MEd Student (Adv. Harald Krenn)

Unit for Integrative Zoology, Department of Evolutionary Biology
University of Vienna

Abstract

Colletidae are short-tongued bees. In contrast to long-tongued bees, the glossa and the labial palpi are not elongated and the second one do not form a tube.

Their mouthparts are unique among the bees and because of its broad, short, bilobed shape their glossa looks similar to those of Vespidae. Also, the mandibles are described as looking ancestral. Colletes use their glossa to line the brood cells with a cellophane-like structure, which gave them their name plasterer bee or german name Seidenbienen.

Colletes cunicularius is one of the 21 domestic bees of the genus Colletes and flies from march to may and prefers pollen from Salix but is described as polylectic. The present study examines the morphology and function of the mouthparts of this bee. The underlying questions relate to which parts form the proboscis, what kind of sensilla and structures characterize them and if there are differences between the male and the female mouthparts, since only the females use the glossa for breeding. There will also be a focus on the differences in the mouthparts compared to other short-tongued bees. For answering these questions, lightmicroscopy and REM were used. The results show that the proboscis is formed by the labiomaxillarcomplex. The mandibles can be described as slender and bidental. They have different kinds of sensilla in grooves on the outer surface. The inner surface needs to be further investigated. One maxilla consists of cardo, stipes, a maxillary palpus with six segments and the galea. The galea can be described to be parted in three segments. An upper, prepalpal part and a lower, postpalpal part, between which the galea can be folded, and the galeal velum, which owns no sensilla. On the inner surface, the galea owns a comb. The labium consists of the paired cardo, the single lorum and mentum, the single prementum, the paired labial palps that have four segments, the paired paraglossae that enclose the single, bifid glossa. When not fully extended, the glossa can be folded under the galea. The paraglossa hat a basal sclerite that owns a comb whose long sensilla stretch over the glossa. The glossa owns a variety of different sensilla, which need to be examined in greater detail. The so far examined glossae did not always look alike. The different types of sensilla still have to be determined.

As other studies already described differences between male and female are little and were only found in the size of the mouthparts, but not concerning their structure.