Tarsal Contact Chemosensory Hairs of the Large White Butterfly Pieris Brassicae and Their Possible Role in Oviposition Behavior

The study identified a type of trichoid sensilla, termed "B-type" hairs, on the tarsi of the Large White butterfly, Pieris brassicae, with a higher number in females than males, particularly on the forelegs' fifth tarsomere. These B-type hairs were found to contain five receptor cells, with four functioning as contact chemoreceptors and one as a mechanoreceptor. Electrophysiological experiments suggested that these hairs played a role in detecting mustard oil glucosides, which were identified as specific chemical stimuli for oviposition behavior. The study concluded that the presence of B-type hairs was likely linked to the butterfly's oviposition selection behavior, as females did not show a significant preference among different mustard oil glucosides tested.