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The invasive mealybug Delottococcus aberiae De Lotto (Hemiptera: Pseudococcidae) has become a key pest in Mediterranean citrus. This mealybug species excretes honeydew that can be consumed by ants, which may give rise to mutualistic relationships and increase the invasibility of this exotic pest. Here, we studied the interaction between D. aberiae and ants in 16 citrus orchards located in the main citrus-growing area of Spain (Valencia) during two consecutive years. Four native ant species were observed feeding on D. aberiae honeydew, and Lasius grandis Forel (Hymenoptera: Formicidae) represented more than 95% of these ants. Lasius grandis was observed attending D. aberiae throughout the year and in all the orchard sites where the mealybug was present. Mealybug colony size had a positive effect on both relative and absolute ant-attendance by L. grandis, but these interactions varied across seasons. Moreover, we found a positive correlation between L. grandis activity and D. aberiae density in all citrus orchards. Our results suggest that the native ant L. grandis and the invasive pest D. aberiae have established a mutualistic association that promotes the establishment and accelerate the invasion of D. aberiae in Spanish citrus orchards. Further research with the aim of evaluating whether the management of this ant species can improve the control of D. aberiae in citrus would be recommended. [ABSTRACT FROM AUTHOR]

Insects pests such as Mastigimas anjosi Burckhardt (Hemiptera: Calophyidae), native to Brazil, limit the establishment of commercial plantations of the tropical cedar Cedrela fissilis Vell. (Meliaceae), reducing growth and affecting tree shape. Insecticides have been used to suppress M. anjosi outbreaks, but sustainable alternatives should be developed to manage this pest. The objective of this work was to report, for the first time, the predator Atopozelus opsimus Elkins (Hemiptera: Reduviidae) preying on M. anjosi attacking C. fissilis trees in Minas Gerais State, Brazil. Trees of this plant were observed between Apr and May 2018 in Montes Claros, Minas Gerais State, Brazil. Atopozelus opsimus adults preyed on M. anjosi nymphs and adults, and fed on their honeydew. This predator did not eliminate the damage to C. fissilis, which may be related to the temperatures of the region, and which may have affected reproduction and increased its development period. [ABSTRACT FROM AUTHOR]

Nylanderia fulva (Mayr) (Hymenoptera: Formicidae), or tawny crazy ant, is an invasive ant from South America that is spreading in the southern US. Extremely large populations of this ant can inundate urban and natural landscapes, and efficient control methods are lacking. This study was conducted to determine if activity of N. fulva would decline after controlling the hemipteran honeydew-producers they were tending. Potted plants infested with cottony cushion scale (Icerya purchasi Maskell) (Hemiptera: Monophlebidae) were treated with 2 imidacloprid insecticide formulations, and changes in N. fulva survival and foraging behavior were monitored. There were fewer ant trails, lower trailing intensity, less foraging, and less nesting in potted plants treated with either product than in the control pots. The use of low application rates of systemic insecticide to reduce honeydewproducing hemipterans, such as cottony cushion scale, could be an important component of the integrated pest management of N. fulva. [ABSTRACT FROM AUTHOR]

Honeydew production by Hemiptera is an ecologically important process that facilitates mutualisms and increases nutrient cycling. Accurate estimates of the amount of honeydew available in a system are essential for quantifying food web dynamics, energy flow, and the potential growth of sooty mould that inhibits plant growth. Despite the importance of honeydew, there is no standardized method to estimate its production when intensive laboratory testing is not feasible. We developed two new models to predict honeydew production, one based on insect body mass and taxonomic family, and one based on body mass and life stage. We tested the accuracy of both models’ predictions for a diverse range of honeydew-producing hemipteran families (Aphididae, Pseudococcidae, Coccidae, Psyllidae, Aleyrodidae, Delphacidae, Cicadellidae). The method based on body mass and family provided more accurate estimates of honeydew production, due to large variation in honeydew production among families. We apply our methodology to a case study, the recalculation of honeydew available to invasive red imported fire ant (Solenopsis invicta) in the United States. We find that the amount of honeydew may be an order of magnitude lower than that previously estimated (2.16 versus 21.6 grams of honeydew per day) and discuss possible reasons for the difference. We anticipate that being able to estimate honeydew production based on minimal biological information will have applications to agriculture, invasion biology, forestry, and carbon farming. [ABSTRACT FROM AUTHOR]

Ants commonly participate simultaneously in mutualisms with honeydew-producing hemipterans and extrafloral nectar-bearing host plants. These interactions are based on the exchange of resources (honeydew and extrafloral nectar) for ant protection against natural enemies. The benefits may vary according to the species of ant interacting, and the outcomes for the host plant and hemipteran will depend on the results of the ant-plant-hemipteran relationship as a whole. We studied a plant-mealybug association with Camponotus crassus Mayr (Formicinae) and Ectatomma tuberculatum Olivier (Ectatomminae) in a Brazilian tropical savanna. We aimed to elucidate whether the frequency of visitation by different species of ants can be affected by neighbouring colonies of mealybugs, and whether these ant species influence the number of hemipterans in a different way. Furthermore, we intended to find out whether the interaction between ant and hemipteran has any effect on the proportion of fruit production or on the abundance of trophobiont and non-trophobiont herbivores, also influenced by the ant species. Our results show that neighbouring aggregations of mealybugs influenced the frequency of ant visitation and the ants affected the number of nymphs over time, with both positive results only for C. crassus. We also detected an indirect negative effect on proportion of fruit production and an increase in abundance of trophobiont and non-trophobiont herbivores in the presence of C. crassus-mealybug interaction. Thus, we provide further evidence that colonies of hemipterans interacting with ants can be beneficial for these herbivorous insects, but they are quite harmful to the host plant. Nevertheless, the outcomes can be highly conditional in relation to ant species. [ABSTRACT FROM AUTHOR]

This study examines the nature of intraspecific interactions among Nilaparvata lugens ( Stål) ( Hemiptera: Delphacidae) planthoppers feeding on resistant and susceptible rice varieties. Planthopper nymphs produced less honeydew and gained less weight when feeding on rice variety IR62 (resistant) compared to susceptible rice varieties. A series of bioassays was conducted that varied N. lugens nymph densities on IR62 and IR22 (susceptible). Increasing nymph density facilitated feeding by conspecifics; however, intraspecific competition increased mortality of nymphs on IR62 (but rarely on IR22). Furthermore, nymph weights declined with increasing conspecific density on IR22, and the effects were weak on IR62. More female nymphs than males survived on IR62 but this was not affected by density. Nitrogenous fertilizer increased competition among N. lugens on young plants of IR22, but not on IR62. Results indicate that nymphs have a low efficiency in accessing resources when feeding on IR62, even where the plants have received fertilizer. Female-biased survival and biomass compensation for mortality may promote population recovery after development on the resistant plant and accelerate adaptation to the resistant variety. [ABSTRACT FROM AUTHOR]

The Asian citrus psyllid (ACP), Diaphorina citri Kuwayama (Hemiptera: Liviidae), transmits the citrus greening pathogen 'Candidatus Liberibacter asiaticus' (CLas) by feeding on citrus phloem sap. Because phloem sap is rich in sugars but low in amino acids, ACP sucks large quantities and excretes most of it as honeydew. We studied the chemical composition of ACP honeydew on various host plants. Honeydew samples were analyzed with gas chromatography-mass spectrometry. Fourteen sugars, 13 amino acids, and six organic acids were detected in the honeydew of ACP. Sugars composed about 95% of the total compounds. Sucrose and trehalose were the predominant sugars, composing about 58 and 23% of the total sugars, respectively. Proline, asparagine, aspartic acid, and glutamic acid were the most abundant amino acids in ACP honeydew. The host plant and its infection with CLas had some effect on the honeydew composition. Glucose, chiro-inositol, myo-inositol, inositol, maltose, and turanose were lower in honeydew collected from CLas-infected citrus compared to that collected from non-infected trees. In CLas-infected citrus (pineapple sweet orange, Citrus sinensis L. Osbeck) and Bergera koenigii (L.) Spreng. [curry leaf tree (both Rutaceae)] honeydews, valine, alanine, serine, glutamine, glycine, and the organic acids were lower than in honeydew from healthy citrus. Mannose, galactose, inositol, mannitol, an unknown disaccharide, and proline were higher in the honeydew collected from B. koenigii than in honeydew collected from healthy citrus (pineapple sweet orange), whereas fructose, chiro-inositol, myo-inositol, trehalose, and lactic acid were lower. The findings of this study help us understand the metabolism and the nutrient needs of ACP that transmits CLas, the pathogen of huanglongbing in citrus. [ABSTRACT FROM AUTHOR]

In many ecosystems food-web dynamics are driven by spatial and temporal variation in the availability of sugar resources, which form the primary or even exclusive dietary constituents for many species. Scale insects (Hemiptera) produce sugar-rich honeydew, which can be a keystone sugar source in honeydew ecosystems worldwide. In New Zealand, most previous research in honeydew ecosystems has been conducted in areas where herpetofauna are heavily suppressed by introduced predators. Consequently, little is known about potential trophic interactions between endemic lizards and scale insects. Korapuki Island is one of the few remaining locations in New Zealand where endemic scale insects and lizards survive in densities likely to be representative of prehuman conditions. We examined the relative importance of different sugar resources on Korapuki Island to Duvaucel's geckos (Hoplodactylus duvaucelii) and common geckos (Woodworthia maculatus). We recorded the abundance and morphometrics of geckos attending five sugar-producing plant species (two of which host honeydew-producing scale insects) three times daily along a fixed transect. Large numbers of Duvaucel's and common geckos were recorded nocturnally feeding on honeydew produced by the scale insect Coelostomidia zealandica (Coelostomidiidae). Duvaucel's geckos of all sizes and genders fed extensively on honeydew throughout the year, favouring ngaio (Myoporum laetum) trees with high scale insect infestations, but were seldom recorded at other sugar resources. In contrast, juvenile common geckos were infrequently recorded on honeydew-producing trees. Common geckos fed on a variety of other sugar resources, with all sizes and sexes abundant on nectar and sap of flax (Phormium tenax) and seasonally exploiting nectar of pohutukawa (Metrosideros excelsa). The strength of interactions between scale insects and geckos, particularly for the Duvaucel's gecko population on Korapuki Island, indicates the importance of honeydew in addition to more ephemeral sugar resources such as nectar. Accordingly, the re-establishment of honeydew-producing Hemiptera populations should be considered in future conservation and restoration plans. [ABSTRACT FROM AUTHOR]

Diaphorina citri Kuwayama ( Hemiptera: Psyllidae) is the primary vector of Candidatus Liberibacter spp. bacteria that cause citrus greening, a disease of worldwide importance. Olfactometry was employed to test responses of D. citri to odours from intact citrus plants ( Mexican lime, Citrus aurantifolia, sour orange, Citrus aurantium, Marsh grapefruit, Citrus paradisi and Valencia orange, Citrus sinensis), citrus plants previously infested with D. citri, and odours of conspecifics including nymphs, adult insects of same and opposite sex, and their products (honeydew), both alone and in combination. In contrast to other studies, psyllids of both sexes were attracted to volatiles of undamaged Mexican lime leaves, whereas undamaged grapefruit attracted only females, and leaves of Valencia and sour orange did not attract either sex. All four plant species attracted female psyllids when previously infested, but only Mexican lime and sour orange-attracted males. Thus, Citrus species appear to vary in the production of both constituitive and induced volatiles that attract adult psyllids. Volatiles emitted by nymphs did not attract either sex, but psyllid honeydew was attractive to males, likely due to female pheromone residues. Males oriented to the odour of females, whereas the reverse was not true, and neither males nor females oriented to same-sex volatiles. The addition of conspecific cues (adults, nymphs or honeydew) did not increase female attraction to previously infested leaves, but male response was increased by the presence of adults and honeydew, regardless of plant species. Thus, female psyllids appear to orient more strongly to volatiles of plant origin, whereas males respond more strongly to cues emanating from females and conspecific excretions. These results suggest that female psyllids drive the initial colonization of host plants, whereas males orient to females and infested plants. Identification of the specific volatiles involved may permit their use in monitoring and management of this pest. [ABSTRACT FROM AUTHOR]

Feeding behavior of Melanaphis sacchari Zehntner ( Hemiptera: Aphididae) was studied on sugarcane, Saccharum spp. ( Poaceae), cultivars HoCP 91-555 (resistant), LCP 85-384 (moderately resistant), and L 97-128 (susceptible) using the electrical penetration graph ( EPG) technique. Constitutive concentrations of total phenolics and available carbohydrates, water potential at the whole-leaf tissue level, and free amino acids (FAAs) in phloem sap extracts, and in honeydew produced by aphids fed on L 97-128 and HoCP 91-555 were determined. Cultivar did not influence time for M. sacchari to access phloem sieve elements. Total time in sieve elements was ca. two-fold greater on L 97-128 than on HoCP 91-555, whereas it did not differ from LCP 85-384 in either cultivar. The mean duration of individual events associated with phloem sap ingestion was ca. 50% shorter on both HoCP 91-555 and LCP 85-384 than on L 97-128. Although cultivar effects were not detected for levels of total phenolics, available carbohydrates, and water potential, two free essential amino acids, histidine and arginine, were absent from phloem sap in HoCP 91-555. Two free essential amino acids, leucine and isoleucine, and two free non-essential amino acids, tyrosine and proline, were absent from honeydew of aphids fed on HoCP 91-555. These results suggest that despite apparent biosynthesis of some FAAs, the absence of important FAAs in the phloem sap of HoCP 91-555 and the inability of M. sacchari and its endosymbionts (e.g., Buchnera) to derive specific free essential and non-essential amino acids from other ingested molecules, possibly along with other unidentified factors, underlie the pest's decreased phloem sap ingestion and consequently reduced growth potential on HoCP 91-555. [ABSTRACT FROM AUTHOR]

The honeydew of Marchalina hellenica is collected by honeybees for pine honey production, which is of great economic importance in Turkey. During 2009-2011 we investigated the predators of M. hellenica, which is distributed mainly in the areas with a Mediterranean climate - in the Aegean, Marmara and Mediterranean regions of Turkey. The findings showed that M. hellenica has many predators in the studied areas and that these play an important role in the forest ecosystem. These predators are: Anystis baccarum (L.) (Acarina: Anystidae); Allothrombium triticium Zhang and Allothrombium pulvinum Ewing (Acarina: Trombidiidae); Neoleucopis kartliana (Tanasijtshuk) (Diptera: Chamaemyiidae); Myrrha octodecimguttata (L.), Rodolia cardinalis Mulstant, Scymnus subvillosus (Goeze) (Coleoptera: Coccinellidae), Dichochrysa genei (Rambur), Dichochrysa prasina (Burmeister) and Chrysoperla lucasina (Lacroix) (Neuroptera: Chrysopidae); Wesmaelius subnebulosus (Stephens) (Neuroptera: Hemerobiidae), Cardiastethus nazarenus Reuter and Elatophilus pachycnemis Horváth (Hemiptera: Anthocoridae). The most efficient and common predator was N. kartliana, here recorded for the first time from Turkey. [ABSTRACT FROM AUTHOR]

Highlights: [•] Aphytis melinus accepted and fed on five common citrus honeydews. [•] A. melinus fitness (measured as longevity and realized fecundity) entirely depended on the honeydew source. [•] A. melinus discriminated between honeydews with high and poor nutritional quality. [•] The presence of different honeydews in agroecosystems should be considered in biological control programs. [Copyright &y& Elsevier]

Protection mutualisms between ants and honeydew-producing insects influence arthropod food webs by altering the behaviour, activity and local abundance of ants on plants. Ants often tend multiple species of honeydew-producing insects; however, studies that examine such effects typically consider only pairwise mutualisms. This study investigates how multi-species mutualisms between ants and honeydew-producing insects structure arthropod food webs in citrus., In an organic lemon orchard in San Diego County, California, U.S.A., ants or honeydew-producing insects (or neither) were experimentally removed from individual, mature lemon trees and then abundances of the following were estimated over a 2-year period: the Argentine ant, five species of honeydew-producing hemipterans, and California red scale. Red scale produces no honeydew but indirectly benefits from the presence of ants, which disrupt parasitism by Aphytis wasps., Mutualism between ants and honeydew-producing hemipterans indirectly and positively affected red scale. Levels of parasitism decreased with increasing ant recruitment, and red scale density increased with both increasing ant recruitment and increasing honeydew-producing hemipteran abundance. Moreover, abundances of each of three honeydew-producing hemipteran species emerged as positive predictors of red scale density in different analyses; this finding suggests that individual hemipteran taxa exhibit distinct and spatially localised effects on ants., Evidence of positive, indirect effects between two focal species of honeydew-producing Hemiptera was also detected. Guilds of honeydew-producing hemipterans may provide ants with honeydew more consistently or for longer than that produced by any single species. These results argue for an appreciation of how mutualist diversity affects the ecological consequences of mutualisms. [ABSTRACT FROM AUTHOR]

Mutualistic interactions between ants and Hemiptera are mediated to a large extent by the amount and quality of sugar-rich honeydew produced. Throughout the neotropics, the predaceous fire ant Solenopsis geminata ( Fabricius) ( Hymenoptera: Formicidae) is found in association with colonies of the pineapple mealybug, Dysmicoccus brevipes ( Cockerell) ( Hemiptera: Pseudococcidae), which they actively tend and protect from attack by natural enemies. In this study, we evaluate the effects of access to a sucrose solution on the mutualistic association between S. geminata and D. brevipes. Ten colonies of either species were established, with D. brevipes maintained on pumpkin, Cucurbita maxima Duchesne ( Cucurbitaceae), in screen cages. Five of the S. geminata colonies were permitted access to vials with 20% sucrose solution and a pumpkin with 20 adult mealybugs. The remaining ant colonies were allowed access to mealybug-infested pumpkins. Ant colonies with access to the sucrose solution attended mealybugs significantly less than those without additional sugar sources. Mealybug survival rates were similar under both treatments. Total body sugars and fructose were nearly twice as high in ants with access to honeydew and sucrose vs. those with access to honeydew and water. Fructose accumulated on the pumpkins over time in both treatments, suggesting that honeydew was not fully exploited by the ants. In conclusion, D. brevipes enjoy lower degrees of ant attendance when S. geminata have alternative sources of carbohydrates. We further discuss the significance of these findings for the conservation of predaceous ants and mealybug biological control. [ABSTRACT FROM AUTHOR]

The Asian citrus psyllid (ACP), Diaphorina citri (Hemiptera: Psyllidae) is the primary vector of the bacterium causing citrus huanglongbing (citrus greening), the most serious disease of citrus worldwide. Psyllids and other hemipterans produce large amounts of honeydew, which has been used previously as an indicator of phloem sap composition and insect feeding or metabolism. Behavioral, ultrastructural and chemical studies on ACP, its honeydew and waxy secretions showed important differences between nymphs, males and females, and suggested some mechanisms by which the psyllids, especially nymphs and adult females, can minimize their contamination with honeydew excretions. The anal opening in ACP, near the posterior end of the abdomen, is on the ventral side in nymphs and on the dorsal side in adult males and females. Video recordings showed that adult males produce clear sticky droplets of honeydew gently deposited behind their body on the leaf surface, whereas adult females produce whitish honeydew pellets powerfully propelled away from the female body, probably to get their excretions away from eggs and newly hatched nymphs. ACP nymphs produce long ribbons or tubes of honeydew that frequently stay attached to the exuviae after molting, or drop when feeding on the lower side of citrus leaves. Furthermore, honeydew excretions of both nymphs and adult females are covered with a thin layer of whitish waxy material ultrastructurally composed of a convoluted network of long fine filaments or ribbons. This material is extruded from intricate arrays of wax pores in the circumanal ring (around the anus) that is found in nymphs and females but not in males of ACP or other psyllid species. Infrared microscopy and mass spectroscopy revealed that, in addition to various sugars, honeydew excretions of ACP nymphs and females are covered with a thin layer of wax similar in profile to ester waxes. [ABSTRACT FROM AUTHOR]

Nylanderia fulva (Mayr) (Formicidae) is an invasive pest ant that has been reported in Florida, Texas, Louisiana and Mississippi. Workers tend various honeydew producing hemipterans in Florida landscapes and natural areas. We sought to understand the seasonal foraging activities of N. fulva and its relationship with honeydew producing hemipterans. Twenty-two hemipteran species were collected from 15 different plant hosts sampled in Florida from Jul 2010 to Jul 2012. The relative density of hemipterans on 4 plant species [live oak (Quercus virginiana Mill.; Fagales: Fagaceae), holly (Ilex cornuta Lindl.; Aquifoliales: Aquifoliaceae), magnolia (Magnolia grandiflora L.; Magnoliales: Magnoliaceae), and sugarberry (Celtis laevigata Willd.; Urticales: Ulmaceae)] was compared to the relative density of N. fulva at the base or stem of the selected plants. The number of N. fulva and hemipterans on each plant species was positively correlated from spring through fall. Both N. fulva and hemipteran populations increased from May to Sep and decreased from Oct to Apr. In addition, Cinara juniperivora (Wilson) (Hemiptera: Aphididae) on southern red cedar and Toumeyella liriodendri (Gmelin) (Hemiptera: Coccidae) on magnolia were covered with carton shelters presumably constructed by N. fulva, suggesting that this ant potentially protects certain hemipterans species. [ABSTRACT FROM AUTHOR]

The invasive Middle East-Asia Minor 1 ( MEAM1) cryptic species (formerly referred to as the B 'biotype') of the whitefly Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) complex has become a major crop pest worldwide due to its global invasion as well as epidemics of begomoviruses it transmits. Previous studies demonstrated that MEAM1 performed better on tobacco [ Nicotiana tabacum L. (Solanaceae)] plants infected by Tomato yellow leaf curl China virus ( TYLCCNV) than on uninfected plants. However, mechanisms underlying the interactions are not completely understood. In this study, we compared the composition of sugars and amino acids in the phloem sap of uninfected and TYLCCNV-infected tobacco plants with or without whiteflies feeding on the plants. No significant differences were detected in terms of amino acid profiles, percentage of essential amino acids, and sugars:amino acids ratio. However, whiteflies feeding on TYLCCNV-infected plants excreted comparatively a lower percentage of amino acids, especially essential amino acids, or proportionally a higher level of sugars than those feeding on uninfected plants, suggesting that whiteflies feeding on virus-infected plants are able to achieve a more balanced nutritional assimilation. We also compared the honeydew excreted by viruliferous and non-viruliferous whiteflies feeding on cotton [ Gossypium hirsutum L. (Malvaceae)], a non-host plant for TYLCCNV, to test the direct effects of the virus on whiteflies. Although the amino acids profiles in honeydew were similar between viruliferous and non-viruliferous whiteflies, the sugars:amino acids ratio in honeydew excreted by viruliferous whiteflies was lower than that of non-viruliferous whiteflies, suggesting that the viruliferous whiteflies assimilated a more imbalanced nutrition with proportionally more sugar. Taken together, our data indicate that although a plant virus may exert negative direct effects on its vector, feeding by the vector on virus-infected plants may improve nutritional assimilation and consequently performance of the vector. [ABSTRACT FROM AUTHOR]

Abstract: Protopulvinaria pyriformis (Cockerell) (Hemiptera: Coccidae), a scale native to South America, is a major pest of laurel, Laurus nobilis L., and a potential pest of other ornamental plants in urban green areas. We evaluated the potential of Metaphycus helvolus (Compere) (Hymenoptera: Encyrtidae), its major parasitoid, as a biological control agent against P. pyriformis. This parasitoid was imported from South Africa to control soft scales in Europe more than 20years ago. Three factors limited its efficacy: (i) the scale frequently thwart parasitoid attack by removing its stylet and wiggling, a unique defense in soft scales, (ii) scale honeydew extended M. helvolus lifespan little more than water, and (iii) P. pyriformis did not encapsulate Metaphycus spp. eggs but immature parasitoids died during their prepupal stage, which may have been caused by laurel plant secondary compounds from laurel. This parasitoid mortality had not been previously reported in immature parasitoids of genus Metaphycus. These three novel aspects should be considered when choosing a suitable parasitoid in future soft scale biological control programs. [Copyright &y& Elsevier]

Honeydew-excreting hemipterans, such as mealybug pests, can be protected from their natural enemies by tending ants in return for honeydew, thereby compromising the aims of biological control. In this respect, antagonistic interactions between the ant Tapinoma nigerrimum, native to the Mediterranean basin, and the main natural enemies of both the vine mealybug (VMB), Planococcus ficus, and the citrus mealybug (CM), Planococcus citri, were assessed in laboratory conditions. Parasitism of vine and CMs by their respective parasitoids, Anagyrus sp. nr. pseudococci and Leptomastix dactylopii, was negatively affected by the ant T. nigerrimum. Similarly, T. nigerrimum was shown to significantly disrupt the predatory potential of ladybird larvae, Cryptolaemus montrouzieri, when foraging on host CMs. By contrast, the presence of the ant did not negatively influence the predatory activity of C. montrouzieri adults when feeding on CMs. Consequently, the encyrtid parasitoids A. sp. nr. pseudococci and L. dactylopii and the larval stage of the predator C. montrouzieri may be considered as T. nigerrimum-sensitive, whereas the adults of C. montrouzieri may be regarded as T. nigerrimum-resistant predators. Accordingly, the ant T. nigerrimum constitutes a threat to the biological control of mealybugs by either the encyrtids A. sp. nr. pseudococci and L. dactylopii or the larval stage of the ladybird C. montrouzieri. Hence, adequate control of T. nigerrimum is highly recommended before any release of these mealybugs' natural enemies. [ABSTRACT FROM PUBLISHER]

Honeydew-producing psyllids are an important pest of eucalyptus (Myrtaceae) in California, USA, and may influence surrounding litter arthropod communities. In particular, the introduced Australian psyllids Glycaspis brimblecombei Moore and Eucalyptolyma maideni Froggatt (both Hemiptera: Psyllidae) may facilitate the prevalence of invasive ant species. We examined ground-dwelling arthropod communities under eucalyptus trees infested by psyllids. We used a model comparison approach to examine the association of psyllid infestation, ant abundance, and environmental factors with ground arthropod abundance and richness. We found a significant positive association between ant activity on eucalyptus trees and psyllid abundance. Higher psyllid abundance and higher Argentine ant abundance were associated with increased arthropod richness. Irrigation was also associated with increased arthropod richness and abundance. Regardless of location collected, arthropod communities collected in pitfall traps under trees with high psyllid abundance had high similarity to arthropod communities under trees with high ant activity. Abundance of isopods was positively associated with both ant and psyllid abundance. Other arthropod groups differed in their association with ants and psyllids. Argentine ants may exacerbate pest impacts and may also decrease the effectiveness of biological control programs for eucalyptus lerp psyllids. [ABSTRACT FROM AUTHOR]

The chemical elements Fe, Mg, Cu, Zn, and Mn are involved in the various physiological processes of plants. A change in the contents of some chemical elements in rice (Oryza sativa L.) plants is associated with resistance to pests; this includes the slow growth of rice brown planthopper (Nilaparvata lugens Stål) populations. By manipulating the concentrations of Zn, Mn, Fe, and Cu in a hydroponic solution, we tracked the flow of these elements from a hydroponic solution through the rice plant phloem sap, to planthoppers, and ultimately the honeydew excreted by N. lugens. The results showed not only that the contents of Zn, Mn, Fe, and Cu in the rice plants increased with their concentrations in the hydroponic solution but also that the increase in the levels of these four elements in the hydroponic solution affected the level (positively or negatively) of other chemical elements in the rice plants. Furthermore, some of the changes in element levels in the rice plants were reflected in the content of the phloem sap, N. lugens itself and its honeydew. Among the four chemical elements manipulated in the hydroponic solution, only elevated levels of Mn and Na were proportionally transferred to both the rice plants and N. lugens. Therefore, those particular elements could be used as markers to match N. lugens individuals to the rice plants on which they have fed. Our findings have potential applications for determining the provenance of N. lugens migratory populations by examining the levels of chemical elements in N. lugens immigrants, which would lead to a better understanding of the migration sources and routes of this insect. [ABSTRACT FROM AUTHOR]

Abstract: Gut extracts from cereal aphids (Sitobion avenae) showed significant levels of proteolytic activity, which was inhibited by reagents specific for cysteine proteases and chymotrypsin-like proteases. Gut tissue contained cDNAs encoding cathepsin B-like cysteine proteinases, similar to those identified in the closely related pea aphid (Acyrthosiphon pisum). Analysis of honeydew (liquid excreta) from cereal aphids fed on diet containing ovalbumin showed that digestion of ingested proteins occurred in vivo. Protein could partially substitute for free amino acids in diet, although it could not support complete development. Recombinant wheat proteinase inhibitors (PIs) fed in diet were antimetabolic to cereal aphids, even when normal levels of free amino acids were present. PIs inhibited proteolysis by aphid gut extracts in vitro, and digestion of protein fed to aphids in vivo. Wheat subtilisin/chymotrypsin inhibitor, which was found to inhibit serine and cysteine proteinases, was more effective in both inhibitory and antimetabolic activity than wheat cystatin, which inhibited cysteine proteases only. Digestion of ingested protein is unlikely to contribute significantly to nutritional requirements when aphids are feeding on phloem, and the antimetabolic activity of dietary proteinase inhibitors is suggested to result from effects on proteinases involved in degradation of endogenous proteins. [Copyright &y& Elsevier]

Honeydew from phloem-feeding insects and fruit fly insecticidal baits may serve as adult food resources for some insect species. In California (USA) olive orchards, the black scale [ Saissetia oleae (Olivier) (Hemiptera: Coccidae)] is a common honeydew producer, and spinosad-based fruit fly bait (GF-120) is used to control the olive fruit fly [ Bactrocera oleae (Rossi) (Diptera: Tephritidae)]. We investigated the effects of black scale honeydew and GF-120, as food resources, on adult foraging behaviour and survival of the olive fruit fly and two parasitoids in the olive agroecosystem: Scutellista caerulea (Fonscolombe) (Hymenoptera: Pteromalidae), a natural enemy of black scale, and Psyttalia humilis (Silvestri) (Hymenoptera: Braconidae), a parasitoid of the fruit fly. In food choice tests, female flies did not show a preference between GF-120 bait and honeydew, whereas male flies and the parasitoids we tested preferred honeydew. Adults of the three insect species readily fed on honeydew, but the natural enemies never ( P. humilis) or rarely ( S. caerulea) fed on GF-120 bait. Olfactometer tests further confirmed that the tested natural enemies were not attracted to GF-120 bait. The presence of honeydew significantly reduced fruit fly mortality when both honeydew and GF-120 were provided, compared with GF-120 given alone. A single meal of honeydew increased longevity in all insect species tested. The mean longevities of honeydew-fed insects were not significantly different from those feeding on clover honey. Our results suggest that the presence of honeydew would benefit the three insect species and may reduce the efficacy of GF-120 for fruit fly control because of preference of honeydew rather than fruit fly bait as a food resource. [ABSTRACT FROM AUTHOR]

Plant-ants live in a mutualistic association with host plants known as ''myrmecophytes'' that provide them with a nesting place and sometimes with extra-floral nectar (EFN) and/or food bodies (FBs); the ants can also attend sap-sucking Hemiptera for their honeydew. In return, plant-ants, like most other arboreal ants, protect their host plants from defoliators. To satisfy their nitrogen requirements, however, some have optimized their ability to capture prey in the restricted environment represented by the crowns of trees by using elaborate hunting techniques. In this study, we investigated the predatory behavior of the ant Azteca andreae which is associated with the myrmecophyte Cecropia obtusa. We noted that up to 8350 ant workers per tree hide side-by-side beneath the leaf margins of their host plant with their mandibles open, waiting for insects to alight. The latter are immediately seized by their extremities, and then spread-eagled; nestmates are recruited to help stretch, carve up and transport prey. This group ambush hunting technique is particularly effective when the underside of the leaves is downy, as is the case for C. obtusa. In this case, the hook-shaped claws of the A. andreae workers and the velvet-like structure of the underside of the leaves combine to act like natural Velcro® that is reinforced by the group ambush strategy of the workers, allowing them to capture prey of up to 13,350 times the mean weight of a single worker. [ABSTRACT FROM AUTHOR]

Associations between ants and Hemiptera are common in the families Membracidae, Coccoidea and Aphidoidea, but there are only a few cases of ants using honeydew of Cicadellidae species. We surveyed plants of Roupala montana Aubl. (Proteaceae) in the cerrado area (savanna like vegetation) in the Federal District (Brazil) during the rainy season of 2006 and 2007. In this period the plants produce new leaves, which are consumed by the nymphs of a probable new species of Rotundicerus (Cicadellidae: Idiocerinae). The nymph groups are of variable size, with a mean of 20 individuals. We found 83% of them being tended by ants. A total of 21 ant species was documented, with predominance of Camponotus spp. and Cephalotes spp. There is a clear species turnover of ants on the nymph groups and attendance is not continuous in most of the cases, suggesting an opportunistic association between ants and Rotundicerus sp. [ABSTRACT FROM AUTHOR]

Ants in the genus Iridomyrmex cause extensive problems for citrus producers in southern Australia by disrupting the biological control of honeydew-producing Hemiptera. We used baited pitfall traps to survey ant communities in 20 commercial citrus groves and test the hypothesis that populations of Iridomyrmex rufoniger gp spp. and Iridomyrmex purpureus can be reduced by conserving volunteer inter-row vegetation. Nine groves (five in the Murrumbidgee Irrigation Area, New South Wales, and four in the Sunraysia area, Victoria) were classified as ‘bare’ groves, where inter-row vegetation was routinely eliminated using herbicides and cultivation. The remaining ‘grassed’ groves (five in the MIA, six in Sunraysia) had inter-row vegetation controlled only by intermittent mowing. All groves had been managed consistently for between 9 and 22 years. MIA groves were trapped on three occasions (October 1997, January 1998 and April 1998), and Sunraysia groves once (March 1999). Over 190 000 ants were recovered, with I. rufoniger gp spp. accounting for 74% of overall captures and dominating collections in both ‘bare’ and ‘grassed’ groves. A linear mixed model analysis showed that ground cover management history had no significant effect (P > 0.05) on captures of I. rufoniger gp spp., I. purpureus, other Dolichoderinae, Ponerinae, Formicinae or Myrmicinae. High variability between ant populations in groves under the same management regime in each region suggests that aspects of grove management may be affecting ant community composition, however, our results indicate that suppression of pest Iridomyrmex species cannot be reliably achieved simply by altering the management of volunteer inter-row vegetation. [ABSTRACT FROM AUTHOR]

Abstract: The effect of five different food resources (Coccus hesperidum honeydew, honey-water, Lobularia maritima, Fagopyrum esculentum and water only) on the longevity, fecundity, and progeny fitness of female Gonatocerus ashmeadi, an egg parasitoid of the glassy-winged sharpshooter (Homalodisca vitripennis) was investigated in the laboratory. Female G. ashmeadi survived 208–405% longer (up to 11.7 days longer) when fed C. hesperidum honeydew, honey-water, L. maritima and F. esculentum compared with water only. Similarly, all food treatments resulted in up to 378% more progeny (up to 80 more total progeny) than those females provisioned with water only. Mean percentage female progeny ranged from 70 to 81% and did not significantly differ between food treatments. The highest daily fecundity (22–29 progeny) occurred on the first day of oviposition for each food treatment and generally declined as female G. ashmeadi aged. Females deposited 61–100% of offspring within the first 5 days, after which, daily fecundity usually declined to 0–6 offspring per day. For all experimental diets except L. maritima, the number of male progeny oviposited remained relatively constant over time (∼2 males per oviposition bout) but the proportion of males oviposited increased as female G. ashmeadi aged, as oviposition rates declined and fewer female eggs were subsequently laid. There was a strong positive correlation between hind tibia length (HTL) and total progeny produced by G. ashmeadi fed honey-water. There was no correlation between HTL and longevity of female G. ashmeadi fed honey-water. Mean HTL of G. ashmeadi progeny did not significantly differ between food treatments. Estimated progeny fecundity based on HTL, indicated that offspring produced by females provided with water only was 12–15 eggs or 9–12% lower than females that had access to food resources. This difference was not statistically significant. Female progeny that were oviposited by females 9–13 days of age with access to food resources were significantly larger and contained on average 14–17 more eggs than those female progeny resulting from eggs deposited by females 1–8 days of age. [Copyright &y& Elsevier]

Abstract: The effect of dietary supplements on the longevity of male and female Gonatocerus ashmeadi, G. triguttatus and G. fasciatus (Hymenoptera: Mymaridae), was determined in the laboratory. Treatments included: water only, 3:1 honey–water solution, floral and extra-floral nectars from five different plants (excised stems from Fagopyrum esculentum, Lobularia maritima, Phacelia tanacetifolia, Anethum graveolens and Vicia faba), honeydew from Coccus hesperidum and Homalodisca vitripennis (formally H. coagulata), a commercially available food supplement (Eliminade) and citrus foliage. Additionally, the sugar composition of each food resource was determined using HPLC and whole flower extracts. Honey–water and F. esculentum nectar significantly increased longevity of male and female G. ashmeadi, G. triguttatus, and G. fasciatus up to 1860%, 1323% and 1459%, respectively, when compared with water. For both sexes and all three parasitoid species, survival on citrus foliage, H. vitripennis excrement, and P. tanacetifolia flowers was equivalent to that on water only. The longevity of G. ashmeadi and G. triguttatus was up to 539% higher on Eliminade compared with water only, however there was no significant effect of Eliminade on survival of G. fasciatus. Coccus hesperidum honeydew increased survival times up to 665% for all mymarid species compared with citrus foliage alone. HPLC analysis indicated that food resources most beneficial to Gonatocerus parasitoids possessed a high proportion of glucose (up to 44%) and fructose (up to 53%), suggesting that sucrose may not be as important for parasitoid survival. Citrus and P. tanacetifolia flowers contained favorable proportions of glucose and fructose, but the inability of Gonatocerus spp. to benefit from this may be related to flower morphology which could prevent access to nectar. [Copyright &y& Elsevier]

In order to assess if ants attracted to honeydew-producing Hemiptera switched food sources when offered an additional, considerably rich and abundant food source, we studied the interaction between the plant Solanum lycocarpum (Solanaceae), an efn-lacking shrub, the predominantly diurnal ant Camponotus crassus (Hymenoptera: Formicidae), and two species of membracids (Enchenopa spp.; Homoptera: Membracidae). The study was done during September of 1999 at the Reserva Ecológica of IBGE (ca. 35 km S of Brasilia-DF, Brasil). The results show that ants were attracted both to the experimental food source and to the membracids. Moreover, the mean number of ants visiting the experimental nectary was significantly higher than those visiting the membracids. However, the membracids were never left unattended, which suggests that ants, even though presented with an abundant and rich food source, do not abandon other sources. The latter can be explained due to an increment in the honeydew production rate by the membracids, thus the attention levels of ants does not vary Another possibility is the fidelity of worker ants to a food source and its location. To show that ants switch food sources based on quality and/or quantity, and not merely based of their presence and/or absence, requires future research, both for plants with and without extrafloral nectaries. [ABSTRACT FROM AUTHOR]

The incidence of phloem sap feeding by animals appears paradoxical. Although phloem sap is nutrient-rich compared with many other plant products and generally lacking in toxins and feeding deterrents, it is consumed as the dominant or sole diet by a very restricted range of animals, exclusively insects of the order Hemiptera. These insects display two sets of adaptations. First, linked to the high ratio of non-essential:essential amino acids in phloem sap, these insects contain symbiotic micro-organisms which provide them with essential amino acids. For example, bacteria of the genus Buchnera contribute up to 90% of the essential amino acids required by the pea aphid Acyrthosiphon pisum feeding on Vicia faba. Second, the insect tolerance of the very high sugar content and osmotic pressure of phloem sap is promoted by their possession in the gut of sucrase-transglucosidase activity, which transforms excess ingested sugar into long-chain oligosaccharides voided via honeydew. Various other animals consume phloem sap by proxy, through feeding on the honeydew of phloem-feeding hemipterans. Honeydew is physiologically less extreme than phloem sap, with a higher essential:non-essential amino acid ratio and lower osmotic pressure. Even so, ant species strongly dependent on honeydew as food may benefit from nutrients derived from their symbiotic bacteria Blochmannia. [ABSTRACT FROM PUBLISHER]

A mass rearing program was developed for the pink pineapple mealybug (PPM), Dymsicoccus brevipes (Cockerell) (Hemiptera: Pseudococcidae), to provide host material for producing the encyrtid parasitoid Anagyrus ananatis (Gahan). PPM individuals produce honeydew that accumulates on heavily infested squash and entraps crawlers and older instars. A new protocol was tested to reduce accumulated honeydew with minimal mortality to PPM. Butternut and kobocha squash were placed in rearing containers and covered with coarse vermiculite (>2.36?mm diameter) after being infested with PPM. Use of vermiculite removed the honeydew from the squash surface. PPM produced using vermiculite were easily harvested from the host squash, but mealybugs produced on squash without vermiculite were embedded within the honeydew. When individual kobocha squash fruit were inoculated with 300–400 mature PPM adults (>0.6?mm length), about 700 adult PPM (appropriate for A. ananatis production) were produced for each dollar value (USA) of squash fruit (i.e., ~1500?PPM per individual squash). [ABSTRACT FROM AUTHOR]

Female adults of the aphidopagous gall midge, Aphidoletes aphidimyza (Rondani) (Diptera: Cecidomyiidae), showed an olfactory response to honeydew excreted by the green peach aphid, Myzus persicae (Sulzer) (Hemiptera: Aphididae) under laboratory conditions. The response was only elicited by treatments with honeydew, whereas aphids, aphids with pepper plants or leaves, and pepper plants or leaves were not attractive to the midges. Dose-dependent responses were observed from whole honeydew, honeydew volatiles extracted in pentane, and honeydew volatiles captured on Porapak Q®. When honeydew was eluted with three sequential pentane washes, a positive response was only observed from the midges for the first wash. Female midges laid more eggs on pepper plants infested with higher densities of M. persicae. The olfactory response of midges to honeydew is discussed with respect to prey location. [ABSTRACT FROM AUTHOR]

An earlier study showed that two phytoseiid species, Euseius scutalis (Athias-Henriot) and Typhlodromips swirskii (Athias-Henriot) (Acari: Phytoseiidae), are capable of suppressing populations of Bemisia tabaci (Gennadius) (Hemiptera: Aleurodidae) on isolated cucumber plants supplied with Typha latifolia L. pollen. However, the predators did not exterminate their prey, and this may be caused by the existence of invulnerable B. tabaci stages. Little is known of the differential vulnerability of the immature B. tabaci stages. Here, we quantified their vulnerability by assessing the rate of predation on each of the immature stages when offered alone at a density high enough to allow for a maximal predation rate. All immature stages of B. tabaci were vulnerable to predation by each of the two predator species. However, the per capita predation rates, the oviposition rates of phytoseiids, as well as the percentage of predators feeding and the percentage ovipositing decreased with increasing stages of B. tabaci. Compared to that of eggs and 1st instars, the vulnerability of 2nd and later B. tabaci instars is an order of magnitude lower. To investigate how the presence of alternative food changes the rates of predation, we added pollen to a diet of 1st instars, one of the most vulnerable instars. This resulted in a decrease in the predation rate of E. scutalis, but not of T. swirskii, while the oviposition rate of both phytoseiid species remained equally high. The decreased predation of the 1st instars probably resulted from E. scutalis switching to pollen feeding. [ABSTRACT FROM AUTHOR]

The article discusses Coccoidea fauna in Greece and mentions genus Phenaococcus Longoi. Topics discussed include Abies cephalonica, species distribution and hemiptera. Other topics such as fir forests in Greece, honeydew-producing scale insects and study of scale insects in the country are also mentioned.