Selection And Validation Of Reference Genes For Functional Studies In The Calliphoridae Family.

The genera Cochliomyia and Chrysomya contain both obligate and saprophagous flies, which allows the comparison of different feeding habits between closely related species. Among the different strategies for comparing these habits is the use of qPCR to investigate the expression levels of candidate genes involved in feeding behavior. To ensure an accurate measure of the levels of gene expression, it is necessary to normalize the amount of the target gene with the amount of a reference gene having a stable expression across the compared species. Since there is no universal gene that can be used as a reference in functional studies, candidate genes for qPCR data normalization were selected and validated in three Calliphoridae (Diptera) species, Cochliomyia hominivorax Coquerel, Cochliomyia macellaria Fabricius, and Chrysomya albiceps Wiedemann . The expression stability of six genes ( Actin, Gapdh, Rp49, Rps17, α -tubulin, and GstD1) was evaluated among species within the same life stage and between life stages within each species. The expression levels of Actin, Gapdh, and Rp49 were the most stable among the selected genes. These genes can be used as reliable reference genes for functional studies in Calliphoridae using similar experimental settings.

Phenotypic Polymorphism Of Chrysomya Albiceps (wiedemann) (diptera: Calliphoridae) May Lead To Species Misidentification.

Species identification is an essential step in the progress and completion of work in several areas of biological knowledge, but it is not a simple process. Due to the close phylogenetic relationship of certain species, morphological characters are not always sufficiently distinguishable. As a result, it is necessary to combine several methods of analysis that contribute to a distinct categorization of taxa. This study aimed to raise diagnostic characters, both morphological and molecular, for the correct identification of species of the genus Chrysomya (Diptera: Calliphoridae) recorded in the New World, which has continuously generated discussion about its taxonomic position over the last century. A clear example of this situation was the first record of Chrysomya rufifacies in Brazilian territory in 2012. However, the morphological polymorphism and genetic variability of Chrysomya albiceps studied here show that both species (C. rufifacies and C. albiceps) share very similar character states, leading to misidentification and subsequent registration error of species present in our territory. This conclusion is demonstrated by the authors, based on a review of the material deposited in major scientific collections in Brazil and subsequent molecular and phylogenetic analysis of these samples. Additionally, we have proposed a new taxonomic key to separate the species of Chrysomya found on the American continent, taking into account a larger number of characters beyond those available in current literature.

Competição larval em Chrysomya megacephala (F.) (Diptera: Calliphoridae): efeitos de diferentes níveis de agregação larval sobre estimativas de peso, fecundidade e investimento reprodutivo

In insects that utilize patchy and ephemeral resources for feeding and egg laying, the outcome of larval competition for food resources depends on the amount of resources and the spatial distribution of immatures among patches of food. In the present study, the results of larval competition for food in Chrysomya megacephala, in traits such as female weight, fecundity and reproductive investment, were different in situations where the level of larval aggregation (proportion of competitors per amount of food) was the same, but with densities of competitors and amounts of food proportionally different. These results are indicative that the larval competition may depend both on the larval density and the amount of food, in different situations with the same proportion of larvae per gram of food.