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 arthropod 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 mitogenomes, 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.

Natural enemy conservation is known to be affected by ecological processes that range from local to landscape scales. At the farm scale, there are cropped and noncropped areas that differ in their management and plant diversity; these differences affect the spatiotemporal dynamics of natural enemies. We investigated how different habitat types can affect the conservation and spatial dynamics of predatory and herbivore insects in organic vegetable crops in Brazil. Insects were simultaneously sampled in two cropped (focal and neighbourhood crops) and two noncropped habitats (fallow and native forests) during five consecutive focal crop cycles. We found a higher species richness of predators and herbivores in noncropped habitats. All of the habitats shared species from both functional groups throughout the year, indicating that species could disperse among habitats. Fallow areas can serve as a source and sink for species migrating to/from cropped habitats where predators and herbivores can numerically increase their populations during the crop cycles. The spatiotemporal dynamics of herbivores and predators depend on the management and maintenance of natural, seminatural and cropped habitats within the farm.

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-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.Index terms: Anthonomus grandis, Gossypium hirsutum, alternative food, cotton bolls. Padrão de sobrevivência do bicudo-do-algodoeiro durante o pousio na região Centro-Oeste do BrasilResumo -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 totalizaram 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.Termos para indexação: Anthonomus grandis, Gossypium hirsutum, alimento alternativo, maças ...

Algumas espécies de forídeos do gênero Neodohrniphora Malloch, 1914 ovopositam na cabeça das operárias de Atta sexdens rubropilosa Forel, 1908 durante o forrageamento (Tonhasca 1996, Bragança et al. 1998, Brown 2001. A freqüência do parasitoidismo desta saúva por espécies de Neodohrniphora spp. é normalmente baixa (cerca de 2%) (Bragança et al. 1998). Todavia, os ataques destas moscas, em campo e laboratório, alteram o ritmo de forrageamento das operárias, reduzindo o número e tamanho dos indivíduos presentes nas trilhas e aumentando o abandono de fragmentos vegetais (Tonhasca 1996, Bragança et al. 1998 This suggests that these two Neodohrniphora species are not active in the field during the night (darkness) and that visual stimulus could be an essential component to the location and recognition of the host.