A test of species–energy theory: patch occupancy and colony size in tropical rainforest litter‐nesting ants

Abstract

Species -energy theory can account for spatial variation in the abundance and community composition of animals, though the mechanisms of species -energy theory are under contention. We evaluated three competing mechanisms at the local spatial scale by conducting an in vivo light manipulation over supplemental ant nests placed in the leaf litter of a Costa Rican tropical rainforest . We found that the light environment did not alter the 10% rate of occupation of the supplemental nests, but light did alter the size of colonies and the genus-level composition of the community. Light levels in the foraging range were positively associated with colony sizes of all ants, whereas light levels directly on the nest site were predictive of the occurrence of ant genera. Colonies of specialized predators, dacetine ants, were larger in more shaded foraging environments, and the functional group of generalized myrmicines exhibited an opposite pattern, with smaller-sized colonies in response to shading. Responses of twig-dwelling ants to the light environment were most consistent with the metabolic cost hypothesis as a mechanism of species -energy theory. We found mixed support for the thermal energy availability hypothesis, and scant support for the chemical energy hypothesis, as the litter depth, a measure of prey density, was not predictive of ant responses. In summary, at the local scale, we found patterns in colony size and life history are governed by light-dependent mechanisms.

Tree diversity promotes predator but not omnivore ants in a subtropical Chinese forest

“…Shading levels of the forest floor relate closely to the cover of the shrub and canopy layers. Levings & Windsor, 1984;McGlynn et al, 2013). The cover of lower vegetation strata is known to influence epigeic ant species richness (e.g.…”

“…Ants are sensitive to both effects (e.g. Levings & Windsor, 1984;McGlynn et al, 2013). In the GNNR, the hottest time of the year coincides with the period of highest precipitation (Geißler et al, 2012), making desiccation risk less likely to have negative effects on ants.…”

How predictable are the responses of ant and dung beetle assemblages to patch and landscape attributes in fragmented tropical forest landscapes?

“…This pattern is consistent with other studies on ants (Leal et al 2012) and may be a mechanism through which fragmentationinfluences hypogeic ant species diversity. Thermal and light conditions for nesting and foraging on the ground are more optimal in more shaded areas, which appear to increase the size of litterdwelling ant colonies (Fitzgerald and Gordon 2012;McGlynn et al 2013). Accordingly, our findings suggest that, in patches, the BA of shade-tolerant trees reflects environmental conditions on the ground; greater BA therefore indirectly enhances nesting and foraging activity for a high number of species of hypogeic ants in both landscapes.…”

Diversity gradients of Neotropical freshwater fish: evidence of multiple underlying factors in human‐modified systems

“…Additional mechanisms make the link between energy availability and species richness (see Srivastava & Lawton, ; Evans et al ., ; McGlynn et al ., ). The niche breadth hypothesis (or more specialization hypothesis ; De Angelis, ; Abrams, ) could apply to fishes in reservoirs.…”