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- Characters that differ between diploid and haploid honey bee (Apis mellifera) drones
- Matthias Herrmann1, Tina Trenzcek2, Hartmut Fahrenhorst1 and Wolf Engels1
- 1Zoologisches Institut der Universität Tübingen, Entwicklungsphysiologie,
- Auf der Morgenstelle 28, D-72076 Tübingen, Germany
- 2Institut für Allgemeine Zoologie der Universität Gießen, Zelluläre Erkennungs- und Abwehrprozesse, Stephanstr, 24, D-35390 Gießen, Germany
- Corresponding author: W. Engels
- E-mail: [email protected]
- Genet. Mol. Res. 4 (4): 624-641 (2005)
- Received March 7, 2005
- Accepted May 27, 2005
- Published October 31, 2005
ABSTRACT. Diploid males have long been considered a curiosity contradictory to the haplo-diploid mode of sex determination in the Hymenoptera. In Apis mellifera, ‘false’ diploid male larvae are eliminated by worker cannibalism immediately after hatching. A ‘cannibalism substance’ produced by diploid drone larvae to induce worker-assisted suicide has been hypothesized, but it has never been detected. Diploid drones are only removed some hours after hatching. Older larvae are evidently not regarded as ‘false males’ and instead are regularly nursed by the brood-attending worker bees. As the pheromonal cues presumably are located on the surface of newly hatched bee larvae, we extracted the cuticular secretions and analyzed their chemical composition by gas chromatograph-mass spectrometry (GC-MS) analyses. Larvae were sexed and then reared in vitro for up to three days. The GC-MS pattern that was obtained, with alkanes as the major compounds, was compared between diploid and haploid drone larvae. We also examined some physical parameters of adult drones. There was no difference between diploid and haploid males in their weight at the day of emergence. The diploid adult drones had fewer wing hooks and smaller testes. The sperm DNA content was 0.30 and 0.15 pg per nucleus, giving an exact 2:1 ratio for the gametocytes of diploid and haploid drones, respectively. Vitellogenin was found in the hemolymph of both types of imaginal drones at 5 to 6 days, with a significantly lower titer in the diploids.
Key words: Apis mellifera, Diploid and haploid drones, Vitellogenin, Larval cuticular hydrocarbons, Adult size, Sperm DNA content, Wing hooks
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