Plant productivity and seasonality in plant productivity were likely the primary underlying factors generating the observed pattern of geographic variation in body size. Thus, our results supported primary productivity and seasonality hypotheses. From these results, we see that McNab’s ‘resource rule’ or Huston and Wolverton’s ‘eNPP rule’ (i.e. spatial variation in food availability) is an explanation for a Bergmannian size pattern in Richardson’s ground squirrels, but not the only explanation. “
“The learn more structural-function hypothesis provides an alternative to signalling-based predictions to explain the remarkable diversity observed in avian eggshell colour. According to the

hypothesis, protoporphyrin, the common pigment of visible speckles, lubricates and thus strengthens the shell and simultaneously moderates gas transfer across it. Correlational evidence for the structural-function hypothesis in form of a coincidence of both shell thinning and reduced evaporation with eggshell speckles PD0325901 comes from a restricted set of species with limited calcium supply or little nest predation and no need for camouflage of the eggs. Here, we investigate whether protoporphyrin-based pigmentation similarly affects a species

with cryptically marked eggs and ample dietary calcium, the black-headed gull, Larus ridibundus. Although shell thinning of speckles occurred, this effect was minimal compared with thinning through embryonic growth. Furthermore, speckled and plain selleck chemicals llc areas of the shell did not differ in water vapour conductance through the shell. We conclude that protoporphyrin speckling does not fulfil a structural function in gull eggs. Instead, during

shell formation where the protoporphyrin of speckles is deposited in place of calcite it could inflict a structural cost. We propose that the mechanical and water vapour conductance functions of shell speckling need to be evaluated as separate hypotheses and that both functions could, in fact, negatively affect each other. “
“Understanding microhabitat requirements for species vulnerable to anthropogenic threats can provide important information to conservation managers. This may be particularly true for ectotherms, where behaviour and physiology (e.g. digestion, responsiveness and activity patterns) are strongly influenced by thermal conditions of microhabitat retreat sites. Retreat sites selected by south-west carpet pythons (Morelia spilota imbricata) were identified through radiotracking 46 pythons over 3 years. Tree hollows appear to be a very important resource for pythons: 61% (22 of 36 individuals tracked over winter) used tree hollows as retreat sites (56% of all observations in winter), and remained in hollows for an average of 124 ± 49 (range 34 to 210) days.

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