Abstract
Normal matings of Choristoneura fumiferana (Clem.) resulted in the transfer of single, persistent spermatophores. The mean duration of copulation was 4 hours with a range from 21/2 to 81/2 hours. All the first matings of males were fertile and the spermatophores were large, while an increasing proportion of the subsequent matings were infertile and the spermatophores became progressively smaller. Only fertilized females laid normal numbers of eggs. There was no evidence to show that insemination can be accomplished without the transfer of a spermatophore. However, the presence of a spermatophore in the bursa of the female was not always indicative of successful insemination.Males mated only once within a 24-hour period; they were least responsive to females just after emergence (< 0.5 day old) and most responsive when 2 to 4 days old. Females mated most readily when < 0.5 day old and became progressively less attractive or less receptive with age. Mated females were not as attractive as unmated females.