The neglected sex: male reproductive interests and sexual selection in social insects
Final Report Abstract
Ants and other social Hymenoptera exhibit a unique sex life which might allow testing predictions from sexual selection theory. For example, females produce large numbers of sterile workers before rearing sexuals and do not re-mate later in life, which at least in theory makes any male attempts to manipulate female fecundity at the cost of female longevity futile and minimizes sexual conflict. Furthermore, because of sperm limitation, males should be extremely choosy about the female they mate with. Despite of these unusual and interesting features, mating in social insects is remarkably little understood. In our project we have set out to examine and describe various aspects of the reproductive biology of the ant Leptothorax gredleri and related species. Combining chemical, genetic, histological, and behavioural approaches we documented that a) male and female sexuals are choosy at least in that they avoid mating with related individuals, which they presumably recognize through the colony-specificity of cuticular hydrocarbon patterns in both sexes, b) females are presumably capable of sperm selection, because males transfer sperm during copulation into the female's bursa copulatrix, from where it very slowly migrates into the spermatheca through an extremely narrow constriction in the spermathecal duct, c) the gelatinous spermatophore transmitted by males during copulation prevents the loss of sperm from the female's vagina but does not prevent mating with other males, d) male accessory gland proteins are conserved among species, which is in accordance with the lack of sexual conflict, e) the length of sperm cells varies between different species with the presumed extent of sperm competition.
Publications
- (2006) Mate choice in the ant Leptothorax gredleri. 99th Annual Meeting of the German Zoological Society, Münster
Oppelt A, Spitzenpfeil N, Heinze J
- (2006) Reproductive physiology of Leptothorax ants. Proceedings of XV Congress lUSSI, Washington, p 78
Oppelt A, Heinze J
- (2007) Dynamics of sperm transfer in the ant Leptothorax gredleri. Naturwissenschaften 94: 781-786
Oppelt A, Heinze J
- (2007) Male accessory gland protein patterns of Leptothorax gredleri and related ants. Meeting of Genman section of lUSSI, Schwerte
Oppelt A, Heinze J
- (2007) Sexual selection in ants - The male's part. Insect Chemical Ecology. Alnarp, Sweden
Oppelt A
- (2007): Sperm transfer in Leptothorax gredleri, Annual Meeting of the Study Group Evolutionary Biology of the German Zoological Society, Bayreuth
Oppelt A, Heinze J
- (2007): Sperm transfer in the ant Leptothorax gredleri. 2nd Central European Myrmecology Meeting, Szeged, Hungary
Oppelt A, Heinze J
- (2008) Male accessory gland protein patterns of Leptothorax gredleri (Hymenoptera: Formicidae) and related ant species. Annual Meeting of the Study Group Evolutionary Biology of the German Zoological Society, Hamburg
Oppelt A, Heinze J
- (2008) Mating biology of Leptothorax gredleri (Hymenoptera, Formicidae). International Congress of Zoology, Paris, France
Oppelt A, Hartfelder K, Heinze J
- (2008) Rapid hydrocarbon profile change in Leptothorax gredleri queens after mating. Meeting of Ethologische Gesellschaft, Regensburg
Oppelt A, Heinze J
- (2008) The significance of intercolonial variation of cuticular hydrocarbons for inbreeding avoidance in ant sexuals. Anim Behav 76:1029-1034
Oppelt A, Spitzenpfeil N, Kroiss J, Heinze J
- Mating causes rapid hydrocarbon profile changes in queens of the ant Leptothorax gredleri. Journal of Insect Physiology, Vol. 55. 2009, Issue 7, pp. 624–628.
Oppelt A, Heinze J
(See online at https://dx.doi.org/10.1016/j.jinsphys.2009.03.010)
