Heritable variation for female remating in Lobesia botrana, a usually monandrous moth

The occurrence of heritable variation for polyandry in the usually monandrous moth Lobesia botrana Den. and Schiff. (Lepidoptera: Tortricidae) was studied in the laboratory, using isofemale lines, a selection experiment and F₁ and F₂ crosses between the selected line (S) and an unselected control line (C). We assessed polyandry by observing the frequency of recalling in once mated females (i.e. the frequency of females resuming calling after mating). Polyandry differed significantly between isofemale lines, ranging from 0 to 100% in a normal distribution. Heritability of polyandry ±SE, estimated as a threshold trait using a full-sib design, wash² =0.40±0.12. Artificial selection for polyandry resulted in a significant increase from 32 to 65% in which a plateau occurred. Realized heritability in the first and second generations of selection yielded estimates ofh² =0.41 and h²=0.53, respectively. We also found a concomitant, significant increase in matings per female. In the sixth generation (S line), when only females that had mated more than twice were used as parents, polyandry rose again from 65 to 80%. Results from F₁ crosses supported the hypothesis that polyandry was recessive and autosomally inherited. Cavalli's joint scaling test confirmed these results, yielding values ±SE ofd =0.18±0.03 and h=−0.16±0.05. Observed and expected frequencies of polyandry in F₂ fitted significantly under the hypothesis of a two-loci model. The underlying implications of heritable variation in polyandry in a usually monandrous species are outlined, from an evolutionary perspective, in the context of the adaptive significance of this aspect of insect mating systems. Copyright 2002 The Association for the Study of Animal Behaviour. Published by Elsevier Science Ltd. All rights reserved.