Spatial-temporal dynamics of neotropical velvet ant (Hymenoptera: Mutillidae) communities along a forest-savanna gradient

At wide spatial-temporal scales, the role of speciation, extinction, and dispersion is more prominent, whereas at local scales community assembly is mediated by neutral processes, environmental filters, and ecological interactions. Environmental filters promote the co-occurrence of species that share suitable traits, either due to inheritance from a common ancestor or due to convergence, whereas competition acts in the opposite direction, limiting the coexistence of similar species. The integration of phylogenies with ecological data obtained at different scales is regarded as essential in contemporary studies on community assembly. However, this integration is limited by the Darwinian deficit, or the lack of knowledge on the phylogenetic relationships between species, especially in tropical regions. The identification of relevant scales for conducting studies on community assembly is a major challenge, especially in multitaxonomic approaches, given the great variation in body size, dispersal capacity, and generation time between species. Velvet ants are ectoparasitoid wasps that use larvae or pupae of other insects, mainly bees or other solitary wasps, as hosts. They can regulate host populations and play a fundamental role in ecosystem functioning. Velvet ants comprise about 4200 species distributed mainly in the tropical region. They have marked sexual dimorphism, evidenced by the usually winged males as opposed to wingless females, but also reflected in body size, pattern of setae, and coloration, which makes the taxonomy of the group complicated. The phylogenetic relationships among the major lineages of velvet ants are not well established, and virtually nothing is known about the relationships among Neotropical species. Most Neotropical velvet ants are diurnal, more active early in the morning and late in the afternoon, and seem to prefer open and dry environments. Temperature plays an essential role in the development and survival of ectothermic parasitoids, as well as on their hosts and the asynchronous pattern of population fluctuations of both. A study was conducted to examine the roles of spatial distances, microclimate parameters, and taxonomic relationships upon the structure of velvet ant communities along a forest-savanna gradient in the Cerrado of central Brazil. The study aimed to understand the response of velvet ant communities to spatial and environmental variation, to assess the role of environmental filters and interspecific interactions on the assembly of these communities. The study also aimed to determine whether the abundance and richness of velvet ants vary predictably throughout the year and along the environmental gradient, and whether velvet ants are taxonomically structured along the environmental gradient. The study was conducted over a one-year period, during which velvet ants were sampled using 25 arrays of Y-shaped pitfall traps with drift fences along an environmental gradient from cerrado sensu stricto (open canopy, warmer, drier) to cerradão (closed canopy, cooler, moister). Dataloggers installed on each trap recorded microclimate parameters throughout the study period. The effects of spatial distances, microclimate parameters, and shared ancestry on species abundances and turnover were assessed with canonical correspondence analysis, generalized dissimilarity modeling, and variance components analysis.