Several studies have focused on understanding the biochemistry and morphology of the fat body of the hematophagous mosquito Aedes aegypti (L.) (Diptera: Culicidae). In contrast, few studies, if any, have focused on morphological characters of the fat body in other mosquitoes, especially non-hematophagous taxa such as the culicid Toxorhynchites. Larvae of Toxorhynchites prey upon the larvae of other mosquito species and are used in vector mosquito control. We investigated aspects of the fat body trophocytes, including the morphometric analyses of the lipid droplets, protein granules and nuclei, during Toxorhynchites theobaldi (Dyar & Knab) post-embryonic development. Following the body weight increase from larval stage L2 to L4, the size of lipid droplets within the trophocytes also increase, and are likely the result of lipogenesis. Lipid droplets decrease in size during L4 to the female pupal stage and increase once again during the period from newly-emerged to mature adult females. Protein granules are observed for the first time in female pupae, and their appearance might be related to protein storage during metamorphosis. The size of the nucleus of trophocytes also increases during larval development, followed by a decrease during metamorphosis and an additional increase as adult female ages. In conclusion, the morphology of the fat body of T. theobaldi changes according to the developmental stage. Our study provides for the first time important insights into T. theobaldi fat body development and contributes to understand this species biology.

No abstract

First record of genus Toxorhynchites Theobald (Diptera, Culicidae) in Mata Atlântica,

Variation of Aedes aegypti Larvae Predation by Toxorhynchites violaceus Larvae (Diptera: Culicidae) According to Habitats Dimensions ABSTRACT -Non-biodegradable containers that accumulate water are commonly found in urban environment, and make ease the larval development of Aedes aegypti mosquito, which can make chemical control very difficult and less effective. Biological control is an alternative method, and the predators larvae of the genre Toxorhynchites (Diptera: Culicidae) are a model widely used. In this article we check the effect of habitat heterogeneity on Ae. aegypti larvae predation by larvae of Toxorhynchites violaceus. The predation model defines that the habitat heterogeneity has a significant effect on predation level. Larvae suffers a higher predation in containers with 1.8 centimeters in high of the water column than in containers with 4 and 13.4 centimeters high. In large containers, the predation of Ae. aegypti larvae by Tx. violaceus larvae may not be efficient. However, in containers that accumulate small water volume, as in the majority of the non-biodegradable containers, the model may be efficient.KEY WORDS -Toxorhynchites, containers, heterogeneity, Ae. aegypti.RESUMO -Recipientes não biodegradáveis que acumulam água espalham-se pelo ambiente urbano e favorece o desenvolvimento larval do mosquito Aedes aegypti, o que aliado a outras questões torna o controle químico larval difícil e/ou pouco efetivo. O controle biológico é um método alternativo e um modelo já utilizado são larvas predadoras do gênero Toxorhynchites (Diptera: Culicidae). O efeito da altura da coluna d'água e área da superfície utilizada para respiração sobre a predação de larvas de Ae. aegypti por larvas de Tx. violaceus foi avaliado. O modelo de predação obtido determina que a variação da altura da coluna d'água e área da superfície de respiração afeta significativamente a predação. Larvas de Ae. aegypti são mais predadas em recipientes com coluna de água de 1,8cm, do que em recipientes com colunas de 13,4 cm e 4,0 cm, a medida que se aumenta a superfície utilizada para respiração. Segundo o modelo obtido, em grandes recipientes, aqueles com grandes medidas para altura de coluna d'água e superfície de respiração, a predação de larvas de Ae. aegypti por larvas de Tx. violaceus pode não ser eficiente. Já em recipientes que acumulam pequeno volume de água como a maioria dos recipientes não biodegradáveis, o modelo sugere que a predação possa ser eficiente.