DIFFERENTIAL CANID PREDATION OF TRANSLOCATED JUVENILE DESERT TORTOISES AND CHEMICAL SIGNATURE DIFFERENCES BETWEEN FEMALE AND MALE ADULT AND JUVENILE DESERT TORTOISES

Journal Article · Sat Jan 01 04:00:00 EST 2022 · Herpetological Conservation and Biology - ISSN # 1931-7603 - http://www.herpconbio.org/

OSTI ID:1834352

Hall, Derek B ^[1]; Kimbaall, Bruce A ^[2]; Germano, Jennifer M ^[3]; Gesse, Eric M ^[4]; Perry, Jeanette A ^[1]

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1. Mission Support and Test Services, LLC (MSTS), North Las Vegas, NV (United States)
2. USDA National Wildlife Research Center 3500 Market Street, Philadelphia, Pennsylvania 19104, USA
3. Institute for Conservation Research, San Diego Zoo 15600 San Pasqual Valley Road, Escondido, California 92027, USA.
4. U.S. Department of Agriculture, Wildlife Services, National Wildlife Research Center, Predator Research Facility, Millville, Utah 84326, USA

Differential predation was observed in a population of 59 translocated juvenile Desert Tortoises (Gopherus agassizii) of known sex during a juvenile translocation survival study between September 2012 and November 2017. The main source of mortality (77%; 24 of 31 deaths) was attributed to Coyote (Canis latrans) and Kit Fox (Vulpes macrotis) predation. Predation was skewed with 71% (n = 17) female mortality versus 29% (n = 7) male mortality. We tested the hypothesis that juvenile females smell different than males which leads to increased canid predation. We also explored differences in chemical signatures of resident adult female and male Desert Tortoises. We collected oral, cloacal and chin/forelimb swabs from translocated juvenile and resident adult female and male tortoises during fall 2015 and fall 2017 and analyzed them using headspace gas chromatography/mass spectrometry to determine potential differences in the chemical signatures among the four groups. Standardized chromatographic peak responses were subjected to repeated analyses of variance (ANOVA). For development of artificial scents, mean responses were calculated for each juvenile tortoise from standardized responses representing all collections (i.e., oral, cloacal, and chin/forelimb swabs) and grand means were determined for males and females. Repeated measures ANOVAs clearly demonstrated that the collections of volatiles differed according to age and/or sex depending on the body location of collection. Among the plausibly endogenous volatiles that differed by age, many of them are alcohols. Two field trials using captive Coyotes and one field trial partially within the translocation area were conducted to test if Coyotes showed a preference for female or bias against male synthesized scent. No consistent preference or bias was shown, suggesting that no innate preference for female odor was evident.

• Research Organization: Nevada National Security Site/Mission Support and Test Services LLC, Las Vegas, NV (United States)
• Sponsoring Organization: USDOE National Nuclear Security Administration (NNSA)
• DOE Contract Number: NA0003624
• OSTI ID: 1834352
• Report Number(s): DOE/NV/03624--1253; STIP WF - 26946469
• Journal Information: Herpetological Conservation and Biology - ISSN # 1931-7603 - http://www.herpconbio.org/, Journal Name: Herpetological Conservation and Biology - ISSN # 1931-7603 - http://www.herpconbio.org/
• Country of Publication: United States
• Language: English

Related Subjects

60 APPLIED LIFE SCIENCES
mortality
predation ecology
sex bias
translocation