In particular, insects occupy a wide range of ecologically diverse niches and, so, exhibit a variety of strategies to avoid desiccation.
Desiccation sensitive plants include members of Arabidopsis genus, Lindernia subracemosa, Gossypium hirsutum, Triticum aestivum and Zea mays.
Higher hemolymph volume is linked to an increase in carbohydrates, in particular trehalose, a common sugar found in many plants and animals with high desiccation resistance.
[6] During periods of aridity, cells dehydrate and draw upon hemolymph stores to replenish intracellular water; therefore, insects with higher levels of this fluid are less prone to desiccation.
[3] Furthermore, the crop may also act not only to store food prior to digestion but to provide an additional reservoir for water and sugar.
The three main ways through which insects can lose water are (1) the surface of the body (integument); (2) the tracheae (respiration); and (3) excretion, or waste products.
However, the outer cuticular layer (epicuticle) is a protein-polyphenol complex made up of lipoproteins, fatty acids, and waxy molecules, and is the insect's primary defense against water loss.
[11] Immediately following head removal, decapitated cockroaches exhibit a large increase in transpiration across the cuticle, leading to severe dehydration.
For example, Tsetse flies maintained at a high relative humidity, and thus non-arid conditions, excrete fecal matter with approximately 75% water content, whereas Tsetse flies maintained at a low relative humidity, and thus dry conditions, excrete fecal matter with only 35% water content.
[15] In addition to physiological adaptations that increase desiccation resistance, behavioral responses of insects to arid environments significantly decrease dehydration potential.
Drosophila melanogaster fruit flies, for example, will actively move to areas with higher atmospheric water content when placed in dry environments.
[16] Also, the dung beetle buries food in underground chambers, thereby ensuring water and energy sources during periodically dry conditions.
[19] In response, P. vanderplanki larvae enter an anhydrobiotic state, during which changes in body osmolarity trigger the production of large amounts of trehalose.