Heritability of multiple mating by female field crickets, Gryllus integer (Orthoptera: Gryllidae)

The heritability of multiple mating in female Gryllus integer crickets \nwas studied. Two preliminary experiments were conducted to determine when \nfemales first mate following the post-imaginal moult and to ascertain \nwhether constant exposure to males affects female mating rate. Female Q. \ninteger first mated at an average age of 3.6 days (S.D. = 2.3, Range = 0-8 \ndays) . Exposing female crickets to courting males 24 hr daily did not \nsignificantly alter mating rates from those females in contact with males \nfor only 5 hr per day. \nA heritability value of 0.690 ± 0.283 was calculated for multiple \nmating behavior in female Q. integer using a parent-offspring regression \napproach. Parental females mated between land 30 times (x 9.8, \nS . D. = 6. 6 ) and offspring matings ranged from 0 to 26 times (x 7 .3, \nS.D. = 3.4). \nMultiple mating is probably a sexually selected trait which functions \nas a mechanism of female choice and increases reproductive success through \nincreased offspring production. Classical theory suggests that traits \nintimately related with fitness should exhibit negligible heritable \nvariation. However, this study has shown that multiple mating, a trait \nclosely linked with reproductive fitness, exhibits substantial heritability. \nThese results are in concordance with a growing body of empirical evidence \nsuggesting many fitness traits in natural populations demonstrate heritabilities \nfar removed from zero. Various mechanisms which may maintain \nheritable variation for female multiple mating in wild, outbred Q. integer \npopulations are discussed.