| Abstract | Mercury (Hg) is an anthropogenic contaminant found in all aquatic ecosystems across the world. One method to monitor levels of Hg contamination in an ecosystem is assess Hg in sentinel organisms: abundant and widely distributed organisms within th food web that accumulate contaminants in body tissues without negative effects. Riparian spiders are a potential sentinel organism for Hg contamination in aquatic ecosystems, accumulating Hg when they consume Hg-contaminated emergent aquatic insects. The present study examined the effects of spider body size and season on two genera of orb-weaving spiders in the family Araneidae: Larinioides sp. and Metazygia sp. We collected 574 orb-weaving spiders from a boat dock on Eagle Mountain Lake, Texas, USA, from May to September 2019. The spiders were preserved in 95% ethanol and sorted based on genera, month collected, and size class. Size class was determined by measuring the spider's front left leg length (tibia + patella). Mercury concentration was analyzed through direct Hg analysis. A positive correlation was observed between spider size and total Hg concentration in all but one month. Total Hg concentrations increased from May to September. Future studies using shoreline spiders as sentinels of Hg contamination need to collect a size array of spiders in different seasons. |
