Oil-Mediated Mortality and Induced Behavioral Modifications of Coastal Insects

• Main Author: Adams, Benjamin Jacob
• Other Authors: R. Eugene Turner
• Format: Others
• Language: en
• Published: LSU 2012
• Subjects: Entomology
• Online Access: http://etd.lsu.edu/docs/available/etd-11152012-160909/

The Deepwater Horizon oil spill affected over one thousand kilometers of the southeastern United States coast in the Gulf of Mexico especially Louisianas salt marshes. These marshes are a vital part of the states economy and coastal ecology; however, the insects residing in this area remain largely unstudied. The goal of my project was to answer specific questions arising from two ongoing investigations of the insects in the oiled marshes. I sampled insects using sweep nets and insect vacuums to determine the most efficient technique to use in the marsh, compared insects collected in oiled and non-oiled marshes, and completed a taxonomic list of all of the insects collected in the marsh. I determined the effect of weathered oil on the mortality and foraging behavior of the ant Crematogaster pilosa. I used the house cricket, Acheta domesticus, to test the effect of direct and indirect oil exposure on insect mortality. I also used colonies of A. domesticus to determine if any sub-lethal effects occurred as a result of exposure to oil vapors. Sweep-net sampling collected four times more insects than vacuuming and collected significantly more insect taxa (p = 0.0005). Oiled marshes had increased insect populations compared with non-oiled areas (p = 0.0495). Over 108 insect morphospecies were collected in the marsh. C. pilosas foraging behavior was drastically reduced by oil presence (p < 0.0001) though oil did not usually increase mortality. The time for 50% and 100% mortality to occur in A. domesticus was significantly less when exposed to direct contact with oil (p < 0.0001 for both 50% and 100%) and indirect contact with oil (p = 0.0053, p = 0.0005 for 50% and 100%, respectively). House crickets exposed to oil vapors showed reduced adult life spans, longer time to maturation, and changes in resistance to parasites when compared with controls. All these data indicate oil exposure can change insect populations, rates of mortality, and behaviors