Cotesia urabae

Cotesia urabae Austin & Allen is a solitary larval endoparasitoid which is part of a large complex of 11 primary parasitoids of Uraba lugens Walker, many of which are polyphagous (Allen, 1990a, 1990b). Adult C. urabae have a black body with yellow–brown legs, and they are 2.5-3.2 mm long (Austin and Allen, 1989). The female oviposits its eggs inside a U. lugens by inserting its ovipositor into the larva, and it has been found that one female may carry up to 400 eggs (Allen, 1989). It has been observed that C. urabae females are able to attack the same larva several times; despite this only one single parasitoid completes its development in each larva (Berndt, 2010).

Once the C. urabae larvae emerges from the host larvae, a tightly woven sulphur-yellow pupal cocoon in a loose surrounding silk matrix is spun by C. urabae to pupate alongside the host (Allen, 1990a). There is considerable variation in the time that the larval stage spends developing inside the host, and it ranges between 14 days in summer and 20 days in winter. The adults’ emergence takes place after 8 days pupation, when a cap is cut and pushed off at the end of the cocoons allowing the adult to emerge and disperse. The adult lives for approximately 27 days (Allen, 1990b). It has been described that C. urabae has 2 generations within each generation of its host U. lugens, and no overlapping of adults of each C. urabae generation has been observed in the field (Allen, 1990a).

Cotesia urabae was introduced in New Zealand in 2011 as a biological control agent against the eucalyptus pest Uraba lugens, commonly known as the gum leaf skeletoniser (Avila et al. 2013). The biological control of the gum leaf skeletonizer is a novel biocontrol program, being the first attempt at control of this invasive moth in New Zealand. It has been predicted that C. urabae will lead to a considerable decrease on the existing population of U. lugens, along with providing several social and economic benefits (Avila et al. 2013).

References

• Allen, G. R. (1989). Behaviour and ecology of the primary parasitoids Cotesia urabae and Dolichogenidea eucalypti (Hymenoptera: Braconidae) and their host Uraba lugens (Lepidoptera: Noctuidae). PhD Thesis. The University of Adelaide, Australia
• Allen, G. R. (1990a). Uraba lugens Walker (Lepidoptera: Noctuidae): Larval survival and parasitoid biology in the field in South Australia. Journal of the Australian Entomological Society, 29, 301-312
• Allen, G. R. (1990b). The Phenologies of Cotesia urabae, Dolichogenidea eucalypti (Hymenoptera: Braconidae) and their Host Uraba lugens (Lepidoptera: Noctuidae) in the Adelaide Region. Australian Journal of Zoology, 38, 347-362
• Allen, G. R. (1990c). Influence of host behavior and host size on the success of oviposition of Cotesia urabae and Dolichogenidea eucalypti (Hymenoptera: Braconidae). Journal of Insect Behavior, 3(6), 733-749
• Austin, A. D., & Allen, G. R. (1989). Parasitoids of Uraba lugens Walker (Lepidoptera: Noctuidae) in South Australia, with description of two new species of Braconidae. Transactions of the Royal Society of South Australia, 113(4), 169-184
• Avila, G.A., Berndt, L.A., Holwell, G.I. 2013. First releases and monitoring of the biological control agent Cotesia urabae Austin and Allen (Hymenoptera: Braconidae). New Zealand Entomologist, 36(2), 65–72
• Berndt, L. A. (2010). Will competition from Meteorus pulchricornis (Wesmael) (Hymenoptera: Braconidae) limit the success of the potential biocontrol agent Cotesia urabae Austin & Allen (Hymenoptera: Braconidae)? Australian Journal of Entomology, 49(4), 369-376