ECOLOGY, GENOMICS, AND MANAGEMENT OF STORED PRODUCT INSECTS
Location: Stored Product Insect Research Unit
Title: Performance of diapausing parasitoid wasps, Habrobracon hebetor, after cold storage
Submitted to: Biological Control
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: November 25, 2012
Publication Date: February 22, 2013
Citation: Chen, H., Zhang, H., Zhu, K., Throne, J.E. 2013. Performance of diapausing parasitoid wasps, Habrobracon hebetor, after cold storage. Biological Control. 64(3):186-194. doi: http://dx.doi.org/10.1016/j.biocontrol.2012.11.007.
Interpretive Summary: The Indianmeal moth is a major pest of stored grain and processed commodities. There is a small wasp that does not sting humans but naturally parasitizes the Indianmeal moth, and releasing these parasitic wasps would be an environmentally friendly way to control the Indianmeal moth. But, there is currently no way to store these wasps for when they are needed for controlling the Indianmeal moth. We found that the adult wasps entered reproductive diapause (a resting stage where they don’t produce offspring) when they are reared at a cool temperature and short daylength (68°F and 10 hours of light), and these diapausing wasps could be stored for up to two months in a refrigerator and still perform well. Being able to store these parasitic wasps in a refrigerator will enable mass production of the wasps for release for pest management.
The ectoparasitoid Habrobracon hebetor Say (Hymenoptera: Braconidae) is an important potential biological control agent for lepidopterous pests of stored products. We investigated the effects of long-term cold storage of diapausing and non-diapausing H. hebetor on their performance after cold storage. Mortality during storage increased with increasing storage duration, and the mortality of diapausing females was lower than that of nondiapausing females after 8, 12, and 16 weeks of storage. Longevity, egg laying, number of progeny produced, and time to 50% egg laying were all reduced, as compared with the culture females reared at conditions that do not induce diapause. But, for females reared at 20°C at conditions that induce diapause, all of these quality parameters did not differ from those of culture insects when the storage duration was 8 weeks or less. The percentage of female F1 offspring was always lower for cold stored insects than for the culture insects. Presence of a male after cold storage did not impact any of the quality parameters measured. Thus, rearing parasitoids at 20°C and 10L:14D for up to 8 weeks would produce parasitoids that are similar to culture parasitoids, except that the percentage of females is lower than that in the cultures (36 versus 52%).