Proboscis sensilla in Vanessa cardui (Nymphalidae, Lepidoptera): functional morphology and significance in flower-probing |
| |
Authors: | Harald W Krenn |
| |
Institution: | Institut für Zoologie, Universit?t Wien, Althanstrasse 14, A-1090 Vienna, Austria Fax: +43 1 31 336 778; e-mail: hwkrenn@zoo.univie.ac.at, AT
|
| |
Abstract: | Morphology and distribution of the proboscis sensilla in Vanessa cardui have been investigated in order to contribute to the understanding of flower-probing behaviour in butterflies. The proboscis
has a bend region approximately one-third of the length from the base. A short tip region is characterized by rows of intake
slits leading into the food canal. Along the dorsal, lateral and ventral sides of the proboscis, sensilla trichodea, sensilla
basiconica and sensilla styloconica are distributed in varying patterns depending on their distance from the b ase. The medial
food canal bears one longitudinal row of sensilla basiconica only. The bristle-shaped sensilla trichodea are longer in the
proximal region of the proboscis and become gradually shorter towards the tip. They are most frequent in number near to the
bend region and near the beginning of the tip region. Sensilla basiconica arranged in longitudinal rows increase in number
the more distal they are on the proboscis. The tip region is characterized by rows of sensilla styloconica on the dorsal side
whereas the sensilla trichodea are mostly restricted to the ventral side. The ultrastructure suggests that the aporous sensilla
trichodea function as mechanosensilla while the uniporous sensilla basiconica act as contact chemosensilla. The sensilla styloconica
are regarded as bimodal contact chemo/mechanosensilla since their sensory cones are equipped with a single terminal pore and
a tubular body at the base. The mouthpart sensilla appear to provide tactile cues on the positioning of the proboscis and
on the degree of its insertion into a floral tube. Furthermore, they receive chemical stimuli on the availability of nectar
and on the immersion status of the food canal.
Accepted: 12 September 1997 |
| |
Keywords: | |
本文献已被 SpringerLink 等数据库收录! |
|