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Communication at the NABS Annual meeting, Keystone, 2000
(379) GENETIC EVIDENCE FOR 'LEAKY' COHORTS IN THE SEMIVOLTINE STONEFLY, PELTOPERLA ARCUATA.
A.S. Schultheis and A.C. Hendricks. Department of Biology, Virginia Tech, Blacksburg, VA 24061-0406
The stonefly Peltoperla arcuata (Plecoptera: Peltoperlidae) has a semivoltine life cycle throughout the Appalachian Mountains. This life cycle comprises a six month egg diapause followed by an ~16 month larval development period. We tested the hypothesis of ‘leaky’ cohorts in this stonefly species by sequencing 600 base pairs of the hypervariable 'A-T rich' region of mitochondrial DNA in 40 individuals (20 adults, and 20 larvae) from four localities in Giles County, Virginia. Analysis of molecular variance (AMOVA) and pairwise FST differentiation tests were used to determine levels of genetic differentiation between cohorts. Within-population differences accounted for the majority of the genetic variation (91%), while the amount of variation between cohorts was much lower (4.7%). In addition, the number of migrants per generation (Nm) was >>1 for all pairwise comparisons regardless of life stage or geographic location, indicating that there is considerable gene flow between cohorts in this species. Our life history data suggest that gene flow between cohorts is made possible because, in any given cohort, some individuals do not undergo diapause. As a result, these individuals may complete the life cycle in one-year and be available to mate with individuals from the previous year’s cohort.
Presented at 1:00 PM on Wednesday, May 31, 2000 in Life History Characteristics
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