Potential of Cicindellidae as bioindicators of arsenic uptake in a marine food web

Species of tiger beetles (Coleoptera: Cicindelidae) occurring at South Padre Island, Texas provided the opportunity to evaluate their usefulness as bioindicators of arsenic uptake and accumulation. The marine environments of South Padre Island include both oceanic and lagoon shorelines, where tiger beetles exist as predators consuming insects with aquatic and/or terrestrial life cycles. The Laguna Madre is hypersaline and is known to contain varying levels of arsenic originating from agricultural runoff of Willacy, Cameron, and Hidalgo counties that enters the Arroyo Colorado and ultimately into the lagoon. The potential for arsenic to enter the shoreline food web and be found in tiger beetles was examined using Rhodamine B and confocal microscopy, and additionally microanalysis by energy dispersive x-ray spectroscopy and the Zeiss Evo LS10 scanning electron microscope was experimented with. The results are evaluated to determine the usefulness of tiger beetles as bioindicators of arsenic exposure pathways.