Current Research Projects
Convergent evolution between birds and bats:
There are fundamental differences in skin lipid composition between birds and most mammals. However, a recent study has shown that bats have a skin lipid composition that has many similarities with birds. Of particular interest is the presence of cerebroside molecules in both birds and bats. These lipid molecules contain a sugar attached to the head group, and thus may lend strength and pliability to the skin to help birds and bats cope with the rigors of flight. We recently published a paper showing that lipid composition in desert bats may favor heat dissipation from the wings at high temperature. Currently, in collaboration with Joy O'Keefe at the University of Illinois, we are currently quantifying lipids in different skin regions of Big Brown Bats to look for patterns in lipid content and flight stress.
Skin lipids of alligators:
To gain insight into the evolution of bird skin, we are investigating the skin of birds' closest living relatives - Alligators and crocodiles. In collaboration with biologist Frank Robb, we have acquired skin from American Alligators, and are investigating lipid composition and molecular interactions in the stratum corneum.
Lifespan and body size in dogs:
In most animals, lifespan and metabolic rate are inversely correlated. Animals with fast metabolic rates generally age faster and live shorter lives. However, in dogs, smaller breeds with higher metabolic rates live longer than larger breeds. These differences may be attributed to a variety of factors, including levels of metabolic rate and oxidative stress. In correlation with Ana Jimenez at Colgate University, we are looking for links between cellular lipid composition, cellular metabolic rate, and longevity.
Development of water loss and skin lipids:
As birds develop from hatchlings to adults, their ability to regulate cutaneous water loss may be affected by ontogenetic, evolutionary, or environmental factors. Previous studies on House Sparrows show that water loss and skin lipid composition change as young birds develop. However, other species of birds follow very different developmental trajectories. Whereas House Sparrows exhibit an altricial mode of development, and are featherless, blind, and dependent on their parents upon hatching, other species follow a precocial mode of development, and are fully feathered and active within a few hours of hatching. This difference in lifestyle may dictate differences in the skin’s ability to prevent water loss. Using Coturnix quail as a model precocial species, we are investigating changes in water loss, lipid arrangement, and lipid composition as birds develop.