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ARS Home » Pacific West Area » Corvallis, Oregon » Horticultural Crops Research Unit » Research » Publications at this Location » Publication #319533
Title: The influence of temperature and photoperiod on the reproductive diapause and cold tolerance of spotted-wing drosophila, Drosophila suzukii

Author
item WALLINGFORD, ANNA - Cornell University
item Lee, Jana
item LOEB, GREGORY - Cornell University

Submitted to: Entomologia Experimentalis et Applicata
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/15/2016
Publication Date: 6/8/2016
Citation: Wallingford, A.K., Lee, J.C., Loeb, G.M. 2016. The influence of temperature and photoperiod on the reproductive diapause and cold tolerance of spotted-wing drosophila, Drosophila suzukii. Entomologia Experimentalis et Applicata. 159(3):327–337. doi: 10.1111/eea.12443.

Interpretive Summary: Understanding the reproductive status of spotted-wing drosophila (SWD), Drosophila suzukii is helpful for predicting potential infestations in crops. This study looked at if reproductive diapause occurs during the fall (fly no longer produces offspring), what environmental cues trigger diapause, what ends diapause, and the ability of the fly to tolerate cold temperatures. The initiation of diapause was studied by counting the number of mature eggs carried by field-captured SWD and laboratory-reared SWD held under various temperature and photoperiod cycles. The number of eggs in the ovaries of females declined from July to December at sites in Oregon and New York, and reached zero eggs by December. Photoperiods below 14 h of light lead to reduced egg maturation in lab-reared flies held at moderate temperatures (15 or 20°C). While very few mature eggs were found in females held at 10°C under short or long light periods for several weeks after eclosion, a spontaneous return to reproductive maturity was observed in females after 7 weeks that were exposed to short light periods initially and moved to long light period. Cold tolerance was evaluated by observing SWD's recovery rates after 24 h exposure to -1°C. Cold-acclimated (diapausing) females recovered from chill coma faster than cold-hardened or un-acclimated females.

Technical Abstract: Knowledge regarding the reproductive status of spotted-wing drosophila, Drosophila suzukii (Matsumura)(Diptera: Drosophilidae) is of critical importance in predicting potential infestations of this invasive pest, as eggs are laid in ripe or ripening fruit of several commercially important small fruit crops. Token environmental stimuli for the induction of reproductive diapause and improved cold tolerance were identified for D. suzukii. Diapause induction was evaluated by assessing, via dissection, the number of mature eggs carried by field-captured D. suzukii and laboratory-reared D. suzukii held under various temperature and photoperiod regimes. Egg load decreased over time in females trapped from July to December at sites in Benton Co., OR and Ontario Co. NY, USA and reached zero eggs by December at all sites. Photoperiods below 14 h of day length lead to reduced egg maturation in lab-reared flies held at moderate temperatures (15 or 20°C). While very few mature eggs were found in females held at 10°C under short or long day photoperiods for several weeks after eclosion, a spontaneous return to reproductive maturity was observed in short day entrained females after 7 weeks. Diapause termination was investigated by evaluating fecundity in diapausing females returned to optimal environmental conditions. While long day entrained flies began producing offspring immediately upon return to optimal conditions, short day entrained flies returned after 1 and 6 weeks at 10°C were slower to produce offspring than colony flies or short day entrained flies returned after 7 weeks. Cold tolerance was evaluated by observing chill coma recovery rates after 24 h exposure to -1°C. Cold-acclimated (diapausing) females recovered from chill coma faster than cold-hardened or un-acclimated females.