40
Respiratory Metabolism
uted evenly among the age classes, especially when temperatures fluctuate
and animals are active over a broad temperature range. In contrast, rising
temperature stimulates energy dissipation, and animals encountering a relatively long period of low temperature in winter can profit from sudden temperature increases to accomplish part of their development. During favourable periods, respiratory activity appears to be relatively temperature independent, and consequently the energetic costs of egg deposition and further
development remain low. The overall conclusion is that the Mediterranean
arthropods which appear to conserve energy are broad temperature selected,
and moderate expenditure of energy resulting from oscillating temperatures
is counterbalanced by low energy transformation rates at constant temperatures. This results in broader habitat selection and longer periods of activity.
Moreover, Mediterranean arthropods appear highly sensitive to temperatures
beyond the optimum. In general, such temperatures in Mediterranean
regions are coupled with drought. Accordingly, specific responses are needless,
since these conditions are overcome by water adaptations such as anhydrobios is and fasting (see Chap. 2).