Extreme-environment heterosis and genetic loads

Alternative smooth or stepped altitudinal cline of fecundity in Drosophila teissieri and D. yakuba in the Ivory Coast.

“…Considering that fecundity is mostly affected by mother, this may be due to a maternal effect. It is also of interest to connect this result with the assumption that heterosis is higher in extreme environments (see Parsons, 1971 andDavid et al, 1984, for reviews).…”

Inbreeding depression and the outcrossing rate in natural populations of Allium schoenoprasum L. (wild chives)

“…Fitness differentials between inbred and normal individuals may be lower in an experiment carried out under "ideal" conditions (e.g., in cultivation) than in one conducted in a "stressful" environment (e.g., in the field) (Antonovics, 1968;Parsons, 1971;Schemske, 1983). Some research workers have attempted to determine the relative fitnesses of cross and self zygotes in the field (e.g., Schemske, 1983;Schoen, 1983).…”

Effects of inbreeding in three life stages of Drosophila buzzatii after embryos were exposed to a high temperature stress

“…One effect may be reduced stress tolerance if the tolerance trait is dominant or overdominant (Parsons, 1971(Parsons, , 1987Hoffmann & Parsons, 1991), or alternatively, if tolerance covaries with overall fitness. The ability of Drosophila subobscura adults to acclimate during development to a high-temperature stress was reduced by inbreeding (Maynard Smith, 1956) as was cold-shock tolerance in adult D. melanogaster (Ehiobu et al, 1989).…”