Contrasting Responses of Wing Morphology of Three Blowfly (Diptera: Calliphoridae) Species to Competition.

Competition influences the expression of morphological, physiological, and behavioral traits and also regulates ecological and evolutionary dynamics. This study aims to identify and characterize changes in wing morphology in response to intra- and interspecific competition in three necrophagous blowfly species. Using geometric morphometry, we analyzed 3,238 wings from Lucilia sericata (Meigen, 1826), Calliphora vicina Robineau-Desvoidy, 1830, and C. vomitoria (Linnaeus, 1758) raised under cloistered and pairwise conditions. The three species reacted similarly to intraspecific competition-reducing wing size with increased competition-but displayed contrasting patterns of response to interspecific competition. Lucilia sericata displayed a directional change in wing shape in response to an interspecific competitor, while C. vicina increased the scattering of individuals across the morphospace, and C. vomitoria displayed no significant change in response to the same stimulus. Our results show that the same stimulus yields distinctive responses; thus, different competition-related strategies are expected to occur in the three species.

Structure and ultrastructure of spermatozoon in six species of Drosophilidae (Diptera).

The Drosophilidae family is formed by Brachycera Diptera distributed widely across different regions of the planet. It is composed of about 4000 species, 304 of which are found in Brazil. The objective of this work was to characterize morphologically the structure of the male internal reproductive apparatus and the ultrastructure of the spermatozoon in four Neotropical (Drosophila cardini, D. mercatorum, D. nebulosa and D. sturtevanti) and two invasive (D. simulans and Zaprionus indianus) species of drosophilids. The structural aspect of the internal reproductive apparatus corresponds with that described for other drosophilids; however, there are differences in the size and coloration of the structures, such as the testes, in each species analyzed. The spermatozoon of these species was seen to be long and fine, presenting morphological variation. The ultrastructure of the spermatozoon revealed that the morphological pattern is similar to that found in the majority of insects. The head region presents a nucleus with condensed chromatin and the acrosome positioned laterally to the nucleus. In the tail region, the axoneme presents the 9+9+2 pattern commonly described for other species of Diptera. The species presented differences regarding the shape and size of the mitochondrial derivatives. Cytochemical analysis using EPTA also revealed differences in terms of the location of the basic proteins in the mitochondrial derivates. The results obtained contribute to expanding the database for the Drosophilidae family, providing information that may contribute to intra- and inter-specific identification and supplying phylogenetic analyses.

High abundance of neotropical drosophilids (Diptera: Drosophilidae) in four cultivated areas of central Brazil.

The drosophilid assemblages of four cultivated areas (soy, bean, corn, and orange plantations) grown in the core of the Neotropical region were analyzed by comparing their abundances and compositions. The collections, which were gathered using 38 banana traps, captured 12,560 drosophilids, including nine Neotropical and six exotic species. Most of the flies were collected in the bean (43%) and soy (42%) fields. The composition and relative abundance of species also varied among cultivated areas, with orange orchards presenting the highest relative abundance of exotics due to the dominance of the Afrotropical Zaprionus indianus (Gupta). Crop plantations were dominated by a Neotropical species, Drosophila cardini (Sturtevant), which has been shown to be well adapted to dry and disturbed environments. We discuss the drosophilid assemblages of the cultivated areas, comparing them with assemblages from neighbor urban and natural environments. The low drosophilid richness found in this study is similar to the richness found in urban environments and lower than the drosophilid richness of forests, supporting a pattern already known for other taxa. The high abundance of drosophilids in cultivated areas, as well as the dominance of a Neotropical species (D. cardini) in the crop assemblages, was a surprising result.