BIOSYSTEMATICS OF THE GENUSEUXOA(LEPIDOPTERA: NOCTUIDAE): X. INCIDENCE AND LEVEL OF MULTIPLE MATING IN NATURAL AND LABORATORY POPULATIONS

Abstract

In most species of Euxoa a high proportion of the females mate more than once. The mean number of matings per mated female in natural populations of 13 species ranged from 1.65 to 10.86. Mating frequency data for laboratory populations of three of these species indicate that laboratory rearing and confinement does not significantly alter the incidence and level of multiple mating. The propensity for multiple mating is species characteristic although the observed level in samples from the field can vary significantly depending on the age structure of the populations sampled and probably also on other parameters of populations or environmental factors. Since species differences in the tendency for multiple mating are probably manifestations of different reproductive strategies some of the possible advantages of this behavior are discussed.

Differences in mating strategies in two closely related small ermine moth species (Lepidoptera: Yponomeutidae)

“…Several studies show that female mating frequencies inferred from laboratory experiments match well with those obtained from counts of spermatophores and colla in field-collected females (Byers, 1978, Torres-Vila et al, 2001Välimäki & Kaitala, 2006). However, mating frequencies obtained from laboratory tests are expected to be overestimates, as partner encounter rates can be often much higher than in natural situations, and there are few possibilities for females to escape insisting males (Drummond, 1984, and references therein).…”

“…Few species mate only once or nearly only once, such as Erebia ligea (Nymphalidae) and Aphantopus hyperanthus (Nymphalidae; Wiklund, 1982;Svärd & Wiklund, 1989), and many mate 1-2 times (Drummond, 1984;Svärd & Wiklund, 1989). Others, such as Euxoa perolivalis (Noctuidae), mate more than ten times (Byers, 1978). Furthermore, within species, individual female mating frequencies can differ widely; for example, in laboratory experiments with Pieris napi (Pieridae) females, which had mating opportunities with non-virgin males throughout their life span (about 15 days), females mated between two and more than ten times (see Bergström et al, 2002).…”

Genital variation within and between three closely related Euxoa moth species: testing the lock‐and‐key hypothesis

“…We used three closely related Euxoa moth species as study organisms. Species of the genus Euxoa are polyandrous (Byers, 1978) and hence provide good opportunities for sexual selection. We explored whether the male genital structures of Euxoa differ enough to form safe lock‐and‐key mechanisms among three closely related, but undoubtedly biologically distinct species, which occur sympatrically on sandy meadows in coastal Finland.…”

Sexual Selection in Moths: The Role of Chemical Communication

“…Dissection of the bursa copulatrix of the female permits the number of spermatophores that she carries to be counted and, by inference, the number of matings determined. Byers (1978) found no difference in mating frequencies between samples of female noctuids collected at light traps and caged laboratory females with unlimited access to males, which suggests that laboratory experiments may approximate mating frequencies in natural populations. There is, so far, no record of multiple spermatophore transfer within a single copulation in Lepidoptera.…”

“…Thus, the most accurate estimate of lifetime mating frequencies for females can be gained by only examining the oldest, or preferably post-reproductive females, or alternatively by considering only the maximum number of spermatophores recorded for wild-caught females (Drummond, 1984). Byers (1978) found no difference in mating frequencies between samples of female noctuids collected at light traps and caged laboratory females with unlimited access to males, which suggests that laboratory experiments may approximate mating frequencies in natural populations.…”