Spatial and temporal variation in thermal melanism in the aposematic common wasp (Vespula vulgaris) in northern Europe

摘要

Climate affects the survival and distribution of animals in various ways. Insects respond to the changing environment with shift in geographical range or with modification of phenotypic characteristics. Conspicuous melanin-based warning colouration may be a traded off against thermal melanism, as darker individuals often have a thermoregulatory advantage in cold climates. Our study focused on climate-related phenotypic adaptations in the common wasp, Vespula vulgaris, which is an important predator and plant pollinator. Wasp workers were collected from three regions in Finland (Oulu, Turku and Kuopio) using beer traps. The analyses of the individual body size, melanisation and fluctuating asymmetry (FA) of wasps from different climatic conditions revealed that thermoregulation may constrain aposematism in colder environments. Wasps from higher latitudes were darker and bigger, however this tendency was not linear and there might be some location-specific differences between coastal and continental zones. The overall FA decreased with an increase of melanisation area. Variation in temperature and rainy days in different years affected abundance and body size to some degree but long-term studies are needed to validate the association between climate and morphology of the common wasp.