The effects of periodic warming on the survival and fecundity of Diadromus pulchellus during long-term storage.

Murdoch, V.J., Cappuccino, A.A., and Mason, P.G. (2013). "The effects of periodic warming on the survival and fecundity of Diadromus pulchellus during long-term storage.", Biocontrol Science and Technology, 23(2), pp. 211-219. doi : 10.1080/09583157.2012.748183  Access to full text

Abstract

Biological control strategies capitalise on natural mechanisms such as predation and parasitism to reduce the need for chemical applications to control insect pests. In Canada, the parasitic wasp Diadromus pulchellus Wesmael (Hymenoptera: Ichneumonidae) is being investigated for its use in the biological control of an invasive crop pest, the leek moth, Acrolepiopsis assectella (Zeller) (Lepidoptera: Acrolepiidae). Large numbers of insects will be needed for releases to ensure that populations of D. pulchellus establish quickly and impact leek moth populations. Since the current culture is not producing the number of insects required for large-scale releases, the accumulation and storage of D. pulchellus might be a viable option to obtain ideal numbers. Currently, little is known about the optimal conditions for the long-term storage and release of D. pulchellus, which overwinter in nature as adults. Using insects from the active culture, the effect of intermittent, short-term warming on cold-stored adults was evaluated for survivorship and fecundity. In accordance with previous findings, females survived cold storage more readily than males. However, the warming regimes employed had no significant impacts on overall survivorship. Cold-stored females had reduced fecundity compared to females maintained in the culture, though no significant differences were noted between the treatments. In addition, the offspring sex-ratio for all treatments was male skewed. Thus, the warming procedures utilised provided no advantages over current techniques for the long-term storage of D. pulchellus intended for release.

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