Efeitos da orfandade sobre o comportamento e longevidade de operárias de Scaptotrigona aff. postica (Hymenoptera: Apidae, Meliponini)

Abstract

The death of the physogastric queen may imply the behavioral disorganization of eusocial bees workers, where they can assume diverse reproductive and behavioral strategies. For the worker longevity is related to the physiological effort exerted during their lifetime, but the colony's internal conditions also affect longevity, such as the presence or absence of a queen. In this sense, the objective of the study was to study the behavior and longevity of the population of stingless bee workers in orphaned colonies, comparing them with colonies with the present laying queen. In this sense, the objective of the study was to study the behavior and longevity of the population of stingless bee workers in orphaned colonies, comparing them with colonies with the present physogastric queen. For this, eight colonies of Scaptotrigona aff. postica were used, of those eight there were four colonies with a queen and four without a queen. Each colony had a total of 1.200 workers marked with different colors by day of birth (age zero), thus obtaining age groups. For 100 days, we observed the colonial foraging activity, the age of the workers who attending brood cells, age of foraging and longevity in all colonies, queenright (QR) and queenless (QL). Over time in QR colonies the foraging activity decreased slightly; however, the QL colonies presented a greater reduction in the number of foragers (X2 = 48.874; df = 1; p <0.001). In orphaned colonies we observe that over time, besides the young workers, the older workers also construct the brood cells; in the colonies with queen, the workers who participated in the construction of new brood cells were only those of young age (X2 = 116.11, df = 1, p < 0.001). In both colonies, QR and QL, the age of foraging increased over time, but in QL colonies we observed foragers with very advanced age (X2 = 66.546; df = 1; p < 0.001). The maximum longevity found for colonies workers with queen was 54 days of age and for orphaned workers was 79 days of age. Kaplan-Meier survival curves indicated significant differences between colonies QR and QL (p < 0.001). Thus, we conclude that (1) workers of S. aff. postica in colonies without queen actually decrease the external activity over time; (2) advanced orphan female workers continue to perform breeding cell construction, probably to try to produce males; (3) it is possible that the workers QL colonies start to avoid the foraging and perform this task only occasionally or they tend to perform this activity later; (4) the selfish behavior of reproducing itself, avoiding foraging and its risks, and thus staying longer in the colony can prolong the longevity of S. aff. postica in orphaned colonies.