Orientador : Paulo Sergio Oliveira

Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Biologia

Resumo: Este estudo investigou a predação em grupo e o hábito migratório da formiga neotropical Pachycondyla marginata. O trabalho de campo foi realizado em floresta semidecidua, na Reserva Municipal de Santa Genebra, Campinas, SP. Um total de 202 incurses em grupo a cupinzeiros foi observado de...

Resumo: Este estudo investigou a predação em grupo e o hábito migratório da formiga neotropical Pachycondyla marginata. O trabalho de campo foi realizado em floresta semidecidua, na Reserva Municipal de Santa Genebra, Campinas, SP. Um total de 202 incurses em grupo a cupinzeiros foi observado de fevereiro de 1991 a setembro de 1993. Pachycondyla marginata predou exclusivamente cupins da espécie Neocapritermes opacus (Termitidae). As incursões ocorreram de dia e à noite, numa freqüência aproximada de uma vez a cada duas semanas, podendo durar de duas a mais de 24 horas. As colônias the P. marginata tiveram de 500 a 1500 operárias, 20% das quais estiveram envolvidas na caça. A atividade de caça na estação chuvosa foi mais intensa durante a noite. Por outro lado, o pico desta atividade na estações seca ocorreu por volta das 16:00 h. As formigas capturaram cupins operários e soldados, numa proporção média de 13:1. A distância entre o ninho de P. marginata e o cupinzeiro atacadci variou de 0~12 a 38 m e foi maior na estação seca. A remoção de partículas de solo do interior do ninho foi freqüentemente observada nas colônias de P. marginata. Esta atividade foi constante ao longo do dia na estação chuvosa, mas apresentou uma pico em torno das 16:00 h na estações seca. A porcentagem de colonias engajadas na caça ao longo do ano Ifoi mais alta na estação seca. A limpeza dos ninhos, entretanto, foi mais intensa na estações chuvosa. Migrações

Abstract: This study investigates the group-raiding behavior and migratory habit of the neotropical ant Pachycondyla marginata. Field work was carried out in the semideciduous forest of the Reserva Municipal de Santa Genebra, Campinas, SP. A total of 202 group-raid of termite nests was observed from...

Abstract: This study investigates the group-raiding behavior and migratory habit of the neotropical ant Pachycondyla marginata. Field work was carried out in the semideciduous forest of the Reserva Municipal de Santa Genebra, Campinas, SP. A total of 202 group-raid of termite nests was observed from February 1991 to September 1993. Pachycondyla marginata preyed exclusively on the termite Neocapritermes opacus (Termitidae). Raids on termite nests can occur both by day and by night, approximately every two weeks, lasting two ta 24 hours. Colonies of P. marginata contained 500 ta 1500 workers, 20% whom were engaged in hunting activity. In the rainy season, hunting activity was more intense during the night. On the other hand, the peak of hunting activity in the dry season was around 16:00 h. Worker and soldier termites were captured by the ants in an approximate proportion of 13:1. The distance between a colony of P. marginata and a target termite nest varied from 0.12 to 38 m. The removal of soil particles from the interior of the nest was frequently observed in colonies of P. marginata. This activity was constant throughout the day in the rainy season, being more frequent at 16:00 h during the dry season. The proportion of colonies engaged in hunting activity was higher during the dry season. Cleaning activity, however, was more frequent in the rainy season. Migration by colonies of P. marginata was recorded on occasions; nest relocations lasted 1-2 days and covered distances Df 2 to 97 m. Colonies relocated their nests to greater distances during the dry season. The approximate residence time Df ant colonies at a given location was 150 days. Some colonies Df P. marginata had more than one dealated 1emale and colony 1ission could occur when these reached maturity. Success Df colony foundation was approximately 43%. Group-raiding and nomadism are considered diagnostic behavioral patterns Df army-ants. The predatory and migratory behaviors Df P. marginata probably represent an early stage in the evolution Df the true army-ant habito