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In recent years, Liorhyssus hyalinus (Fabricius) (Hemiptera: Rhopalidae) and Nysius simulans Stål (Hemiptera: Lygaeidae) have emerged as important pests of quinoa in Peru, when the crop started to be cultivated at relatively low elevations. The potential of the native lacewing Chrysoperla externa (Hagen) (Neuroptera: Chrysopidae) was evaluated as a biological control agent of these two pest species. Prey consumption on all immature stages of L. hyalinus and N. simulans was assessed, as well as development on first instars of these heteropterans and eggs of Sitotroga cerealella (Olivier) (Lepidoptera: Pyralidae) as a factitious prey. In addition, prey preference was examined in the absence and presence of a preferred prey, Macrosiphum euphorbiae (Thomas) (Hemiptera: Aphididae). Larvae of the predator were not able to feed on L. hyalinus eggs, but they effectively did on N. simulans eggs as well as on all nymphal instars of both species. Nymphs of L. hyalinus were less suitable prey for larval development of C. externa than eggs of S. cerealella, whereas N. simulans was overall an unsuitable prey. There was a clear prey preference of C. externa for aphids over the two heteropteran species, as well as a preference for N. simulans over L. hyalinus. The predation rates in this study indicate the potential of C. externa as a predator of these heteropteran pests that can play a role in both conservation and augmentation biological control programs.

Many animals lay their eggs in clusters. Eggs on the periphery of clusters can be at higher risk of mortality. We asked whether the most commonly occurring clutch sizes in pentatomid bugs could result from geometrical arrangements that maximize the proportion of eggs in the cluster’s interior. Although the most common clutch sizes do not correspond with geometric optimality, stink bugs do tend to lay clusters of eggs in shapes that protect increasing proportions of their offspring as clutch sizes increase. We also considered whether ovariole number, an aspect of reproductive anatomy that may be a fixed trait across many pentatomids, could explain observed distributions of clutch sizes. The most common clutch sizes across many species correspond with multiples of ovariole number. However, there are species with the same number of ovarioles that lay clutches of widely varying size, among which multiples of ovariole number are not over-represented. In pentatomid bugs, reproductive anatomy appears to be more important than egg mass geometry in determining clutch size uniformity. In addition, within this group of animals that has lost most of its variation in ovariole number, clutches with a broad range of shapes and sizes may still be laid.

This chapter addresses several key aspects of rearing procedures for predatory bugs. The value of natural, factitious, and artificial foods for the major species used in biological control is reviewed. Whereas several types of factitious foods are routinely used in the production of heteropteran predators, the adoption of artificial diets in mass production systems has remained negligible. Special attention is given to the implications of zoophytophagy for the production of predatory bugs. The use of plants and plant materials as sources of water and supplementary nutrients, and as living and oviposition substrates, is discussed, as well as the potential of alternative substrates. The impacts of crowding, cannibalism, and the presence of microorganisms on the performance of rearing systems are also addressed. Although important gaps in our ability to produce heteropteran predators are identified, equally important is that production will clearly benefit from new technologies that are rapidly expanding our knowledge of genetics and of developmental and reproductive biology.

When quinoa, Chenopodium quinoa Willd., is cultivated in South America outside of its Andean origin, the heteropterans Liorhyssus hyalinus (Fabricius) and Nysius simulans Stal may emerge as important pests. Here we studied the development and reproduction of both species at different constant temperatures in the laboratory. Egg and nymphal development were investigated at 18, 22, 26, 30, 34, and 36 degrees C. For both species, egg incubation time significantly decreased as the temperature increased. Nymphs did not successfully develop at 18 degrees C and the total nymphal time significantly decreased as the temperature increased from 22 to 36 degrees C. Based on a linear day-degree (DD) model, the lower developmental threshold (LDT) temperatures for eggs and nymphs were estimated to be 16.0 and 17.9 degrees C for L. hyalinus, and 16.1 and 19.7 degrees C for N. simulans, respectively. Thermal requirements for egg and nymphal development were 68.6 and 114.8 DD for L. hyalinus, and 77.7 and 190.3 DD for N. simulans, respectively. Reproduction and adult longevity were studied at 22, 26, 30, and 34 degrees C. For both species preoviposition time decreased as temperature increased, and the oviposition period was longest at 26 degrees C. The highest fecundity and egg viability were observed at 30 degrees C, whereas longevities were higher at 22-26 degrees C than at 30-34 degrees C. As the lowest tested temperatures were not suitable to both heteropterans and 30 degrees C was found to be the optimal temperature for development and reproduction, peak densities are expected in warm areas and seasons.

Background: Spotted wing drosophila (SWD), Drosophila suzukii (Matsumura) (Diptera: Drosophilidae), is a pest of stone and small fruits causing considerable economic losses. Current management strategies rely primarily on calendar‐based spraying, owing to the poor relationship between monitoring data and damage levels, and the lack of success of mass‐trapping tools. The aim of this study was to evaluate different trap models for SWD, with an emphasis on their fly‐retention capacity. To this end, we examined and quantified the added value of two fly‐retaining trap features; tunnel entries to impede escape and an insecticide‐coated inner surface as a killing agent. Results: An insecticide‐coated inner surface resulted in significantly higher trap retention after 24 h in the laboratory (4.9‐ to 7.4‐fold greater, depending on trap type) compared to a noncoated trap. Trapping efficacy was significantly improved in field trials by such a killing agent in the trap (1.2‐ to 4.5‐fold greater). Tunnel entries significantly improved trap retention in the laboratory and field (by 1.5‐fold). Conclusion: The outcomes of this study clearly reveal the substantial impact of the fly‐retention capacity of SWD traps on their overall capture performances. It was demonstrated for the first time that an insecticide‐coated inner surface as a killing agent significantly improves trap efficacy for SWD. This finding can readily be implemented in any trap model to improve monitoring and mass trapping of SWD. Also tunnel entries were shown to have a significant influence on the fly retention and, hence, substantially enhance trapping efficacy.

Quinoa is an Andean grain that is increasingly gaining international attention. In recent years, the crop has also emerged in Peruvian regions at lower altitudes (including the Coast). This study investigated the insect diversity associated with quinoa by collecting insects with pitfall traps throughout the crop phenology in three altitudinal zones of Peru: San Lorenzo, in the traditional production region, Junin; and Majes and La Molina in the non-traditional regions Arequipa and Lima, respectively. Our data revealed that the alpha diversity (in terms of species evenness and species richness) was highest in the Andean zone, San Lorenzo, and lowest in Majes. As to the functional groups (herbivores and natural enemies), no differences between field sites in species evenness were found but San Lorenzo was significantly superior to the other zones in species richness of both functional guilds. The analysis of beta diversity revealed large differences among field sites in terms of entomofauna composition, with few species in common; the key pest of quinoa in South America, Eurysacca melanocampta, was found at the three localities. The results of this study can contribute to a more sustainable pest management system taking into account insect-mediated ecosystem services like biological control.

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BACKGROUND Acaricide application remains an integral component of IPM for the two-spotted spider mite Tetranychus urticae. Species and strains of phytoseiid predatory mites vary significantly in their response to acaricides. For the success of IPM, it is imperative to identify the determinants of selectivity and molecular stress responses of acaricides in predatory mites. RESULTS The three classical acaricides bifenazate, cyflumetofen, and fenbutatin oxide, did not affect survival and fecundity of Phytoseiulus persimilis regardless of the route of exposure. Selectivity of the orange oil- and terpenoid blend-based botanical acaricides was low via a combination of direct exposure, acaricide-laced diet, and residual exposure but improved when limiting exposure only to the diet. To gain insights into the molecular stress responses, the transcriptome of P. persimilis was assembled. Subsequent gene expression analysis of predatory mites orally exposed to fenbutatin oxide and orange oil yielded only a limited xenobiotic stress response. In contrast, P. persimilis exhibited target-site resistance mutations, including I260M in SdhB, I1017M in CHS1, and kdr and super-kdr in VGSC. Extending the screen using available Phytoseiidae sequences uncovered I136T, S141F in cytb, G119S in AChE, and A2083V in ACC, well-known target-sites of acaricides. CONCLUSION Selectivity of the tested botanical acaricides to P. persimilis was low but could be enhanced by restricting exposure to a single route. Differential gene expression analysis did not show a robust induced stress response after sub-lethal exposure. In contrast, this study uncovered target-site mutations that may help explain the physiological selectivity of several classical acaricides to phytoseiid predators. This article is protected by copyright. All rights reserved.

Neoseiulus californicus (McGregor) (Mesostigmata: Phytoseiidae) is considered a specialized predator of spider mites and has mainly been used to control Tetranychus urticae Koch (Acari: Tetranychidae). However, this phytoseiid is also able to feed and reproduce on certain pollens. In the present laboratory study, survival, development time, and reproduction of N. californicus were determined when reared on T. urticae, Typha angustifolia pollen, or on a combined diet of both foods. The immature stages of N. californicus developed faster when T. urticae was present in the diet. The total developmental time of females was longer when offered T. angustifolia pollen only (6.6 days), than when fed on T. urticae (4.5 days) or T. urticae + pollen (4.5 days). The oviposition rate of N. californicus was higher on the two diets containing T. urticae (3.1-3.3 eggs/female/day) than on T. angustifolia pollen alone (0.9 eggs/female/day). The intrinsic rates of natural increase (rm) were estimated to be 0.273, 0.268 and 0.149 females/female/day on T. urticae, T. urticae + T. angustifolia and T. angustifolia, respectively. Our results indicate that supplementing a T. urticae diet with T. angustifolia pollen would not improve population parameters. However, in the absence of spider mites, providing commercial pollen might help sustain populations of the phytoseiid in the field.

Simple Summary The ladybird Cryptolaemus montrouzieri is a widely commercialized biological control agent of mealybugs. The green lacewing Chrysoperla carnea is mainly released for aphid control, but also attacks mealybugs. Both species have shown potential to control various economically important species of mealybug pests of greenhouse crops. As these predators may be simultaneously present in a crop, the risk of negative interactions between both predators was evaluated in this laboratory study. Individuals of different life stages of either predator were placed together in petri dish arenas and predation was recorded. Attacks between individuals of both species were frequently observed, with lacewing larvae being the dominant predators in most combinations. When mealybug nymphs or lepidopteran eggs were added to the arena, the incidence of attacks between the predators was greatly diminished. The relevance of these observations for the use of the predators in the biological control of greenhouse pests is discussed. The ladybird Cryptolaemus montrouzieri and the green lacewing Chrysoperla carnea have shown potential for use in augmentative biological control of mealybug pests in greenhouse crops. In the context of combining these predators within an integrated pest management system, the risk of negative intraguild interactions between both predators was evaluated in a laboratory setting. Different life stages of either predator were confronted in petri dish arenas containing a Ficus benjamina leaf, and after 24 h the incidence and direction of intraguild predation (IGP) was recorded for each combination. The effect of adding Planococcus citri nymphs or Ephestia kuehniella eggs as extraguild prey on the level of IGP was also studied. IGP was frequently observed between the two predator species and was asymmetrical in favour of C. carnea in most cases. The presence of extraguild prey reduced the number of IGP events between the predators to a similar extent. The relevance of the observed intraguild interactions for the combined use of these predators in protected cultivation is discussed.

The scelionid parasitoid Trissolcus basalis (Wollaston,1858) has been detected in Belgium for the first time based on specimens reared from a parasitized egg mass of Nezara viridula (Linnaeus,1758) collected in an urban garden at Sint-Amandsberg, Ghent. Identification was based on adult morphology and DNA barcoding. This is presently believed to be the northernmost record in Europe of T. basalis and could be the consequence of a northward expansion of this species due to climate change. This first record may be of economic importance for the biological control of stink bug pests in Belgian vegetable and fruit production.

The spotted wing drosophila, Drosophila suzukii, is an invasive pest in Europe and North America. Access to resources may be challenging in late fall, winter and early spring and flies may suffer from food deprivation along with cold stress in these periods. Whereas a plethora of studies have been performed on the overwintering capacity of D. suzukii, the effects of starvation on the fly's cold tolerance have not been addressed. In the present study, young D. suzukii adults (reared at 25°C, LD 12:12 h) were deprived of food for various periods (0, 12, 24 and 36 h), after which chill coma recovery time, critical thermal minimum, as well as acute and chronic cold tolerance were assessed. Additionally, the body composition of adults (body mass, water content, total lipid, glycerol, triglycerides, glucose and proteins) before and after starvation periods was analysed to confirm that starvation had detectable effects. Starved adults had a lower body mass, and both lipid and carbohydrate levels decreased with starvation time. Starvation slightly increased critical thermal minimum and affected chill coma recovery time; however, these changes were not gradual with starvation duration. Starvation promoted acute cold tolerance in both sexes. This effect appeared faster in males than in females. Food deprivation also led to enhanced survival to chronic cold stress. Short-term starvation was thus associated with significant changes in body composition in D. suzukii, and these alterations could alter some ecologically relevant traits related to cold tolerance, particularly in females. Our results suggest that food deprivation during short time (D. suzukii flies. Future studies should address the ecological significance of these findings as short food deprivation may occur in the fields on many occasions and seasons.

Over the last decade, the tomato russet mite, Aculops lycopersici, has become a major pest in tomato crops worldwide, both in open-field and protected cultivation. Its minute size of 150 to 200 μm complicates early detection and monitoring in tomato crops. Passive dispersal occurs via air currents, crop management practices and commercial trade. Chemical control of Aculops lycopersici is difficult. Altered product use from broad spectrum pesticides towards selective acaricides, to meet integrated pest management (IPM) standards, has created better conditions for the rapid expansion of this specialized eriophyid mite. Moreover, practical implementation of promising natural enemies is challenging due to the complexity of biological control in tomato crops. Trichomes on tomato negatively affect arthropod natural enemies, but provide a refuge for the tomato russet mite. Despite the cosmopolitan nature of Aculops lycopersici, knowledge associated with IPM is limited and fragmented. This review describes fundamental biological data on Aculops lycopersici from the last 20 years and novel developments in the field of prevention, monitoring, chemical and biological control. The recent analysis of the genome sequence will be helpful in the development of a sustainable control strategy for Aculops lycopersici. © 2021 Society of Chemical Industry.

Simple Summary : The Chinese cordyceps is a valuable parasitic Ophiocordyceps sinensis fungus–Thitarodes/Hepialus larva complex. In view of culturing this complex, a method for the artificial rearing of the Thitarodes/Hepialus ghost moth hosts was established. Deterioration of the host insect population and low mummification rates in infected larvae constrain effective cultivation. Hybridization of Thitarodes/Hepialus populations may overcome this problem. Thitarodes shambalaensis and Thitarodes sp. were inbred or hybridized, and the biological parameters, larval sensitivity to the fungal infection and mitochondrial genomes of the resulting populations were investigated. Hybridization of T. shambalaensis and Thitarodes sp. allowed producing a new generation. One hybrid population (T. shambalaensis females mated with Thitarodes sp. males) showed increased population growth as compared with the parental Thitarodes sp. population. The sensitivity of the inbred larval populations to four fungal isolates of O. sinensis differed. The complete mitochondrial genomes of T. shambalaensis, Thitarodes sp. and the hybrid population were 15,612 bp, 15,389 bp and 15,496 bp in length, respectively. A + T-rich regions were variable in sizes and repetitive sequences. The hybrid population was located in the same clade with T. shambalaensis, implying the maternal inheritance of mitochondrial DNA. Abstract : The Chinese cordyceps, a parasitic Ophiocordyceps sinensis fungus–Thitarodes/Hepialus larva complex, is a valuable biological resource endemic to the Tibetan Plateau. Protection of the Plateau environment and huge market demand make it necessary to culture this complex in an artificial system. A method for the large-scale artificial rearing of the Thitarodes/Hepialus insect host has been established. However, the deterioration of the insect rearing population and low mummification of the infected larvae by the fungus constrain effective commercial cultivation. Hybridization of Thitarodes/Hepialus populations may be needed to overcome this problem. The species T. shambalaensis (GG♂ × GG♀) and an undescribed Thitarodes species (SD♂ × SD♀) were inbred or hybridized to evaluate the biological parameters, larval sensitivity to the fungal infection and mitochondrial genomes of the resulting populations. The two parental Thitarodes species exhibited significant differences in adult fresh weights and body lengths but not in pupal emergence rates. Hybridization of T. shambalaensis and Thitarodes sp. allowed producing a new generation. The SD♂ × GG♀ population showed a higher population trend index than the SD♂ × SD♀ population, implying increased population growth compared with the male parent. The sensitivity of the inbred larval populations to four fungal isolates of O. sinensis also differed. This provides possibilities to create Thitarodes/Hepialus populations with increased growth potential for the improved artificial production of the insect hosts. The mitochondrial genomes of GG♂ × GG♀, SD♂ × SD♀ and SD♂ × GG♀ were 15,612 bp, 15,389 bp and 15,496 bp in length, with an A + T content of 80.92%, 82.35% and 80.87%, respectively. The A + T-rich region contains 787 bp with two 114 bp repetitive sequences, 554 bp without repetitive sequences and 673 bp without repetitive sequences in GG♂ × GG♀, SD♂ × SD♀ and SD♂ × GG♀, respectively. The hybrid population (SD♂ × GG♀) was located in the same clade with GG♂ × GG♀, based on the phylogenetic tree constructed by 13 PCGs, implying the maternal inheritance of mitochondrial DNA.

Over the last decade, the sown area of quinoa (Chenopodium quinoa Willd.) has been increasingly expanding in Peru, and new production fields have emerged, stretching from the Andes to coastal areas. The fields at low altitudes have the potential to produce higher yields than those in the highlands. This study investigated the occurrence of insect pests and the natural enemies of quinoa in a traditional production zone, San Lorenzo (in the Andes), and in two new zones at lower altitudes, La Molina (on the coast) and Majes (in the &ldquo, Maritime Yunga&rdquo, ecoregion), by plant sampling and pitfall trapping. Our data indicated that the pest pressure in quinoa was higher at lower elevations than in the highlands. The major insect pest infesting quinoa at high densities in San Lorenzo was Eurysacca melanocampta, in La Molina, the major pests were E. melanocampta, Macrosiphum euphorbiae and Liriomyza huidobrensis, and in Majes, Frankliniella occidentalis was the most abundant pest. The natural enemy complex played an important role in controlling M. euphorbiae and L. huidobrensis by preventing pest resurgence. The findings of this study may assist quinoa producers (from the Andes and from regions at lower altitudes) in establishing better farming practices in the framework of integrated pest management.

The commercial production of Orius spp. (Hemiptera: Anthocoridae), including Orius majusculus (Reuter), relies on the use of eggs of Ephestia kuehniella (Zeller) (Lepidoptera: Pyralidae) as rearing diet. However, E. kuehniella eggs have become an expensive fodder thus increasing the price of these key biological control agents. The use of artificial diets potentially decreases the production costs. In this regard, establishing a link between dietary composition and fitness could advance the development of an optimum alternative artificial diet for these predatory insects. The aim of the current study was to test the effect of six artificial diets with different macronutrient composition on the development and reproductive fitness of O. majusculus when compared with the effect of E. kuehniella eggs. In general, nymphal survival was not affected by diet, whereas development was slightly delayed on artificial diets. However, female body mass and fecundity were significantly lower on all of the artificial diets compared with the E. kuehniella eggs diet, suggesting that artificial diets were of inferior quality. Within artificial diets, females fed the viable diet with highest content in lipid laid more eggs than those raised on the most protein-rich diets. We found there was some variation in carcass composition between the O. majusculus fed the various diets, but these variations did not match the differences found in the fitness parameters measured.

The Chinese cordyceps is a unique and valuable parasitic complex of Thitarodes/Hepialus ghost moths and the Ophiocordyceps sinensis fungus for medicine and health foods from the Tibetan Plateau. During artificial cultivation of Chinese cordyceps, the induction of blastospores into hyphae is a prerequisite for mummification of the infected Thitarodes larvae. To explore the microbial involvement in the induction of mycelia-blastospore transition, the microbiota of the hemolymph and gut from Thitarodes xiaojinensis larvae with or without injected O. sinensis blastospores were investigated by culture-dependent and -independent methods. Twenty-five culturable bacterial species and 14 fungal species, together with 537 bacterial operational taxonomic units (OTUs) and 218 fungal OTUs, were identified from the hemolymph and gut of samples from five stages including living larvae without injected fungi (A) or with high blastospore load (B), mummifying larvae without mycelia coating (C), freshly mummifying larvae coated with mycelia (D), and completely mummified larvae with mycelia (E). Two culturable bacterial species (Serratia plymuthica, Serratia proteamaculans), and 47 bacterial and 15 fungal OTUs were considered as shared species. The uninfected larval hemolymph contained 13 culturable bacterial species but no fungal species, together with 164 bacterial and 73 fungal OTUs. To our knowledge, this is the first study to detect large bacterial communities from the hemolymph of healthy insect larvae. When the living larvae contained high blastospore load, the culturable bacterial community was sharply inhibited in the hemolymph but the bacterial and fungal community greatly increased in the gut. In general, high blastospore load increased bacterial diversity but sharply decreased fungal diversity in the hemolymph and gut by OTUs. The bacterial loads of four culturable species (Chryseobacterium sp., Pseudomonas fragi, S. plymuthica, S. proteamaculans) increased significantly and O. sinensis and Pseudomonas spp. became dominant microbes, when the infected larvae became mummified, indicating their possible involvement in the larval mummification process. The discovery of many opportunistic pathogenic bacteria in the hemolymph of the healthy larvae, the larval microbial diversity influenced by O. sinensis challenge and the involvement of dominant bacteria during larval mummification process provide new insight into the infection and mummification mechanisms of O. sinensis in its Thitarodes hosts.

The life-history parameters and predation capacity of Macrolophus pygmaeus Rambur and Nesidiocoris tenuis (Reuter) (Hemiptera: Miridae) fed on eggs of Plutella xylostella (L.) (Lepidoptera: Plutellidae) at 25 degrees C were investigated in the laboratory and analyzed based on the age-stage, two-sex life table. Also, we evaluated the survival and the duration of different stages of these two predators on cabbage plants without prey. The developmental times of different stages of M. pygmaeus and N. tenuis fed on the eggs of P. xylostella were significantly different. The nymphs of N. tenuis only survived until the fourth instar without prey, and nymphs of M. pygmaeus succeeded in completing the third instar without prey. The population and predation parameters of the two predators were statistically different. The total consumption rate of the two predators during the oviposition period was higher than the total consumption rate during the post oviposition period and the total preoviposition period. The highest predation rates for female adults of N. tenuis and M. pygmaeus were on days 33 and 31, respectively. The nymphs of N. tenuis only survived until the fourth instar without prey, and nymphs of M. pygmaeus succeeded in completing the third instar.

The tomato russet mite (TRM), Aculops lycopersici, is a worldwide pest of cultivated tomatoes. Currently, no effective biological control agents are available on the market. Therefore, chemical spray applications are required. Fast and reliable detection, monitoring and evaluation of interventions are a challenge, slowing down the development of an appropriate integrated pest management (IPM) strategy. This study describes a binomial sampling plan with the aim to reduce the efforts and costs for an accurate monitoring of A. lycopersici. Sampling was performed by taking pictures of the upper leaf surface with a smartphone through an attached magnification lens. A binomial sampling plan was developed based on the linear relationship between ln(mean TRM densities) and ln(-ln(1-P-T), where P-T is the proportion of samples with more than T (tally threshold) mites. The minimum precision threshold of 0.30 was determined for the different models. A resampling for validation of sample plans (RVSP) programme with a fixed sample number was used for validation of the model on an independent data set. The binomial sampling plans were validated at tally thresholds of T = 9 and T = 15 with fixed sample sizes of 15, 20, 25 and 30. Precision levels were satisfying within a range of P-T-values from 0.29 to 0.97 for T = 15 at a fixed sample size of 20. This range was much smaller for T = 9, where the P-T-values range between 0.40 and 0.92 at the same sample size. A binomial sampling model with T = 9 with a fixed sample size of 15, which has the lowest time investment, is feasible for glasshouse tomato growers in practice. However, for the development of pest management programmes, a more intensive and more accurate binomial sampling plan with T = 15 and a sample size of minimum 20 is suggested.

Recently there was an expansion in the geographic range of Rhipicephalus microplus in Zimbabwe. In order to understand gene flow patterns and population structure in this highly invasive and adaptable cattle tick, a population genetics study was carried out. Eighty-seven R. microplus tick samples drawn from 5 distinct populations were genotyped using eight polymorphic microsatellite loci. Genetic diversity (He) was high (0.755-0.802) in all the populations, suggesting high levels of gene flow with 97% of genetic variation found within populations and 3% amongst populations. No isolation by distance was observed with low but significant genetic differentiation amongst the populations (0-0.076). Most of the sampled individuals had admixed genetic backgrounds, except for those from Matabeleland North whose genetic makeup appeared different from the rest. Rhipicephalus microplus was recently recorded in this area and the environmental conditions do not support survival of the tick there. These results confirm recent range expansion of the tick and the lowest genetic diversity recorded in the Matabeleland North population is suggestive of a founder effect, which may lead to genetic drift. Generally, the very low levels of genetic differentiation amongst the populations could be a result of the frequent movement of livestock from one area to another, which will have implications for disease control. This study offers further opportunities to study evolutionary adaptation of R. microplus in Zimbabwe and southern Africa.

Prepupae of the black soldier fly (BSF) are a potential source of high value protein that could be incorporated in feed for monogastric farm animals. These prepupae are also rich in fat, with lauric acid (C12:0) as the predominant fatty acid, known for its antimicrobial effects on Gram positive bacteria. First, the effects of BSF fat on the porcine gut microbiota were assessed in vitro by simulating digestion in the upper small intestine of piglets. Different amounts of BSF fat were added to an incubation medium, which contained a synthetic diet, a phosphate buffer (pH 5) and a microbial inoculum from one donor piglet. The medium was incubated at 37 °C for 4 h. Using selective media, coliforms, D-streptococci, lactobacilli and total anaerobic bacteria were counted on aliquots taken at the end of the incubations. Second, weaned piglets were reared on diets including full-fat (4 and 8%) and defatted (5.4%) BSF prepupae and compared to a control diet (i.e. with soybean as protein and fat source). Next to the effects on gut microbiota, selected gut health parameters were investigated, performance was recorded and digestibility of the diets was calculated. In vitro , the prepupal fat at 0.58 g C12:0/100 mL, suppressed growth of lactobacilli, but the most substantial antibacterial effects were recorded against D-streptococci. At the highest inclusion level (equivalent to 0.87 g C12:0/100 mL), around 2 log fold reductions of D-streptococci were observed. From the animal trial, only 0.5 log fold reductions were observed for D-streptococci in the gut of piglets fed BSF containing diets. No differences were recorded for daily gain, feed intake and feed to gain ratio among treatments. The apparent fecal digestibility of the control feed did not differ significantly to that of the insect-containing feed (protein digestibility between 77 and 78% for all treatments). Whereas the ileal protein digestibility of the 8% full-fat BSF diet (67.4%) was lower than that of the control (69.7%), the values for the 4% full-fat and the defatted BSF diets were higher (73.3%). In conclusion, our trial with piglets showed that a substantial amount of soybean products (meal and/or toasted beans) can be replaced by BSF without adverse effects on performance. However, given that the current price of BSF prepupae is substantially higher than that of soybean, future research should focus on exploring the potential added value of BSF compared to conventional protein sources.

Acaricide resistance is one of the greatest threats towards the successful control of vector ticks worldwide. Communal farmers of Zimbabwe use amitraz as the most common acaricide with occasional usage of pyrethroids and organophosphates. As a strategy towards developing an effective acaricide resistance management system in Zimbabwe, screening was done by genotyping Rhipicephalus microplus tick populations using molecular markers associated with resistance to these chemicals. The frequency of the mutant allele for the octopamine/tyramine receptor marker associated with amitraz resistance was high (0.55) and a large proportion 78.5% (288/367) of heterozygote genotypes were observed indicating balancing selection. Of the communal dipping tanks where R. microplus occurred 37.8% (39/103) showed complete resistance genotypes for amitraz. The carboxylesterase marker that has been associated with resistance to organophosphate and pyrethroids indicated no selection pressure in these chemical groups with a low frequency (0.052) of the mutant allele and 89.6% (329/367) sampled ticks showing homozygous susceptibility genotypes. Heterozygous genotypes were present at 27.2% (28/103) of the dipping tanks. The L641 mutation in the voltage-gated sodium channel gene associated with pyrethroid resistance was not detected in Zimbabwean samples. This would suggest a different mechanism of resistance to pyrethroids in these tick populations. Sequence analysis of the octopamine/tyramine receptor gene revealed the presence of other mutations in this region, it will be important to investigate their association with amitraz resistance. These results present the first molecular genotyping of resistance profiles of R. microplus tick populations from Zimbabwe.

Cryptolaemus montrouzieri (mealybug destroyer) is a predatory ladybird of Australian origin and has been introduced worldwide to control mealybugs. However, no simple sequence repeat (SSR) marker has been developed for C. montrouzieri, hampering study of its population genetics. We developed and characterized 12 novel SSR markers from expressed sequence tags (ESTs) in C. montrouzieri, which proved to be sufficiently polymorphic for population genetic analysis. The results of a population genetic analysis using these markers reveal strong genetic differentiation in ten native and introduced populations, which were not seen in our previous results using mitochondrial markers. Four populations probably underwent a recent genetic bottleneck and one wild population was probably the result of an admixture of two lab-reared populations. Our results from these newly developed EST-SSR markers suggest a strong genetic differentiation among populations of this widely introduced biological control agent. Greater attention should be paid to bottleneck effects, mito-nuclear discordance and admixture for further population genetic analysis, prediction of invasiveness and practical use of the ladybird in biological control.

The marking of Drosophila suzukii can be an important instrument for studying the ecology and behaviour of this economically important fruit pest, aiding the development of new Integrated Pest Management (IPM) tools or strategies. There is, however, a need for a cost-effective methodology that provides an easily detectable and stable mark. Whereas fluorescent pigment powders are often used in entomological research, the pigments (series, dyes), application techniques, or doses need to be evaluated for each studied species in terms of their efficacy and possible adverse effects on the performance of the insect. The effectiveness of different application techniques and dyes (RadGlo® TP-series) and their effect on the survival of adult D. suzukii were investigated in the laboratory. Furthermore, the influence of the marking on the behaviour of the flies was examined in laboratory trap assays (olfaction) and a field recapture study (general orientation). The persistence and detectability of the marks was evaluated both on living flies (for different application techniques) and dead flies under trapping/storage conditions. The use of fluorescent powders to mark D. suzukii flies yielded a clearly detectable and highly persistent mark, without any adverse effects on the survival and behaviour of the flies.

BACKGROUND The temperature-size rule is a well-known example of phenotypic plasticity in ectothermic organisms. When exposed to colder temperatures, ectotherms develop more slowly, but mature at larger body sizes and vice versa at higher temperatures. We investigated whether a phytoseiid predatory mite can obtain a larger body size by rearing it at a low temperature and how the increased body size affected predatory performance on its natural prey. Therefore, we allowed the predatory mite Amblydromalus limonicus (Garman & McGregor) (Acari: Phytoseiidae) to develop at either 15 or 25 degrees C. RESULTS A. limonicus reared at 15 degrees C had a 6% larger body size than those reared at 25 degrees C. Larger predators showed higher predation rates on first instars of the western flower thrips, Frankliniella occidentalis Pergande (Thysanoptera: Thripidae), with 9.6 instars/female/day and 8.5 instars/female/day, for larger and standard-sized females, respectively. After three generations reared at 15 degrees C, body size did not increase any further. When reared for five generations at 15 degrees C, larger A. limonicus females demonstrated a better ability to subdue second-instar F. occidentalis. CONCLUSION Low juvenile rearing temperatures may result in phytoseiid predators with a predator/prey size benefit that could improve their biological control function. (c) 2019 Society of Chemical Industry