"Got rats?" Global environmental costs of thirst for milk include acute biodiversity impacts linked to dairy feed production.

Rodents damaging alfalfa crops typically destined for export to booming Eastern markets often cause economical losses to farmers, but management interventions attempting to control rodents (i.e., use of rodenticides) are themselves damaging to biodiversity. These damages resonate beyond dairy feed producing regions through animal migration and are an overlooked part of the transferred environmental burden caused by a growing thirst for milk in China and elsewhere.

Density-Dependent Prevalence of Francisella tularensis in Fluctuating Vole Populations, Northwestern Spain.

Tularemia in humans in northwestern Spain is associated with increases in vole populations. Prevalence of infection with Francisella tularensis in common voles increased to 33% during a vole population fluctuation. This finding confirms that voles are spillover agents for zoonotic outbreaks. Ecologic interactions associated with tularemia prevention should be considered.

Performance of Rodent Spermatozoa Over Time Is Enhanced by Increased ATP Concentrations: The Role of Sperm Competition.

Sperm viability, acrosome integrity, motility, and swimming velocity are determinants of male fertility and exhibit an extreme degree of variation among closely related species. Many of these sperm parameters are associated with sperm ATP content, which has led to predictions of trade-offs between ATP content and sperm motility and velocity. Selective pressures imposed by sperm competition have been proposed as evolutionary causes of this pattern of diversity in sperm traits. Here, we examine variation in sperm viability, acrosome integrity, motility, swimming velocity, and ATP content over time, among 18 species of closely related muroid rodents, to address the following questions: (a) Do sperm from closely related species vary in ATP content after a period of incubation? (b) Are these differences in ATP levels related to differences in other sperm traits? (c) Are differences in ATP content and sperm performance over time explained by the levels of sperm competition in these species? Our results revealed a high degree of interspecific variability in changes in sperm ATP content, acrosome integrity, sperm motility and swimming velocity over time. Additionally, species with high sperm competition levels were able to maintain higher levels of sperm motility and faster sperm swimming velocity when they were incubated under conditions that support sperm survival. Furthermore, we show that the maintenance of such levels of sperm performance is correlated with the ability of sperm to sustain high concentrations of intracellular ATP over time. Thus, sperm competition may have an important role maximizing sperm metabolism and performance and, ultimately, the fertilizing capacity of spermatozoa.