this relevant study area. [ABSTRACT FROM AUTHOR]

Simple Summary: The brown marmorated stink bug, Halyomorpha halys, is an invasive pest of agricultural crops, ornamentals, and human structures. In its native range, populations are suppressed primarily by parasitoid wasps that attack the egg stage. A promising adventive parasitoid, the samurai wasp, Trissolcus japonicus, has become established in the U.S., including Utah. According to ecological models, Utah is marginally suitable for the samurai wasp and poses unique challenges to its establishment from extreme climates and high elevation. Biological control enhancement efforts, such as deploying stink bug kairomones to attract parasitoids, may lead to the enhanced suppression of the brown marmorated stink bug. To evaluate the efficacy of this approach, experimental lures loaded with varying blends and release rates of stink bug kairomones were tested in field and mesocosm trials. This study found low parasitism in the field, while mesocosm trials demonstrated the efficacy of a single- and dual-compound blend at the 10 mg load rate for the attraction of the samurai wasp. These results support the validity of using rubber septa as a release device for kairomones of stink bugs and provide a baseline for future work on attracting samurai wasps with lures in a field environment. In its native range, Halyomorpha halys (Stål) is suppressed by parasitoids in the genus Trissolcus (Hymenoptera: Scelionidae). Trissolcus native to Utah have demonstrated low parasitism of H. halys, while adventive Trissolcus japonicus (Ashmead) have shown parasitism of up to 20%. Custom rubber septa lures containing stink bug kairomones, n-tridecane (attractant), and (E)-2-decenal (repellent), at 100%, 90%, and 80% levels of attractant (10 mg load rate), were placed adjacent to sentinel H. halys egg masses in northern Utah field trials. Egg masses were evaluated for the presence and intensity (proportion of parasitized eggs) of parasitism. Parasitism by T. japonicus and T. euschisti (Ashmead) was low; however, the 100% lure showed double the parasitism of the control and more than three times that of the 90% and 80%. Two-way choice mesocosm trials in the laboratory evaluated previous lures and a lower load rate of 5 mg—100% attractant treatment. Lures of 10 mg at 100% and 80% were more attractive to T. japonicus than the control, while 5 mg at 100% and 10 mg at 90% showed no significant attraction. Our results support a proof-of-concept of rubber septa as release devices for kairomones to attract T. japonicus and provide a baseline for future field-based studies. [ABSTRACT FROM AUTHOR]

A widely applicable, practical, and scalable synthetic method for efficient ene‐type double oxidation of alkenes is reported via a two‐step alkenyl thianthrenium umpolung/Kornblum‐Ganem oxidation strategy. This chemo‐ and stereoselective procedure allows easy access to various α,β‐unsaturated carbonyls that may be otherwise difficult or cumbersome to synthesize by conventional methods. For α‐olefins, this metal‐free transformation can be tuned according to synthetic needs to produce either the elusive (Z)‐unsaturated aldehydes or their (E) counterparts. Moreover, this strategy has enabled streamlined synthesis of distinct butadienyl pheromones and kairomones. [ABSTRACT FROM AUTHOR]

A widely applicable, practical, and scalable synthetic method for efficient ene‐type double oxidation of alkenes is reported via a two‐step alkenyl thianthrenium umpolung/Kornblum‐Ganem oxidation strategy. This chemo‐ and stereoselective procedure allows easy access to various α,β‐unsaturated carbonyls that may be otherwise difficult or cumbersome to synthesize by conventional methods. For α‐olefins, this metal‐free transformation can be tuned according to synthetic needs to produce either the elusive (Z)‐unsaturated aldehydes or their (E) counterparts. Moreover, this strategy has enabled streamlined synthesis of distinct butadienyl pheromones and kairomones. [ABSTRACT FROM AUTHOR]

Simple Summary: Like many aphids, the sorghum aphid (SA) Melanaphis sorghi produces honeydew, a waste product that can increase parasitoid retention and elicit foraging behaviors on plants. We determined the potential of SA honeydew to retain a common aphid parasitoid, Aphelinus nigritus, to assess the practicality of SA biological control on grain sorghum, Sorghum bicolor. Since SAs also feed on Johnson grass, Sorghum halepense, an alternative plant host, we characterized the composition of honeydew from aphids feeding on either grain sorghum or Johnson grass and evaluated A. nigritus preference for honeydew produced on either plant species. Our study found that A. nigritus often remained on honeydew produced by SAs feeding on both grain sorghum and Johnson grass. However, despite sharing similar sugar, amino acid, and organic acid profiles, honeydew produced on Johnson grass was preferred by A. nigritus over honeydew produced on grain sorghum. Our results suggest that SA honeydew could facilitate A. nigritus parasitoid retention on Johnson grass to lower SA populations before the grain sorghum growing season. How aphid parasitoids of recent invasive species interact with their hosts can affect the feasibility of biological control. In this study, we focus on a recent invasive pest of US grain sorghum, Sorghum bicolor, the sorghum aphid (SA), Melanaphis sorghi. Understanding this pest's ecology in the grain sorghum agroecosystem is critical to develop effective control strategies. As parasitoids often use aphid honeydew as a sugar resource, and honeydew is known to mediate parasitoid–aphid interactions, we investigated the ability of SA honeydew to retain the parasitoid Aphelinus nigritus. Since SAs in the US have multiple plant hosts, and host–plant diet can modulate parasitoid retention (a major component in host foraging), we measured SA honeydew sugar, organic acid, and amino acid profiles, then assessed via retention time A. nigritus preference for honeydew produced on grain sorghum or Johnson grass, Sorghum halepense. Compared to a water control, A. nigritus spent more time on SA honeydew produced on either host plant. Despite similar honeydew profiles from both plant species, A. nigritus preferred honeydew produced on Johnson grass. Our results suggest the potential for SA honeydew to facilitate augmentation strategies aimed at maintaining A. nigritus on Johnson grass to suppress SAs before grain sorghum is planted. [ABSTRACT FROM AUTHOR]

The aim of this study was to explore whether the widespread zooplankter Daphnia magna is able to differentiate between the kairomones of planktivorous common bleak (Alburnus alburnus) and omnivorous black bullhead (Ameiurus melas). We expected different responses in some plastic defensive traits because the presence of a planktivorous and an omnivorous fish pose a different degree of threat to daphnids. Our mesocosm study showed that the size distribution of D. magna in the bleak treatment tended to differ from both black bullhead and control treatments, while there was no apparent difference between the latter two treatments. The eye diameter/body length ratio and tail spine/body length ratio of D. magna were highest in the bleak treatment, differing from both black bullhead and control treatments, and without any significant difference between the latter two treatments. We found that only bleak triggered detectable responses in D. magna, suggesting either that kairomones of the studied fish species could differ in their chemical composition, or that black bullhead may exude less kairomone than bleak. [ABSTRACT FROM AUTHOR]

The Symphyta is the most basal sub‐order of the Hymenoptera and includes the woodwasps, horntails and sawflies, many of which are pests. Adults are generally short‐lived and as a result males and females experience strong selection to rapidly find a mate and females to find oviposition sites. Mate‐searching typically relies on visual and olfactory stimuli such as sexually dimorphic morphology (i.e., body parts used in signalling) and pheromones.Here we review the available literature on the chemical and visual ecology of the Symphyta with potential for use in survey and detection programmes. Stimuli reviewed include but are not limited to sex pheromones, larval defensive compounds, plant kairomones and colour preferences.Sex pheromones are known for 19 species of Symphyta and show shared evolutionary patterns in chemistry, production site and ecological role.In general, sex pheromones in the Symphyta are female‐produced, oxidized cuticular hydrocarbons and yellow traps capture more individuals than other colours, although exceptions do exist. More work is needed to expand on these and identify new patterns in the visual and chemical ecology of the Symphyta. [ABSTRACT FROM AUTHOR]

Although I X. glabratus i is still regarded as the most efficient vector, I H. lauricola i has been recovered from nine additional ambrosia beetle species in Florida, including I Ambrosiodmus lecontei i Hopkins, I Xyleborinus andrewesi i (Blandford), I Xyleborinus gracilis i (Eichhoff), I Xyleborinus saxesenii i (Ratzeburg), I Xyleborus affinis i Eichhoff, I Xyleborus bispinatus i Eichhoff, I Xyleborus ferrugineus i (Fabricius), I Xyleborus volvulus i (Fabricius), and I Xylosandrus crassiusculus i (Motschulsky) [[44], [46], [52]]. However, species like I X. andrewesi i , I X. affinis i , I X. volvulus i , and I X. crassiusculus i were most attracted when ethanol and cubeb oil were presented in tandem. Keywords: chemical ecology; essential oil lures; ethanol lures; Euwallacea perbrevis; invasive species; kairomones; Persea americana; Persea palustris; pest monitoring; Xyleborus glabratus EN chemical ecology essential oil lures ethanol lures Euwallacea perbrevis invasive species kairomones Persea americana Persea palustris pest monitoring Xyleborus glabratus 971 15 11/17/22 20221101 NES 221101 1. Additionally, the beetle assemblages captured in this study provide evidence that the best lure combination for I X. andrewesi, X affinis, X. volvulus i , and I X. crassiusculus i is a combination of cubeb + ethanol; and that ethanol alone is sufficient for attracting and capturing I X. saxesenii i . 5. [Extracted from the article]

The volatiles extracted by the dynamic headspace collection system from the undamaged and conspecific damaged Cucurbita maxima were analyzed by Gas chromatography–mass spectrometry (GC-MS). The olfactory responses of antennal chemosensilla by male and female A. foveicollis towards the plant volatiles were studied by electroantennography (EAG), while the behavioral responses were analyzed by olfactometer bioassay under laboratory conditions. Scanning electron microscopic study revealed the predominance of antennal olfactory sensilla of seven different types with four types of mechanosensilla. The antennae are sexually dimorphic, with differences in density of the chemosensillae present in the apical band region of segment IX, called the circumferential band, being higher in the females. Female antennae showed maximum peak amplitudes for 2-methyl phenol (at 10 mg/mL), followed by 1,4, dimethoxybenzene (at 5 mg/mL), while male antennae showed maximum amplitudes for heneicosane (at 5 mg/mL). Y-tube bioassays revealed maximum attractiveness towards 1,4, dimethoxy benzene that decreased progressively across heneicosane, pentacosane, tetradecane, ethyl benzene, D-limonene, nonadecane, eicosane, nonanal, decanal, α-pinene, phytol and benzaldehyde in females. However, male species were more responsive towards heneicosane, followed by 1,4 dimethoxybenzene, while the responses to pentacosane and tetradecane were equal, followed by equal responses to decanal, ethyl benzene and nonadecane, and thereafter, a progressively reducing response was observed towards α-pinene, eicosane, nonanal, D-limonene, phytol and benzaldehyde. The study assists in understanding the role of olfaction by A. foveicollis in the host plant Cucurbita maxima by listing compounds that act as potential kairomones for the beetle, and can be expected to facilitate development of an eco–friendly trap and/or by attracting the natural enemies for control of the pest. [ABSTRACT FROM AUTHOR]

Humans have used weaver ants, Oecophylla smaragdina, as biological control agents to control insect pests in orchards for many centuries. Over recent decades, the effectiveness of weaver ants as biological control agents has been attributed in part to deterrent and oviposition inhibiting effects of kairomones produced by the ants, but the chemical identity of these kairomones has remained unknown. We have identified the kairomone responsible for deterrence and oviposition inhibition by O. smaragdina, providing a significant advance in understanding the chemical basis of their predator/prey interactions. Olfactometer assays with extracts from weaver ants demonstrated headspace volatiles to be highly repellent to Queensland fruit fly, Bactrocera tryoni. Using electrophysiology and bioassays, we demonstrate that this repellence is induced by a single compound, 1-octanol. Of 16 compounds identified in O. smaragdina headspace, only 1-octanol evoked an electrophysiological response from B. tryoni antennae. Flies had greatly reduced oviposition and spent significantly less time in an olfactometer arm in the presence of 1-octanol or a synthetic blend of headspace volatiles containing 1-octanol than in the presence of a synthetic blend of headspace volatiles without 1-octanol, or clean air. Taken together, our results demonstrate that 1-octanol is the functional kairomone component of O. smaragdina headspace that explains repellence and oviposition deterrence, and is hence an important contributor to the effectiveness of these ants as biological control agents. [ABSTRACT FROM AUTHOR]

Prey animals use various signals to detect their predators and respond accordingly to enhance their survival. Since responding to a predator is costly, prey species may cut cost by using other strategies such as behavioural tactics, morphological changes, seeking natural refuge or unique habitat acquisition. Tadpoles of Microhyla nilphamariensis have a transparent body and live in a neustonic environment, which provides them protection against benthic predators. As a result, we investigated the predator detection mechanism in M. nilphamariensis tadpoles using different cues from an insect predator, dragonfly larvae, to determine if the presence of natural shelter and unique habitat acquisition influences the chemo-ecology of predator recognition in this species. We also exposed these tadpoles to active caged predators and a stress hormone, corticosterone (CORT) to study physiological mechanism underlying their behavioural anti-predator responses toward alarm cues. In the predator avoidance assay, M. nilphamariensis tadpoles did not respond to the predator using visual or chemical signals. The tadpoles did not change their activity in response to alarm, heterospecific, kairomones, and dietary cues released from the predator. Pre-conditioning of M. nilphamariensis tadpoles with caged predator and different concentrations of CORT also did not alter their activity in response to alarm cues. These results clearly demonstrated that neustonic tadpoles of M. nilphamariensis do not detect and respond to co-existing insect predator. We discuss these results in the context of unique habitat occupied by these prey tadpoles, the presence of alternate prey, and inherent factors such as transparent body. [ABSTRACT FROM AUTHOR]

Simple Summary: Many animals that have to cope with predation have evolved mechanisms to reduce their predation risk. One of these mechanisms is change in morphology, for example, the development of spines. These spines are induced, when mothers receive chemical signals of a predator (kairomones) and their daughters are then equipped with defensive spines. We studied the behaviour of a prey and its predator when the prey is either defended or undefended. We used common aquatic micro-invertebrates, the rotifers Brachionus calyciflorus (prey) and Asplanchna brightwellii (predator) as experimental animals. We found that undefended prey increased its swimming speed in the presence of the predator. The striking result was that the defended prey did not respond to the predator's presence. This suggests that defended prey has a different response behaviour to a predator than undefended conspecifics. Our study provides further insights into complex zooplankton predator-prey interactions. Predation is a strong species interaction causing severe harm or death to prey. Thus, prey species have evolved various defence strategies to minimize predation risk, which may be immediate (e.g., a change in behaviour) or transgenerational (morphological defence structures). We studied the behaviour of two strains of a rotiferan prey (Brachionus calyciflorus) that differ in their ability to develop morphological defences in response to their predator Asplanchna brightwellii. Using video analysis, we tested: (a) if two strains differ in their response to predator presence and predator cues when both are undefended; (b) whether defended individuals respond to live predators or their cues; and (c) if the morphological defence (large spines) per se has an effect on the swimming behaviour. We found a clear increase in swimming speed for both undefended strains in predator presence. However, the defended specimens responded neither to the predator presence nor to their cues, showing that they behave indifferently to their predator when they are defended. We did not detect an effect of the spines on the swimming behaviour. Our study demonstrates a complex plastic behaviour of the prey, not only in the presence of their predator, but also with respect to their defence status. [ABSTRACT FROM AUTHOR]

• Effect of L. a mazonensis infection was evaluated. • Attractiveness of uninfected and infected Hasmters was evaluated to Lu. longipalpis. • Behavioral trials did not show any influence of infection on the blood meal rates. • Analysis of VOCs profiles from infected host also did not show differences. Lutzomyia longipalpis is the primary vector of Leishmania infantum in the Americas and a permissive vector for Leishmania amazonensis. Previous studies showed that Leishmania infantum -infected hosts can release different volatile organic compounds (VOCs) compared with uninfected hosts, presenting a higher attractiveness to vectors. In this study, we aimed to evaluate a possible effect of L. amazonensis infection of golden hamsters in three parameters: attractiveness to Lu. longipalpis females; blood volume ingested by sand fly females; and VOCs released by the animals.. Attractiveness was measured indirectly by the number of Lu. longipalpis females that blood fed in each L. amazonensis -infected and uninfected animal. For VOCs extraction, solid phase micro extraction fibers were used, which were analyzed by gas chromatography-mass spectrometry. Behavioral trials did not show any effect of L. amazonensis infection on the attraction of sand flies nor difference on blood meal rates of Lu. longipalpis fed in both goups of hamsters. Additionally, there was no difference between the VOCs profiles of L. amazonensis -infected or uninfected hamsters. [Display omitted] [ABSTRACT FROM AUTHOR]

Simple Summary: The ambrosia beetles Xyleborus affinis and Xyleborus ferrugineus are wood borers reported as secondary vectors of pathogenic fungi that cause lethal vascular diseases in mango, cacao, and trees within the laurel family. The use of specific attractants or repellants is one potential method for monitoring or controlling these pests. Chemical ecology studies to develop such tools often use wild or laboratory-reared beetles without first determining whether there are differences in their responses. We compared the antennal olfactory responses of wild and laboratory-reared X. affinis and X. ferrugineus to bark odors of gumbo-limbo (Bursera simaruba), mango (Mangifera indica) and chinini (Persea schiedeana) with different aging times and used GC–MS to analyze the chemical composition of these bark odors. The antennal responses of laboratory-reared and wild females differed in X. affinis and X. ferrugineus when interacting with odors. In addition, both beetle species displayed stronger antennal responses to aged bark odors of gumbo-limbo and chinini, apparently due to changes in volatile emissions over time. Chemical ecology studies on ambrosia beetles are typically conducted with either wild or laboratory-reared specimens. Unlike laboratory-reared insects, important aspects that potentially influence behavioral responses, such as age, physiological state, and prior experience are unknown in wild specimens. In this study, we compared the electroantennographic (EAG) responses of laboratory-reared and wild X. affinis and X. ferrugineus to 70% ethanol and bark odors (host kairomones) of Bursera simaruba, Mangifera indica, and Persea schiedeana aged for 2, 24, and 48 h. Chemical analyses of each odor treatment (bark species x length of aging) were performed to determine their volatilome composition. EAG responses were different between laboratory-reared and wild X. ferrugineus when exposed to ethanol, whereas wild X. affinis exhibited similar EAG responses to the laboratory-reared insects. Ethanol elicited the strongest olfactory responses in both species. Among the bark-odors, the highest responses were triggered by B. simaruba at 48 h in X. affinis, and P. schiedeana at 24 and 48 h in X. ferrugineus. Volatile profiles varied among aged bark samples; 3-carene and limonene were predominant in B. simaruba, whereas α-copaene and α-cubebene were abundant in P. schiedeana. Further studies are needed to determine the biological function of B. simaruba and P. schiedeana terpenes on X. affinis and X. ferrugineus, and their potential application for the development of effective lures. [ABSTRACT FROM AUTHOR]

Researche have shown that the parasitisation percentage of Trichogramma evanescens in kairomone-treated variants is significantly higher than in the control and the comparison variant (alcohol 30%), because the biologically active substance serves as an entomophagous attractant. The mode of examination of the interaction - phytophagous and entomophagous as the procedure which stimulates the Trichogramma to find its food sources. The entomophagous reacts to the host's chemicals, the so-called kairomones, which have high potential in regulating harmful insects. To carry out research on the behavior of the entomophagous Trichogramma evanescens W., the bean plants were treated with alcohol extract and eggs of cereal moth with kairomone (concentration of 30%), exposure of 5min. In the variants treated with kairomone, where the action of the fractions extracted from the scales from the cereal moth was appreciated, on the search capacity of T. evanescens, its quality is higher than in the control. [ABSTRACT FROM AUTHOR]

Kairomones are semiochemicals that are emitted by an organism and which mediate interspecific interaction that is of benefit to an organism of another species that receives these chemical substances. Parasitoids find and recognize their hosts through eavesdropping on the kairomones emitted from the by-products or the body of the host. Hemipteran insect pests feed on plant sap and excrete the digested plant materials as honeydew. Honeydew serves as a nutritional food source for parasitoids and a medium for micro-organisms whose activity induces the release of volatiles exploited by parasitoids for host location. The parasitoid Encarsia formosa preferentially parasitizes its host, the greenhouse whitefly, Trialeurodes vaporariorum, on tomato Solanum lycopersicum, but little is known about the chemicals that mediate these interactions. We investigated the olfactory responses of the parasitoid E. formosa to odours from honeydew and nymphs of T. vaporariorum in a Y-tube olfactometer. Arrestment behaviour of the parasitoid to honeydew and nymph extracts, as well as to synthetic hydrocarbons, was also observed in Petri-dish bioassays. We found that T. vaporariorum honeydew volatiles attracted the parasitoid E. formosa but odours from the whitefly nymphs did not. We also found that the parasitoid spent more time searching on areas treated with extracts of honeydew and nymphs than on untreated areas. Gas-chromatography-mass spectrometric analysis revealed that the honeydew volatiles contained compounds such as (Z)-3-hexenol, δ-3-carene, 3-octanone, α-phellandrene, methyl salicylate, β-ocimene, β-myrcene, and (E)-β-caryophyllene which are known to be attractive to E. formosa. The cuticular extracts of the nymphs predominantly contained alkanes, alkenes, and esters. Among the alkanes, synthetic nonacosane arrested the parasitoid. Our findings are discussed in relation to how the parasitoid E. formosa uses these chemicals to locate its host, T. vaporariorum. [ABSTRACT FROM AUTHOR]

There are only limited experimental or observational data on vertical and horizontal flight capacity of Coccotrypes dactyliperda Fabricius, 1801 (Coleoptera, Curculionidae, Scolytinae), a major pest in date palm plantations throughout the Mediterranean and Middle East. This paper provides a set of proxy data, using actual observations of colonisation rates of Phoenix canariensis (Chabaud, 1882) (Arecales, Arecaceae) seeds in a linear planting array at Alma Park (NSW, Australia). The majority of dispersal movements occurs between adjacent or near adjacent seeds, followed by palms in close proximity with movements less than 4-5 m. While the maximum observed dispersal distance is 350 m, data suggest that a 36 m gap between two groups of palms is beyond the flight/dispersal range of most C. dactyliperda individuals and that colonisation over such distances would be a rare event. Since seed location is aided by temperature-sensitive alcohol-mediated kairomones, the chances of a beetle finding a new seed to colonise over longer distances are increasingly diminished during the summer months, thereby reducing reproductive success. [ABSTRACT FROM AUTHOR]

Avoiding detection is perhaps the ultimate weapon for both predators and prey. Chemosensory detection of predators via waterborne or airborne cues (predator‐released kairomones) is a key prey adaptation in aquatic ecosystems. Pirate perch, Aphredoderus sayanus, a largely insectivorous mesopredatory fish, are considered to be chemically camouflaged because they are unavoided by all colonizing organisms tested, including treefrogs and aquatic insects, despite stronger predatory effects on target taxa than several avoided fish. To address the mechanism behind camouflage we used aquatic insect colonization as a bioassay to test (1) whether increasing pirate perch density/biomass leads to increased avoidance, and (2) whether pirate perch mask heterospecific fish kairomones. Insect abundances, species richness, and community structure showed no response to pirate perch density. Last, pirate perch did not mask the kairomones of heterospecific predatory fish. Results support the idea that fish kairomones are species‐specific, and chemical camouflage is driven by a unique chemical signature that is either undetectable or has no negative associations for colonists. [ABSTRACT FROM AUTHOR]

Many aquatic organisms anticipate predation risk via infochemical detection. In a laboratory experiment, we investigated the expression of life-history responses in planktonic Daphnia magna under long-lasting exposure to various concentrations of fish kairomones (FK) and alarm substances of Daphnia (AS). Daphnia were exposed to one of six concentrations of AS (0, 0.0005, 0.005, 0.05, 0.5, 5 homogenized D. magna /L) mixed with the highest concentration of FK, or to one of six concentrations of FK (diluted fish feces of 0, 0.001, 0.002, 0.01, 0.02, 0.1 fish/L) accompanied by the highest concentration of AS. FK alone at the highest concentration were sufficient to induce diapause in 21% of Daphnia, while AS alone at the highest concentration did not trigger diapause. Mixed at the highest concentrations, both cues induced diapause in 94% of Daphnia, whereas in the control treatment free of infochemicals no ephippial individuals occurred. No significant size or fecundity changes accompanied the diapause response. The graded type of diapause response observed across a wide concentration AS concentrations suggests that Daphnia use AS concentration as a proxy for the level of non-specific predation risk. In contrast, the abrupt change of diapause response across a narrow concentration of FK suggests that they were more critical to identify predator origin than level of risk. [ABSTRACT FROM AUTHOR]

Pheromone traps play a crucial role in the integrated pest management of the red palm weevil, Rhynchophorus ferrugineus (Olivier) (Coleoptera: Curculionidae). The objective of this study was to increase the effectiveness of pheromone traps by evaluating the effects of location, temperature, degree of palm fruit fermentation, and pheromone lure source on red palm weevil capture rates. Traps baited with either Ferrolure or Rhylure were positioned in 3 rows and checked twice per wk for 12 wk starting 20 Apr 2019. Overall weekly capture rate per trap varied from 1.25 to 9.00. Those traps that were placed in the shade near infested date palm trees in areas of relatively high soil moisture captured more red palm weevil (9 adults per trap per wk) than traps exposed to direct sunlight (1.25 adults per trap per wk). Additionally, traps placed at the field edge captured more adults than those in the middle of the field. Capture rates were highly negatively correlated with temperature. Ferrolure traps captured significantly more red palm weevils than Rhylure traps. The sex ratio of captured weevils in all traps was female-biased. Results obtained from Y-tube olfactometer assays indicated that the response of red palm weevil adults to 5- and 8 d old fermented date fruits were relatively high (86.7–100%). In kairomone field tests more red palm weevil adults were attracted to traps with 8 d fermented date fruits compared with 5 d old. Our results indicated that placing traps containing Ferrolure, water, and kairomones in red palm weevil preferred sites near the edges of the orchard in moderate air temperatures (22–33 °C) increased the efficacy of pheromone traps. [ABSTRACT FROM AUTHOR]

Non-native species introductions are becoming increasingly common, but long-term consequences of the introduction of non-native predators on native prey species remains poorly understood. Bythotrephes cederströmii is an invasive zooplanktivore with potential negative impacts on Daphnia across North America. However, Daphnia may be responding to this invader by developing anti-predator defenses. We investigated whether escape ability of three Daphnia species (D. ambigua, D. mendotae, and D. pulicaria) differed in the absence and presence of Bythotrephes chemical cues, whether the escape ability of pre- and post- invasion clones of each Daphnia species differed, and whether the three Daphnia species differed in their escape ability. We conducted a series of transfer experiments in the presence and absence of Bythotrephes chemical cues to evaluate the escape ability of the three Daphnia species from both pre- and post-Bythotrephes invasion time periods. Comparison of Daphnia from pre- and post-invasion time periods revealed a constitutive increase in the escape ability of D. pulicaria which may help them avoid attack by Bythotrephes. These data contribute to a growing body of research that demonstrates that ecological invasions can prompt adaptive responses, altering the nature of interactions between invasive predators and native prey species. [ABSTRACT FROM AUTHOR]

The bee louse Braula spp. had until recently a distribution coincident with its host the honey bee. The adult fly usually attaches to a worker honey bee and steals food from its mouth. However, not all worker bees carry Braula spp. and the mechanism used by Braula spp. to select hosts is not well understood. Using choice remounting bioassays and chemical analyses, we determined host selection and the cues used by B. coeca, a species associated with the African honey bee Apis mellifera scutellata. Braula coeca successfully remounted bees from which they were initially removed and preferred their mandibular gland pheromones (MDG) over those of bees not carrying them. The bee lice did not show any preference for the cuticular hydrocarbons of both types of workers. Chemical analyses of the MDG extracts, revealed quantitative differences between the two categories of workers, with workers carrying B. coeca having more of the queen substance (9-oxo-2(E)-decenoic acid) and worker substance (10-hydroxy-2(E)-decenoic). Braula coeca showed a dose response to the queen substance, indicating its ability to use host derived kairomones as cues that allowed it to benefit from trophallactic dominance by individuals that have a higher probability of being fed by other workers. [ABSTRACT FROM AUTHOR]

In the conditions of an urban environment, insects, including Pyrrhocoris apterus (Linnaeus, 1758) (Hemiptera, Pyrrhocoridae), are subject to dozens of volatiles: solvents, food flavorings, cosmetic products. For firebugs, some attract them, some scare them off, and to some they are indifferent. In this article, in the conditions of laboratory experiment, we evaluated the influence of chemical substances on rates of movement of firebugs. Under the influence of the substances we studied, there occurred no significant increase or decrease in the activity of firebugs. The most significant effect on rates of movement of firebugs was exerted by solvent, white spirit and solvent 646 p – firebugs travelled 12 cm distance for 24.2%, 49.6% and 58.7% of the time the control group did. Movement activity of firebugs was insignificantly decreased by aromatic extracts Royаl milk extract, Butcher’s broom extract and chrysalis oil: firebugs travelled 12 cm distance for 132.7%, 135.2% and 146.8% of time the control group. Aromatic substances likely interact with receptors on antennae of firebugs, and therefore the insects need additional time for orienting reactions, deciding whether those substances signal presence of potential food objects in the accessibility zone. [ABSTRACT FROM AUTHOR]

Tribolium castaneum has a long history as a model species in many distinct subject areas, but improved connections among the genetics, genomics, behavioral, ecological, and pest management fields are needed to fully realize this species' potential as a model. Tribolium castaneum was the first beetle whose genome was sequenced, and a new genome assembly and enhanced annotation, combined with readily available genomic research tools, have facilitated its increased use in a wide range of functional genomics research. Research into T. castaneum's sensory systems, response to pheromones and kairomones, and patterns of movement and landscape utilization has improved our understanding of behavioral and ecological processes. Tribolium castaneum has also been a model in the development of pest monitoring and management tactics, including evaluation of insecticide resistance mechanisms. Application of functional genomics approaches to behavioral, ecological, and pest management research is in its infancy but offers a powerful tool that can link mechanism with function and facilitate exploitation of these relationships to better manage this important food pest. [ABSTRACT FROM AUTHOR]