Prevalence of six viral and bacterial diseases in wild hogs in South Carolina (2007-2013)

The wild hog (Sus scrofa) is an invasive species that can pose a serious threat to native ecosystems, the domestic livestock industry, and human health. It is estimated that wild hog damage in the United States amounts to roughly $1.5 billion each year; however, this estimate could substantially increase if wild hogs transmitted a viral or bacterial disease to the country’s domestic livestock industry. From 2007-2013, blood and nasal secretion samples were collected from 629 wild hogs in South Carolina to test for 6 selected diseases including classical swine fever, swine brucellosis, pseudorabies virus, porcine circovirus, porcine reproductive and respiratory syndrome, and swine influenza virus all of which can be transmitted to domestic livestock. The sex, age class, and geographic location of each wild hog sampled were also recorded. Results indicate that age class was significantly associated with swine brucellosis, pseudorabies virus, and porcine circovirus prevalence. Positive swine brucellosis, pseudorabies virus, and porcine circovirus samples were found in 50.0-92.3% of counties sampled. Because wild hogs are present in every county of South Carolina, this information is crucial to determine disease hotspots in the state and can be shared with at-risk individuals and domestic livestock operations in affected counties

Daily energy expenditure in free-ranging Gopher Tortoises (Gopherus polyphemus)

Studies of ecological energetics in chelonians are rare. Here, we report the first measurements of daily energy expenditure (DEE) and water influx rates (WIRS) in free-ranging adult Gopher Tortoises (Gopherus polyphemus). We used the doubly labeled water (DLW) method to measure DEE in six adult tortoises during the non-breeding season in south-central Mississippi, USA. Tortoise DEE ranged from 76.7-187.5 kJ/day and WIR ranged from 30.6-93.1 ml H2O/day. Daily energy expenditure did not differ between the sexes, but DEE was positively related to body mass. Water influx rates varied with the interaction of sex and body mass. We used a log/log regression model to assess the allometric relationship between DEE and body mass for Gopher Tortoises, Desert Tortoises (Gopherus agassizii), and Box Turtles (Terrapene carolina), the only chelonians for which DEE has been measured. The slope of this allometric model (0.626) was less than that previously calculated for herbivorous reptiles (0.813), suggesting that chelonians may expend energy at a slower rate per unit of body mass compared to other herbivorous reptiles. We used retrospective power analyses and data from the DLW isotope analyses to develop guidelines for sample sizes and duration of measurement intervals, respectively, for larger-scale energetic studies in this species

Variation in Energy Expenditure among Black‐Legged Kittiwakes):Effects of Activity‐Specific Metabolic Rates and Activity Budgets

We sought to determine the effect of variation in time‐activity budgets (TABs) and foraging behavior on energy expenditure rates of parent black‐legged kittiwakes (Rissa tridactyla). We quantified TABs using direct observations of radio‐tagged adults and simultaneously measured field metabolic rates (FMR) of these same individuals (n = 20) using the doubly labeled water technique. Estimated metabolic rates of kittiwakes attending their brood at the nest or loafing near the colony were similar (ca. 1.3 × basal metabolic rate [BMR]), although loafing during foraging trips was more costly (2.9 × BMR). Metabolic rates during commuting flight (7.3 × BMR) and prey‐searching flight (6.2 × BMR) were similar, while metabolic rates during plunge diving were much higher (ca. 47 × BMR). The proportion of the measurement interval spent foraging had a positive effect on FMR (R2 = 0.68), while the combined proportion of time engaged in nest attendance and loafing near the colony had a negative effect on FMR (R2 = 0.72). Thus, more than two‐thirds of the variation in kittiwake FMR could be explained by the allocation of time among various activities. The high energetic cost of plunge diving relative to straight flight and searching flight suggests that kittiwakes can optimize their foraging strategy under conditions of low food availability by commuting long distances to feed in areas where gross foraging efficiency is high

Evidence of an interannual effect of maternal immunization on the immune response of juveniles in a long-lived colonial bird.

Little is known about the maternal transfer of antibodies in natural host-parasite systems despite its possible evolutionary and ecological implications. In domestic animals, the maternal transfer of antibodies can enhance offspring survival via a temporary protection against parasites, but it can also interfere with the juvenile immune response to antigens. We tested the functional role of maternal antibodies in a natural population of a long-lived colonial seabird, the kittiwake (Rissa tridactyla), using a vaccine (Newcastle disease virus vaccine) to mimic parasite exposure combined with a cross-fostering design. We first investigated the role of prior maternal exposure on the interannual transmission of Ab to juveniles. We then tested the effect of these antibodies on the juvenile immune response to the same antigen. The results show that specific maternal antibodies were transferred to chicks 1 year after maternal exposure and that these antibodies were functional, i.e. they affected juvenile immunity. These results suggest that the role of maternal antibodies may depend on the timing and pattern of offspring exposure to parasites, along with the patterns of maternal exposure and the dynamics of her immune response. Overall, our approach underlines that although the transgenerational transfer of antibodies in natural populations is likely to have broad implications, the nature of these effects may vary dramatically among host-parasite systems, depending on the physiological mechanisms involved and the ecological context