Dalin, Peter
- Department of Ecology, Swedish University of Agricultural Sciences
Research article2010Peer reviewedOpen access
Dalin, Peter; Bean, Daniel W.; Dudley, Tom L.; Carney, Vanessa A.; Eberts, Debra; Gardner, Kevin T.; Hebertson, Elizabeth; Jones, Erin N.; Kazmer, David J.; Michels jr, G. J.; O'Meara, Scott A.; Thompson, David C.
Seasonal adaptations to daylength often limit the effective range of insects used in biological control of weeds. The leaf beetle Diorhabda carinulata (Desbrochers) was introduced into North America from Fukang, China (latitude 44 degrees N) to control saltcedars (Tamarix spp.), but failed to establish south of 38 degrees N latitude because of a mismatched critical daylength response for diapause induction. The daylength response caused beetles to enter diapause too early in the season to survive the duration of winter at southern latitudes. Using climate chambers, we characterized the critical daylength response for diapause induction (CDL) in three ecotypes of Diorhabda beetles originating from 36,38, and 43 degrees N latitudes in Eurasia. In a field experiment, the timing of reproductive diapause and voltinism were compared among ecotypes by rearing the insects on plants in the field. CDL declined with latitude of origin among Diorhabda ecotypes. Moreover, CDL in southern (<39 degrees N latitude) ecotypes was shortened by more than an hour when the insects were reared under a fluctuating 35-15 degrees C thermoperiod than at a constant 25 degrees C. In the northern (>42 degrees N latitude) ecotypes, however. CDL was relatively insensitive to temperature. The southern ecotypes produced up to four generations when reared on plants in the field at sites south of 38 degrees N, whereas northern ecotypes produced only one or two generations. The study reveals latitudinal variation in how Diorhabda ecotypes respond to daylength for diapause induction and how these responses affect insect voltinism across the introduced range.
Critical daylength response; voltinism; biological control; biological invasions
Environmental Entomology
2010, volume: 39, number: 5, pages: 1666-1675
Publisher: ENTOMOLOGICAL SOC AMER
Environmental Sciences and Nature Conservation
https://res.slu.se/id/publ/47838