<p>Mayflies are important macroinvertebrate members of steam
communities and are highly sensitive to agricultural insecticides. In this
dissertation I sought to explore whether Heptageniidae<i> </i>mayflies in
Indiana have evolved greater tolerance to clothianidin, a neonicotinoid
insecticide that has been widely applied over the predominant corn and soybean
crops of the state for the last 20 years. Over the five chapters of this
dissertation, I investigate different aspects of the effects of clothianidin on
mayfly populations. First, I collected mayfly populations from streams around
the state across a gradient of agricultural landscape to see if proximity to corn
and soybean crops was associated with tolerance to the insecticide. I found
significant variation in tolerance between the populations but only connected
it to land use for one species and one insecticide. Second, I investigated the
potential for increases in predation rates due to exposure to low concentrations
of clothianidin by both a vertebrate and invertebrate predator. Sublethal
exposure did increase the risk of predation by the invertebrate predator but
not the vertebrate. Third, I collected four populations of mayflies and placed
them in a common stream which is heavily impacted by agricultural runoff. The
most tolerant of the four populations had the highest survival rates and was
native to the polluted stream, suggesting that it was best adapted to the local
conditions. Finally, the last chapter is a discussion of the factors
influencing the evolution of contaminant tolerance, the implications for
biomonitoring, and a series of recommendations for incorporating evolved
tolerance into biomonitoring practices. Collectively, this work suggests that
the lethal and sublethal effects of clothianidin exposure create conditions
suitable for the evolution of tolerance in Heptageniid mayflies. While there are
already differences in tolerance between populations, it seems likely that
mayfly pesticide tolerance will continue to increase as pesticides continue to impact
aquatic ecosystems. </p>
| Identifer | oai:union.ndltd.org:purdue.edu/oai:figshare.com:article/14489247 |
| Date | 26 April 2021 |
| Creators | Daniel R Rackliffe (10675833) |
| Source Sets | Purdue University |
| Detected Language | English |
| Type | Text, Thesis |
| Rights | In Copyright |
| Relation | https://figshare.com/articles/thesis/EVOLUTIONARY_IMPLICATIONS_OF_NEONICOTINOID_EXPOSURE_TO_MAYFLIES_OF_THE_HEPTAGENIIDAE/14489247 |
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