Straight from the Coyote’s Mouth: Genetic Identification of Prey through Oral Swabs of Predators

Human-carnivore conflicts often involve the depredation of domestic livestock. These depredation events are rarely observed, yet mitigation typically involves identifying the species or individual involved for removal or relocation. We tested a molecular method to identify individuals involved in depredation events using mouth swabs to determine if prey DNA could be detected, and for how long. We fed mule deer Odocoileus hemionus meat to captive coyotes Canis latrans and swabbed their mouths at five predetermined intervals between 2–72 h after consumption of the deer meat. We assessed two different molecular forensic methods to analyze the saliva swabs: qPCR for species identification and microsatellites for individual prey identification. We found that qPCR analysis was highly effective, detecting the deer DNA in the coyote saliva for up to 72 h post-deer consumption. Our results suggest that if an individual carnivore suspected of livestock depredation is captured within 72 h of a depredation incident, it is possible to confirm their potential involvement with a buccal swab and qPCR analysis. Utilizing this method could aid in more targeted and effective removal of individual problem carnivores as opposed to widespread removal of involved species

Using Noninvasive Genetics for Estimating Density and Assessing Diet of Urban and Rural Coyotes in Florida, USA

Coyotes (Canis latrans) are expanding their range and due to conflicts with the public and concerns of Coyotes affecting natural resources such as game or sensitive species, there is interest and often a demand to monitor Coyote populations. A challenge to monitoring is that traditional invasive methods involving live-capture of individual animals are costly and can be controversial. Natural resource management agencies can benefit from contemporary noninvasive genetic sampling approaches aimed at determining key aspects of Coyote ecology (e.g., population density and food habits). However, the efficacy of such approaches under different environmental conditions is poorly understood. Our objectives were to 1) examine accumulation and nuclear DNA degradation rates of Coyote scats in metropolitan and rural sites in Florida to help optimize methods to estimate population density; and 2) explore new genetic methods for determining diet of Coyotes based on vertebrate, plant, and invertebrate species DNA identified in scat. Recently developed DNA metabarcoding approaches make it possible to simultaneously identify DNA from multiple prey species in predator scat samples, but an exploration of this tool for assessing Coyote diet has not been pursued. We observed that scat accumulation rates (0.02 scats/km/day) did not vary between sites and fecal DNA amplification success decreased and genotyping errors increased over time with exposure to sun and precipitation. DNA sampling allowed us to generate a Coyote density estimate for the urban environment of eight Coyotes per 100 km2, but lack of recaptures in the rural area precluded density estimation. DNA metabarcoding showed promise for assessing diet contributions of vertebrate species to Coyote diet. Feral Swine (Sus scrofa) were detected as prey at higher frequencies than previously reported. We identify several considerations that can be used to optimize future noninvasive sampling efforts for Coyotes in the southeastern United States. We also discuss strengths and drawbacks of utilizing DNA metabarcoding for assessing diet of generalist carnivores such as Coyotes

Identification of Brucella suis from Feral Swine in Selected States in the USA

Serologic tests currently available for brucellosis diagnosis detect antibodies to Brucella but do not distinguish between species of Brucella. Although Brucella suis is known to circulate within various feral swine (Sus scrofa) populations, our objective was to determine the primary species of Brucella circulating in feral swine populations in areas of the US with high brucellosis prevalence. We cultured lymph nodes from 183 feral swine. We identified 22 isolates from 21 animals, and all isolates were genotyped as B. suis. Most isolates were B. suis biovar 1, with the exception of two genetically distinct isolates from one feral swine in Hawaii, which were identified as B. suis biovar 3. Serum from each feral swine was also tested by the fluorescence polarization assay when possible, but only 52% (95% CL529.8–74.3) of culture-positive animals were antibody positive. Our results indicate that brucellosis infections in feral swine within the US are typically caused by B. suis. However, improved serologic tests are needed to more accurately determine exposure to Brucella spp. and to monitor disease trends in feral swine populations