Predatory capacity and intraguild interaction between aphidophagous predators in the control of rose bush aphids

ABSTRACT Chrysoperla externa (Hagen) and Hippodamia convergens (Guérin-Meneville) are voracious generalist predators, and important aphid control agents. In an environment containing a complex of species, the occurrence of intraguild interactions can interfere in the predator behavior and consumption. The aim of this work was to know the number of nymphs of Rhodobium porosum (Sanderson) and Macrosiphum rosae (Linnaeus) consumed by larvae of C. externa and H. convergens, and the interaction between these predators when confined together. First, second and third instar nymphs of R. porosum and M. rosae were provided in Petri dishes containing rose leaflets and second instar larvae of the predators. Intraguild interaction was studied in Petri dishes containing first instar nymphs of both aphid species and a second instar larva of C. externa plus one of H. convergens. A third treatment consisted of dishes containing a second instar larva of both predators maintained in the absence of prey. The evaluations took place throughout the entire instar of the predators. C. externa consumed a greater number of R. porosum nymphs and H. convergens a greater number of M. rosae nymphs. For both species of prey, the highest consumption was verified on the last day of evaluation. There was a positive interaction when the predator's larvae were confined in the presence of aphid nymphs, with no mortality observed for any of them. In the absence of prey, there was 70% mortality of H. convergens larvae due to intraguild predation.

The Neuroptera of São Tomé e Principe

ABSTRACT Two new entomological surveys were carried out in the República Democrática de São Tomé e Principe in 2019 (earlier surveys were in 1956 and 2001). Of 16 species of Neuroptera identified, only one, a Mantispidae, appears endemic to the archipelago. Chrysopidae and Hemerobiidae account for the majority of species and individuals collected, concentrated here in plantations and anthropized environments, and known to be widely distributed in Africa and even worldwide. Unusually, the family Coniopterygidae is again absent, this time on natural terrains, confirming its earlier absence in 2001 on anthropized and plantation terrains. The findings and ecological distribution support the hypothesis that Hemerobiidae and Chrysopidae were introduced with cash crop cultivation, some of them as late as the 19th century. Their isolation in island environments is probably too recent to have allowed speciation mechanisms to generate endemic species in São Tomé.

Influência de diferentes cultivos e fatores climáticos na ocorrência de crisopídeos em sistema agroecológico / Influence of different crops and climate factors on the occurrence of green lacewings in agroecological system

Os insetos predadores da família Chrysopidae têm sido relatados tanto em ecossistemas naturais como nos agroecossistemas, sejam eles cultivos consorciados ou monocultivos. Porém, são escassas as informações sobre o comportamento das populações desses insetos nos agroecossistemas diversificados, como aqueles de base agroecológica. O presente trabalho teve o objetivo de determinar a riqueza de espécies de crisopídeos e avaliar a influência de diferentes cultivos agrícolas, assim como de fatores climáticos na abundância desses insetos em sistema de produção orgânica diversificada. O estudo foi conduzido de setembro de 2008 a agosto de 2009, por meio de amostragens semanais de adultos de Chrysopidae em áreas do Sistema Integrado de Produção Agroecológica, em Seropédica (RJ), cada qual com um tipo de sistema de cultivo (rotação milho-mucuna/olerícolas, cafeeiros sombreados e rotação cana-de-açúcar/pastagem de braquiária). Um total de 424 espécimes de crisopídeos foi coletado, sendo distribuídos em três espécies: Chrysoperla externa (98,1%), Ceraeochrysa cubana (1,7%) e Ceraeochrysa paraguaria (0,2%). Não houve diferença no número de adultos coletados em função dos diferentes cultivos, embora a análise de correlação evidencie que as rotações com poáceas favoreçam o aumento da sua abundância. A abundância dos crisopídeos foi influenciada pelo clima apenas no sistema de cafeeiros sombreados, sendo correlacionada negativamente com a temperatura média do ar e a com a precipitação pluvial acumulada.(AU)

The green lacewings (Chrysopidae) have been reported in natural ecosystems as well in agroecosystems, intercropping or monocropping. However, the knowledge on their behavior on different agroecosystems is scarce. The present work aimed to determine the diversity of green lacewing species and to evaluate the influence of different agricultural crops, as well as climate factors, on the abundance of these insects in an agroecologically-based organic production system. The study was conducted from September 2008 to August 2009, by performing weekly sampling of Chrysopidae adults in areas of the Integrated Production Agroecological System (SIPA) in Seropédica (RJ), each with one type of cropping system (corn-mucuna rotation/vegetable crops; shaded coffees and sugar cane/brachiaria pasture rotation). A total of 424 adult specimens were collected, belonging to three species: Chrysoperla externa (98.1%), Ceraeochrysa cubana (1.7%) and Ceraeochrysa paraguaria (0.2%). There were no differences on the number of green lacewing adults collected in the crops, although the correlation analysis showed that the crop rotations with grasses favor their abundance. The abundance of green lacewings was also influenced by the climate conditions only in the system of shaded coffees, being negatively correlated with mean air temperature and accumulated rainfall.(AU)

Efeito de diferentes dietas sobre o desenvolvimento pós-embrionário de Chrysoperla defreitasi Brooks (Neuroptera: Chrysopidae) / Effect of different diets on post-embryonic development of Chrysoperla defreitase Brooks (Neuroptera: Chrysopidae)

The post-embryonic period of the predator Chrysoperla defreitasi Brooks, fed on eggs of Sitotroga cerealella (Olivier) and Diatrea saccharalis (Fabricius) was evaluated under laboratory conditions at 25±2ºC temperature, 70±10% RU, and 14h photophase. The chrysopidae eggs wereindividualized in glass tubes and after eclosion the larvae were fed on the respective preys and maintained under controlled conditions in a climatic chamber. The experimental design used was completely randomized with 150 replications for each diet. The duration of the 1st, 2nd, and 3rd instars as well as of the pupal phase were 3.4, 2.7, 3.5, and 11.9 days, respectively, for the larvae fed on D. saccharalis and 3.6, 2.8, 2.7, and 9.3 days, respectively, when the diet provided was S. cerealella eggs. Chrysopidae larvae fed on eggs of D. saccharalis took an average of 21.5 days to complete the post-embryonicdevelopment, with 34.0% of adults emerged, while the individuals fed on S. cerealella eggs took 18.4 days in average, with 55.3% of adults emerged. Data allowed to conclude that the best diet for postembryonic development of C. defreitasi are eggs of S. cerealella, since insects fed on that diet had a shorter development period, higher viability of the three larval instars as well as of the pupal stage, producing higher number of adults.

Avaliou-se o período pós-embrionário do predador Chrysoperla defreitasi Brooksalimentada com ovos de Sitotroga cerealella (Olivier) e Diatraea saccharalis (Fabricius) em condiçõesde laboratório à temperatura de 25±2°C, UR de 70±10% e fotofase de 14h. Os ovos do crisopídeo foram individualizados em tubos de vidro e, após a eclosão, as larvas foram alimentadas com as respectivas presas e mantidas em sala climatizada, sob condições controladas. O delineamento estatístico utilizado foi inteiramente casualizado com 150 repetições para cada dieta. As durações do 1o, 2o e 3oínstar e da fase pupal foram, respectivamente, 3,4, 2,7, 3,5 e 11,9 dias para larvas alimentadas com D.saccharalis e 3,6, 2,8, 2,7 e 9,3 dias, quando a dieta oferecida foi ovos de S. cerealella. Larvas de crisopídeos alimentados com ovos de D. saccharalis levaram em média 21,5 dias para completar o desenvolvimento pós-embrionário, com 34,0% de adultos emergidos, enquanto que os alimentadoscom ovos de S. cerealella levaram 18,4 dias com 55,3% de adultos. Pode-se, pois, constatar que a melhor dieta para o desenvolvimento pós-embrionário de C. defreitasi foram os ovos de S. cerealella, sendo que insetos alimentados com esta dieta apresentaram período mais curto de desenvolvimento, maior viabilidade nos três ínstares larvais e no período pupal, produzindo maior número de adultos.