Multiple queens in founding colonies of the neotropical ant Pachycondyla striata smith (Formicidae: Ponerinae)

Abstract

In social insects, the typical mode of colony foundation occurs when a single queen is inseminated by a male and establishes a new colony, although we can find interspecific and intraspecific variations in queen number and queen-mating frequencies in a single colony. This study aimed to verify the queen number in Pachycondyla striata (Smith) colonies and to evaluate the level of aggressiveness among workers. We collected 14 colonies of P. striata. The behaviors of individuals from five multiple-queen colonies maintained in laboratory were studied by the method of scan sampling. In order to evaluate aggressiveness, dyadic encounters among heterocolonial and homocolonial workers were performed. The results showed that colonies of P. striata can have two or more mated queens (polygynous colonies) besides to monogynous ones (colony containing one queen). Because in polygynous colonies the number of workers was relatively low, such colonies could represent colonies in the foundation phase that characterize a pleometrosis state. In fact, ovarian development analysis from queens showed that the number of queens in the colonies seemed to be unstable. Despite a few cases of oophagy (egg cannibalism), social hierarchy among queens is unclear in comparison to other Pachycondyla species. In addition, aggressiveness increased with distance among nests. Nearby colonies (less than 1 m apart) showed a low level of aggressiveness, suggesting the presence of polydomy, that is, a unique colony can occupy multiple nests. Polygyny associated to polydomy in founding colonies may confer benefits on growth and dispersion of colonies in the studied environments.

Notes on biology of Brazilian populations of ants of the Pachycondyla foetida species complex (Formicidae: Ponerinae)

“…In Pachycondyla obscuricornis Emery the destruction of unfertilized eggs (trophic eggs) by the queen and/ or workers is relatively common (Rodrigues et al, 2011). Trophic eggs (eggs that cannot develop but are used exclusively as food) are characteristically flaccid or differ in shape from reproductive eggs (Hölldobler & Wilson, 1990).…”

Ecological Drivers of Non-kin Cooperation in the Hymenoptera

“…In a closely related species, Neoponera villosa, queen cooperation has been demonstrated in the lab (Trunzer et al, 1998) and unrelated queens have been documented in field colonies (Kellner et al, 2007), strongly suggesting primary polygyny. Mature Neoponera striata Smith colonies have also been found with multiple queens, but more work is needed on queen relatedness to confirm primary polygyny (Rodrigues et al, 2011). The arboreal trap jaw ant Odontomachus hastatus has been found in colonies containing several queens and workers, but it is unknown if these queens are related (Oliveira et al, 2011).…”

Forrageamento de Pachycondyla striata Smith, 1858 (Hymenoptera: Formicidae: Ponerinae) em ambiente urbano

“…As colônias podem ser monogínicas ou poligínicas (Rodrigues, Vilela, Azevedo & Hora, 2011). Como é característico de insetos eussociais, as formigas desta espécie possuem divisão de tarefas de acordo com as castas.…”