Apidologie 34 (2003) 577-584
DOI: 10.1051/apido:2003051

Sperm numbers in drone honeybees (Apis mellifera) depend on body size

Helge Schlüns^a, Ellen A. Schlüns^a, Job van Praagh^b and Robin F.A. Moritz<sup>a

a</sup>  Institut für Zoologie, Martin-Luther-Universität Halle-Wittenberg, Kröllwitzer Str. 44, 06099 Halle (Saale), Germany
^b  Niedersächsisches Landesinstitut für Bienenkunde Celle, Herzogin-Eleonore-Allee 5, 29221 Celle, Germany

(Received 18 October 2002; revised 14 March 2003; accepted 22 April 2003)

Abstract
The effect of drone honeybee's body size on semen production was evaluated. In the same colonies, drones were either reared in drone cells (large drones) or in worker cells (small drones). Wing lengths (size indicator) and sperm numbers of small and large drones were compared. Small drones (~13% reduced wing size) produce significantly fewer spermatozoa (  million) than normally sized drones (  million spermatozoa). There is a significant positive correlation between sperm number and wing size within the small drones and in both groups combined. In the large group alone no correlation was found. The rearing investment per spermatozoon is lower for small than for normally sized drones because small drones produce more spermatozoa in relation to their body weight. Since colonies usually produce large drones, the enhanced investment must be outweighed by a mating advantage of large drones.

Key words: Apis mellifera / spermatozoa / male size / small drone / large drone / reproductive success

Correspondence and reprints: Helge Schlüns schluens@zoologie.uni-halle.de

© INRA, EDP Sciences, DIB, AGIB 2003