spermatic cyst diameter, germinal epithelium depth, and gonadosomatic index were smaller in the injected males compared to males injected with saline (control) as well as their noninjected counterparts. This suggests that sperm production decreases under immunological stress. More generally and importantly, these results demonstrate that resource investment in reproduction decreases as more resources must be allocated to the immune system under immunologically-challenging conditions. Thermoregulation Northern cricket frogs are diurnal and generally active much of the year, except in midwinter in northern areas when the water is frozen. They are freeze resistant so during winter months, they stay underground near the surface to resist freezing. Individuals can increase the concentration of body fluids to lower their freezing points, making them resistant to supercooling and flashpoint freezing. Morphology Acris crepitans morphologically unique among hylidaes because of their unusually small size. A snout vent length of 20mm marks sexual maturity. Females are slightly larger than males and can reach a maximum snout vent length of 38mm. The northern cricket frog's overall small size and limited skull ossification suggests miniaturization of this species. Miniaturization, or the evolution of a smaller body size, due to changes in anatomy, physiology, life history, and behavior over time. For this species, the necessity to rapidly attain sexual maturity could explain its miniaturization; frogs grow 12 to 26 mm within a few months in preparation for the breeding season. The cranial cartilages of these frogs are very mineralized with calcium, which reinforce cartilage as frogs develop into adulthood. These frogs possess small, thin, and long nasals, which is consistent with its being a small anuran. The nasals take a triangle-like shape. Other skeletal abnormalities of A. crepitans include lateral asymmetry in development of vomerine teeth and parasphenoid alae as well as tumor-like growth on the femur. Several hypotheses have been presented in an attempt to explain the observed abnormalities in this frog: small skeletal malformations are normally present at a high rate in this species, stress caused by habitat fragmentation, or there is environmental contamination. References External links Animal Diversity Web: Acris crepitans USGS: Northern Cricket Frog Frogs & Toads of Georgia: Acris crepitans crepitans Conant et al. (1998). A Field Guide to Reptiles and Amphibians of Eastern and Central North America. Boston: Houghton Mifflin. . Martof et al. (1980). Amphibians and Reptiles of the Carolinas and Virginia. Chapel Hill: University of North Carolina Press. . Acris Amphibians of