The Association between Body-size and Habitat-type in Tiger Beetles (Coleoptera, Cicindelidae) of Sri Lanka

Body size is an important feature of an animal that is linked with its life history, morphology, physiology and ecology. Understanding the association between body size and habitat type of an animal and the underlying causes for this are important for determining their distribution. The present study examines the association between body size and habitat types of tiger beetles in Sri Lanka and the environmental correlations for these associations. Morphometric parameters of tiger beetles and environmental parameters (air temperature, solar radiation, relative humidity, wind speed and, the colour, temperature, moisture content, pH and salinity of soil) in each habitat were recorded. Ten tiger beetle species were found from 37 locations which included coastal, riverine, urban and reservoir habitats. Species with larger body and mandible sizes prefer coastal and reservoir habitats with high wind speed, low soil moisture and high soil pH, whereas species with smaller body and mandible sizes prefer riverine habitats with low wind speed, high soil moisture and low soil pH. Species with smaller body size may also prefer urban habitats which may be due to similarity of environmental conditions that prevails in these two sites. These findings will assist in predicting the distribution of tiger beetles within various habitat types of Sri Lanka.