Nesting Ecology of Polistes Species (hymenoptera, Vespidae) in Urban Areas of South-western Iberian Peninsula

Abstract

Urbanization is increasing across the globe and it is recognized as a major factor affectingspecies, populations and assemblages. Although urbanization is recognized as a major threat to biodiversity, there is increasing evidence that urban habitats may play a role in conservation. The objective of this work was to verify the occurrence of Polistes species (Vespidae) and the substrates used for nesting in urban areas in south-western Iberian Peninsula. The study was carried out from March to August of 2018 in three small towns in the Llanos de Olivenza region (SW Spain). Active searching was conducted for colonies of social wasps along and for each colony that was found we identified the species, type of substrate used for nesting, height of the colony in relation to the ground level and orientation. 753 colonies of social wasps were found belonging to two species: Polistes dominula and P. gallicus.  The most used nesting substrate was clay roof tile followed by metals. The height of the nests was related to the height of the buildings on which they were built. In all the tree towns nests exposure were oriented to the SE with mean angle values oscillating between 127.42° and 140.68°. In addition, our results confirm the prediction that wasps are more abundant in less or non-urbanized areas even if they are small urban areas such as those studied in our case.