Contribution
Zur Funktion der Mundwerkzeuge von Schwebfliegen bei der Nahrungsaufnahme (Diptera: Syrphidae)
[Functional Analysis of the Mouth parts of Hover-flies when Feeding (Diptera: Syrphidae)]
Schuhmacher, Helmut; Hoffmann, Heinz
Entomologia Generalis Volume 7 Number 4 (1982), p. 327 - 342
13 références bibliographiques
publié: Jun 30, 1982
DOI: 10.1127/entom.gen/7/1982/327
ArtNo. ESP146000704006, Prix: 29.00 €
Abstract
In the proboscis of Syrphidae, the inner surface of the labellum shows various cuticular structures which are essential for the uptake of food: an underlying system of pseudotracheal channels and a system of food-furrows lying above. The first is formed by a sclerotisized cuticula, the latter by soft interpseudotracheal folds. These can only be recognized in the living animal, where they protrude to form food-furrows or, when the labella are put together, food-tubes. When the labella are spread and pressed against the substrate, nectar is sucked in along these furrows. Dry pollen grains are tabbed with the inner labellar surface and passed into the food-furrows by twisting movements of the labella. Simultaneously saliva, ejected from the tip of the hypopharynx, becomes dispersed in the pseudotracheal channels from where it exudes through longitudinal slits into the food-furrow. There, the saliva is sucked to the proximal bases of the labella, taking with it the suspended pollen. The movement of the fluid food is effected by 3 pump stations, the sucking and pressing phases of which enhance each other: (1) The prelabral pump is effective in the food-furrows, drawing the food to the distal end of the labrum-hypopharynx tube. (2) From there the labral pump passes the food in small portions towards the cibarium, where (3) the cibarial pump conveys it into the pharynx. The diameter of the food-furrows seems to be adapted to a specific pollen size (20—40 µm). Chemoreceptors at the inner surface of the labellum are similar to the interpseudotracheal organs of Calliphora.
Mots-clefs
mouthpart • hover-fly