Non-random mating in wild populations of polymorphic Adalia bipunctata

Abstract

SUMMARYThe nature of the factors maintaining the colour polymorphism in Adalia bipunctata has been the subject of much discussion and in some populations a tendency for the melanic morphs to mate more frequently than the nonmelanics has been reported. The morph frequencies among mating pairs in wild populations of A. bipunctata in England have been scored and analysed in order to discover whether mating between morphs is a random process. Data from the literature are also analysed in the same way and the methods of analysis adopted by earlier workers are discussed. It is concluded that mating between morphs is frequency dependent so that it is the rare morph irs the population, regardless of colour, which mates more frequently. This appears to be a further method by which the polymorphism in this species is maintained.

Sexual selection and the evolution of preferential mating in ladybirds I. Selection for high and low lines of female preference

“…The "rare male effect" so very often observed in experiments in which females are offered a choice between two different male genotypes or phenotypes will almost inevitably occur when females have specific mating preferences: rare males are preferred by a relatively greater proportion of females than common males; the selection is negatively frequency-dependent, becoming weaker as the preferred males become more common. This "rare male effect" has been observed very commonly in Drosophila (Ehrman, 1967;1970;1972;Spiess, 1968; 1969; Spiess and Ehrman, 1978), in a parasitic wasp Mormoniella vitripennis (Grant, Snyder and Glessner, 1974), in the guppy (Farr, 1977) and in the Two-spot Ladybird (Muggleton, 1979;O'Donald and Muggleton, 1979; O'Donald and Weir, l982a).…”

Sexual selection at a multiallelic locus with complete or partial dominance

“…The following examples represent polymorphisms of this sort: the mimics of the butterflies Papilio dardanus and Papilio memnon (Sheppard, 1961;Clarke et al, 1968), and Hypolimnas misippus (Smith, 1973); melanic and non-melanic forms of the moth Biston betularia (Kettlewell, 1973), of the feral pigeon (Murton et al, 1973), and of the ladybird beetle Adalia bipunctata (Hodek, 1973;Muggleton, 1978Muggleton, , 1979; shell colours of the snail Cepaea memoralis (Cain et al, 1960), and colours and * Supported in part by NIH 5R01 GM10452-17, NSF MCS79-24310 and SRC GR/B30807. 209 shell banding patterns in many other snails.…”

“…Burns (1966) showed that sexual selection may operate between morphs of Hypolimnas misippus. Muggleton (1979) and O'Donald and Muggleton (1979) showed that melanic and non-melanic morphs of Adalia bipunctata were the objects of strong sexual selection. In Adalia, the polymorphism consists of a series of morphs that can be arranged in a series of increasing melanism.…”

Sperm competition and melanic polymorphism in the 2-spot ladybird, Adalia bipunctata (Coleoptera, Coccinellidae)

“…Field data have provided evidence for different forms of sexual selection as sociated with the different colour morphs: (i) a female preference for melanic males has been described in some British populations (Majerus et at., 1982;O'Donald & Majerus, 1988; but see Kearns et al, 1990Kearns et al, , 1992; (ii) a frequency-dependent mating advantage for melanics has been recorded (Muggleton, 1979;Kearns et at., 1990); (iii) a general mating advantage to melanics over non-melanics was found in The Netherlands (Brakefield,1 984c). An understanding of the extent of sperm competition in this species is necessary to interpret the consequences of any deviation from random mating.…”