LABORATORY COLONIZATION AND LIFE TABLE STATISTICS FOR GEOGRAPHIC STRAINS OF SIMULIUM-DECORUM (DIPTERA, SIMULIIDAE)

  • 1 January 1980
    • journal article
    • research article
    • Vol. 31  (4) , 487-497
Abstract
Colonization techniques were developed to select mating strains from 4 geographic populations of S. decorum. Although mating strains were established from each locale, emphasis was shifted toward developing permanent colonies from Dryden Lake, New York, USA and Warm Springs, Georgia, USA. The net reproductive rate (Ro) was computed for the parental, F1 and F2 generations of each strain to assess the effects of colonization through successive generations. Ro increased rapidly for both strains from parental (range of 0.34-3.5) through F2 generations (range of 16.2-21.6). Analysis of Ro components indicated that the increases in Ro were the result of 2 parameters that reflect the propensity of flies to mate in confinement, suggesting that selection for mating is rapid. Multiple regression analysis indicated no significant differences between strains or generations when tested against fecundity (range of 391-519) and survival of immatures (range of 90.3-97.2%). A slight positive correlation (regression coefficient of 0.0016, P < .01) was observed between larval density (range of 284-4439 larvae/rearing) and survival of immatures, suggesting that the limits of the rearing system with regard to crowding were not approached. Both strains readily adapt to the laboratory and are currently in the 5th generation.