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Irena Rot-Nikcevic Christopher N. Taylor Richard J. Wassersug 《Behavioral ecology and sociobiology》2006,60(1):116-25
Tadpoles can alter their behavior, morphology, and life history in response to habitat change. Although chemical signals from
conspecifics or predators play an important role in tadpole habitat assessment, little is known about the role of visual cues
and the extent to which tadpoles rely on their vision for intraspecific social assessment. The aim of our experiments was
to determine whether larval anurans use visual images of other tadpoles as indicators of density and to analyze how, and to
what extent, images of conspecifics alone affect tadpole development, growth, and behavior. To assess this, we raised both
Rana sylvatica and Bufo americanus tadpoles in aquaria with either quarter- or half-mirrored walls. Both physically increased density and increased density
simulated with mirrors decreased tadpole growth and developmental rates, and increased activity in Rana tadpoles. Bufo tadpoles did not significantly alter their growth and development in response to visually increased density. Only true, i.e.,
physically, increased density had an effect on growth and activity in Bufo tadpoles. Our data show that images of conspecifics are used as visual cues by Rana tadpoles and can induce phenotypically plastic changes in several traits. This response to visual cues is taxon-specific.
An erratum to this article can be found at 相似文献
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Predators can have significant nonlethal effects on prey by modifying prey behaviour through chemically mediated interactions.
We examined behavioural responses of wood frog (Ranasylvatica) and American toad (Bufoamericanus) tadpoles to both direct and indirect chemical signals associated with a predatory odonate (Anaxjunius). In laboratory trials, tadpoles of both species responded strongly to water conditioned with Anax nymphs by decreasing foraging rates, becoming immobile, and moving away from the stimulus. The responses to water conditioned
with starved Anax versus Anax that fed on conspecific tadpoles did not differ significantly; these results suggest that tadpoles rely primarily on direct
signals to detect odonates. Rana did not respond to water conditioned with conspecific tissue extracts, while Bufo responded with behaviours that were indistinguishable from those of tadpoles exposed to Anax chemicals. In a field experiment, the responses of R. sylvatica tadpoles to Anax chemicals were similar to those of tadpoles observed in the laboratory. Collectively, our data indicate that tadpoles of
both species use chemical cues to assess predation risk from other community members. Tadpoles can selectively distinguish
members who pose a threat, and only evacuate food patches or reduce foraging rates when in danger. These behaviours appear
to be adaptive and are consistent with the predictions of optimality theory.
Received: 1 August 1997 / Accepted after revision: 22 November 1997 相似文献
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Reinier M. Mann Ross V. Hyne Catherine B. Choung Scott. P. Wilson 《Environmental pollution (Barking, Essex : 1987)》2009,157(11):2903-2927
Agricultural landscapes, although often highly altered in nature, provide habitat for many species of amphibian. However, the persistence and health of amphibian populations are likely to be compromised by the escalating use of pesticides and other agricultural chemicals. This review examines some of the issues relating to exposure of amphibian populations to these chemicals and places emphasis on mechanisms of toxicity. Several mechanisms are highlighted, including those that may disrupt thyroid activity, retinoid pathways, and sexual differentiation. Special emphasis is also placed on the various interactions that may occur between different agro-chemicals and between chemicals and other environmental factors. We also examine the indirect effects on amphibian populations that occur when their surrounding pond communities are altered by chemicals. 相似文献
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Michael J. Barry 《毒物与环境化学》2018,100(2):205-213
The aim of this study is to measure the effects of two selective serotonin reuptake inhibitors, fluoxetine and sertraline, and one selective serotonin and norepinephrine reuptake inhibitor, venlafaxine, on the swimming and lateralization behaviour of Sclerophrys arabica tadpoles exposed to predator alarm cues. Tadpoles were exposed to the three pharmaceuticals either at 0.5 µg/L or 2.0 µg/L, either individually or as a mixture for 14 days. Control tadpoles and those exposed to high concentration of drugs individually or as a mixture, and those exposed to the low-concertation mixture reduced their swimming speed. Tadpoles exposed to 0.5 µg/L fluoxetine or venlafaxine did not respond to the alarm cues. Tadpoles exposed to the mixture had similar responses to that of the control. Results indicate that these drugs have an additive mode of action. Tadpoles exposed to the low-concentration mixture increased lateralization of movement. 相似文献
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Recent investigations have indicated that animals are able to use chemical cues of predators to assess the magnitude of predation
risk. One possible source of such cues is predator diet. Chemical cues may also be important in the development of antipredator
behaviour, especially in animals that possess chemical alarm substances. Tadpoles of the common toad (Bufo bufo) are unpalatable to most vertebrate predators and have an alarm substance. Tadpoles of the common frog (Rana temporaria) lack both these characters. We experimentally studied how predator diet, previous experience of predators and body size
affect antipredator behaviour in these two tadpole species. Late-instar larvae of the dragonfly Aeshna juncea were used as predators. The dragonfly larvae were fed a diet exclusively of insects, R. temporaria tadpoles or B. bufo tadpoles. R. temporaria tadpoles modified their behaviour according to the perceived predation risk. Depending on predator diet, the tadpoles responded
with weak antipredatory behaviour (triggered by insect-fed predators) or strong behaviour (triggered by tadpole-fed predators)
with distinct spatial avoidance and lowered activity level. The behaviour of B. bufo in predator diet treatments was indistinguishable from that in the control treatment. This lack of antipredator behaviour
is probably related to the effective post-encounter defenses and more intense competitive regime experienced by B. bufo. The behaviour of both tadpole species was dependent on body size, but this was not related to predator treatments. Our results
also indicate that antipredator behaviour is largely innate in tadpoles of both species and is not modified by a brief exposure
to predators.
Received: 22 August 1996 / Accepted after revision: 31 January 1997 相似文献
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Barbara A. Han Paul W. Bradley Andrew R. Blaustein 《Behavioral ecology and sociobiology》2008,63(2):241-250
Behaviors have evolved in response to various selection pressures over evolutionary time. However, not all behaviors are adaptive.
Some presumably “ancient” behaviors, persistent for millions of years, may be detrimental in the face of novel selection pressures
in modern times. These pressures include a multitude of emerging infectious diseases which may be stimulated by environmental
changes. We examined how a globally emerging amphibian pathogen, Batrachochytrium dendrobatidis (BD), affected two key evolutionarily persistent behaviors displayed by amphibian larvae: aggregation and thermoregulation.
Larval aggregation behavior is often essential for foraging, thermoregulation, and antipredator defense, but varies among
species. Thermoregulatory behavior speeds larval development in ephemeral habitats. Specifically, we examined whether aggregation
and thermoregulatory behaviors changed when exposed to the BD pathogen in two species (Bufo boreas and Rana cascadae) whose larvae aggregate in nature. In laboratory choice tests, larvae of neither species avoided infected conspecifics. BD-exposed
B. boreas larvae aggregated, while unexposed R. cascadae larvae associated more frequently with BD-exposed conspecifics. There was no evidence of behavioral fever or altered thermoregulation
in larvae of four species we examined (Pseudacris regilla, Rana aurora, B. boreas, R. cascadae). The absence of behavioral fever may suggest an inability of the larvae of some host species to mediate infection risk by
this pathogen. Thermoregulatory behaviors may exhibit a high degree of evolutionary inertia in amphibian hosts because they
are linked with host physiology and developmental rates, while altered aggregation behaviors could potentially elevate pathogen
transmission rates, leading to increased infection risk in social amphibian species. 相似文献
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