Females prefer to associate with males with longer intromittent organs in mosquitofish.
Sexual selection is a major force behind the rapid evolution of male genital morphology among species. Most within-species studies have focused on sexual selection on male genital traits owing to events during or after copulation that increase a male's share of paternity. Very little attention has been given to whether genitalia are visual signals that cause males to vary in their attractiveness to females and are therefore under pre-copulatory sexual selection. Here we show that, on average, female eastern mosquitofish Gambusia holbrooki spent more time in association with males who received only a slight reduction in the length of the intromittent organ ('gonopodium') than males that received a greater reduction. This preference was, however, only expressed when females chose between two large males; for small males, there was no effect of genital size on female association time.
Kahn
Andrew T
AT
Research School of Biology, The Australian National University, , Canberra, Australian Capital Territory 0200, Australia. andrew.kahn@anu.edu.au
Mautz
Brian
B
Jennions
Michael D
MD
D000704:Analysis of Variance; D000818:Animals; D020958:Australian Capital Territory; D005075:Biological Evolution; D049628:Body Size; D003532:Cyprinodontiformes / Q000033:anatomy & histology / Q000502:physiology*; D005260:Female; D005837:Genitalia, Male / Q000033:anatomy & histology*; D008297:Male; D052586:Mating Preference, Animal / Q000502:physiology*; D009929:Organ Size / Q000502:physiology