Biological Sciences Department

Degree Name

BS in Biological Sciences




Larisa K. Vredevoe


Acanthocephalan worms infect two hosts to reach full development. Some species have been demonstrated to change their intermediate host’s behavior or coloration to increase the likelihood they will reach the final host. The pacific mole crab, Emerita analoga, is commonly parasitized by Profilicollis altmani along the Pacific coast of North and South America, but the impact of parasitism on the crab intermediate host is unclear. We investigated whether P. altmani alters the concentration of dietary carotenoids present in E. analoga tissues and if the parasite may also acquire pigments normally allocated to the host. Fifty eight gravid female crabs were collected and dissected during the summer of 2008 from Pismo Beach, California. Ovaries, eggs, esophagus, and carapace, as well as cystacanth stage acanthocephalans, were removed from each crab. The samples were weighed and extracted in HPLC grade acetone. Carotenoids extracted from each tissue type were analyzed by UV-vis spectrophotometry, with the maximum absorbance and maximum wavelength recorded for each sample. Results were compared to the wavelength and absorbencies of previously identified carotenoids in E. analoga. The carotenoid content of each tissue type with respect to parasite load group was compared. Host carotenoid profile patterns differed between tissues and some with respect to parasite loads. Carapace and ovary tissue had differences between some absorbance groups, but as the data were not normally spread due to uneven sample sizes, the results cannot be confirmed. Cystacanths found in infected crabs contained carotenoids, but their UV-vis profile appears to differ from that of host tissues. This suggests that the parasites may modify host-acquired carotenoids.

Included in

Zoology Commons