TY - JOUR
T1 - Are bottlenecks associated with colonization? Genetic diversity and diapause variation of native and introduced Rhagoletis completa populations
AU - Chen, Yolanda H.
AU - Opp, Susan B.
AU - Berlocher, Stewart H.
AU - Roderick, George K.
N1 - Funding Information:
Acknowledgements This project would not have been possible without the collecting help of Frances Cave, Rachel Elkins, Dennis Haines, Ken Hunt, Terry Woods, Rick Hilton, Bob Van Steenwyck, Bill Reid, Alyssa Ing, Cullen Wilkerson, Wee Yee, and Joe Zermeno. John Andrews and Gregory Fanslow helped monitor Xy emergence. We thank Sebastian Velez and JeV Feder for sharing the microsatellite primers. This project was supported by an USDA NRI grant 2002-35302-11570 to Y. H. Chen, and NSF OISE, NSF RCN, and University of California Agricultural Experiment Station funds to G. K. Roderick. This study complies with the current laws of the United States of America.
PY - 2006/10
Y1 - 2006/10
N2 - The success of invasive species appears to be a paradox: despite experiencing strong population bottlenecks, invasive species are able to successfully establish in new environments. We studied how the walnut husk fly, Rhagoletis completa, was able to successfully colonize California from the Midwestern United States, by examining genetic diversity and diapause variation of native and introduced fly populations. Climate plays an important role in the successful establishment of introduced insects, because insect diapause is highly dependent upon external climatic conditions. We examined if: (1) fly populations show signs of a population bottleneck, (2) native and introduced flies differ in diapause length when exposed to California and Midwestern climatic conditions, and (3) population genetic diversity is related to variation in diapause length. We assessed if fly diapause conformed more to a model of establishment by local adaptation or to a model of a highly plastic "general-purpose genotype". Our results indicate that only two populations close to the original introduced location showed signs of a population bottleneck, and native and introduced populations did not differ in genetic diversity. Genetic diversity increased in the northern introduced populations, suggesting that multiple introductions have occurred. Flies emerged about 2 weeks earlier under the Midwestern treatment than the California treatment, and introduced flies emerged about a week earlier than native flies. All flies emerged when walnuts are typically available in California. Although variance in diapause length differed between populations, it did not vary between populations or regions. Furthermore, genetic diversity was not associated with diapause variation. Therefore, multiple introductions and a "general-purpose genotype" appear to have facilitated the fly's invasion into California.
AB - The success of invasive species appears to be a paradox: despite experiencing strong population bottlenecks, invasive species are able to successfully establish in new environments. We studied how the walnut husk fly, Rhagoletis completa, was able to successfully colonize California from the Midwestern United States, by examining genetic diversity and diapause variation of native and introduced fly populations. Climate plays an important role in the successful establishment of introduced insects, because insect diapause is highly dependent upon external climatic conditions. We examined if: (1) fly populations show signs of a population bottleneck, (2) native and introduced flies differ in diapause length when exposed to California and Midwestern climatic conditions, and (3) population genetic diversity is related to variation in diapause length. We assessed if fly diapause conformed more to a model of establishment by local adaptation or to a model of a highly plastic "general-purpose genotype". Our results indicate that only two populations close to the original introduced location showed signs of a population bottleneck, and native and introduced populations did not differ in genetic diversity. Genetic diversity increased in the northern introduced populations, suggesting that multiple introductions have occurred. Flies emerged about 2 weeks earlier under the Midwestern treatment than the California treatment, and introduced flies emerged about a week earlier than native flies. All flies emerged when walnuts are typically available in California. Although variance in diapause length differed between populations, it did not vary between populations or regions. Furthermore, genetic diversity was not associated with diapause variation. Therefore, multiple introductions and a "general-purpose genotype" appear to have facilitated the fly's invasion into California.
KW - Establishment
KW - Genetic diversity
KW - Insect dormancy
KW - Invasive species
KW - Phenotypic variation
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U2 - 10.1007/s00442-006-0482-4
DO - 10.1007/s00442-006-0482-4
M3 - Article
C2 - 16858586
AN - SCOPUS:33947327532
VL - 149
SP - 656
EP - 667
JO - Handbook of Environmental Chemistry, Volume 5: Water Pollution
JF - Handbook of Environmental Chemistry, Volume 5: Water Pollution
SN - 1433-6863
IS - 4
ER -