Influence of the hypogaeic army ant Dorylus (Dichthadia) laevigatus on tropical arthropod communities

Abstract

The majority of army ant species forage hypogaeically. Due to the difficulties in observing these ants, their potential influence on hypogaeic and epigaeic arthropod communities has not yet been investigated. As the first hypogaeically foraging army ant studied in detail, we attracted Dorylus laevigatus to areas monitored for their arthropod diversity. Here, for the first time, the same sites were sampled before and after an army ant raid. Furthermore, interactions between D. laevigatus and the five most common ground-nesting ant species were noted and their life-history traits compared, allowing first inferences on possible mechanisms of their coexistence. The occurrence of D. laevigatus within a study plot had no evident effect on the number of arthropod taxa or individuals collected with epigaeic and hypogaeic pitfall traps. Likewise, juvenile arthropods, which are less mobile and thus are potentially easier prey for D. laevigatus, showed no differences in their collected numbers before and after the army ant had visited a plot. However, significantly fewer ant species were collected with hypogaeic traps after D. laevigatus had been within the study plots, indicating a possible predation of D. laevigatus especially on two Pseudolasius and one Pheidole species. The five most common ground-foraging ant species demonstrated their ability to avoid, kill, and even prey on the army ant. The reaction of Lophomyrmex bedoti towards D. laevigatus indicated the former to be a potential prey species, while Pachycondyla sp. 2 showed signs of "enemy specification." Odontoponera diversus and O. transversa actively preyed on D. laevigatus, while Pheidologeton affinis fought with D. laevigatus over resources. All ant species could co-occur with D. laevigatus at palm oil baits. Adding to the differences detected in previous studies between D. laevigatus and epigaeically foraging army ant species, the occurrence of this hypogaeic army ant seems to have less devastating effects on arthropod community compositions than those of epigaeically mass raiding species.

Spatio-temporal patterns of ground-dwelling ant assemblages in a lowland rainforest in southeast Cameroon

“…Eciton) and Southeast Asia (e.g. Aenictus, Dorylus) negatively affect the litter ant community during a short time, but in the end can increase ant diversity by freeing up areas for new, incipient colonies (Franks and Bossert, 1983;Kaspari, 1996;Hirosawa et al, 2000;Berghoff et al, 2003). In Cameroon also negative correlations were found between army ant activity and both ant activity and species density in NPF, VOSF and LGF.…”

“…Another factor that structures tropical ground-dwelling ant assemblages is the raid frequency of army ants (Franks and Bossert, 1983;Kaspari, 1996;Berghoff et al, 2003;Kaspari and ODonnell, 2003). It can temporarily decrease the abundance and diversity of other ants, but recovery occurs in a relatively short time and species diversity might even increase (Franks and Bossert, 1983;Hirosawa et al, 2000;Berghoff et al, 2003).…”

“…It can temporarily decrease the abundance and diversity of other ants, but recovery occurs in a relatively short time and species diversity might even increase (Franks and Bossert, 1983;Hirosawa et al, 2000;Berghoff et al, 2003). Quantitative information on army ant raid frequency and on its effect on the ant assemblages in Afro-tropical forests is lacking.…”

Riqueza da fauna de formigas (Hymenoptera: Formicidae) que habita as camadas superficiais do solo em Seara, Santa Catarina

“…Por exemplo, alguns grupos de invertebrados como Collembola são encontrados em grande número no folhiço e podem constituir um recurso abundante para espécies especialistas, como Strumigenys e Pyramica (Brühl et al, 1998). Observações quantitativas sugerem que nas amostras de solo, outros grupos de invertebrados também foram menos abundantes em comparação com as amostras de serapilheira (observação pessoal, veja também Berghoff et al, 2003).…”

Hypogaeic pitfall traps: methodological advances and remarks to improve the sampling of a hidden ant fauna

“…Berghoff et al, 2003b). However, it was proposed as a specific technique, without the character of a standard method to sample subterranean ants.…”