Wu, Grace (2008)
Mites (Acarina: Teneriffidae) push physiological limits: Water balance, thermal tolerance, and biomechanics. Pomona College, Biology.
Advisor: Jonathan Wright.
Diminutive teneriffiid mites have been observed running rapidly on ground surfaces with temperatures that exceed 50°C in the California coastal sage scrub habitat. This study examined three main aspects of the mites’ physiology that reflected their adaptation to harsh environmental conditions — water balance, thermal tolerance, and biomechanics. Experimental results demonstrate that these mites, being obligatory thermoconformers as a result of their small size, possess the highest recorded critical thermal maximum for any terrestrial metazoan. These teneriffiid mites are also able to combat great forces driving water loss—stemming from the arid and hot environment as well as its great surface area to volume ratio—by possessing an extremely low average permeability that is second only to the permeability of the spider beetle Mezium affine. Biomechanics studies have demonstrate that these teneriffiid mites exhibit relative running velocities that are amongst the fastest speed recorded. Due to its high muscle contraction frequency (up to 130 Hz), we suspect that these mites have the shortest Ca2+ latency period and fastest Ca2+ transient times for any locomotory muscle. This study has only touched the surface of elucidating the incredible adaptations of these mites and their underlying mechanisms. There is still an incredible amount of work left to be done. This thesis concludes by proclaiming that “it is by studying little things that we attain the great knowledge of having as little misery and as much happiness as possible” [Boswell’s London Journal 1762-63].