Characterization of intraspecific variation is required to assess the potential nontarget effects of augmentative releases of Hippodamia convergens (Guerin) (Coleoptera: Coccinellidae) from the Western United States on local populations of this species in the Eastern United States. Adults of this predatory lady beetle species overwinter in adult reproductive diapause, thus examining responses to photoperiods can characterize geographic variation influencing their seasonal biology. This laboratory study quantified the induction and duration of adult reproductive diapause in five North American populations of H. convergens in response to four constant photoperiods (16:8, 14:10, 12:12, and 10:14 [L:D] h) at 22C. Three populations were collected over a range of latitudes (31 N to 42 N) in the central portion of the United States (Texas, Kansas, and Iowa); two populations were purchased from commercial sources in the Western United States. All populations exhibited a long-day response to photoperiods: =17% of females reared at 16:8 (L:D) h entered diapause, whereas shorter photoperiods (12:12 and 10:14 [L:D] h) induced diapause in 82 to 100% of females. The response to 14:10 (L:D) h showed significant variation among the populations, ranging from 0 to 89% of females in reproductive diapause. Both the phenotypic variation in response to diapause inducing photoperiods and the genetic variation in North American populations of H. convergens document the geographic variability in this widely distributed predatory species.
|Number of pages||5|
|State||Published - Dec 7 2018|
Bibliographical noteFunding Information:
This is publication no. 18-08-042 of the Kentucky Agricultural Experiment Station and is published with the approval of the Director. This work is supported by the National Institute of Food and Agriculture, U.S. Department of Agriculture, Hatch project accession number 1008480. Data are deposited at UKnowledge: https://doi.org/10.13023/K22Q0W. We thank the following for collecting H. convergens: James Nechols, Kansas State University and Laura Weiser-Erlandson, Texas A&M University Central Texas. We thank Catherine A. Tauber, Cornell University, for her review and constructive suggestions of this manuscript.
© 2018. Published by Oxford University Press on behalf of Entomological Society of America.
- geographic variation
- ladybird beetle
- reproductive diapause
- seasonal development
ASJC Scopus subject areas
- Ecology, Evolution, Behavior and Systematics
- Insect Science