Multiple paternity and sperm competition in the sibling species Drosophila buzzatii and Drosophila koepferae

HURTADO, J.; IGLESIAS, P.P.; LIPKO, P.; HASSON, E.

MOLECULAR ECOLOGY

WILEY-BLACKWELL PUBLISHING, INC

Lugar: Oxford; Año: 2013 vol. 22 p. 5016 - 5026

0962-1083

Sperm competition (SC) is a major component of sexual selection that enhances intra-and intersexual conflicts and may trigger rapid adaptive evolution of sexual characters.The actual role of SC on rapid evolution, however, is poorly understood. Besides, therelative contribution of distinctive features of the mating system to among speciesvariation in the strength of SC remains unclear. Here, we assessed the strength of SCand mating system factors that may account for it in the closely related speciesDrosophila buzzatii and Drosophila koepferae. Our analyses reveal higher incidence ofmultiple paternity and SC risk in D. buzzatii wild-inseminated females. The estimatednumber of fathers per brood was 3.57 in D. buzzatii and 1.95 in D. koepferae. In turn,the expected proportion of females inseminated by more than one male was 0.89 inD. buzzatii and 0.58 in D. koepferae. Laboratory experiments show that this patternmay be accounted for by the faster rate of stored sperm usage observed in D. koepferaeand by the greater female remating rate exhibited by D. buzzatii. We also found thatthe male reproductive cost of SC is also higher in D. buzzatii. After a female matedwith a second male, first-mating male fertility was reduced by 71.4% in D. buzzatiiand only 33.3% in D. koepferae. Therefore, we may conclude that postmating sexualselection via SC is a stronger evolutionary force in D. buzzatii than in its sibling.