THE REPRODUCTIVE MATURITY AND MATING STATUS OF HELICOVERPA-ARMIGERA, HELIOTHIS-PUNCTIGERA AND MYTHIMNA-CONVECTA (LEPIDOPTERA, NOCTUIDAE) COLLECTED IN TOWER-MOUNTED LIGHT TRAPS IN NORTHERN NEW-SOUTH-WALES, AUSTRALIA

The reproductive condition and mating status of female Helicoverpa armigera (Hubner), H. punctigera (Wallengren) and the mating status of the armyworm Mythimna convecta (Walker), trapped in tower-mounted light traps were studied over a four and a half year period, from November 1985 to December 1989. The traps were mounted on towers (40 and 50 m high) in two geographically distinct sites, one located at Point Lookout and the other at Mt Dowe both in north-eastern New South Wales, Australia. At the Point Lookout site, 132 females of H. armigera and 366 of H. punctigera were examined and of those, 88.7% and 89.9% were unmated and immature, respectively. Most of the remaining females of both species were mature and mated. Of the mated H. armigera females, 78.6% carried only a single spermatophore, the remainder having either two or three spermatophores. Most of the mated H. punctigera females (97.1%) carried only a single spermatophore and the remainder had no more than two. Females of M. convecta were predominantly (97.1%) unmated. At the Mt Dowe site H. punctigera adults were predominant and all 44 females of this species examined were unmated and non-gravid. Pre-reproductive flight by Helicoverpa spp. and M. convecta is considered as an important component of the life-history strategies of these insects. Flexibility in the timing and spacing of reproductive effort is seen as enabling colonization of heterogeneous environments.