Biology of the striped chafer,Odontria striata(Coleoptera: Scarabaeidae) I. The adult, flight and ground surface activity, female reproductive maturation, and food-plant selection

Abstract

Aspects of the biology of Odontria striata White included in this report are seasonal activity patterns, female reproductive development, and food-plant selection by adult beetles. Observations made during flights are noted. Flight activity commenced 30 min after sunset and lasted approximately 30 min; it was shown to be closely linked with air temperature, and a dusk temperature threshold of 6-rC is suggested. Major flight periods were found to occur during April-May (soon after eclosion) and again in August-September. Males predominated in light-trap catches; females never exceeded 20% of the total. Pitfall trapping revealed autumn and spring peaks in above-ground activity. In March, males were predominant in pitfall trap catches; through April and May females outnumbered males by 2:1 or more, but in spring and summer the sex ratio was normally closer to unity. Reasons for this pattern and exceptions to it are discussed. The female reproductive system and timing of ovary maturation are described. Ageing by reference to the degree of wear on the galeal teeth of the maxillae revealed a clear generation overlap during March-May 1980 and a less evident one the following autumn. Females were examined for presence of plant material in the crop and degree of crop distension, size of ovaries and bursa copulatrix, incidence and size of spermatophores, and numbers of mature eggs in the ovarian calyces. A small peak of mating activity in May was followed by a larger peak in August, but full maturity and fecundity were not attained until late September. Mating and egg maturation continued until late January. Analysis of crop contents of females revealed that several pasture plant species were ingested, but not necessarily in proportion to their availability in the pasture sward. Agrostis tenuis, Holcus lanatus, and Trifolium repens were favoured food plants.

Activity patterns and population characteristics of the New Zealand endemic Cromwell chafer,Prodontria lewisii(Scarabaeidae; Melolonthinae)

“…However, there is no clear trend of increase towards a peak. This is contrary to findings for the striped chafer (Odontria striata), for which peak flight activity was recorded during the summer months (Barratt & Campbell 1982). If individual chafers emerge and disappear at different times, individual activity budgets have to be equal to maintain the activity indices recorded during the spring and summer months.…”

The female reproductive system ofCostelytra zealandica(White) (Coleoptera: Scarabaeidae: Melolonthinae)

“…(Dajoz 1972). Less detail is provided by Barratt & Campbell (1982) for Odonlria striata White (Melolonthinae), Hardy (1981) for Adoryphorus couloni (Burmeister) (Dynastinae), Krause (1947) for Passalus cornutus F. (Passalidae), Lopez-Guerrero & Blume (1983) for 0 nt hophag us gazella F. (Scarabaeinae), TyndaleBiscoe (1978) for Euoniticellus intermedius (Reiche) (Scarabaeinae), and Watt (1971) for Prodontria longitarsis (Broun) (Melolonthinae).…”

Gross features of the alimentary canal and reproduction organs inProdontria lewisii(Coleoptera: Scarabaeidae: Melolonthinae)

“…Ovary maturation in the specimens we examined followed a similar sequence to that described in Heteronychus arator by Mercer & King (1976). Ovaries increased in size with maturation, and produced progressively more eggs of both A-and B-types, as in other scarabs including Costelytra zealandica (Fenemore 1971), Phyllopertha horticola (Milne 1959), Accrosidius tasmaniae (Maelzer 1961) and Odontria striata (Barratt & Campbell 1982).…”

“…The presence of a spermatophore in the bursa copulatrix indicated that in this study only females with mature ovaries had mated, in contrast to O. striata (Barratt & Campbell 1982). In Melolontha melolontha, and perhaps also in P. lewisii, the spermatophore was formed in the bursa copulatrix during copulation (Landa 1960).…”

“…In Melolontha melolontha, and perhaps also in P. lewisii, the spermatophore was formed in the bursa copulatrix during copulation (Landa 1960). Furthermore, Johannesson (1975) reported that spermatophoric breakdown took 4 months in H. arator, while Barratt & Campbell (1982) recorded 6 weeks for O. striata. Considering the juxtaposition between the activity period of P. lewisii (September-January, peaking on 12 November ± 23.3 days, Ferreira & McKinlay 1999a) and our sampling periods, we are confident that our classification of females as not mated is correct and not an artefact of spermatophore degradation.…”