Parasitoids of the endangered leafcutter ant Atta robusta Borgmeier in urban and natural areas

Abstract

ABSTRACT. Parasitoids of the endangered leafcutter ant Atta robusta Borgmeier in urban and natural areas. Hosts of parasitoids in urban areas may suffer from a double threat of habitat destruction by urbanization and parasitism pressure. Moreover, the parasitoids themselves might be at risk if they are specialists. Here, we studied whether Atta robusta (Hymenoptera, Formicidae), which is on the red list of Brazilian threatened species, suffers from higher parasitism pressure in an urban area compared to a natural one. In addition, we determined whether their specialist parasitoids, Eibesfeldtphora breviloba and Myrmosicarius exrobusta (Diptera, Phoridae), are in risk and evaluated whether they are influenced by habitat structure, temperature, humidity, ant traffic, and time of the day. The study was carried out in an urban park and in a natural protected area in the city of Rio de Janeiro. In each site we chose an open area and a closed area (forest) and sampled nine nests in each area. We found that parasitism pressure was similar in urban and natural areas, with the same two parasitoid species present in both areas. The main difference was related to habitat structure, since M. exrobusta was mainly present in open areas while E. breviloba was almost exclusively found in closed areas. Myrmosicarius exrobusta was not present during the hottest midday times, and its abundance was negatively correlated to vapor pressure deficit. These results suggest that green areas can be an important component in efforts to conserve diversity in urban areas. However, the complexity of the habitats in those areas is a fundamental issue in designing urban parks.

Phorid parasitoids of the leaf‐cutting ant Atta laevigata in the Atlantic Forest: occurrence, parasitism rate, and host size

“…The phorids E. bragancai, E. erthali, E. declinata, A. vicosae, and M. grandicornis were collected near foraging trails and nest hole entrances of A. laevigata at an Atlantic Forest site. The abundant phorid genus in the was Eibesfeldtphora, which was also reported to be the most abundant near Atta sexdens (L.) nests in the Atlantic Forest (Galvão et al, 2019) and Atta robusta Borgmeier nests in the Restinga biome (Gomes et al, 2013).…”

Parasitism of the leaf‐cutting ant Atta bisphaerica by phorid flies: biology and seasonal and inter‐colonial parasitism rates

“…The number and distribution of parasitoid species is not influenced by the geographic location of the colonies when the colonies are located in natural habitats with predominantly dicots or in natural or cultivated habitats with a predominance of monocots (Bragança & Medeiros, 2006; Guillade & Folgarait, 2011; Brown et al, 2012; Bragança et al, 2016; Arruda et al, 2019). However, the parasitism rate may vary between colonies at different sites and even in similar locations, possibly depending on the habitat structure (Gomes et al, 2013; Arruda et al, 2019). This could be due to the characteristics of host plants available for foraging in some settings that influence the flow and size of ants on their trails and, as a consequence, the behavior of flies that are waiting to attack these ants (Farder‐Gomes et al, 2017; Tonhasca & Bragança, 2000).…”

Parasitoids of Acromyrmex (Hymenoptera: Formicidae) Leaf-Cutting Ants in Continuous and Fragmented Atlantic Forest

“…Several studies have shown the negative effect that habitat fragmentation has on parasitoids, both in tropical and nontropical areas (see Tscharntke et al, 2002 for a review;Cagnolo et al, 2009). In addition, parasitoids will be more susceptible to habitat fragmentation because of their narrow host range, as most of them are specialist, developing on few hosts only (Godfray, 1994). It has been proposed that species with narrower niches are more affected than generalists by fragmentation of their habitat (Henle et al, 2004;Cagnolo et al, 2009).…”