Cirton, Shawn R. 1999. Phototaxis, metal concentrations, and fluctuating asymmetry in isopods from metropolitan Chicago, Illinois. Masters Thesis. Department of Biological Sciences, Chicago State University, Chicago, Illinois.

Abstract The Lake Calumet area of south Chicago, Illinois has a long history of metal contamination due to industrial activities and waste production. Many of these sources of metal contamination are in close proximity to human habitation. Because of the hydrology of the Lake Calumet area, the bioavailability of metal contaminants is an issue of concern for those living in the Lake Calumet area. Terrestrial isopods are proposed as potential biological indicators for the presence of metal contaminants in the Lake Calumet area biota. Light avoidance behavior and ommatidia asymmetry in the terrestrial isopod Armadillidium vulgare were investigated as means of assessing the effects of contamination in several sites in the Lake Calumet area, and these were compared with isopods from a site from the Chicago area outside the zone of influence from Lake Calumet metalworking industries. It was hypothesized that the environmental stress of high levels of metal pollutants would cause altered negative phototactic behavior in the isopods as well as induce fluctuating asymmetry. There were significant differences for light avoidance times by location. Elevated concentrations of metals were found in all Lake Calumet area isopods, indicating that metals in the area are accumulating in the biota. However, there were no significant relationships between light avoidance times and population asymmetry and no significant relationships between light avoidance times and concentrations of the 16 metals and metalloids examined, except for nickel. There were also no significant relationships between population asymmetry and metal concentrations, also except for nickel. The results did show, however, that there is a trend towards increasing asymmetry with increasing metal concentrations. This suggests that additional research into behavioral responses and other indicators of the effects of metal pollutants should be investigated in terrestrial isopods in the Lake Calumet area.