Fugitive species in a harlequin environment: Ants (Hymenoptera : Formicidae) and banana baits in the Amazon

A total of 9 ant species were sampled from four sites covering 2000 km in the Amazon Basin using banana fruit baits: two sites on the Jurua River, one site on the Xingu River and in a dry forest of eastern Amazon, Paragominas. Camponotus abdominalis was present in all sites, and Camponotus sericeiventris, Camponotus sp. and Crematogaster sp. were present in two sites. All other species were present in only one site. Paragominas had the highest species richness because of a higher number of site restricted species. However, Jaccard faunas similarities among sites were not significantly related with distance between sites. Mosaic diversity showed a relatively simple taxonomic composition. The strong differences of the fauna sampled at banana fruit baits from other reported Neotropical ant faunas suggests that the fauna represents widespread fugitive species in an apparently complex environment

FUNCTIONAL POLYGYNY, AGONISTIC INTERACTIONS AND REPRODUCTIVE DOMINANCE IN THE NEOTROPICAL ANT ODONTOMACHUS-CHELIFER (HYMENOPTERA, FORMICIDAE, PONERINAE)

Intracolony aggression among dealated queens of the ponerine ant Odontomachus chelifer leads to a dominance order within the colony. Behavioral domination between queens entails an array of stereotyped displays which may escalate from vigorous antennation bouts to full mandibular strikes. In extreme situations a dominant queen may also suspend her subordinate opponent, who remains in pupal posture while being lifted up. As a rule the individual initiating a contest normally wins it. Subordinate queens may assume a crouching posture at the approach of a dominant nestmate from behind, a fact suggesting that chemical cues may also play a role in the establishment of the dominance order. Behavioral performances during domination contests and the rank position of different dealated queens correlated well with the data on individual egg production, ovarian development and other parameters of division of labor within the colony. Therefore, highly-ranked queens laid more eggs, had better developed ovaries and engaged less frequently in foraging activities outside the nest. Inseminated queens occupied the top positions in the dominance structure of the colony, and accounted for most of the aggressive interactions recorded within the nest tubes. Aggression toward egg-laying queens and the destruction of newly-laid eggs were conspicuous behavioral traits in the reproductive dominance of the O. chelifer colony. High ranking dealated queens were also the ones more frequently seen attacking alate females. The latter were observed to lay eggs, and some of them had developed ovaries. Our results with Odontomachus chelifer are in accordance with the data obtained elsewhere for other ponerine ants, and provide the first demonstration of a dominance structure linked to reproductive status among queens in a functionally polygynous ant colony.91213414