Social wasps in an urban fragment: seasonality and selection of nesting substrates

Abstract

ABSTRACT Harsh weather and natural enemies are the two main causes of colony abandonment by social wasps. The selection of nesting sites with characteristics that provide shelter from these threats is therefore a key factor for colony survival. Our study aimed to understand the selection and association between social wasps and nesting substrate. Data collection was carried out between February 2011 and February 2014 in an urban fragment named Jardim Botânico da Universidade Federal de Juiz de Fora, in the southeastern part of Minas Gerais. In order to assess the type of substrate used, we divided them into natural vegetative substrates and man-made substrates. Five-day sampling campaigns were carried out monthly, in which the colonies found were photographed and their distance from the ground and substrate were catalogued. Colonies were generally more abundant during the rainy season. Colonies in man-made substrates were recorded in greater frequencies in heights between two and five metres, while for vegetal substrates these heights were usually below two metres. We observed that independent-founding social wasps in an emergent ecosystem tend to nest in man-made substrates and, generally, in exotic plants, which highlights the importance of such substrates in maintaining the colonies.