Morfologia e evolução em vespas parasitoides (Hymenoptera: Chalcididae: Chalcidinae)

Abstract

Parasitoids are organisms that exploit a single host, obtaining from him all the needed resources for survival and development, eventually resulting in the host death. Parasitoidism is an evolutionary strategy of great success, present in at least 10% of described insect species. Hymenoptera is one of the megadiverse Holometabola orders, with more than 146 000 described species. Parasitoidism evolved at least once in the evolutionary history of the order, and is present in half of its species. One of the major lineages of parasitoid Hymenoptera is Chalcididae, divided in eight subfamilies, with Chalcidinae among them. Chalcidinae are mainly present in the New World, with the majority of its biodiversity at the Neotropical Region. The Chalcidinae are represented by six genera: Stenosmicra, Melanosmicra, Chalcis, Corumbichalcis, Pilismicra, and Conura, with circa 400 described species. There are known hosts for two genera. Chalcis has a specificity for soldier flies (Diptera: Stratiomyidae), while Conura has a diversified host range, acting as parasitoids and hyperparasitoids. This heterogeneous host range is accompanied by a great morphological diversity, unique among the Chalcididae. As morphology is intrinsically connected to biological functions, this raises the question of what is the association between shape and function in the Chalcidinae. In the Chapter 1, a revised and updated world catalog of biological interactions of the Chalcidinae with their hosts is provided, with 105 species of Chalcidinae and 412 different host taxa, summing up to 2 581 records. 127 records are for Chalcidinae and plants. Of the 2 708 records, 105 are new. In the Chapter 2, this knowledge is applied to build a classification of taxonomic guilds for the Chalcidinae, according to how they explore their hosts, and its relationship to body shape, represented by the head, mesosoma and metatibia, through a geometric morphometrics approach. Head and mesosoma shape displayed considerable variation, while metatibia was quite invariant. Chalcidinae presented a moderate morphological structuring when taxonomy was considered, and a tenuous pattern for the ecology. Parasite-host interactions alone do not explain the shape diversity. Size is of little influence on shape. The dissociation between taxonomic and ecological groupings suggest that the species groups of Conura lacks a host range specialization. Furthermore, it suggests that similar shapes between its species are products of convergent evolution.