The problem of explaining size clines in insects (and in ectotherms
in general) is directly related to the so-called temperature-size rule which was first analysed by Bergmann (1847) in endotherms.
The long biological half-times of several important long-lived radionuclides in ectotherms
suggests it is unlikely that many of these animals could attain a significant fraction of [q.
Martin and Huey (2008) hypothesized that, for most ectotherms
, environmental variability (such as that typical of the intertidal zone) decouples preferred body temperatures from physiologically optimal body temperatures.
Intertidal invertebrates are marine ectotherms
that must regularly contend with a terrestrial environment, and as such provide a unique perspective on examining the effects of fluctuating temperatures on organismal physiology and ecology (e.
Body size clines, with genetically larger individuals at higher latitudes, have been reported for a diverse array of ectotherms
including several Drosophila species (e.
are just the opposite, having body temperatures that fluctuate with outside conditions.
Protein turnover in ectotherms
and its relationship to energetics.
In many mammals and birds SSD is male biased, but in the majority of ectotherms
, it is female biased, although with many exceptions (Ralls 1976, Andersson 1994, Monnet & Cherry 2002, Schulte-Hostedde et al.
1999) found that ectotherms
showed a stronger relationship between FA and heterozygosity than endotherms, but the issue is still controversial (see Kat 1982, Palmer & Strobeck 1986, Vollestad et al.
In a recent paper, Van Voorhies (1996) suggested that Berg-mann size clines in ectotherms
might result from developmental processes that cause cells to grow larger at lower temperatures.
For that reason, lizards and other ectotherms
slow down when outside temperatures drop.
Another issue with this assay is that its efficacy will vary for animals that are acclimated to different environmental temperatures, because lipid saturation levels in ectotherms
change with temperature (Weber et al.