Human-induced environmental change is occurring at an unprecedented rate and scale. Many freshwater habitats, in particular, have been degraded as a result of increased salinity. Little is known about the effects of anthropogenic salinization on freshwater organisms, especially at sublethal concentrations, where subtle behavioural changes can have potentially drastic fitness consequences. Using...

Predator recognition often requires learning by prey individuals. Iberian green frog tadpoles (Pelophylax perezi) have the ability to learn to recognize new potential predators when their chemical cues are found paired with conspecific alarm cues. However, a random pairing of alarm cues and chemical stimuli of a nonpredator might later induce costly antipredator responses to nondangerous specie...

Correlation of the number of primordial germ cells (PGCs) at stage 47 with the amount of germ plasm at the 8-cell stage and with the number of the germ-plasm-containing cells (GPCCs) was analysed using two different laboratory-raised colonies of Xenopus laevis, HD and J groups. The average number of PGCs in J group tadpoles was significantly larger than that in HD group tadpoles. The amount of ...

Predator-induced phenotypic plasticity is the ability of prey to adapt to their native predator. However, owing to environmental changes, encounters with unknown predators are inevitable. Therefore, study of prey and non-native predator interaction will reveal the primary stages of adaptive strategies in prey-predator interactions in the context of evolutionary processes. Here, Xenopus tadpoles...

Metamorphosis of tadpoles into frogs is accompanied by the induction of the enzymes of the urea cycle in the liver (I), which leads to the transition from ammonotelism in tadpoles to ureotelism in the frog. Paik and Cohen (2) observed that thyroxine, which is known to promote anatomical metamorphosis (3, 4), induces a marked increase in the level of carbamyl phosphate synthetase activity in the...

The tadpoles of many anuran amphibians inhabit lotic habitats and evolved oral devices to adhere to the substratum. Although published anatomical descriptions of rheophilous tadpoles exist, little is known about the modifications in gastromyzophorous tadpoles that possess abdominal suckers and live in torrential sections of streams. We describe the gastromyzophorous tadpoles of Huia cavitympanu...

Pesticides used in agriculture can have hazardous effects on aquatic organisms, and amphibians are even more threatened than other aquatic vertebrates. Maneb is widely used to control fungal diseases on crops, fruits, and vegetables. The aim of this study was to investigate the acute toxic effects of maneb on the common (Bufo bufo) and green toad (Pseudepidalea viridis) tadpoles. Tadpoles at th...

For decades, the extraction of minerals has intensified in order to meet the demand of industry. Iron ore deposits are important sources of metals, such as iron (Fe) and manganese (Mn). The particulate ores can be dispersed during extraction, transport and storage, with potential to induce biological impacts. Amphibians are very sensitive to environmental stressors. Therefore, the present study...

Organisms in aquatic ecosystems must often tolerate variable environmental conditions, including an uncertain risk of predation. Individuals that can maintain plastic defenses against predation will increase their survival when predators are present, but will not incur the costs of these defenses when the risk of predation is low and the defense is not induced. Larvae of the pond-breeding anura...

The natural diet of northern temperate tadpoles is a largely neglected area of study. We investigated the natural diets in three anuran larvae, the wood frog (Rana sylvatica), the American toad (Bufo americanus), and the spring peeper (Pseudacris crucifer), from several ephemeral ponds in northern Minnesota. Previous laboratory studies suggest that these species, as well as others with similar ...