Active water vapor absorption in the mealworm Tenebrio molitor: modeling water and ion fluxes

Start: 11/10/2014 - 12:00pm
End  : 11/10/2014 - 1:00pm

Applied Math Seminar

Jonathan Wright (Biology, Pomona College)


Several arthropod families have evolved specialized water abstraction mechanisms that are amenable to mathematical modeling. One example is the larvae of tenebrionid beetles, including mealworms, which are able to absorb water vapor from sub-saturated humidity. Such water vapor absorption (WVA) provides an effective means of rehydration for insects living in arid microclimates or exploiting foods of low water content. The mealworm uptake mechanism employs an elaborate cryptonephric system ensheathing the rectum. Active transport of potassium ions into this structure generates high osmotic concentrations and colligative lowering of water vapor pressure. In sufficiently high relative humidity, the vapor pressure gradient is inward, causing water vapor to diffuse from the rectal lumen into the cryptonephric system. Key unresolved questions with this system include: (i) how potassium is cycled from the cryotonephric system into the blood and back again, and (ii) how water is ultimately moved into the blood against a large osmotic gradient. This talk will discuss our current understanding of the ion gradients and WVA kinetics, and how we might model ion and water fluxes during steady-state uptake.

CMC, Kravis Center, KRV 164