Necrophagous Diptera associated with wild animal carcasses in southern Brazil. The aim of this study was to acquire a better knowledge concerning the diversity of necrophagous Diptera that develop on wild animal carcasses. For this purpose, the decomposition of six wild animal carcasses was observed in order to collect and identify the main species of necrophagous flies associated with the decomposition process. The carcasses were found on highways near the cities of Pelotas and Capão do Leão in the initial stage of decomposition, with no significant injuries or prior larval activity. Four wild animal models were represented in this study: two specimens of Didelphis albiventris Lund, 1840; two Tupinambis merianae Linnaeus, 1758; one Nothura maculosa Temminck, 1815; and one Cerdocyon thous Linnaeus, 1766. A total of 16,242 flies from 14 species were reared in the laboratory, where Muscidae presented the greatest diversity of necrophagous species. Overall, (i) carcasses with larger biomass developed a higher abundance of flies and (ii) the necrophagous community was dominated by Calliphoridae, two patterns that were predicted from published literature; and (iii) the highest diversity was observed on the smaller carcasses exposed to the lowest temperatures, a pattern that may have been caused by the absence of the generalist predator Chrysomya albiceps (Wiedemann, 1819). (iv) An UPGMA analysis revealed a similar pattern of clusters of fly communities, where the same species were structuring the groupings.

As espécies de Calliphoridae são importantes componentes das comunidades de necrófagos na Região Neotropical. Além de estarem envolvidas na degradação da matéria orgânica animal podem também veicular diversos patógenos e parasitos, bem como causar míiases primária e secundária. O padrão de ocorrência destas espécies está bem definido, mas ainda não se tem muito claramente quais fatores ambientais determinam a estrutura destas assembleias. Desenvolvemos este trabalho com o objetivo de avaliar a influência da temperatura média e umidade relativa do ar na variação da abundância e riqueza de espécies de califorídeos no sul do Rio Grande do Sul, onde a variação da temperatura é bem demarcada ao longo do ano. Para avaliar este objetivo, foram instaladas armadilhas WOT (Wind Oriented Trap) com fígado bovino como isca em três ambientes por 10 dias seguidos em cada mês, entre julho de 2003 e junho de 2004. Foram coletados 13.860 dípteros distribuídos entre 16 espécies com maior abundância de Lucilia eximia (Wiedemann, 1819) e Chrysomya albiceps (Wiedemann, 1819). A temperatura média e a umidade relativa influenciaram a variação da riqueza de espécies de califorídeos, com maior riqueza e abundância no final da primavera e inicio do verão, sendo que a abundância foi influenciada apenas pela temperatura. Cada espécie reagiu diferentemente com relação a estas variáveis, com L. eximia não sendo influenciada por nenhuma das duas, apesar da alta abundância apresentada. Este trabalho, apresenta resultados sobre a sensibilidade quanto à presença ou ausência das espécies de califorídeos e sobre a variação da abundância destas espécies sob um regime de alteração da temperatura e umidade relativa do ar com implicações para a saúde pública e manejo animal.

The blowfly species are important components in necrophagous communities of the Neotropics. Besides being involved in the degradation of animal organic matter, they may serve as vectors for pathogens and parasites, and also cause primary and secondary myiasis. The occurrence pattern of these species is well defined, yet it is still not very clear which of these environmental factors determine the structure of the assemblies. This paper was developed to evaluate the influence of mean temperature and relative humidity variation in the abundance and richness of blowflies in the Brazilian southernmost state, Rio Grande do Sul, where temperature variation is well marked throughout the year. To evaluate this objective, WOT (Wind Oriented Trap) were installed with beef liver as bait in three environments for 10 consecutive days in each month between July 2003 and June 2004. A total of 13,860 flies were collected distributed among 16 species with a higher frequency of Lucilia eximia (Wiedemann, 1819) and Chrysomya albiceps (Wiedemann, 1819). The mean temperature and relative humidity influence the richness of blowflies, with greater richness and abundance in late spring and early summer, whereas abundance was only influenced by temperature. Each species responded differently with respect to these variables, where L. eximia is not influenced by any of the two abiotic factors, despite the high abundance presented. This paper presents the results of the sensitivity for the presence or absence of species of Calliphoridae and on the variation of the abundance of these species under regime temperature changes and relative humidity with implications for public health and animal management.

The mosquito Aedes aegypti (Linnaeus, 1762) is the main vector of dengue and yellow fever viruses. Different methods have been used to control A. aegypti, including chemical and biological tools. However, chemical control can lead to a subsequent increase in the mosquitoes' insecticide resistance, and biological control represents an important method as an alternative to insecticide usage. Larvae from the Toxorhynchites genus (Diptera: Culicidae) are predators of other mosquitoes and represent a potential natural biocontrol agent of A. aegypti larvae. In the present work, A. aegypti larval survival was studied in the presence of the neotropical Toxorhynchites violaceus (Wiedemann, 1821) fourth instar larvae. Toxorhynchites violaceus consumption of A. aegypti increased during the 192 hours of the experiment and was more marked in the intervals between 96 and 120 hours and between 168 and 192 hours, when the A. aegypti survival reached 0%. During the fourth instar, T. violaceus increased its predation on A. aegypti larvae, possibly in order to increase its nutrient storage prior to pupation. Otherwise, low prey consumption can lead to a nutritional deficit for the larvae, delaying the adult's sexual development and reducing its egg production. Here we show that A. aegypti survival can be reduced by the T. violaceus fourth larvae predation under laboratory conditions

The distribution of muscid species (Diptera) in grasslands fragments of southern Brazil was assessed using null models according to three assembly rules: (a) negatively-associated distributions; (b) guild proportionality; and (c) constant body-size ratios. We built presence/absence matrices and calculated the C-score index to test negatively-associated distributions and guild proportionality based on the following algorithms: total number of fixed lines (F L), total number of fi xed columns (F C), and the effect of the average size of the populations along lines (W) for 5000 randomizations. We used null models to generate random communities that were not structured by competition and evaluated the patterns generated using three models: general, trophic guilds, and taxonomic guilds. All three assembly rules were tested in each model. The null hypothesis was corroborated in all F L X F C co-occurrence analyses. In addition, 11 analyses of the models using the W algorithm showed the same pattern observed previously. Three analyses using the W algorithm indicated that species co-occurred more frequently than expected by chance. According to analyses of co-occurrence and guild proportionality, the coexistence of muscid species is not regulated by constant body size ratios. In fl ies of the grasslands, no rule was identified. Yet, a consensus did emerge from our analyses: species co-occur more frequently than expected by chance, indicating that aggregation is a recurring phenomenon among flies with saprophagous adults and predatory larvae. Therefore, competition does not seem to play an important role in the determination of muscid assemblages in the grasslands in Southern Brazil.

Larvas de dipterous foram coletadas em carcaças de coelho-doméstico (Oryctolagus cunniculus L.) ao longo das quatro estações de 2005 no extremo-sul do Rio Grande do Sul, Brasil. As larvas foram alimentadas com carne bovina moída e acondicionadas em temperatura ambiente. O desenvolvimento de cada espécie foi acompanhado nestas condições. As espécies mais abundantes na carcaça foram Lucilia eximia (Wiedemann) e Chrysomya albiceps (Wiedemann) (Calliphoridae) em todas as estações. Os dados foram ajustados a um modelo linear da relação entre a taxa de desenvolvimento destas espécies e a temperatura média diária do ambiente. Estas duas espécies são as principais indicadoras forense no sul do Brasil. Outras espécies como Hemilucilia semidiaphana (Rondani) (Calliphoridae), Synthesiomyia nudiseta (Wulp), Muscina stabulans (Fallen) (Muscidae) e Fannia pusio (Wiedemann) (Fanniidae) foram menos importantes porque ocorreram em alta abundância em determinadas estações do ano no decorrer dos primeiros dias de decomposição.

Dipteran larvae were collected from rabbit (Oryctolagus cunniculus L.) carcasses during the four seasons in 2005 in the southernmost state of Rio Grande do Sul, Brazil. The larvae were fed ground beef at ambient temperatures following collection from carcasses. The development of each species under these conditions was estimated. The most abundant species in the carcasses were Lucilia eximia (Wiedemann) and Chrysomya albiceps (Wiedemann) (Calliphoridae), and they were found in all seasons. The data were fitted to a linear model that describes the relationship between temperature and linear developmental rating. These two species are primary forensic indicators in southern Brazil. Other species such as Hemilucilia semidiaphana (Rondani) (Calliphoridae), Synthesiomyia nudiseta (Wulp), Muscina stabulans (Fallen) (Muscidae), and Fannia pusio (Wiedemann) (Fanniidae) were forensically less important because they only occurred in high frequency in certain seasons and during the first days of carcass decomposition.

A reprodução e a sobrevivência de Synthesiomyia nudiseta (Wulp, 1883) foram estudadas entre 22 e 28ºC, UR de 70% e fotoperíodo de 12h. Os dados foram analisados através de classes de idade, tabelas de vida de fecundidade, análise de sobrevivência pela distribuição de Weibull e análise das curvas de sobrevivência através do conceito de entropia (H). A taxa intrínseca de aumento natural (r m), taxa finita de aumento (lambda), taxa de reprodução líquida (R0) e tempo médio de uma geração (T) foram 0,534; 1,7; 59,439 e 7,65 respectivamente, sugerindo rápido crescimento populacional nestas condições. Isso foi causado pela alta fecundidade, confirmando o que ocorre para esta espécie, com média de 266 ovos/fêmea e período de pré-oviposição de 10,25 dias. O modelo de Weibull demonstrou que a sobrevivência não foi constante ao longo da vida de adultos, com mortalidade pronunciada depois da quarta e quinta semanas e valores de H intermediários aos valores teóricos esperados (0,0-0,5) para os ambos sexos, demonstrando que a curva de sobrevivência é retangular (com maior impacto da mortalidade na quarta e quinta semanas após a emergência). Os resultados apresentados podem ser considerados como base para estudos pormenorizados da dinâmica e do crescimento populacional desta espécie em hábitats naturais.

The reproduction and survival of Synthesiomyia nudiseta (Wulp, 1883) were studied between 22 and 28ºC, 70% R.H. and 12h photoperiod. The raw data were analyzed based on age-class, sex life table, Weibull distribution and entropy curve (H). The intrinsic rate of increase (r m), finite rate of increase (lambda), net reproduction rate (R0) and mean generation time (T) were 0.534, 1.7, 59.439 and 7.65 respectively, suggesting fast population growth in these conditions. That is caused by the high fecundity that was confirmed for this species with mean number of eggs/female of 266 and mean preoviposition period of 10.25 days. The Weibull survival model showed that the survival was not constant throughout the adults life: the mortality rate was more pronounced after the fourth and fifth week because both sexes had H values intermediate to those theoretically expected (0.0-0.5), showing that the survival curve is rectangular (with more impact of mortality on the fourth and fifth week from pupal emergence). The presented results can be considered as base for detailed studies on dynamics and population growth of this species in natural habitats.

Aspects related to the longevity and oviposition of Ophyra albuquerquei Lopes, 1985 are studied. Males had a mean lifespan longer than females (40.24 vs. 33.15 days, respectively), while still possessing qualitative advantages during this period. Females O. albuquerquei were fed on powdered milk, fish flour, refined sugar and water, and provided fish flour and moistened sawdust for oviposition. The length of the oviposition period for females was 46.75 days, and most of the deposition of the eggs occurred in the first days of the colony. Females completed 50% of their egg deposition by Day 16, seven days before the large last mortality peak and about 12 days after the first oviposition in the colony. Females deposited an average of 184 eggs per individual. Mortality of males, unlike females, was low until the 28th day, and increased thereafter. It was demonstrated that it is possible to maintain colonies of this species under laboratory conditions for at least 28 days with high fertility and low cost.

A colony of Synthesiomyia nudiseta (WULP, 1883) was established in the laboratory to obtain eggs, larvae and puparium, to determine the period of development and viability at constant temperature with RH above 75% and photoperiod of 12 h. The viability of development cicle was 48.68%. Incubation period was 21.17 h, larvae development 25.97; 48.08 and 233.65 h for the first, second and feeding phase of third instars, respectively. The development period of postfeeding larva, prepupa and pupa development was 322.26 h.