Environmental Entomology (2020) 49, 580-585

Ian M. Jones, Martin Lukas Seehausen, Robert S. Bourchier and Sandy M. Smith (2020)
The effects of photoperiod on diapause induction in Hypena opulenta (Lepidoptera: Erebidae), a biological control agent against invasive swallow-worts in North America
Environmental Entomology 49 (3), 580-585
Abstract: Many insects exhibit a short-day diapause response, whereby diapause is induced when daylength falls below a critical threshold. This response is an adaptation to ensure synchrony between periods of insect activity, and the availability of resources, but it can cause problems when organisms are moved to new locations, where early or late-induced diapause can prove a barrier to establishment. We explored the role of photoperiod in diapause induction in Hypena opulenta, a recently introduced classical biological control agent for invasive swallow-worts in North America. We conducted four experimental cage releases as well as a growth chamber experiment to determine the threshold photoperiod for diapause induction in H. opulenta. We determined that the critical photoperiod for inducing diapause in 50% of H. opulenta is 15 h 35 min, which the moth only experiences in the Ottawa release site around summer solstice. This may lead to univoltinism, premature diapause, and poor establishment at some North American release sites. Our results can inform practical aspects of the biological control program for H. opulenta, such as fine-tuning methodologies for stockpiling diapausing pupae in the laboratory and narrowing down the optimal time window for releases at a given location. Additionally, our results will be important for the development of a temperature-based phenology model to more accurately predict voltinism in H. opulenta across the invasive range of swallow-worts in North America.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
Link to article at publishers website
Database assignments for author(s): Martin Lukas Seehausen, Robert S. Bourchier, Sandy M. Smith

Research topic(s) for pests/diseases/weeds:
biocontrol - natural enemies
Research topic(s) for beneficials or antagonists:
general biology - morphology - evolution

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Vincetoxicum (weeds)
Hypena opulenta (weed bioagent)	Vincetoxicum (weeds)