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United States Department of Agriculture

Agricultural Research Service

Research Project: BEE DIVERSITY AND THE DEVELOPMENT OF HEALTHY, SUSTAINABLE BEE POLLINATION SYSTEMS Title: Structural Examination of the Dufour's Gland of the Cavity-nesting Bees Osmia lignaria Say and Megachile rotundata (Fabricius) (Hymenoptera: Megachilidae)

Authors
item Pitts Singer, Theresa
item Buckner, James
item Freeman, Thomas -
item Guedot, Christelle

Submitted to: Arthropod Structure and Development
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: August 19, 2011
Publication Date: January 1, 2012
Citation: Pitts Singer, T., Buckner, J.S., Freeman, T.P., Guedot, C.N. 2012. Structural examination of the Dufour's gland of the cavity-nesting bees Osmia lignaria say and Megachile rotundata (Fabricius) (Hymenoptera: Megachilidae). Annals of the Entomological Society of America. 105(1): 103-110.

Interpretive Summary: The Dufour’s gland of two solitary cavity-nesting bees, Osmia lignaria and Megachile rotundata (Hymenoptera: Megachilidae), were examined with microscopy to determine the structure and arrangement of the gland as part of the sting apparatus. The bee Dufour’s gland is attached to the sting, and secretions from this gland are thought to be used to form a protective film on the inner linings of ground and cavity nests and also may be used to uniquely mark nest entrances. In the bees we studied, the gland was similar for both species in appearance and relative size. The end portion of the Dufour’s gland in enters into the sting bulb along with the venom duct. Within the sting bulb, the Dufour’s gland is beneath the venom duct and is longer than the venom duct. The findings presented here and elsewhere in support the hypothesis that the Dufour’s gland is the source of an individual nest recognition cue in these two bee species are: 1) the presence of a duct and exit pore at the end of the Dufour’s gland that may release a secretion, 2) the location of thick, brushy hairs that could be used to apply a secretion, 3) and the observed use of the tip of the abdomen during nest-marking. Studies of the morphology, chemistry, and function of the Dufour’s glands of other solitary bees of various bee families may prove valuable for interpreting and inferring natural and evolutionary histories of related bees and also wasps and ants.

Technical Abstract: The Dufour’s gland of two solitary cavity-nesting bees, Osmia lignaria and Megachile rotundata (Hymenoptera: Megachilidae), were examined with microscopy to determine the structure and arrangement of the gland as part of the sting apparatus. The Dufour’s glands of these two bee species are similar in appearance and relative size. Unlike the termination of the Dufour’s gland at the base of the sting in the honey bee, Apis mellifera (Apidae), the posterior portion of the Dufour’s gland in these megachilids enters into the sting bulb along with the venom duct. Within the sting bulb, the Dufour’s gland is positioned ventral to the venom duct and is longer than the venom duct. The evidential findings presented here and elsewhere in support of the hypothesis that the Dufour’s gland is the source of an individual nest recognition cue in these two bee species are: 1) the presence of a duct and exit pore at the posterior end of the Dufour’s gland that may release glandular secretion, 2) the location of thick, brushy metasomal setae and the setosa membrane that could be used to apply a secretion to a substrate, 3) and the observed dragging of the tip of the abdomen during nest-marking. Studies of the morphology, chemistry, and function of the Dufour’s glands of other solitary bees of various bee families may prove valuable for interpreting and inferring natural and evolutionary histories of Hymenoptera.

Last Modified: 11/28/2014
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