Sexual activity in Coccinellidae (Coleoptera): a review

Abstract

Abstract. Although there are few studies of the sexual life of coccinellids these phenomena have attracted the interest of isolated groups of coccinellidologists. Probably the most important finding is that at least some coccinellid species (Adalia bipunctata and Harmonia axyridis) do not mate at random with the females prefering certain males. This phenomenon was first observed in Adalia bipunctata by Lusis and then studied in detail by Majerus, O'Donald, de Jong and others. In Japan, Harmonia axyridis was similarly studied by Osawa and Ueno. While the former author found that in this species (as in A. bipunctata) the colour of the elytra is most important in mate choice by females, the latter stresses that size and activity are important. Sperm competition is another interesting phenomenon, most often the sperm of the last male fertilizes the eggs (Ueno, Katakura). Obata and Hidaka have contributed in an important way to elucidating the function of the spermatophore in mating. The studies by Hodek and Ceryngier recorded the matura tion and regression of testicular follicles and the relation of mating activity to diapause in four coccinellid species. In contrast to females, where induction of diapause prevents maturation of ovaries, in diapausing males the tissue of testicular follicles remains active until the temperatures decrease in late autumn. Dissection of spermathecae revealed principal difference in autumn mating activity between Coccinella septempunctata, in which 40-60% of the beetles mated before hibernation and Ceratomegilla (syn. Semiadalia) undecimnotata, which does not mate in autumn.

Occurrence of Harmonia axyridis (Coleoptera: Coccinellidae) in field crops

“…It is likely that the H. axyridis adults that leave broad bean early (20/7) colonize other crops such as corn. Indeed, H. axyridis is a good flyer (Hodek et al, 1993), with a high dispersal capacity .…”

The reproductive behaviour of an aphidophagous ladybeetle, Coccinella septempunctata (Coleoptera: Coccinellidae)

“…Apart from a few reproductive aspects of C. septempunctata such as the maturation of testes (Isogai et al, 1990), mating duration (Obata & Johki, 1991) and ovipositional preference for different substrata (Isogai et al, 1990;Omkar & Srivastava, 2001), other important reproductive aspects remain unknown. The relative lack of information on the various aspects of reproduction has recently been highlighted in a review on the sexual activity in coccinellids (Hodek & Ceryngier, 2000). We therefore studied the attainment of sexual maturity, mate recognition, courtship and mating behav iour, effect of sexual status of individuals on mating dura tion and effect of one, two and multiple matings on oviposition period, fecundity and percent hatching to fill this gap in knowledge.…”

Fecundity and fertility of ladybird beetle Harmonia axyridis after prolonged cold storage

“…The higher proportions of fertilized H. axyridis females are similar to the values found in C. septempunctata (28-47 %; Ceryngier et al 1992). In Coccinella quinquepunctata L., the proportion of fertilized females was low (10 %) in September, but high (80 %) in January (Hodek and Ceryngier 2000), indicating that females mated at the overwintering sites. While most overwintering females of C. septempunctata and C. quinquepunctata belong to the new generation that mated but did not lay eggs before overwintering, many females of H. axyridis that migrate to the overwintering sites seem to belong to the early summer generation (they appear older according to their deep red elytral colour-unpublished observation) and have already reproduced.…”

“…This could explain why the overwintering females of H. axyridis have a high The females of many ladybirds need not copulate in spring to start reproduction soon after winter dormancy. However, in some species such as C. undecimnotata, no females were found to store sperm during dormancy (Hodek and Ceryngier 2000) and only a few diapausing females of Adalia bipunctata (L.) were reported to contain sperm (Arnaud et al 2001). It is notable that most unfertilized females of H. axyridis also laid some eggs after transfer to suitable conditions, but the pre-oviposition period of these virgin females was much longer and fecundity much smaller than in fertilized females.…”

“…Diapause of males of ladybirds is usually weaker than in females: males may keep active testicular follicles despite otherwise showing signs of dormancy (Hodek and Ceryngier 2000). Mating thus may occur in ladybirds both before entering overwintering shelters and after activation in spring.…”