Access

You are not currently logged in.

Access your personal account or get JSTOR access through your library or other institution:

login

Log in to your personal account or through your institution.

If You Use a Screen Reader

This content is available through Read Online (Free) program, which relies on page scans. Since scans are not currently available to screen readers, please contact JSTOR User Support for access. We'll provide a PDF copy for your screen reader.

Chromosomal Analysis of Heat-Shock Tolerance in Drosophila melanogaster Evolving at Different Temperatures in the Laboratory

Sandro Cavicchi, Daniela Guerra, Vittoria La Torre and Raymond B. Huey
Evolution
Vol. 49, No. 4 (Aug., 1995), pp. 676-684
DOI: 10.2307/2410321
Stable URL: http://www.jstor.org/stable/2410321
Page Count: 9
  • Read Online (Free)
  • Download ($4.00)
  • Subscribe ($19.50)
  • Cite this Item
Since scans are not currently available to screen readers, please contact JSTOR User Support for access. We'll provide a PDF copy for your screen reader.
Chromosomal Analysis of Heat-Shock Tolerance in Drosophila melanogaster Evolving at Different Temperatures in the Laboratory
Preview not available

Abstract

We investigated the heat tolerance of adults of three replicated lines of Drosophila melanogaster that have been evolving independently by laboratory natural selection for 15 yr at "nonextreme" temperatures (18⚬C, 25⚬C, or 28⚬C). These lines are known to have diverged in body size and in the thermal dependence of several life-history traits. Here we show that they differ also in tolerance of extreme high temperature as well as in induced thermotolerance ("heat hardening"). For example, the 28⚬C flies had the highest probability of surviving a heat shock, whereas the 18⚬C flies generally had the lowest probability. A short heat pretreatment increased the heat tolerance of the 18⚬C and 25⚬C lines, and the threshold temperature necessary to induce thermotolerance was lower for the 18⚬C line than for the 25⚬C line. However, neither heat pretreatment nor acclimation to different temperatures influenced heat tolerance of the 28⚬C line, suggesting the loss of capacity for induced thermotolerance and for acclimation. Thus, patterns of tolerance of extreme heat, of acclimation, and of induced thermotolerance have evolved as correlated responses to natural selection at nonextreme temperatures. A genetic analysis of heat tolerance of a representative replicate population each from the 18⚬C and 28⚬C lines indicates that chromosomes 1, 2, and 3 have significant effects on heat tolerance. However, the cytoplasm has little influence, contrary to findings in an earlier study of other stocks that had been evolving for 7 yr at 14⚬C versus 25⚬C. Because genes for heat stress proteins (hsps) are concentrated on chromosome 3, the potential role of hsps in the heat tolerance and of induced thermotolerance in these naturally selected lines is currently unclear. In any case, species of Drosophila possess considerable genetic variation in thermal sensitivity and thus have the potential to evolve rapidly in response to climate change; but predicting that response may be difficult.

Page Thumbnails

  • Thumbnail: Page 
676
    676
  • Thumbnail: Page 
677
    677
  • Thumbnail: Page 
678
    678
  • Thumbnail: Page 
679
    679
  • Thumbnail: Page 
680
    680
  • Thumbnail: Page 
681
    681
  • Thumbnail: Page 
682
    682
  • Thumbnail: Page 
683
    683
  • Thumbnail: Page 
684
    684