Meeting Abstract
Cave animals are striking and amazing animals with common features such as reduced eyes, reduced pigment, elongated appendages, and enhanced sensory systems. Few cave-dwelling species are amenable to genetic and developmental techniques making it challenging to ask questions about the evolution of these traits. To address this limitation, we have been developing Asellus aquaticus, an isopod crustacean, as a developmental and genetic model. Asellus aquaticus has both cave and surface dwelling forms that vary in many characters such as eye size, pigmentation, and number of antennal segments. Our first goal was to utilize comparative embryology to examine when in development these different morphologies came about. We found that eye loss, pigment loss, increased number of antennal articles, and different morphologies of chemosensory sensilla are already established by the end of embryogenesis. Our second goal was to take advantage of the multiple cave populations of this species and ask whether the same or different regions were responsible for the evolution of eye and pigment traits in different cave populations. Of the two populations examined so far, we found that the same regions are responsible. Future studies will examine additional populations to see if the same regions are commonly associated with eye and pigment loss. In summary, we have shown that Asellus aquaticus is an excellent species to study the developmental and genetic basis of cave specific characteristics and contains all of the necessary characters to more completely dissect the developmental and genetic mechanisms responsible for these evolutionary changes.
