In laboratory experiments, conspecific excretions and ammonia solutions evoked avoidance reactions in tadpoles of three anuran species, Bufo bufo, Rana temporaria, and Rana arvalis. A differential sensitivity of ammonia chemoreception was determined for two anuran species. For Bufo bufo tadpoles, these characteristics at ammonia background concentration of 0.2 mg/l lied in the range 150 % < dI/...

We determined the levels of brain acetylcholinesterase (AChE) and tail butyrylcholinesterase (BChE) activities in tadpoles of Odontophrynus americanus exposed to a commercial formulation of fenitrothion. The mean brain AChE activities in the controls tadpoles varied from 6.91 to 6.39 micromol min(-1) mg(-1) protein, whereas tail BChE activities ranged among 0.26 to 0.17 micromol min(-1) mg(-1) ...

Nonvanishing tadpoles and possible infinities associated in the multiparticle amplitudes are discussed with regard to the disk and RP 2 diagrams of the Type I ′ compactification. We find that the infinity cancellation of SO(32) type I theory extends to this case as well despite the presence of tadpoles localized in the D-brane worldvolume and the orientifold surfaces. Formalism of string S-matr...

Mammalian prolactin at doses of l-50 pg/day promoted growth (increased wet weight, dry weight and body length) in Rana pipiens tadpoles. Mammalian growth hormone (GH) promoted growth only at the higher doses (50 pg/day and above) and was not so effective as prolactin. Prolactin also inhibited metamorphosis (at doses of 5 pg/day and above). Inhibition of metamorphosis did not appear to be due to...

1. Understanding the trophic status of consumers in freshwater habitats is central to understanding their ecological roles and significance. Tadpoles are a diverse and abundant component of many freshwater habitats, yet we know relatively little about their feeding ecology and true trophic status compared with many other consumer groups. While many tadpole species are labelled herbivores or det...

Tadpoles of Rana catesbiana, possessing about two million lymphocytes, were immunized with 2,4-dinitrophenyl- and 2,4,6-trinitrophenyl-conjugated bacteria and proteins, and the antibodies produced were studied by inactivation of dinitrophenyl- and trinitrophenyl-conjugated bacteriophages. Crossreactions were determined by inhibition of inactivation of modified phages with the lysine derivatives...

I studied the invasion of Rana catesbeiana (the bullfrog) into a northern California river system where bullfrogs are not native. Native yellow-legged frogs, Rana boylii, a species of special concern, were almost an order of magnitude less abundant in reaches where bullfrogs were well established. I assessed the potential role of larval competition in contributing to this displacement in a seri...

Two hundred and twenty-four anurans of 6 species (47 adults and 16 tadpoles of Rana blairi, 35 R. catesbeiana, 31 Hyla chrysoscelis, 30 adults and 46 tadpoles of Pseudacris triseriata triseriata, 11 Bufo woodhousii, and 8 Acris crepitans) from Pawnee Lake, Lancaster County, Nebraska, were surveyed for coccidian parasites during March 2001 to May 2002. Of these, 23 of 30 (77%) adults and 4 of 46...

Little is known about the life history, ecology, and distribution of genus Allopaa (Dicroglossidae) far less recent data are available larvae this taxon. Here, we provide on larval stage hazarensis (Dubois &amp;amp; Khan, 1979) from northern Pakistan based examination three tadpoles. Specimens were obtained two sites in Buner, Khyber Pakhtunkhwa province, Pakistan. Morphological genetic analysi...

Microplastics (MPs) pollution is arousing growing attention, yet knowledge about its occurrence in amphibians scant to date. With this study, we aimed determine whether plastic (&gt;5000 ?m) and MPs (10–5000 could be detected adult Rana temporaria from a high-mountain ecosystem (the Cottian Alps, northwest Italy). To do this, aquatic compartments the digestive tract of R. were analyzed. Water, ...