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The presence of Brazilian native bees can improve tomato production by increasing pollination effectiveness. However, the extensive use of pesticides in tomato cultures may be harmful to bees. Imidacloprid-based insecticides are used in tomato plantations because of its high efficiency against tomato pests. This study investigated the effects of oral intake of field-realistic concentrations of imidacloprid by M. quadrifasciata workers, a stingless native bee from Brazil and effective pollinators of tomato crops. The oral intake of sucrose syrup added with 10, 35, or 70 ppb of imidacloprid did not increase the mortality rate when compared with the control group. However, we observed a reduction in the workers’ motility and food consumption. We also treated M. quadrifasciata workers with sucrose syrup mixed with an imidacloprid-based insecticide (Evidence 700 WG®, Bayer), with the final concentration of 250 ppb of imidacloprid. This treatment did not cause visible alterations of the intestine absorptive cells of the bees’ midgut and did not increase DNA damage. Therefore, the observed reduction of food consumption and locomotion behavior of M. quadrifasciata workers may contribute to the global effort to understand the contribution of neonicotinoids on bees’ population decline process.

Brazil is one of the main users of chemical pesticides in the world. These products threaten human and environmental health, and many of them are prohibited in countries other than Brazil. This paradigm exists in contrast with worldwide efforts to make the need for food production compatible with biodiversity conservation, preservation of ecosystem services, and human health. In this scenario, the development of sustainable methods for crop production and pest management such as organic agriculture and biological control are necessary. Herein, we describe how the process of registration of natural enemy-based products in organic agriculture is simpler and faster than the conventional route of chemical insecticides and can favor the development of the biological control market in Brazil. Since the regulatory mechanisms have been established in Brazil for organic agriculture, the number of biological control products registered has increased exponentially. Today, 50 companies and associations are marketing 16 species/isolates and 95 natural enemy-based products. Although this scenario presents a series of new opportunities to increase and stimulate a more sustainable agriculture in the country, biological control is not always aligned with the aims and philosophy of organic agriculture and agroecology. Therefore, we also argue that new research efforts are needed on understanding how conservation biological control strategies can be integrated with augmentation biological control to promote a sustainable agriculture under the concepts of organic agriculture and agroecology.

An enzootic is reported of Ophiocordyceps myrmicarum in field populations of a non-Formicidae insect, the brown shield stink bug Scaptocoris castanea (Hemiptera: Cydnidae). An on-farm epidemiological study was conducted in three previously established integrated crop-livestock systems (ICLSs), seen as sustainable approaches to farming intensification and characterized by rotation or succession of crops and pastures, as follows: (1) 4 y of annual crops (soybean in the summer and a cover crop in the winter), followed by 4 y of pasture (Panicum maximum and Cajanus cajan consortium); (2) 4 y of pasture and 4 y of annual crops (same species as before); (3) 3 y of pasture (Brachiaria brizantha) and 1 y of annual crops (same as before); as well as areas with either continuous pasture (Brachiaria decumbens) or continuous annual crops (same as before). The incidence of this fungus on S. castanea was monitored over a 2 y period, and areawide average infection levels of nymphs and adults were in the 39.7–89.6% and 65.0–98.1% ranges, respectively. Although the number of infected bugs was positively correlated to insect density, different ICLSs had minimal influence on the incidence of the disease. This is the first report of O. myrmicarum in its anamorphic stage (Hirsutella-like) causing infection on burrowing bugs, and the observed infection levels reported under different farming systems could lead to interest in assessment of its potential as a biological control agent of S. castanea, a severe pest of many pastures and crops in the Neotropical region.

Management of the whitefly Bemisia tabaci biotype B (Hemiptera: Aleyrodidae) has challenged scientists and famers worldwide because this insect is highly polyphagous and resistant to traditional control methods. Innovative management tools, such as the use of the ecosystem service of biological control, are necessary, especially in a century in which sustainable crop systems are emerging. We investigated how management practices and farm diversity within the property limits affect the relationship between biodiversity conservation and the biological control of B. tabaci. We determined the mortality factors of whitefly nymph cohorts on 33 small farms growing tomatoes. The sampled farms formed a gradient of increasing farm diversity and decreasing management intensity. The diversity of natural enemies increased from conventional to agroecological farms, and predation was identified as the key mortality factor of B. tabaci nymphs on all farm types except the conventional farms. Biological control provided by biodiversity components (predators, parasitoids and pathogens) was enhanced on more diverse and less intensively managed farms. Higher predator richness and abundance resulted in more effective biological control and made it less variable among farms. Different components of natural enemy biodiversity were conserved and acted in a complementary way on agroecological farms, and the enhanced ecosystem services reduced the need for insecticides.

The interplay between natural, non-cropped, and cropped habitats affects insect movement in the landscape. Polyphagous, highly mobile pests are more likely to cross habitat-edges and colonize crops. However, local differences within habitats can affect pest populations and modulate their broad response to the landscape. We investigated how different habitat types influence the spatiotemporal dynamics and spillover of a polyphagous pest on tropical organic vegetable farms. We simultaneously sampled the abundance of the worldwide pest Bemisia tabaci (Hemiptera: Aleyrodidae) on crops, fallow areas, agroforests, and forests fragments on five farms for two years. This whitefly species achieved higher population growth rates in open-field habitats (mostly crops), where resources are more easily found and concentrated. The lack of density dependence on population growth suggests that migration drives habitat occupancy. Crops were the main source of individuals to other habitat types, while agroforests and forest fragments (both sink and stepping-stones habitats) are most likely temporary habitats for whiteflies where they face a populational bottleneck. Regardless of habitat features, higher precipitation and low temperatures independently regulated population densities throughout seasons. Fragmented agricultural landscapes reduced bottom-up effects of forests and facilitated whitefly infestation on crops due to edge effects. In summary, the source-sink dynamics of whiteflies was largely determined by sink habitats that differ in local characteristics and management but was also influenced by landscape type. These findings indicate that the farmland habitat scale was adequate to integrate the scale-dependent processes operating on different spatial (local and landscape) and temporal (seasonality) scales on pest populations.

The Whitefly, Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) causes damages to crops by feeding and/or transmitting various plant pathogenic viruses. Morphologically indistinguishable populations of B. tabaci can exhibit variable molecular features and biological behavior. The objective of this work was to present the molecular profile and genetic variability of B. tabaci collected from several crops and localities in Brazil. The molecular identification of 100 whiteflies samples collected from these crops and localities in Brazil revealed 14% of non B biotype of B. tabaci. About the biotypes of B. tabaci, 2% indigenous Brazilian whitefly was found, 1% A biotype, 2% Q biotype, 1% African cassava and 80% B biotype. The dendrogram obtained by molecular markers showed that biotype A of B. tabaci from the United States differed from the other biotypes as it showed around 8% of genetic similarity. For the remaining populations previously identified as biotype B, separation was observed among them based on location and crop of collection. The B. tabaci native Brazilian biotype did not form a separate grouping from the B biotype. This information may serve as a basis for studies aiming to identify which factors influence the population distribution in a given area. Key words: Genetic markers, whitefly, oligonucleotides, b biotype, host plants association.

Evidence shows that pollinator abundance has declined and, consequently, so has their services, which has possible negative impacts on ecosystem functioning. The goal of this study was to evaluate the influence of landscape context at multiple spatial scales on the abundance of bee pollinators of tomato crops in Brazil. Pollinator abundance was obtained from tomato crops grown in a conventional system in the Cerrado region. Around each tomato field circular buffers of 0.75, 1, 1.5, 2, and 3 km radius were defined. Inside each buffer the landscapes were manually classified into native and non-native cover and, the proportion of native vegetation, the relative largest patch size, and the distance of the nearest native vegetation to each field were calculated. Pollinator species were categorized into five groups: Exomalopsis, Centris, Bombus/Eulaema, Halictidae, and all buzz pollinators combined (Buzzers). The results showed that the landscape context influenced the abundance of the five groups of tomato pollinators. Bees with a smaller body size, such as Exomalopsis spp., responded at smaller scales, while bees with a larger body size, such as the Centris and Bombus/Eulaema groups, responded at larger scales. The abundance of all pollinator groups increased with native vegetation cover. Most groups showed higher abundances in landscapes with similar-size fragments. The results reinforce the recommendation for maintaining natural habitats around crop areas, even if fragmented, for the conservation of the tomato pollinator assemblage. These findings are valuable for planning landscape management in the studied area to improve bee conservation, ecosystem services, and food production.

The objective of this work was to determine the survival pattern of the cotton boll weevil during fallow in Midwestern Brazil. The percentage of adults that remained in the cotton reproductive structures, the percentage of adults searching for shelters, and the longevity of adults fed on pollen and nectar as alternative food sources were determined. For this, four populations were sampled in cotton squares and bolls, totaling 11,293 structures, from 2008 to 2012. The emergency of cotton weevil adults was monitored from the collection of the structures until the next cotton season. In the laboratory, newly-emerged adults were fed on hibiscus or Spanish needle, and their life span was monitored individually. Most adults (85.73%) left the reproductive structures, regardless of the cotton plant phenology, up to 49 days after the structures were collected. One individual (0.0002%) from 5,544 adults was found alive after the fallow period. The diet with hibiscus and Spanish needle provided adult longevity of 76±38 days, which was enough time for adults to survive during the fallow period. Most of the boll weevils leave the cotton structures at the end of harvest, survive using alternative food sources, and do not use cotton plant structures as shelter during the legal cotton fallow period in Midwestern Brazil. Resumo: O objetivo deste trabalho foi determinar o padrão de sobrevivência do bicudo-do-algodoeiro durante o pousio no Centro-Oeste do Brasil. Foram determinadas as percentagens de adultos das populações que permaneceram nas estruturas reprodutivas do algodoeiro, as percentagens de adultos que saíram para os refúgios, e a longevidade dos adultos alimentados com pólen e néctar como fontes de alimentos alternativos. Para tanto, foram amostradas quatro populações em botões florais e maçãs do algodoeiro, que totalizam 11.293 estruturas, de 2008 a 2012. A emergência de adultos do bicudo-do-algodoeiro foi monitorada desde a coleta das estruturas até a próxima safra de algodão. Em laboratório, adultos recém-emergidos foram alimentados com hibisco ou picão, e sua longevidade foi monitorada individualmente. A maioria dos adultos (85,73%) saiu das estruturas reprodutivas, independentemente da fenologia do algodoeiro, até 49 dias após as estruturas terem sido coletadas. Um indivíduo (0.0002%) entre 5.544 adultos foi encontrado vivo após o período da entressafra. A dieta de hibisco e picão permitiu uma longevidade de 76±38 dias, tempo suficiente para manter os adultos vivos durante a entressafra. A maioria dos bicudos-de-algodoeiro deixa as estruturas reprodutivas do algodoeiro no final da colheita, sobrevive com alimento alternativo e não usa as estruturas da planta como abrigo durante o período legal de pousio na Região Centro-Oeste do Brasil.

Understanding how climate change may affect species distribution helps predict how ecosystem services, such as pollination, could be impaired in the future. We examine the potential consequences of climate change on the geographical distribution of five native bee species and estimate the possible effects of bee distribution shifts on tomato crops in Brazil. Ensemble forecasting was implemented through five algorithms in two carbon emission scenarios to predict range shifts for five tomato-visiting bee species for the year 2100. We then calculated the total tomato crop area in the cells with at least 50% bee suitability, for each bee species, in each scenario. Results showed that all species will undergo a reduction in suitable areas in both scenarios. Bombus morio had the greatest area reduction in 2100 under the optimistic and pessimistic scenarios: near 38% and 71%, respectively. Centris tarsata had the smaller area reduction under the same scenarios: 8.5% and 19.5% respectively. The high agreement between tomato crops and bee distribution observed in the present will also be reduced in both scenarios for all species, especially in the pessimistic scenario. B. morio had the highest reduction in range due to habitat suitability and will be restricted to some parts of southeastern and southern Brazil. Over 60% of the tomato crop area presently within the distribution of B. morio will become climatically unsuitable in the pessimistic emission scenario. This study indicates that the predicted climate change may negatively impact several species associated with tomato crops in Brazil by the year 2100. This is troubling, as it could result in tomato production losses, which would bring economic and environmental losses to the tomato-producing regions with implications for pollinator conservation.

Stilt-legged flies play an important ecological role in the process of decomposition of organic matter and, on occasion, in the biological control of insects. Currently, there are 46 known species of Taeniaptera Macquart (Diptera: Micropezidae), and their occurrence is reported in various environments throughout the tropics. In contrast, population information on their temporal and spatial distribution is scarce in areas of the Cerrado biome in Brazil, where habitats are highly disturbed and fragmented by agricultural practices and, therefore, the abundance of the group may change. This study assessed abundance of Taeniaptera species in habitats associated with farmland, and determined the change in abundance throughout the year. The stiltlegged flies were sampled in various habitats, namely, organically produced vegetable crops, fallow areas, agroforestry, and native vegetation associated with 4 farms located in the Federal District. In each habitat, one Malaise trap was installed, which remaine...

Habitat management enhances heterogeneity in agroecosystems and also has the potential to increase recruitment of spiders, which can improve the biological control services afforded by these important predators. A paucity of studies has documented the associations of spiders with plant communities or the efficacy of non-crop plants for increasing the density and diversity of spider populations. Here we examined natural associations of spiders with native non-crop plants within Brazilian chili pepper agroecosystems. Following this characterization, a manipulative experiment was undertaken at two locations to identify the effects of non-crop plant strips and borders on spider community structure. The composition of native plants altered the community of spiders. The abundance of these predatory spiders was highest on Asteraceae. Spatial Analyses by Distance Indices (SADIE) determined that there was significant aggregation of spiders in chili pepper fields under these plant management strategies. Although incorporating this habitat management approach reduced the overall cropping area, the corresponding increase in generalist predator abundance could offset costs by improving the natural control of pests. This study revealed associations between native plants and spider communities, and how these help to conserve predator biodiversity. Targeted management of native non-crop plants promote the abundance of natural enemies and enhances biological control in chili pepper agroecosystems.

Multiple predator species can provide effective biological control of pest insects if predators have complementary effects. This could be the case of predatory ants in species-rich assemblages, such as in the tropics. However, predator assemblages are structured by variation in local and landscape factors. Different spatial scales can affect species interaction and consequently the biological control provided. We investigated ant suppression of pest insects in organic vegetable crops, and the role of local and landscape factors on biological control. We used a sentinel prey assay to determine the effectiveness of ant biological control on 18 organic farms in the Brazilian Federal District. Ants and other predatory groups were sampled on farms to determine natural enemy assemblage composition. Ants were the group that most contributed to the predation rates, and the other predator groups complemented the predation rates exerted by ants. The predation of sentinel prey increased 3.07-fold when ants were present. These results varied with the farming management practices employed. The species richness and occurrence were positively related to the predation rates, indicating that ant species-rich assemblage may be more relevant than single species in providing biological control. The predation exerted by ants and other predators were benefited by the abundance of predators in the landscape. Tree cover and cropped area in the landscape reduced ant predation but increased the predation exerted by other predators, because most ant species we sampled usually occur in open habitats. In conclusion, species-rich assemblages play a central role in providing biological control, and biological control provided by ants and other predators depends on local habitat management and landscape composition and therefore is a scale dependent process.

Dose-response assays and surrogate species are standard methods for risk analysis for environmental chemicals. These assume that individuals within a species have unimodal responses and that a surrogate species can predict responses of other related taxa. We exposed immature individuals of closely related aphidophagous coccinellid predators, Cycloneda sanguinea and Harmonia axyridis, to Cry1Ac and Cry1F toxins through uniform and constant artificial tritrophic exposure through Myzus persicae aphids. Both toxins were detected in coccinellid pupae, with individual and interspecific variation. Uptake was significantly higher in H. axyridis than in C. sanguinea, both in the proportion of individuals and the concentrations per individual. We also observed bimodal uptake of the Cry toxins by H. axyridis, which indicated that some individuals had low bioaccumulation and some had high bioaccumulation. This suggests that standard dose-response assays need to be interpreted with caution and future assays should examine the modality of the responses. In addition, the similarity in the biological effects of the Cry toxins in the two predators was due to different biological exposure mechanisms. The majority of H. axyridis were exposed both internally and in the gut, while C. sanguinea was exposed primarily in the gut. Thus, despite their close phylogenetic relatedness, these species would not be good surrogates for each other and the surrogate species methodology should be tested more rigorously.

Intercropping tomato plants with coriander is known to attract natural enemies of aphids, mostly coccinellids, but the cues involved in such attraction are not yet known. We investigated why coriander plants attract Cycloneda sanguinea, a generalist aphid predator. We performed a series of controlled experiments with coriander plants in vegetative and reproductive stages to examine the cues attracting C. sanguinea adults and larvae. In a Y-tube olfactometer, C. sanguinea adults were attracted by coriander volatiles produced during the vegetative plant stage suggesting an innate attraction to coriander. Attraction increased when aphid-infested tomato plants were offered together with coriander plants. Moreover, C. sanguinea females used coriander plants as oviposition sites, regardless of plant stage, which could partially explain the attraction to coriander volatiles during vegetative stage. Larvae hatching on coriander plants without prey were able to find nearby aphid-infested tomato plants within about three days after hatching. Additionally, a diet of coriander flowers increased female survivorship, but oviposition only occurred when females had aphids in their diet. Our results indicate that C. sanguinea adults orient to coriander nearing bloom and then use coriander pollen and/or nectar as a supplementary food before aphids become available. The implications of these findings for conservation biological control are discussed.

Maternal effects can result in adaptive phenotypic responses of offspring that increase their fitness. Several recent studies report a positive relationship between maternal choices and offspring fitness. However, few studies have assessed the associations between aphidophagous lady beetle oviposition site selection, the adequacy of food resources for their offspring, and offspring performance. To clarify these issues, we explored whether aphidophagous lady beetle oviposition site selection can influence offspring performance, thereby reflecting adaptive maternal behavior. To assess the effect of food resources on offspring performance, we fed the larvae of 3 lady beetle species: Cycloneda sanguinea (L.), Harmonia axyridis (Pallas), and Hippodamia convergens (Guerin-Meneville) (all Coleoptera: Coccinellidae), with different types of aphids (Uroleucon and Brevicoryne) (both Hemiptera: Aphididae) then measured development time, survival, adult body mass, brightness, and chromatic coloration of the adult beetles. We found that Ha. axyridis larvae fed Brevicoryne exhibited a higher survival rate than those fed Uroleucon. Also more adults emerged from C. sanguinea larvae fed Uroleucon aphids, and these adults were heavier, shinier, with more chroma, and developed faster than those fed on Brevicoryne. Overall, lady beetles performed better when fed aphids commonly found near their respective oviposition sites. We conclude that aphidophagous lady beetle oviposition site selection reflects adaptive maternal choices associated with an adequate food resource positively affecting offspring fitness. Elucidating the links between lady beetle oviposition site choice and optimal resource for their offspring enhances our understanding of habitat use and co-existence of aphidophagous lady beetle communities in Brazilian agroecosystems. Resumo Os efeitos maternos podem resultar em respostas fenotipicas adaptativas da prole que aumentam sua aptidao. Varios estudos recentes relatam uma relacao positiva entre escolhas maternas e aptidao dos filhos. No entanto, poucos estudos avaliaram as associacoes entre a selecao do local de oviposicao de besouros afidofagos, a adequacao dos recursos alimentares para a prole e o desempenho da prole. Para esclarecer essas questoes, avaliamos se a selecao do local de oviposicao de besouros afidofagos pode influenciar o desempenho da prole, refletindo assim o comportamento materno adaptativo. Para avaliar o efeito dos recursos alimentares no desempenho da prole, alimentamos as larvas de tres especies de besouros: Cycloneda sanguinea (L.), Harmonia axyridis (Pallas), e Hippodamia convergens (Guerin-Meneville) (todos Coleoptera: Coccinellidae), com diferentes tipos de pulgoes (Uroleucon e Brevicoryne) (ambos Hemiptera: Aphididae), medimos o tempo de desenvolvimento, a sobrevivencia, a massa corporal adulta, o brilho e a coloracao cromatica dos besouros adultos. Foi observado que larvas de Ha. axyridis alimentadas com Brevicoryne exibiram uma taxa de sobrevivencia mais alta do que aquelas alimentadas com Uroleucon. Tambem emergiram mais adultos de larvas de C. sanguinea quando alimentadas com pulgoes Uroleucone e esses adultos eram mais pesados, mais brilhantes, com mais croma e se desenvolveram mais rapidamente do que aqueles alimentados com Brevicoryne. No geral, as joaninhas tiveram melhor desempenho quando alimentados com pulgoes comumente encontrados perto de suas respectivas posturas. Concluimos que a selecao do local de oviposicao de besouros afidofagos reflete escolhas maternas adaptativas associadas a um recurso alimentar adequado que afeta positivamente a aptidao da prole. A elucidacao dos vinculos entre a escolha do local de oviposicao do besouro e o recurso ideal para seus filhotes aprimora nossa compreensao do uso do habitat e a coexistencia de comunidades de besouros afidofagos nos agroecossistemas brasileiros. Key Words: Cycloneda sanguinea; Harmonia axyridis; Hippodamia convergens; Uroleucon; Brevicoryne; adaptative maternal behavior View this article in BioOne

Adults of the fly family Dolichopodidae (Diptera) are general predators on small soft-bodied invertebrates, and often are abundant in agroecosystems. However, information about their diversity and spatial distribution in agricultural landscapes are scarce. Using structured sampling, we identified the species of Dolichopodidae associated with organic vegetable crops, fallow, agroforestry, and native vegetation in the Federal District of Brazil, and evaluate their richness and abundance. We collected 70 species Dolichopodidae distributed in 17 genera and 9 subfamilies. Of these, some 80% of the specimens belong to the following 5 taxa: Chrysotus spectabilis (Loew), Thrypticus violaceous Van Duzee, Condylostylus depressus (Aldrich), Condylostylus “caudatus group” females, and Condylostylus erectus Becker (all Diptera: Dolichopodidae). Habitats with vegetable crops harbored a higher abundance and number of species (diversity α), with a gradual reduction towards more forested environments of native vegetation. This is an inverse gradient with the general patterns of community studies with other taxa. We also verified the importance of less disturbed habitats over time in the agricultural landscape, such as agroforestry and native vegetation, as complementary habitats for the maintenance and conservation of dolichopodid species in particular, a scenario to be tested for other insect groups. Resumo Os adultos da familia das moscas Dolichopodidae (Diptera) sao predadores generalistas de pequenos invertebrados de corpo mole, sendo geralmente abundantes em agroecossistemas. No entanto, informacoes sobre sua diversidade e distribuicao espacial em paisagens agricolas sao escassas. A partir de amostragens locais, identificamos as especies de Dolichopodidae associadas a hortalicas orgânicas, pousio, agrossilvicultura e vegetacao nativa no Distrito Federal, Brasil, e avaliamos sua riqueza e abundância. Foram coletadas 70 especies de Dolichopodidae distribuidas em 17 generos e 9 subfamilias. Destes, cerca de 80% dos especimes pertencem aos seguintes 5 taxons: Chrysotus spectabilis (Loew), Thrypticus violaceous Van Duzee, Condylostylus depressus (Aldrich), Condylostylus “grupo caudatus” e Condylostylus erectus Becker (todos dipteros: Dolichopodidae). Habitats com hortalicas abrigavam a maior abundância e numero de especies (diversidade α), com uma reducao gradual em direcao a ambientes mais florestados de vegetacao nativa. Este e um gradiente inverso com os padroes gerais de estudos comunitarios com outros taxons. Tambem verificamos a importância de habitats menos perturbados ao longo do tempo na paisagem agricola, como agrofloresta e vegetacao nativa, como habitats complementares para a manutencao e conservacao de especies de diclopodideos em particular. Este e um cenario a ser testado para outros grupos de insetos. Key Words: biological control; Neotropical region; Cerrado; habitat management; species richness; organic agro-ecosystems View this article in BioOne

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The competitive exclusion hypothesis suggests that coexisting related species using similar resources in nature should partition their realized niches. This hypothesis has direct implications for conservation strategies using biological control, taking into consideration the shifts caused by the introduction of natural enemies in a local community. Such introductions typically lead to disruptions in species interactions and interfere with community structure. In this study, we asked whether community structure of aphidophagous lady beetles is determined by the distribution of specific plants and aphids. To answer this question, we describe the distribution patterns of lady beetles (adults, larvae, and egg clusters) relative to plants and aphids in eight crop ecosystems in a central region of Brazil. We used canonical correspondence analysis to evaluate lady beetle distribution relative to selected habitat variables. Cycloneda sanguinea L., Hippodamia convergens Guérin-Méneville, Harmonia axyridis Pallas, and Eriopis connexa Germar (Coleoptera: Coccinellidae) differed in their use of plants and aphids. The association of egg clusters with specific plants/aphids was stronger than that of larvae or adults. In conclusion, lady beetle species occupied different niches, indicating different patterns of habitat use that may facilitate their coexistence in crop ecosystems. Furthermore, immature individuals had more specific environmental associations than adults, likely because female choice of oviposition sites influences their distribution and thus lady beetle community structure.

International audience; DNA methods are useful to identify ingested prey items from the gut of predators, but reliable detection is hampered by low amounts of degraded DNA. PCR-based methods can retrieve minute amounts of starting material but suffer from amplification biases and cross-reactions with the predator and related species genomes. Here, we use PCR-free direct shotgun sequencing of total DNA isolated from the gut of the harlequin ladybird Harmonia axyridis at five time points after feeding on a single pea aphid Acyrthosiphon pisum. Sequence reads were matched to three reference databases: Insecta mitogenomes of 587 species, including H. axyridis sequenced here; A. pisum nuclear genome scaffolds; and scaffolds and complete genomes of 13 potential bacterial symbionts. Immediately after feeding , multicopy mtDNA of A. pisum was detected in tens of reads, while hundreds of matches to nuclear scaffolds were detected. Aphid nuclear DNA and mtDNA decayed at similar rates (0.281 and 0.11 h À1 respectively), and the detectability periods were 32.7 and 23.1 h. Metagenomic sequencing also revealed thousands of reads of the obligate Buchnera aphidicola and facultative Regiella insecticola aphid symbionts, which showed exponential decay rates significantly faster than aphid DNA (0.694 and 0.80 h À1 , respectively). However, the facultative aphid symbionts Hamil-tonella defensa, Arsenophonus spp. and Serratia symbiotica showed an unexpected temporary increase in population size by 1–2 orders of magnitude in the predator guts before declining. Metagenomics is a powerful tool that can reveal complex relationships and the dynamics of interactions among predators, prey and their symbionts.

We studied the influence of synthetic (E)-2-hexenal on the abundance of Telenominae aiming to attract parasitoids and enhance stink bug egg parasitism in treated areas. We conducted experiments in 2006, 2007 and 2008 soybean seasons with two short-term (one week) and one long-term (seven weeks) experiment, respectively. We evaluated the abundance of parasitoids with yellow sticky traps and estimated the incidence and intensity of parasitism with sentinel eggs of Euschistus heros Fabricius (Hemiptera: Pentatomidae) or with tulle bags, enclosing laboratory pregnant E. heros as an egg source. In short-term experiments, there was increased abundance of Trissolcus spp. (Hymenoptera: Platygastridae: Telenominae) in treated areas, associated with greater intensity of parasitism. In long-term experiments, treatment with (E)-2-hexenal did not influence the abundance of Telenominae or parasitism levels, but increased egg predation. Applications of (E)-2-hexenal can be used to increase recruitment of Trissolcus spp. in the early flowering stages of soybean and also to attract other natural enemies, but do not increase egg parasitism.

This study aimed to evaluate the importance of wild bee and feral honeybee visits for cotton production on conventional and organic farms. Experiments were conducted in Brazil, on a conventional cotton farm in Mato Grosso state in the Amazon biome and on an organic farm in Paraíba state in the Caatinga biome. On the conventional farm, bee assemblage and cotton production were measured near to and far from natural vegetation. Bee richness, fibre fraction, seed number and yield (Kg/ha) were higher by 57.14, 1.95, 17.77 and 18.44% respectively in plots near natural vegetation, but bee abundance did not vary with distance to natural vegetation. On the organic farm, because the cropping area is surrounded by natural vegetation, pollination deficit was evaluated using an exclusion experiment where cotton production of flowers bagged to prevent bee visitation (spontaneous self-pollination) was compared to production of flowers open to bee visitation (open pollination). Open pollinated flowers had higher average boll weight, fibre weight and seed number. Although cotton is not directly dependent on bee pollination, bees increased cotton production on the organic farm by more than 12% for fibre weight and over 17% for seed number. Our data confirm the importance of maintaining communities of pollinators on cotton farms, especially for organic production.

The integration of agroforestry plots with ephemeral crops such as vegetables on the farm scale can probably serve as a refuge and source of beneficial insects. Therefore, agroforestry systems possibly represent an alternative that favors ecosystem services and help growers in the transition process from conventional to agro-ecological agriculture. This study aimed to understand the role of introducing agroforestry systems in structuring insect communities, with consequences for the abundance of herbivore and natural enemies, contributing to farm management and favoring biological control as an ecosystem service. Field surveys showed that agroforestry systems can harbor more species than horticultural crops, independent of the functional group. They also contain a greater diversity of herbivores and an even greater diversity profile of natural enemy communities. Agroforestry systems served as a source of natural enemies that can colonize horticultural crops when herbivores are present. As a consequence, natural enemies can establish a numerical response to herbivore abundance, but their communities are also affected by stochastic factors related to climatic conditions. Thus, agroforestry systems and agro-ecological practices might favor an agriculture based on the maintenance and conservation of ecosystem services.

Insect predators are exposed to the Cry1Ac toxin in Bt cotton fields through several pathways. In this study, we investigated the effects of activated Cry1Ac added to a diet on Cycloneda sanguinea (L.) (Coleoptera: Coccinellidae), which is one of the main predators of non-target pests in Brazilian cotton. Direct bitrophic exposure of C. sanguinea to Cry1Ac was done by feeding beetles with Aphis gossypii (Glover) (Hemiptera: Aphidae) sprayed with 500 μg per ml Cry1Ac solution. Larval and pupal survival, development time, aphid consumption, and adult longevity were recorded daily. Couples within the same experimental treatment were paired and numbers of eggs laid and hatched per female were recorded daily. Net replacement rate was calculated for each female. During development, a C. sanguinea larva consumed on average 1.8 μg of activated Cry1Ac. No significant differences due to Cry1Ac were observed for any of the response variables, except aphid consumption. Larvae receiving Cry1Ac consumed more aphids than larvae receiving distilled water alone. Additional statistical analyses were conducted to evaluate independence of responses, and for the independent responses, a simple meta-analysis was conducted to test the null hypothesis that all responses were zero. Nearly all of the response variables were statistically independent. Two pairs of responses were not independent, but the associated multivariate tests were not significant. The meta-analysis suggested that all effects were not different from random variation around zero and no cumulative effects could be detected. Our results indicated that bitrophic exposure to activated Cry1Ac is likely to have little or no adverse ecological effect on C. sanguinea.

International audience; Characterizing trophic networks is fundamental to many questions in ecology, but this typically requires painstaking efforts, especially to identify the diet of small generalist predators. Several attempts have been devoted to develop suitable molecular tools to determine predatory trophic interactions through gut content analysis, and the challenge has been to achieve simultaneously high taxonomic breadth and resolution. General and practical methods are still needed, preferably independent of PCR amplification of barcodes, to recover a broader range of interactions. Here we applied shotgun-sequencing of the DNA from arthro-pod predator gut contents, extracted from four common coccinellid and dermapteran predators co-occurring in an agroecosystem in Brazil. By matching unassembled reads against six DNA reference databases obtained from public databases and newly assembled mito-genomes, and filtering for high overlap length and identity, we identified prey and other foreign DNA in the predator guts. Good taxonomic breadth and resolution was achieved (93% of prey identified to species or genus), but with low recovery of matching reads. Two to nine trophic interactions were found for these predators, some of which were only inferred by the presence of parasitoids and components of the microbiome known to be associated with aphid prey. Intraguild predation was also found, including among closely related ladybird species. Uncertainty arises from the lack of comprehensive reference databases and reliance on low numbers of matching reads accentuating the risk of false positives. We discuss caveats and some future prospects that could improve the use of direct DNA shotgun-sequencing to characterize arthropod trophic networks.

We evaluated an artificial tritrophic exposure system for use in ecotoxicological evaluations of environmental stressors on aphidophagous predators. It consists of an acrylic tube with a Parafilm M sachet containing liquid aphid diet, into which can be added environmental stressors. Immature Cycloneda sanguinea, Harmonia axyridis and Chrysoperla externa, and adult H. axyridis were reared on Myzus persicae. Larval and pupal development and survival of all species and reproductive parameters of H. axyridis were similar to published results. The system provides a suitable tritrophic exposure route, enables ex-ante evaluation of stressors, and improves the accuracy of the assessment.

Decrease in the species composition similarity of herbivore assemblages with increasing phylogenetic distance between host plants is a widespread pattern. Here we used data for caterpillars in the Brazilian Cerrado to investigate how the similarity in caterpillar species composition decreases as the taxonomic level and genetic distance (GD) of their host plants increases. In addition, we elucidate the plant taxonomic level that provides the greatest contribution to turnover in the caterpillar species composition among host taxa. Adult Lepidoptera were reared from caterpillars collected from 52 plants over 13 yr in the same area, with each host plant sampled for 1 yr. Most species were specialists, with 66 percent of genus specialists among the nonsingleton species. The similarity in caterpillar species composition across plant taxa decreased from host species to genera, and from host genera to orders. Above this level, the similarity was consistently low. The GD between plants explained 82 percent of the variation in the similarity of caterpillar species composition. The contribution of caterpillar species turnover among host orders from the same superorder and among host superorders from the same subclass explained 70 percent of the caterpillar species richness as a whole. Our results lend support to the view that most tropical caterpillars are host specialists. Our findings further indicate that the number of orders and superorders of plants provide the greatest contribution to the total caterpillar richness compared with all of the other host taxonomic levels combined. Abstract in Portuguese is available at http://www.blackwell-synergy.com/loi/btp.

Several studies have demonstrated that the diversification of the agroecosystem may reduce insect pest infestation using the strategy of companion planting. We studied the effect of the presence of coriander and Gallant soldier as companion plants in the tomato crop under organic and conventional management on abundance of the tomato pests and predators. The experiment was carried out under field conditions, at Distrito Federal, Brazil, from July to October, 2004. The experimental design was of randomized blocks with three replicates in a 3 x 2 factorial arrangement [Three crop diversification levels: tomato in monoculture, tomato intercropped with coriander, and tomato intercropped with coriander and Gallant soldier; and two cropping systems: organic and conventional]. Each plot had 80 plants of the tomato and the pest-insects and predaceous arthropods were collected every week in five tomato plants/plot. Tuta absoluta (Meyr.) was the commonest pest species in both cropping systems. The tomato intercropped with coriander and Gallant soldier in organic cropping system had lower abundance and higher diversity of pests, and higher abundance and diversity of predaceous arthropods, mainly at 80 days after the tomato transplanting, coinciding with the population peak of T. absoluta (eggs and adults). The more abundant predators were spiders, lady beetles and ants. The spiders were abundant and uniformly distributed in both systems. The lady beetles appeared lately in the organic system, at the flowering season of the coriander. The ants were more abundant in the conventional systems.

Several studies have demonstrated that the diversification of the agroecosystem may reduce insect pest infestation using the strategy of companion planting. We studied the effect of the presence of coriander and Gallant soldier as companion plants in the tomato crop under organic and conventional management on abundance of the tomato pests and predators. The experiment was carried out under field conditions, at Distrito Federal, Brazil, from July to October, 2004. The experimental design was of randomized blocks with three replicates in a 3 x 2 factorial arrangement [Three crop diversification levels: tomato in monoculture, tomato intercropped with coriander, and tomato intercropped with coriander and Gallant soldier; and two cropping systems: organic and conventional]. Each plot had 80 plants of the tomato and the pest-insects and predaceous arthropods were collected every week in five tomato plants/plot. Tuta absoluta (Meyr.) was the commonest pest species in both cropping systems. The tomato intercropped with coriander and Gallant soldier in organic cropping system had lower abundance and higher diversity of pests, and higher abundance and diversity of predaceous arthropods, mainly at 80 days after the tomato transplanting, coinciding with the population peak of T. absoluta (eggs and adults). The more abundant predators were spiders, lady beetles and ants. The spiders were abundant and uniformly distributed in both systems. The lady beetles appeared lately in the organic system, at the flowering season of the coriander. The ants were more abundant in the conventional systems.Vários estudos têm demonstrado que a diversificação do agroecossistema pode reduzir a infestação por insetos-praga pelo uso da estratégia do estabelecimento de plantas companheiras. Neste trabalho estudou-se o efeito da presença do coentro e botão-de-ouro como plantas companheiras na cultura do tomate sob manejo orgânico e convencional, na abundância das pragas do tomate e de predadores. O experimento foi conduzido em condições de campo, no Distrito Federal, de julho a outubro de 2004. O desenho experimental foi em blocos ao acaso, com três repetições e no arranjo fatorial 3 x 2 [três níveis de diversificação cultural: tomate em monocultivo, tomate consorciado com coentro, e consórcio tomate com coentro e botão-de-ouro e dois sistemas de cultivo: orgânico e convencional]. Cada parcela experimental tinha 80 plantas de tomateiro, sendo os insetos-praga e artrópodes predadores semanalmente coletados em cinco plantas/parcela. Tuta absoluta (Meyr.) foi a espécie-praga mais comum em ambos os sistemas de cultivo. O tomate consorciado como coentro e botão-de-ouro, no sistema de cultivo orgânico, apresentou menor abundância e maior diversidade de pragas, e maior abundância e diversidade de artrópodes predadores, principalmente aos 80 dias após o transplantio do tomate, coincidindo com o pico populacional da T. absoluta (ovos e adultos). Os predadores mais abundantes foram aranhas, joaninhas e formigas. As aranhas foram abundantes e uniformemente distribuídas em ambos os sistemas. As joaninhas apareceram tardiamente no sistema orgânico, no período de florescimento do coentro. As formigas foram mais abundantes no sistema convencional.

A mosca-branca Bemisia tabaci Biótipo B (Hemiptera: Aleyrodidae), é um herbívoro de difícil controle devido à alta plasticidade genotípica da espécie. No tomateiro pode causar danos severos principalmente pela transmissão de diversas viroses. O manejo do sistema de produção e o consórcio de culturas podem ter um efeito direto nas populações desse herbívoro, sem que seja necessária a aplicação de inseticidas. Avaliou-se a influência dos sistemas de produção orgânico e convencional e o consórcio tomate-coentro na dinâmica populacional da mosca-branca no campo experimental da Embrapa Hortaliças, de maio a setembro/06. O monitoramento dos adultos da mosca-branca e de seus inimigos naturais foi realizado utilizando-se armadilhas adesivas amarelas fixadas nas bordas e no interior das parcelas experimentais e a amostragem de ninfas foi realizada por observação direta das folhas de tomate no campo. Embora as populações ao redor dos diferentes tratamentos fossem equivalentes, a abundância de adultos de mosca-branca foi significativamente menor nas parcelas de tomate consorciado com coentro, tanto no sistema convencional como orgânico. Apenas o consórcio tomatecoentro em sistema orgânico apresentou redução significativa na quantidade de ninfas por planta em relação aos demais tratamentos. Os inimigos naturais foram significativamente mais abundantes em sistema orgânico e foi verificada uma correlação negativa da abundância dos inimigos naturais e a quantidade de ninfas por planta. A associação tomate-coentro e o manejo orgânico do agroecossistema favoreceram ao controle biológico natural da mosca-branca. Due to its high genotypic plasticity, the control of the silverleaf whitefly Bemisia tabaci B biotype (Hemiptera: Aleyrodidae), is difficult. This insect may cause severe damage to the tomato crop as a vector of several viruses. The management of the production system and the consortium with other crops may have a direct effect on this herbivore population, without the need of chemical insecticide spraying. The effect of organic and conventional production systems and the tomato-coriander consortium were evaluated in this study, in field, during May-September 2006. Adults of whitefly and its natural enemies were monitored using yellow adhesive traps installed at the edge and inside the experimental plots, and nymphs were sampled by direct observation on tomato plants. Although adult populations in the neighborhood of the different treatments were equivalent, the abundance of whitefly adults was significantly lower in the plots with the consortium tomato-coriander in both systems, conventional and organic. Significant reduction in the amount of nymphs per plant was only observed in the consortium tomato-coriander when all treatments were compared. There were more natural enemies in organic system and a negative correlation was observed between natural enemies abundance collected in the traps and whitefly nymphs' density. The association tomato-coriander and the organic management of the agroecossystem favored natural biological control of B. tabaci.

A mosca-branca Bemisia tabaci Biótipo B (Hemiptera: Aleyrodidae), é um herbívoro de difícil controle devido à alta plasticidade genotípica da espécie. No tomateiro pode causar danos severos principalmente pela transmissão de diversas viroses. O manejo do sistema de produção e o consórcio de culturas podem ter um efeito direto nas populações desse herbívoro, sem que seja necessária a aplicação de inseticidas. Avaliou-se a influência dos sistemas de produção orgânico e convencional e o consórcio tomate-coentro na dinâmica populacional da mosca-branca no campo experimental da Embrapa Hortaliças, de maio a setembro/06. O monitoramento dos adultos da mosca-branca e de seus inimigos naturais foi realizado utilizando-se armadilhas adesivas amarelas fixadas nas bordas e no interior das parcelas experimentais e a amostragem de ninfas foi realizada por observação direta das folhas de tomate no campo. Embora as populações ao redor dos diferentes tratamentos fossem equivalentes, a abundância de adultos de mosca-branca foi significativamente menor nas parcelas de tomate consorciado com coentro, tanto no sistema convencional como orgânico. Apenas o consórcio tomatecoentro em sistema orgânico apresentou redução significativa na quantidade de ninfas por planta em relação aos demais tratamentos. Os inimigos naturais foram significativamente mais abundantes em sistema orgânico e foi verificada uma correlação negativa da abundância dos inimigos naturais e a quantidade de ninfas por planta. A associação tomate-coentro e o manejo orgânico do agroecossistema favoreceram ao controle biológico natural da mosca-branca.Due to its high genotypic plasticity, the control of the silverleaf whitefly Bemisia tabaci B biotype (Hemiptera: Aleyrodidae), is difficult. This insect may cause severe damage to the tomato crop as a vector of several viruses. The management of the production system and the consortium with other crops may have a direct effect on this herbivore population, without the need of chemical insecticide spraying. The effect of organic and conventional production systems and the tomato-coriander consortium were evaluated in this study, in field, during May-September 2006. Adults of whitefly and its natural enemies were monitored using yellow adhesive traps installed at the edge and inside the experimental plots, and nymphs were sampled by direct observation on tomato plants. Although adult populations in the neighborhood of the different treatments were equivalent, the abundance of whitefly adults was significantly lower in the plots with the consortium tomato-coriander in both systems, conventional and organic. Significant reduction in the amount of nymphs per plant was only observed in the consortium tomato-coriander when all treatments were compared. There were more natural enemies in organic system and a negative correlation was observed between natural enemies abundance collected in the traps and whitefly nymphs' density. The association tomato-coriander and the organic management of the agroecossystem favored natural biological control of B. tabaci.

Padrão de oviposição e tabela de vida da traça-do-tomateiro Tuta absoluta (Meyrick) (Lepidoptera, Gelechiidae). A traça-do-tomateiro apresentou maior oviposição ao colonizar tomateiros cultivados em sistema convencional em relação ao orgânico em estudos prévios realizados no campo. Visando confirmar e entender o padrão observado no campo, aspectos bioecológicos como oviposição e mortalidade de imaturos foram comparados em condições semi-controladas de casa de vegetação com plantas cultivadas em vasos com solo proveniente do sistema orgânico e convencional. Adultos da traça-do-tomateiro foram liberados na casa de vegetação e após 24h, as plantas infestadas foram transferidas para outra casa de vegetação, para acompanhamento de coortes horizontais. Os ovos naturalmente depositados pela traça-do-tomateiro foram localizados na planta e demarcados. Em seguida, a folha foi ensacada. Diariamente as plantas foram observadas, registrando a fase de desenvolvimento do inseto e a ocorrência de morte, até que todos os insetos completassem seu ciclo de vida. A oviposição pela traça-do-tomateiro em plantas com solos oriundos do sistema convencional foi duas vezes maior do que em plantas com solos do sistema orgânico. A curva de sobrevivência da fase imatura e a tabela de vida da traça-do-tomateiro em casa de vegetação mostraram que a sobrevivência em plantas com solo orgânico e convencional não apresentaram diferenças. Assim as diferenças no comportamento de padrão de oviposição observadas a campo provavelmente não estão relacionadas com o desempenho da progênie e podem ser influenciado pelo ambiente proporcionado pelo sistema orgânico de produção. Oviposition pattern and life table of South American tomato pinworm Tuta absoluta (Meyrick) (Lepidoptera, Gelechiidae). The tomato pinworm presented higher oviposition when colonizing tomato plants cropped in conventional system than in organic system, in previous field studies. Aiming to confirm and to understand the observed pattern in the field, bioecological processes, such as oviposition and mortality of immatures, were compared on ploted plants in soil from organic and conventional systems in semi-controlled conditions of greenhouse. Tomato pinworm adults were released in the greenhouse, the infested plants were transfered to another greenhouse after 24h, to track horizontal cohort. Naturally deposited eggs were located, marked and the leaf was caged. Each plant was observed daily and development stage or death was registered until all individuals completed the life cycle or died. Oviposition by tomato pinworm was 2-fold higher in plants growing in soil from conventional system than from organic system. The survivorship curve of immatures and life table in the greenhouse showed that there was no difference in organic and conventional plants. Thus, the difference in the oviposition pattern observed in the field is not related to the progeny performance and can be influenced by the environment of organic tomato crop system.

New World army ants species have an important role in structuring invertebrate communities. Labidus praedator (Fr. Smith, 1858) is a generalist top predator that can reduce pest densities in agroecosystems. The aim of this study was to describe behavioral attributes, diet composition and interspecific interactions of the ant L. praedator. We searched for army ant raids using standardized trail-walk surveys and plotted army ants raids positions on an aerial image. We photographed events at swarm raids of L. praedator and recorded its diet items in basal columns near bivouacs. Six species from four Ecitoninae genera - Labidus (Jurine, 1807), Nomamyrmex (Borgmeier, 1936), Neivamyrmex (Borgmeier, 1940) and Eciton (Latreille, 1804) - were recorded. Caterpillars dominated the composition of the diet of L. praedator. Flowers and diaspores of weeds and aril and flesh of fruits were also transported to bivouacs. One colony stopped foraging after intense rainfall and discrete groups of hundreds of L. praedator ants were separated under patches covered by shrubs. Groups of Crotophaginae birds, Sarcophaginae flies and Polistinae wasps followed L. praedator swarm raids. We discuss the importance of landscape structure for agroecosystem colonization by Ecitoninae and the existence of chemical opportunism between army ants species through the reuse of unoccupied trails.Algumas formigas neotropicais de correição têm um importante papel na estruturação da comunidade de invertebrados. Labidus praedator (Fr. Smith, 1858) como predador generalista de topo pode reduzir as densidades de pragas em agroecossistemas. O objetivo deste estudo foi descrever atributos comportamentais, composição de dieta e interações interespecíficas da formiga Labidus praedator. Nós buscamos as colunas das formigas de correição por meio de amostragens por caminhamento em trilhas padronizadas. Nós plotamos as posições das colunas sobre uma imagem aérea. Nós fotografamos eventos nas frentes de caça de L. praedator e registramos os itens alimentares transportados para os bivaques. Seis espécies de quatro gêneros de Ecitoninae - Labidus (Jurine, 1807), Nomamyrmex (Borgmeier, 1936), Neivamyrmex (Borgmeier, 1940) e Eciton (Latreille, 1804) - foram registradas. Lagartas dominaram a composição de dieta de L. praedator. Diásporos e flores de ervas daninhas e arilo e polpa de frutos também foram transportados para os bivaques. Uma colônia parou de forragear após chuva intensa e grupos discretos de centenas de L. praedator se formaram sob áreas cobertas por arbustos. Grupos de aves da subfamília Crotophaginae e vespas e moscas dos táxons Sarcophaginae e Polistinae seguiram as frentes de caça de L. praedator. Discutimos a importância da estrutura da paisagem para colonização de agroecossistemas por Ecitoninae e a existência de oportunismo químico entre formigas de correição no mínimo por meio do reuso de trilhas desocupadas.

Current knowledge on coccinellids is primarily focused on their role as natural enemies of soft-bodied insects. However, there is a great diversity of coccinellid parasitoid species that are less studied. Here, we describe new records of coccinellid parasitoids with emphasis on new host–parasitoid interactions in 11 sample sites in Brazil. We collected 122 coccinellid individuals parasitized by six species of parasitoids in the Cerrado and in the Atlantic Rainforest biomes. New records of coccinellid parasitoids and host associations, expansion of habitat ranges and interactions are discussed focusing on the lack of basic information on these interactions in Brazil.

The spittlebug, Deois flavopicta Stål, is the main pest in cultivated pastures of the "Cerrados" (savanna) in the central region of Brazil. The insect has three discrete generations during the rainy season (September-April) and a synchronized population of diapausing eggs during the dry season (May-August). Experiments in cultivated pastures showed that nonspecific predators were able to affect significantly the mortality rates of diapausing eggs and nymphs of D. flavopicta. Predation was a density independent mortality factor that reduced diapausing eggs by approximately 60% and nymphs by 20% to 47%. The nymph mortality rate due to predation did not differ during the first and the second generations of the year. For the third generation however, the mortality rate was lower, related to a greater degree of nymphal aggregation in spatial refuges. Our direct observations indicate that among the types of predators in pastures, ants potentially make the greatest contribution to mortality, although their impact needs experimental verification. High rates of mortality of eggs and nymphs of D. flavopicta exposed to predators indicate that predation can be an important factor determining the size of adult populations. Therefore, management practices that disturb the predator community may increase the population densities of the spittlebug. A cigarrinha-das-pastagens Deois flavopicta Stål é a principal praga de pastagens cultivadas nos Cerrados do Brasil Central. O inseto apresenta distribuição sazonal com três gerações anuais discretas durante a estação chuvosa (setembro-abril) e população sincronizada de ovos diapáusicos durante a estação seca (maio-agosto). Experimentos em pastagens cultivadas mostraram que predadores não-específicos foram capazes de alterar significativamente as taxas de mortalidade de ovos diapáusicos e ninfas de D. flavopicta. Predação foi um fator de mortalidade independente da densidade, reduzindo os ovos diapáusicos em aproximadamente 60% e ninfas de 20% a 47%. A taxa de mortalidade das ninfas resultante da predação não variou significativamente entre a primeira e a segunda geração anual. No entanto, a mortalidade de ninfas na terceira geração foi significativamente mais baixa, fato relacionado ao maior grau de agregação das ninfas em refúgios espaciais. Observações diretas de interações predador-presa nas pastagens sugerem que, potencialmente, as formigas representam o grupo que mais contribui para a mortalidade observada, embora esse impacto deva ainda ser verificado experimentalmente. Taxas de mortalidade mais altas em ovos e ninfas de D. flavopicta expostos aos predadores indicam que a predação pode ser um fator importante na determinação da população de adultos. Desta forma, práticas de manejo das pastagens que perturbam a comunidade de predadores podem resultar em densidades mais altas das cigarrinhas.

We found that variation in temperature and humidity significantly affected mortality rates and population dynamics of the spittlebug Deois flavopicta Still by monitoring cohorts of diapausing eggs and nymphs for three generations. Cohorts of quiescent eggs, when exposed to increasing periods of high moisture (free water), produced higher proportions of eggs resuming embryonic development in laboratory experiments. The accumulated number of eggs resuming development as a function of days of exposure to moist conditions was modeled using a β distribution. Periods of drought and high temperatures after the beginning of postdiapause development increased embryonic and nymphal mortality. Mortality was modeled with a linear function, and in combination with the development model allowed the simulation of varying mortality rates in the newly emerged nymphal population. Comparisons with field data demonstrated a close fit to the observed and expected proportion of nymphs hatching daily. By accurately simulating natural mortality, hatching distribution and population dynamics, the model promises to be useful for managing the spittlebug in the field.

O fungo entomopatogênico Nomuraea rileyi (Farlow) Samson produz epizootias em populações de lagarta da soja, Anticarsia gemmatalis (Huebner), controlando naturalmente a praga em determinadas condições. No entanto, a epizootia nem sempre ocorre a tempo de evitar que as populações desta praga causem dano econômico à cultura. Foi criado um modelo matemático para simular a ocorrência de N. rileyi em populações de A. gemmatalis nas lavouras de soja da Flórida, EUA. O objetivo deste trabalho foi desenvolver um sistema que integrasse esse modelo a outros modelos (fenologia da soja e da praga, interações inseto-planta e dinâmica populacional da praga), a fim de gerar simulações mais precisas no manejo da praga. Estes modelos foram construídos a partir de estudos ecológicos dos organismos envolvidos, conduzidos nas áreas de soja no Brasil. O sistema integrado foi desenvolvido com base em equações de diferenças que são processadas pelo programa STELLA, versão 5.0 Research. A avaliação do modelo em Planaltina, DF, e Londrina, PR, demonstraram que o sistema é capaz de simular a ocorrência de epizootias ou explosões populacionais da lagarta da soja. The entomopathogen fungus Nomuraea rileyi (Farlow) Samson may produce epizooties in populations of velvetbean caterpillar, Anticarsia gemmatalis (Huebner) under specific conditions. However, sometimes the epizooty does not occur in time to avoid that populations of the pest reach economic threshold level in the soybean crop. A mathematical model was created to simulate occurrence of N. rileyi on populations of A. gemmatalis in soybean crops of Florida, USA. The objective of this work was to develop a system to integrate this original model with several other models (phenology of pest and crop, insect plant interactions, and population dynamics of the pest), in order to generate more accurate simulations on the pest management. These models were developed from ecological studies involving organisms in soybean fields of Brazil. The integrated system was proposed based on equations of differences that are processed as differential equations through the software STELLA, version 5.0 Research. The evaluation of the system using data from soybean fields from Planaltina, DF, and Londrina, PR, showed that the model was able to simulate occurrence of epizooties or pest outbreaks in field conditions.

Malaria is a serious problem for public health in Brazil, affecting more than 300,000 people annually. One of the options for controlling malaria is the treatment of breeding-sites infested by this mosquitoes larvae with biopesticides based on Bacillus sphaericus . For this proposal, it is necessary to have a good way for monitoring the presence of the larvae. This study aimed to verify the possibility of colleting Anopheles larvae at any time of the day, having flexibility in terms of collection times. The results showed that it is possible to collect the larvae at any time throughout the day, but the best time is between 7:00 and 9:00h in the morning. The larvae collected were identified at the level of species, and four species were detected: A. triannulatus, A. darlingi, A. peryassui and A. albitarsis .

A field-based experimental study examined the roles of temperature and moisture in the dry-season embryonic dormancy and postdormancy hatching of the spittlebug Deois flavopicta Stal from Brazil’s dry interior region. The results show that dormancy consists of two discrete parts: an initial period of diapause that persists from April to the beginning of July, followed by a period of postdiapause quiescence that prevails until the rainy season begins (usually October). Low temperatures during the early part of the diapause period accelerates diapause development, whereas contact with liquid water determines the timing of postdiapause hatching. Soil temperatures during June and July and the relative humidity of the soil during August and September strongly affect overwintering survival and thus are important in determining the size of the nymphal population after dormancy. The findings indicate that, like hibernation and aestivation in temperate-zone insects, dry-season dormancy in tropical insects is a dynamic state that is influenced by seasonal changes in key environmental factors.

We studied the movement and feeding behavior of nymphs of the grass feeding spittlebug Deois flavopicta Stal to evaluate the role of host plant species on the spatial distribution of the nymphs. The inter- and intraplant foraging patterns of the nymphs contributed to their patchy distributions. The young nymphs, despite their weak motility, moved from the hatching spot and chose feeding sites. They tend to move less when host plants were present. Plant quality near hatching sites influenced the movement pattern of newly hatched nymphs. Egg densities at the oviposition sites did not influence the movement of newly hatched nymphs. The distribution of nymphs in relation to differences in host species and shoot age of host plant was studied in the field and in multiple choice experiments. Both young and old nymphs preferred plants of the introduced host in the genus Brachiaria over the native grass Axonopus marginatus (Trinius) Chase. The nymphs fed gregariously on buds and young shoots as first and second instars and in small groups of third, fourth, and fifth instars on old shoots of different sizes. These patterns of attack may be related to differences in tissue hardness or amino acid content between young and old shoots, and between host species. Nymphal survivorship was higher on B. ruziziensis, the preferred host plant. In addition, survivorship of newly hatched nymphs was higher on young buds and shoots compared with old shoots. The possible consequences of nymphal feeding behavior on population dynamics are discussed.

RESUMO - O efeito do movimento de adultos da cigarrinha-das-pastagens ( Deois flavopicta Stal) emsua dinâmica populacional foi avaliado em pastagens de Brachiaria ruziziensis na regiao do DistritoFederal, Brasil. Foram utilizados paineis de plastico com cola adesiva para monitorar as taxas demovimentacao. Os dados sugerem a ausencia de um padrao predominante de movimentacao em relacaoa posicao geografica das armadilhas. A ocorrencia de vegetacao baixa, semelhante as pastagens em voltada area estudada, aparentemente favoreceu a dispersao, ao passo que a ocorrencia de cerrados ou matasna vizinhanca inibiu o movimento nesta direcao e aumentou a taxa de retorno da cigarrinha as pasta-gens. O inseto se deslocou principalmente mediante saltos ou voos curtos e baixos (abaixo de 1 m).Uma proporcao aproximada de 4:1 (macho:femea) foi capturada nas armadilhas, indicando que osmachos movimentam-se mais que as femeas. A velocidade media de movimentacao, de populacoesmarcadas com po fluorescente atoxico e recapturadas apos periodos variaveis de liberacao, foi inferiora 5 m por dia. O movimento de dispersao de adultos nao contribui significativamente para a perda ourecrutamento de adultos em populacoes de D. flavopicta , a nao ser em casos de explosoes populacionaisou extincao local.Termos para indexacao: Insecta, Homoptera, Cercopidae, padrao de voo, dinâmica populacional,Deois flavopicta .MOVEMENTS OF MIGRATION AND DISPERSION OF ADULT SPITTLEBUGSABSTRACT - The effect of adults of the spittlebug ( Deois flavopicta Stal) movement in their popula-tion dynamics was evaluated in pastures of Brachiaria ruziziensis in Brasilia, DF, Brazil. Plastic panelscontaining adesive trap were used to monitorate the movement rates. The data suggest a lack of patternrelated to the geographical position of the traps. Vegetation landscapes similar to pastures fields aroundthe study area seemed to favour the dispersion, whilst Cerrados or wood vegetation in the neighbor-hood inhibted insect dispersion toward this direction and increased return rate of spittlebugs to thepasture. Spittlebugs moved mainly by short, low jumping flights (bellow 1 m). A proportion of4:1 male:female was captured in the traps, indicating that males move more than females. The move-ment of marked and recaptured populations was monitored with non-toxic fluorescent powder. Speedrates lower than 5 m/day was observed. Adult dispersion movement, apparently, does not contributesignificantly to the loss or recruitment of individuals to populations of D. flavopicta. Consequently,there is no need to consider this movement in modeling this insect population dynamics. Migration mayhave a role in this dynamics except in some cases, such as outbreaks and local extinction.Index terms: Insecta, Homoptera, Cercopidae, flight pattern, population dynamics, Deois flavopicta.

The synthetic racemic mixture of methyl 2,6,10-trimethyltridecanoate, a component of the male produced pheromone of Euschistus heros (F.) (Heteroptera, Pentatomidae), was attractive to pentatomid species in a field test, using homemade pheromone trap designs. The pentatomid Piezodorus guildinii was caught in high numbers in field traps, during two field experiments, indicating a consistent response of this species to the E. heros pheromone. A correlation was found between the range of insects caught in the pheromone-baited traps and a random sampling method. The synthetic stereoisomeric mixture of methyl 2,6,10-trimethyldodecanoate, a minor component of E. heros pheromone, was also field tested and caught no pentatomids. Egg parasitoids were caught in traps baited with E. heros pheromone, indicating that this pheromone can be exploited as a kairomone. A synchrony in the periodicity of trap catch, between the egg parasitoids and their host, was also recorded.

Males of the Neotropical brown stink bug, Euschistus heros, were attractive to conspecific females in bioassays. A synthetic stereoisomeric mixture of methyl-2,6,10-trimethyltridecanoate, previously identified and presumed as the male-produced pheromone, was confirmed to attract females. A 24 h bioassay showed the presence of a diel periodicity, where the females respond to males from noon to midnight. A still-air olfactometer assembled from commercially available food containers was used to test the attractants from E. heros.

A survey of natural enemies ofSenna obtusifolia(Leguminosae: Cesalpinaceae) was made in 46 localities in Brazil. Twenty-one preselected insect species were used in a multivariate analysis in a search for potential biocontrol agents, based on frequency of occurrence of each species, degree of insect/host association, and damage level. Insect communities were organized in a binary matrix (presence/absence of the species); measures of distance and similarities were based on the Jaccard coefficient, and cluster analysis was then conducted. Construction of a dendogram showed similarities among geographically close localities where phenological stages of sicklepod plants were similar. Analysis of correspondence based on the correlation matrix showed that Eigen values of the three first axes explain only 40.1% of the observed variation. Correlation among the scores produced by species Eigenvectors in each locality on axis 1 and the latitude, altitude, and phenological stage showed that only phenological stage was correlated (r = 0.45,P = 0.02). The results indicate that weather will not be a limiting factor for the establishment of these insect species in an environmental gradient similar to that of the surveyed area (12 to 22° latitude and 6 to 1200 m altitude). Distribution in the ordinal space of axes 1 and 2 showed thatAgrilus oceanicum(Buprestidae),Fundella argentina(Pyralidae),Thyphedanus undulatus(Hesperidae), andPhoebis sennae(Pieridae) are grouped and separated from the others in axis 2, suggesting that these species co-occur with each other. Based on their feeding guilds, multiple introduction of these species can be considered. Multivariate analysis showed potential to be used as an additional tool to help in the selection of candidates for biocontrol agents.

The objective of this work was to evaluate the potential control of the ant Pachycondyla obscuricornis Emery (Hymenoptera Formicidae) on populations of nymphs of the spittlebug, Deois flavopicta Stal (Hemiptera Cercopidae). Foraging behavior and prey consumption rate of P. obscuricornis were evaluated. Field data revealed that P. obscuricornis does not show aggressive behavior against individuals of the same species, when they are not carrying a prey; they can patrol distances larger than 10 m searching for prey, and they can build their nest as close as 1 m from each other. The ant has a solitary patrolling habit, there is no recruitment behavior, and individuals dislocate fast, browsing on soil and vegetation for prey. Predation rate on spittlebug nymphs increased relative to the spittlebug abundance, reaching 93.8% of captured prey. Pachycondyla obscuricornis is a voracious predator and may control the population of spittlebugs in cultivated pastures.