Chemically Characterizing Native Nova Scotian Freshwater Turtle Nest Scents for Olfactory Misinformation Applications

Abstract

All native freshwater turtle species in Canada are currently in decline, including four species found in Nova Scotia. One major threat they face is high rates of nest predation, particularly by mammalian predators, which limits successful population recruitment. This problem is exacerbated by habitat loss, forcing turtles to nest in areas that are easily accessible to human-subsidized predators. Current nest protection methods (e.g., nest cages) are costly and inefficient, creating the need for improved methods of predation prevention to meet government mandates to protect turtles. This study proposes a conservation approach known as olfactory misinformation, which targets predators’ reliance on scent to locate nests. Conditioning predators to ignore unrewarded scents mimicking those of vulnerable prey, the method aims to camouflage real nests within the environment. The objective was to identify volatile organic compounds (VOCs) characterizing nest scents of freshwater turtle species native to Nova Scotia to guide the development of artificial scent solutions for use in olfactory misinformation strategies. This study combined field and lab work; swab samples were collected from adult female turtles and hatchlings during the 2024 nesting season, then analyzed using headspace solid-phase microextraction coupled to gas chromatography-mass spectrometry. Across all (n=49) samples, a diverse array (n=160) of volatiles were detected. Focusing on the most frequently observed VOCs found in the highest concentrations across samples revealed linalool oxide and 2-ethylhexanol as key volatiles characterizing nest scents for all species of Nova Scotian freshwater turtles. These VOCs, emitted by both adult turtles and hatchlings, enable the development of a single, generalized scent solution that can be applied to protect all turtle populations during both spring and fall predation seasons. Other volatiles were specifically characteristic of either cloacal fluids (e.g.,2-pentylfuran and 2-butoxyethanol), epidermal secretions (e.g., 3-methylcyclopentyl acetate and 5-hepten-3-yn-2-ol, 6-methyl-5-(1-methylethyl)), or hatchlings (e.g., mesitylene and limonene), their identification allowing for the creation of more complex scent solutions. Future steps of this project will involve testing the solution’s ability to attract mammalian predators in field trials and eventually condition them to ignore the unrewarded scent, making it the first olfactory misinformation approach to utilize artificial scents. Keywords: olfactory misinformation; turtle nest predation; freshwater turtle conservation; volatile analysis.