The ultrastructure and distribution of sensilla on the labial palps of a myrmecophagous
carabid beetle, Siagona europaea, were investigated using scanning
and transmission electron microscopy techniques. Five types of sensilla were
identified: three types of sensilla basiconica on the apical sensory area and two
types, one sensillum trichodeum and one coeloconicum, on the external palp
surface. On morphological grounds, the s. basiconica type 1 were considered as
olfactory, the type 2 as gustatory, the type 3 and the s. trichodeum as mechanoreceptive,
and the s. coeloconicum as a thermo⁄ hygroreceptor. Their function is
discussed in relation to prey detection and habitat adaptations
