Dry Season Migration by Costa Rican Lowland Paper Wasps to High Elevation Cold Dormancy Sites

We report observations here of aggregating behavior by social wasps in the genera Polistes and Mischocyttarus during the nonnesting phase of their colony cycle in Guanacaste Province, Costa Rica, a tropical locale with a pronounced dry season. The aggregating wasps are from many different nests, and they aggregate in a cold, high elevation habitat during the dry season, a time when they are nearly absent from the low elevation habitat where they build nests and reproduce during the rainy season. The aggregating behavior, which occurs after the wasps have seasonally migrated to the upper elevation aggregation site from the lowlands, strongly resembles that of temperate zone Polistes during winter, but it differs by the incorporation of the seasonal migration.