Influence of gut content in immature aquatic insects on assessments of environmental metal contamination

Abstract

We evaluated the effect of metal associated with the gut content in immature aquatic insects (larvae and nymphs) on spatial and interspecific comparisons of whole-body metal concentrations. Four species, common to cobble-bottom rivers and streams, were collected along an established contamination gradient in the Clark Fork River, and from tributaries of the Clark Fork. Metal concentrations were determined in the gut and its content and in the insect body. Whole-body metal concentrations were higher and more variable as a result of gut content. The positive bias produced by the gut content did not alter interpretations of site contamination in most cases. Interspecific comparisons of metal bioaccumulation also were not greatly affected by the presence of gut content. The influence of gut content was specific for metal, species, and site. Feeding habit, gut size, and metal bioaccumulation in the body affected the relative contribution of the gut and its content to metal concentrations in the whole insect.

Time Course of Metal Loss in Lumbriculus Variegatus Following Sediment Exposure

“…These estimated gut contents are within the range of those commonly observed for L. variegatus [6,[14][15][16][17], reinforcing the presumption that purging of sediment from the gut is the primary cause of the initial rapid decline in body burden rather than loss from some other internal metal pool. Variability of total metal body burdens generally decreased after gut contents were eliminated, as previously noted by Cain [18].…”

Stable isotopes as trophic tracers: combining field sampling and manipulative labelling of food resources for macrobenthos

“…In studies of uptake of xenobiotics, this has been reported to result in considerable overestimation of body burdens (e.g. Cain et al 1995) or estimates of uptake rate (e.g. Odin et al 1997).…”

Effect of post-harvest starvation and rinsing on the microbial numbers and the bacterial community composition of mealworm larvae ( Tenebrio molitor )

“…Starvation may be useful to eliminate chemical contaminants, but this has not been demonstrated so far. It is known, for aquatic insects, that the gut content can contribute significantly to the total body load of chemical pollutants (Cain, Luoma, & Axtmann, 1995). Furthermore, faeces of mealworm larvae that were fed with a deoxynivalenol (DON)-contaminated substrate were found to contain the mycotoxin (van Broekhoven, 2014in EFSA scientific committee, 2015.…”