| Abstrakt: |
Abstract: We analyzed the occurrence of non-random mating in relation to body size in a natural population of the ladybird Harmonia axyridis (Pallas, 1773). Mating males were significantly larger than non-mating males in the spring generation. There was no significant difference in the size of mating and non-mating females in the spring generation or among members of either gender in the summer generation. Large males mated more frequently than medium-sized or small males only in the spring generation. Notably, large females mated less frequently than those in other size classes in the summer generation, although the difference was marginally significant, but not in the spring generation. The ratios of the gender size difference in pairs of mating individuals were significantly different among size classes of females and males in both generations. Ratio values may be indicative of the degree to which the mating success of males and/or females depends on mating behaviour (female repulsion vs. male compulsion). Large ratio values may indicate a low degree of mating success because females often refuse males and are more successful in repulsing them when the males that attempt to mate are relatively small. Conversely, when the ratio is small, male mating behaviour may be better able to overcome female refusal, thereby enhancing the degree of mating success. The behaviour that overcomes the differences in the sizes of the different sexes in mating pairs may drive size variability in both genders in natural populations. Mating success also depends on female mating preference, and the condition and activity level of males and females. |
