Utility of fluctuating asymmetry in caddisflies (Trichoptera) as an indicator of coastal wetland health in Lake Erie

Fluctuating asymmetry (FA) in caddisflies can serve as a tool to determine ecosystem stress. Eight Lake Erie coastal wetlands were sampled to determine if different sampling methods detected biotic differences between impacted and un-impacted wetlands of two types (protected embayments and open lacustrine wetlands). Adult caddisflies were sampled with modified light traps to restrict draw from only populations within the wetland site. Hydroptila waubesiana and Agraylea multipunctata were the most abundant trichopteran taxa collected. We investigated whether levels of FA in H. waubesiana and A. multipunctata can be correlated with wetland quality. We also assessed whether habitat generalist species such as H. waubesiana will exhibit less symmetry than habitat specific species such as A. multipunctata. Measurements of the FA on three morphological characters were assessed, 1) length of front tibia, 2) length of costal vein on front wing, and 3) length of antennal scape. In order to calculate FA for each character the absolute value of log right measurement minus log left measurement were taken; FA=/logR-logL/. There was a significant increase of FA in the tibial length of H. waubesiana in impacted wetlands, implying that FA in H. waubesiana may be useful as an indicator in wetland quality. Neither character in A. multipunctata exhibited a significant difference in BCFA between unimpacted and impacted wetlands. There is no evidence that habitat specialists are more susceptible to asymmetry than habitat generalist species.