Effect of the Fire Ant Pesticide Hydramethylnon (AMDRO®) on the Nest Survival and Hatchling Orientation of Loggerhead Sea Turtles


Meeting Abstract

25-6  Friday, Jan. 4 14:45 – 15:00  Effect of the Fire Ant Pesticide Hydramethylnon (AMDRO®) on the Nest Survival and Hatchling Orientation of Loggerhead Sea Turtles SMITH, HE*; HOOVER, SR; SALMON, M; SEAMAN, H; COPPENRATH, CM; HIRSCH, S; PERRAULT, JR; Florida Atlantic University; Florida Atlantic University; Florida Atlantic University; Loggerhead MarineLife Center; Loggerhead MarineLife Center; Loggerhead MarineLife Center; Loggerhead MarineLife Center ichthyodea@gmail.com

Invasive fire ants are voracious predators of ground nesting birds and reptiles, and are spreading rapidly throughout tropical and temperate climates. The pesticide AMDRO® has been widely used on marine turtle nesting beaches to protect nests and hatchlings from these predators, but no studies have been done to thoroughly assess its effect on any reptile species. In other vertebrates, contact with AMDRO® can result in visual impairment, dermal abrasions, and reduced reproductive success. In this field study, we examined its impact on hatching success, emergence success, and orientation behavior in loggerhead sea turtles (Caretta caretta) in Juno Beach, Florida. Pesticide granules were placed on the sand above the nest days in advance of an emergence; corn grit granules served as the vehicle control and were placed above nests for comparison to the AMDRO® treated nests. Sand samples were collected to determine if the toxicant persisted in the environment, and preliminary analyses indicate that the pesticide remained in the sand after dosing. We found that the toxicant had no effect on hatchling morphology, hatching success, or emergence success. It also had no effect on the ability of hatchlings to orient toward the ocean (a visually mediated response). However, we did notice more ant and crab predators at treatment nests than are normally seen at our study site. Thus, while AMDRO® might not directly impact reproductive success or hatchling behavior, it had the unanticipated effect of possibly increasing nest vulnerability to predators.

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