Morphometry and eye morphology in three species of Carabus (Coleoptera: Carabidae) in relation to habitat demands

Morphological features of three common European olfactory hunting carabid beetles, Carabus coriaceus mediterraneus Born, 1906, Carabus lefebvrei Dejean, 1826 and Carabus preslii neumeyeri Schaum, 1856, were compared. According to eye measurements, the three species are nocturnal and/or twilight hunters. They differ, however, in relative length of the antennae, relative surface area of the compound eyes, density of ommatidia and relative head width. These differences can be correlated with the species-specific habitat demands (light intensity, open land or shaded places). In particular, the greater lateral eye protrusion in C. lefebvrei corresponds to its tree-climbing habits, while the larger relative eye surface area and ommatidia density in C. coriaceus correspond to its choice of open habitats.