Date of Award
Amy L. Russell
Microcystis aeruginosa is a species of cyanobacteria capable of producing a hepatotoxin called microcystin. As toxic M. aeruginosa overwinters in the sediments of lakes, it is ingested by some mayfly larvae, such as those of Hexagenia spp., and thus
microcystin bioaccumulates in these insects. When Hexagenia emerge from lakes to
reproduce, they provide an abundant, albeit temporary, food source for many terrestrial
organisms such as bats. Little brown bats, Myotis lucifugus, likely feed opportunistically
on aquatic insects. To test if microcystin moves from aquatic to terrestrial ecosystems via trophic transfer, we 1) tested bat feces for the presence of Hexagenia mayflies and 2) tested bat livers and feces for microcystin. In June 2014, in correspondence with the
Hexagenia emergence, bat feces were collected from underneath a maternity roost near
Little Traverse Lake (Leelanau County, MI). On 20 and 27 June we caught 19 female M.
lucifugus, which were euthanized, and collected their livers and feces. DNA was
extracted from feces, amplified with a Polymerase Chain Reaction (PCR), and sequenced. Concentrations of microcystin in liver tissue and feces were determined using an enzymelinked immunosorbent assay (ELISA) and liquid chromatography with tandem mass spectrometry (LC-MS/MS). Hexagenia were present in the diet of M. lucifugus and the most likely source of microcystin. Our analyses reveal that microcystin was also present, with higher concentrations in the bat feces than the livers. Additionally, histopathology results of three bat livers with highest concentrations of microcystin show little to no cytological damage from the toxin. From these data, it appears that M. lucifugus are not highly affected by the ingestion of microcystin.
Jones, Devin, "Trophic Transfer of a Naturally Occurring Algal Toxin from a Freshwater Lake to Little Brown Bats" (2016). Masters Theses. 816.