Nest density, spatial distribution, and bionomy of Trigona spinipes (Apidae: Meliponini)

Abstract

Trigona spinipes is a generalist species of stingless bee that is dominant in many pollination networks and has a wide distribution in the tropics and subtropics of the Neotropics. This eusocial species builds exposed aerial nests in tree branches. Although some studies have been carried out on nest density, there are surprisingly few studies on its bionomy, and especially on the population size of the colonies. To survey the density and spatial patterns of nests of this stingless bee, three sites within the Northeast region in Brazil were studied, which ranged from urban to rural to forest habitats. A high density of nests was found in rural and urban sites, with 0.6 nests/ha and 0.4 nests/ha, respectively. In comparison, a lower density was found in the forest site, with 0.1 nests/ha in the edge and 0.03 nests/ha in the interior. Thus, the highest density of nests occurred in open areas. In the urban site, the nests showed a uniform distribution, while the distribution was aggregated in the rural site. The majority of nests were oriented so that the entrance faced the opposite direction to prevailing winds. Several aspects of the bionomy of 22 nests were sampled. The mean estimated total population size of colonies (immatures plus imagoes) was 38,813 (range 25,581–53,083) individuals, with 13,202 adults. Our results confirm that this species produces some of the largest colonies within the stingless bees, although lower than previously mentioned, emphasizing its importance in ecosystems of open neotropical areas.