Date of Completion
Honors Thesis - Campus Access
Victor Carmona, Ph.D.
The effects of heavy metal accumulation in ecosystems has increasingly become a topic of discussion as industry continues to invade natural habitats. Salt marshes in industrial areas prove to be an especially good tool for studying the biology of heavy metals because they act as sinks for both nutrients and toxins in their surroundings. In this study the heavy metal content of insects in Ballona Wetlands will be analyzed to better understand how the metals are accumulated and dispersed in this community and what effects they have on individuals. We hypothesized that there are significant differences in heavy metal concentrations among sites, morphospecies, and guilds. We also expect a correlation between heavy metals and wing hue intensity. Insects were collected with nets on November 4, 2014 at three sites in the Ballona Wetlands, Los Angeles California. Two moth and one membracid morphospecies were tested for heavy metal content using Inductively-Coupled Plasma-Mass Spectrometry (ICP-MS). Hues of the wings of moth morphospecies were also analyzed using Digital Imaging Analysis. A significant differences was found between heavy metal concentration and hue of all moths for the metals Barium (Ba137) and Titanium (Ti205) and among morphospecies two for the metals Selenium (Se82) and Cadmium (Cd111). These results suggest that the metals may reach the wetlands by way of runoff from the Ballona Creek, which is closest to site 1. Further experimentation is needed to understand how heavy metal levels affect those insects with the highest concentrations and if change in moth hue has adverse effects on moth reproductive fitness.
Wikholm, Katherine, "Survey of heavy metal concentrations in insects of the Ballona Wetlands of Los Angeles, California" (2015). Honors Thesis. 87.