| The polistine wasp Mischocyttarus collarellus has an unusually elongate nest suspended from a short petiole. In the lowlands of Costa Rica, nests were found primarily on the undersides of tree trunks leaning 5--30° from vertical, below the canopy, usually facing south. Most nest-bearing trees had few epiphytes and either smooth or exfoliating bark; bark shedding may limit nest lifespan. 18% of nests experienced breakage, but 75% survived the event. Nest parasitoids and associates included phorids, signiphorids, and ichneumonids.; Median brood development time was 55 d, and median nest survival was 51 d. Multifounder nests were more likely to survive to offspring emergence (63%) than single-founder nests (44%). For most nests surviving to emergence, average productivity was <20 offspring. Productivity was related to nest lifespan. Overall brood loss was 60% in healthy nests.; Nest replacement after failure was common. Nests of all stages were found year-round, as were males. Marked females were recaptured on up to five successive nests and males on up to two. Recaptured females had survival times up to 351 d (median = 44) and males up to 201 d (median = 8). Existence of long-lived nest series (several >2 yr) suggests that M. collarellus has an indeterminate (perennial) colony cycle obscured by ephemerality of individual nests.; Three post-emergence nests observed each had two egg-layers that were present on the nest >80% of the time. Nests had young and old residents of both sexes. Both sexes performed nest maintenance activities. Dominance interactions and food exchanges were observed between females and males in every direction: f-f, f-m, m-f, and m-m. There was no dominance order among males, but as a group they ranked in the middle of the female hierarchy. High-ranking females dominated males. Males dominated low-ranking females much more frequently than those of high rank, and young males gave food only to high-ranking females and other males. Males were also aggressive toward nonresidents. I propose that behavior of M. collarellus males has a stabilizing effect on social hierarchy in their natal colonies. I also present a new method for quantifying interaction data, based on pairwise presence time. |
