The mating efficiencies (the percentage of females inseminated by males) of fieldcollected and laboratory-colonized Aedes triseriatus (Say) (Diptera: Culicidae) female mosquitoes transovarially infected or uninfected with La Crosse virus (LACV) were compared. The females were placed in cages with age-matched males, and the insemination rates (number of inseminated females of the total number of females examined) were determined daily by detection of sperm in the spermathecae. LACV-infected mosquitoes typically mated earlier than uninfected mosquitoes, i.e., insemination occurred earlier after the mixing of males and females. LACV load was not correlated with increased insemination.