Effects of spider taxa and body size on mercury contamination of riparian spiders: implications for the use of spiders as sentinels

Abstract

Riparian spiders have been proposed as sentinels of aquatic mercury (Hg) contamination since they accumulate Hg through the consumption of emergent aquatic insects. The objective of this study was to assess the effect of spider taxa and body size on Hg concentrations in riparian spiders collected from two rivers with different levels of Hg contamination. In this study, we determined the effect of spider taxa and body size on Hg concentrations in four taxa of riparian spiders (Larinioides sp., Tetragnatha sp., Rabidosa sp., and Pardosa sp.) in Fort Worth, Texas. Average concentrations of Methyl-Hg (MeHg) in riparian spiders were significantly different between rivers. We determined that MeHg concentrations differed between spider taxa and were impacted by body size. These findings suggest that future studies must take these factors into account when using riparian spiders as sentinels.