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Biomedical subjects

A R Blaustein

Publications and source records attributed to A R Blaustein.

9 recordsLinked to original sources
PubMed1995

Synergism between UV-B radiation and a pathogen magnifies amphibian embryo mortality in nature.

Previous research has shown that amphibians have differential sensitivity to ultraviolet-B (UV-B) radiation. In some species, ambient levels of UV-B radiation cause embryonic mortality in nature. The detrimental effects of UV-B alone or with other agents may ultimately affect amphibians at the population level. Here, we experimentally demonstrate a synergistic effect between UV-B radiation and a pathogenic fungus in the field that increases the mortality of amphibian embryos compared with either factor alone. Studies investigating single factors for causes of amphibian egg mortality or population declines may not reveal the complex factors involved in declines.

Animals↗
PubMed1989

Mechanisms and ecological correlates of kin recognition.

Kin recognition, which can be inferred from differential interactions amongst close relatives as compared to unrelated conspecifics, has been documented in a wide range of vertebrates and invertebrates. Kin may be discriminated by phenotypic traits (signatures) that are genetically mediated, acquired from the environment, or arise from an interaction between these two sources. The developmental mechanisms underlying recognition of relatives (or their signatures) include direct contact and familiarization, indirect familiarity (whereby previously unencountered individuals are recognized by their resemblance to familiar kin) and hypothetical recognition alleles. The biological significance and mediating mechanisms of kin recognition vary across species according to their ecology and natural history. To illustrate this point, the results of laboratory and field studies of larvae of several species of toads and frogs are reviewed.

Animal Communication↗
PubMed1985

An investigation of the alarm response in Bufo boreas and Rana cascadae tadpoles.

Tadpoles of the western toad (Bufo boreas) and of the Cascades frog (Rana cascadae) show an alarm reaction to an extract containing chemical cues from damaged conspecifics. The mean time spent by individual B. boreas tadpoles in the half of the test tank to which the extract solution was added was significantly lower than expected by chance. Activity was also significantly greater in Bufo extract tests than in control tests. Tadpoles did not avoid an extract of another tadpole species (Hyla regilla). Rana cascadae tadpoles did not avoid areas containing Rana extract but did significantly increase their level of activity in response to the extract. These results suggest that the R. cascadae tadpole alarm reaction exists but differs from the B. boreas reaction.

Animals↗
PubMed1983

Kin recognition in Rana cascadae tadpoles: effects of rearing with nonsiblings and varying the strength of the stimulus cues.

Experiments with two clutches of Rana cascadae tadpoles were undertaken to determine if (1) rearing tadpoles exclusively with nonkin affects sibling recognition behavior and (2) if tadpoles are capable of distinguishing between groups of varying sibling/nonsibling composition. Individual tadpoles reared from embryonic stages with 12 nonsiblings behaved as tadpoles reared with siblings by exhibiting a preference for siblings over nonsiblings in choice tests. This suggests that experience with siblings is not a necessary prerequisite for the development of sibling recognition in this species. Tadpoles reared with siblings preferred to associate with a group composed of 50% siblings and 50% nonsiblings over a group of 100% nonsiblings, but exhibited no preference for a group composed of 25% siblings and 75% nonsiblings versus one composed of nonsiblings only. Thus tadpoles are capable of discriminating between mixed groups of siblings and nonsiblings, but probably require some minimum proportion of siblings to do so.

Animals↗
PubMed1982

Kin recognition cues in Rana cascadae tadpoles.

The importance of chemical, visual, and auditory cues in kin recognition behavior in Rana cascadae tadpoles was tested in laboratory choice experiments. Tadpoles were given a choice of associating with siblings or nonsiblings by using visual and chemical stimuli together (standard tests), visual stimuli alone, or chemical stimuli alone. We also monitored sound production of tadpoles. We conclude that tadpoles can distinguish between siblings and nonsiblings by using waterborne chemical cues alone that are probably sensed by olfaction or taste. Visual stimuli alone are not sufficient for such discrimination and sound production as a means of communication in tadpoles is probably unimportant.

Animals↗
PubMed1981

Genetic control for sibling recognition?

The ability to distinguish between kin and non-kin is critical to current theories of altruistic behaviour and kin selection. Hamilton predicted that individuals would behave differently towards one another depending on the genetic relatedness between them. When either proximity to or familiarity with kin is a good predictor of relatedness, the mechanism by which favouritism towards kin is accomplished may not require special kin recognition abilities. However, if proximity and familiarity are poor predictors of kinship, favouritism (hence increases in inclusive fitness) could only be achieved by the differential recognition of kin and non-kin. We have previously shown that Cascades frog (Rana cascadae) tadpoles reared with siblings prefer to associate with siblings over non-siblings. The present study is the first to report that totally naive individuals (R. cascadae tadpoles) prefer to associate with siblings over non-siblings. Because tadpoles were separated before hatching and reared apart from other individuals, results suggest that the ability of these tadpoles to discriminate between siblings and non-siblings has some innate component.

Animals↗