Shared Bacterial and Viral Respiratory Agents in Bighorn Sheep (Ovis canadensis), Domestic Sheep (Ovis aries), and Goats (Capra hircus) in Montana.

Transmission of infectious agents from livestock reservoirs has been hypothesized to cause respiratory disease outbreaks in bighorn sheep (Ovis canadensis), and land management policies intended to limit this transmission have proven controversial. This cross-sectional study compares the infectious agents present in multiple populations of bighorn sheep near to and distant from their interface with domestic sheep (O. aries) and domestic goat (Capra hircus) and provides critical baseline information needed for interpretations of cross-species transmission risks. Bighorn sheep and livestock shared exposure to Pasteurellaceae, viral, and endoparasite agents. In contrast, although the impact is uncertain, Mycoplasma sp. was isolated from livestock but not bighorn sheep. These results may be the result of historic cross-species transmission of agents that has resulted in a mosaic of endemic and exotic agents. Future work using longitudinal and multiple population comparisons is needed to rigorously establish the risk of outbreaks from cross-species transmission of infectious agents.

A large cost of female mate sampling in pronghorn.

We measured the energy cost of mate sampling by female pronghorn (Antilocapra americana), a species for which there are no apparent direct benefits of mate choice and for which the sampling tactic most closely resembles best-of-n or comparative Bayes. We used Global Positioning System collars to record the position of individuals at 10-min intervals during the 2 weeks preceding estrus in females that actively sampled and in females that did not sample. The difference in the 2-week energy costs of these two classes of females was 8,200 (+/-2,300) kJ, or roughly one-half of the energy cost of a single day. This value, expressed as the fraction of total yearly energy expenditure, is 59 times the value reported for a lekking bird. Our finding calls into question the common assumption in models of mate search that the cost of search is negligible as well as the common assumption that the cost of sampling must be small when there are only indirect benefits of female choice.