Meeting Abstract
Morphological asymmetry is widely used to measure developmental instability and higher levels of asymmetry often correlate with decreased mating success, increased inbreeding, increased stress, and decreased habitat quality. Links between asymmetry and environmental quality provide a novel context for host-parasite relationships because habitat a parasite experiences consists of host immunological and physiological processes. Parasites colonizing novel host species could therefore exhibit increased asymmetry due to decreased habitat quality. Our goal was to determine if asymmetry in fleas Xenopsylla ramesis and Parapulex chephrenis increased when their mothers were reared on species of rodents differing in their relatedness to the fleas’ principal host. We found significant asymmetry in femurs and tibiae of X. ramesis but asymmetry was not affected by host relatedness. However, tibae of P. chephrenis exhibited significant asymmetry and asymmetry was highest in fleas whose mothers were reared on hosts that were distantly related to the principal host. These results indicate that host species and, in turn, habitat quality significantly impacted asymmetry in P. chephrenis, a host specialist, but not X. ramesis, a more generalist flea. Therefore, fleas parasitizing multiple species may be better at compensating for developmental instability than host specialists when utilizing a novel host species. This suggests that host-switching events in host specialists may be constrained by the relatedness of the different host species in question.
