Using group-specific PCR to detect predation of mayflies (Ephemeroptera) by wolf spiders (Lycosidae) at a mercury-contaminated site.
Bioaccumulation of contaminants can occur across ecosystem boundaries via transport by emergent aquatic insects. In the South River, Virginia, USA, aquatic mercury has contaminated songbirds nesting in adjacent riparian forests. Spiders contribute the majority of mercury to these songbirds' diets. We tested the hypothesis that massive annual mayfly emergences provide a vector for mercury from river sediments to the Lycosid spiders most frequently eaten by contaminated songbirds. We designed mayfly-specific PCR primers that amplified mtDNA from 76% of adult mayflies collected at this site. By combining this approach with an Agilent 2100 electrophoresis system, we created a highly sensitive test for mayfly predation by Lycosids, commonly known as wolf spiders. In laboratory spider feeding trials, mayfly DNA could be detected up to 192h post-ingestion; however, we detected no mayfly predation in a sample of 110 wolf spiders collected at the site during mayfly emergence. We suggest that mayfly predation is not an important mechanism for dietary transfer of mercury to wolf spiders and their avian predators at the South River. Instead, floodplain soil should be considered as a potential proximate source for mercury in the terrestrial food web.
Department of Biology, College of William & Mary, P.O. Box 8795 Williamsburg, VA 23187-8795, USA. wtnort@email.wm.edu
Weston T
WT
Northam
Lizabeth A
LA
Allison
Daniel A
DA
Cristol
D000818:Animals; D004781:Environmental Exposure / Q000009:adverse effects; D004785:Environmental Pollutants / Q000009:adverse effects* / Q000032:analysis; D007313:Insecta / Q000737:chemistry / Q000187:drug effects* / Q000235:genetics; D008628:Mercury / Q000009:adverse effects*; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction / Q000379:methods*; D011235:Predatory Behavior / Q000187:drug effects; D016415:Sequence Alignment; D013112:Spiders / Q000737:chemistry / Q000187:drug effects* / Q000235:genetics / Q000502:physiology
D004785:Environmental Pollutants; D008628:Mercury