Mortalidade de larvas e pupas de Chrysomya megacephala (Fabricius) (Diptera: Calliphoridae) e seu parasitismo por microhimenópteros na cidade do Rio de Janeiro, RJ

Abstract

-Due to the importance of Chrysomya megacephala (Fabricius) as a pathogenic microoganism vector in large human agglomerations, the objective of this research was to understand the host-parasite relationship under field conditions. Third instar larvae of the fly and putrefying ground beef, replaced every seven days under the same conditions, were placed close to the litter bins, on the campus of the Institute Oswaldo Cruz/FIOCRUZ and the Rio de Janeiro Zoological Garden, Rio de Janeiro, RJ, from August 1999 to July 2000. The pupae taken to the laboratory were screened (fly emergence or not), individualized in gelatin capsules, and placed in a climatic chamber (27°C) for approximately 35 days. After this period, the number of pupae with and without parasitoid emergence was counted and the pupae without emergence were dissected. A natural mean loss of 29.6% of fly larva and pupae was detected when exposed to the external environment compared with 16.5% in the control group. An average of 5.6% of the pupae brougth from the field were parasitized, 77.6% produced flies and 16.8% had no emergence. Tachinaephagus zealandicus Ashmead was a promising natural enemy to C. megacephala, with the largest percentage of parasitized pupae (78.6%) and greater mean number of parasitoids per pupae (15.2). Pachycrepoideus vindemiae Rondani and Nasonia vitripennis (Walker) presented lower percentage of parasitism than T. zealandicus, both in IOC and in the ZOO, parasitizing 13.2% and 8.2% of the pupae, with 1.0 and 11.1 parasitoids per pupae, on average, respectively. KEY WORDS: Tachinaephagus zealandicus, Pachycrepoideus vindemiae, Nasonia vitripennis, natural loss, parasitoidism RESUMO -Devido à importância de Chrysomya megacephala (Fabricius) como vetor de microrganismos patogênicos em grandes aglomerações humanas, este trabalho teve por objetivo conhecer a mortalidade da mosca durante as fases larval e pupal e o seu parasitismo por microhimenópteros. Larvas de C. megacephala de terceiro ínstar, juntamente com seu substrato de criação (carne bovina moída putrefata), foram colocadas por sete dias próximo a lixeiras, no campus do Instituto Oswaldo Cruz /FIOCRUZ e no Jardim Zoológico do Rio de Janeiro, Rio de Janeiro, RJ, de agosto de 1999 a julho de 2000. As pupas recolhidas após o período em campo foram individualizadas em cápsulas de gelatina e mantidas em câmara climática (27°C) por aproximadamente 35 dias. Foi verificado o número de pupas com emergência de moscas, com emergência de parasitóides e pupas sem emergência, sendo as últimas dissecadas. Obteve-se mortalidade média de 29,6% durante a fase larval e pupal das moscas quando expostas ao ambiente externo, contra 16,5% do grupo controle. Das pupas trazidas do campo, 5,6% estavam parasitadas, de 77,6% emergiram moscas e de 16,8% não houve emergência. Tachinaephagus zealandicus Ashmead (Encyrtidae) mostrou-se um promissor inimigo natural de C. megacephala, com a maior percentagem de colonização das pupas parasitadas (78,6%) e maior número médio de parasitóides por pupa ...

Durations of immature stage development period of Nasonia vitripennis (Walker) (Hymenoptera: Pteromalidae) under laboratory conditions: implications for forensic entomology

“…Thus, these results are extremely important, since in natural conditions, the C. megacephala are an important forensic indicator and usually one of the first species to arrive and lay eggs on the carcasses (Andrade et al 2005). Moreover, C. megacephala species are naturally parasitized by N. vitripennis (Carvalho et al 2004). In conclusion, these results must be considered in the estimative of PMI, since the presence of these parasitoids interrupt the development cycle of calliphorids and may change, even in weeks, the determination of time of death.…”

“…These microhymenopterans can also be used in biological control programs (Mello 2007;Carvalho et al 2004) since their hosts have considerable medical and sanitary importance, being carriers of enteropathogens such as viruses, bacteria, and helminth eggs (Greenberg 1971(Greenberg , 1973, and may cause myiasis in animals and men (Hall and Wall 1995). Chrysomya megacephala (Fabricius 1798) (Diptera: Calliphoridae) is considered the natural host of N. vitripennis and is also important in forensic entomology (Smith 1986).…”

Preliminary screening of the larvicidal effect of Brevibacillus laterosporus strains against the blowfly Chrysomya megacephala(Fabricius, 1794) (Diptera: Calliphoridae)

“…Approaches for the control of populations of synanthropic Diptera species, including C. megacephala, included improvements in basic sanitation and application of chemical pesticides such as permethrin and deltamethrin (17) , plant extracts (eucalyptol) (18) , plant metabolites (neolignans) (19) , microhymenopteran parasitoids (20) , insect growth regulators (precocenes) (21) and a range of Bacillus thuringiensis strains (22) . Chemical control has been shown to be generally effective (18) , but constant application might lead to the development of resistance and produce environmental contamination.…”

Occurrence of Pachycrepoideus vindemmiae (Rondani, 1875) (Hymenoptera: Pteromalidae) as a parasitoid of Megaselia scalaris (Loew, 1866) (Diptera: Phoridae) in Brazil

“…Pachycrepoideus vindemmiae (Rondani, 1875) (Hymenoptera: Pteromalidae) is considered to be a solitary parasitoid that exercises control over a great number of Diptera in the families Anthomyiidae, Calliphoridae, Muscidae, Sarcophagidae, Tachinidae and Tephritidae. This species cosmopolitan has been found in North America and Africa (Rueda and Axtell, 1985;Marchiori et al, 2002;Marchiori et al, 2003;Carvalho et al, 2004).…”