Gas exchange and metabolic rate during activity

Insects show tremendous scope for the increase of metabolic rates above resting levels. This is due mainly to the energetic demands of flight, which can be responsible for 100-fold increases in metabolic rate. Although many insects, such as ants and honeybees, might never experience levels of metabolism as low as SMRs measured under solitary conditions (sometimes including anaesthesia), and therefore have factorial aerobic scopes more in keeping with those of vertebrates (4-10) (Harrison and...

Molecular Mechanisms Of Insect Amino Acid Absorption

Na K -ATPase are located on apical and basal membranes, respectively. The plasma membrane V-ATPase of M. sexta is well characterized Harvey et al. 1998 . When feeding ceases in preparation for a larval-larval moult, downregulation of the V-ATPase is thought to be achieved by reversible dissociation of the peripheral ATP-hydrolysing complex from the membrane-bound H -translocating complex Sumner et al. 1995 . Expression of V-ATPase genes is also downregulated at this time, under the control of...

Metabolism and gas exchange

The concept that insect respiration depends only on diffusion supplemented in larger species by ventilation is in need of an overhaul the situation is much more complex. Insects, like all living organisms, are far-from-equilibrium, dissipative structures. That is, they actively take up energy and nutrients and in doing so alter both themselves and their surrounding environment. Initially, the changes in both directions might appear insignificant, but on a longer time scale their impact can be...

Microhabitats and activity

The significance of microclimate climate of the microhabitat, see Section 4.4.1 in the thermal and water balance of insects was reviewed by Willmer 1982 . The critical parameters are temperature and the moisture content of the air, continuously modified by solar radiation and air movement. Steep gradients are common near the ground both above and below the surface , and climate can be greatly modified in boundary layers, especially when vegetation is present to transpire, provide shade and slow...

Metabolic rate variation size

Discontinuous gas exchange in ticks is thought to be one of the ways in which these animals maintain the very low metabolic rates required by their sit-and-wait strategy, which includes long periods of fasting Lighton and Fielden 1995 . Scorpions are also thought to have uncharacteristically low metabolic rates, and this has prompted considerable speculation regarding the benefits of low metabolic rates in both groups Lighton et al. 2001 . In turn, this speculation has raised the question of...

Metabolic rate variation temperature and water availability

Temperature and water availability are both thought to influence metabolic rate, especially over the longer term, resulting in adaptations that apparently reflect the need either for water conservation or starvation resistance, or the response to low environmental temperatures Chown and Gaston 1999 . The influence of temperature on metabolic rate over short timescales has been called the most overconfirmed fact in insect physiology Keister and Buck 1964 , and acute modifications of metabolic...

Responses to osmotic stress

Trehalulose

Larval Diptera inhabiting saline waters exhibit extraordinary osmoregulatory abilities. For example, soldier fly larvae Odontomyia cincta Stratiomyidae maintain haemolymph osmolalities of 232 and 419 mOsmol kg-1 when acclimated to external media of 3 and 5414 mOsmol kg-1, respectively Gainey 1984 . The transition from hypo-osmotic to hyper-osmotic regulation occurs at an isosmotic point of 280 mOsmol kg-1, comparable to that of other aquatic insects. Brine flies Ephydridae are superbly tolerant...