The effects of the cyanobaterial toxin, Microcystin-LR, on the developmental stability of the Amber-Winged Spreadwing Damselfly, Lestes eurinus (Odonata)

Cyanobacterial blooms are known to produce significant amounts of hepatotoxins, which are major concerns for eutrophic and hypereutrophic systems. Toxicity studies have shown aquatic insects to be at risk during blooms, however the lethal range far exceeds concentrations measured for bloom conditions around the world. We examined the developmental effects of Microcystin-LR on the Amber-Winged Spread Wing Damselfly, Lestes eurinus. Adults were observed oviposting into plants, which were brought back to the lab for incubation. Nymphs were collected and allowed to develop for 3 wk prior to treatment. 120 nymphs were divided evenly into six groups and then placed individually into 100ml of water containing different concentrations of Microcystin-LR, 0 μg L^-1, 1 μg L^-1, 10 μg L^-1, 20 μg L^-1, 35 μg L^-1, 60 μg L^-1. In addition, half of the nymphs were given food that had been previously exposed to Microcystin-LR, the other half were given food that had never been exposed. Treatments lasted for 6 wk. Phenological and mortality data was taken throughout development, and measurements for fluctuating asymmetry FA were taken at four instances throughout development. Femur measurements were taken just prior to treatment, just after treatment, just before metamorphosis, and after emergence. Wing measurements were taken for adults, and claspers measurements were taken for adult males. These data were used to test first that Microcystin-LR decreases the amount of developmental stability and to test the stressful metamorphosis hypothesis.