Growth and development of larval northern cricket frogs (Acris crepitans) in relation to phytoplankton abundance

SUMMARY. 1. Tadpoles of Acris crepitans were collected from two ponds in central Illinois, Depth, water temperature, distance from shore and water samples were taken at each sample site. The potential for food limitation and non-random habitat selection were examined.
2. Algal densities from water samples averaged over 1.0× 10⁶ cells ml⁻¹ in Scott's pond hut only 4.6×10³ cells ml⁻¹ in Vic's pond.
3. Guts of tadpoles from Scott's pond contained more algal cells than did guts of tadpoles from Vic's pond. Tadpoles from Scott's pond were consistently larger and more advanced in development than tadpoles collected from Vic's pond at the same lime. Therefore, tadpoles of Scott's pond were able to utilize the higher algal densities whereas tadpoles of Vic's pond may be food-limited, causing reduced growth and development.
4. Canonical discriminant analysis was used to test whether sites with different numbers of tadpoles could be distinguished based on environmental variables. Canonical function I was primarily a measure of water depth at a sample site. This function was significant in Scott's pond only. Sites containing one or more tadpoles were not easily distinguished from each other, but were found in consistently shallower water than sites where no tadpoles were found.