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Schooling decisions in guppies (Poecilia reticulata) are based on familiarity rather than kin recognition by phenotype matching 总被引:4,自引:0,他引:4
Evidence from a number of freshwater species indicates that fish prefer to school with familiar individuals. Do they also choose to associate with kin? Our experiment tested this idea using the Trinidadian guppy, Poecilia reticulata, a species whose reproductive biology favours the association of kin groups. Juveniles reared together were able to recognise one another on the basis of either visual or chemical cues, but showed no preference for schooling with unfamiliar kin. We therefore conclude that any naturally occurring kin groups in this species will occur as a result of familiarity rather than as a consequence of kin recognition based on phenotype matching. 相似文献
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Joachim G. Frommen Meike Hiermes Theo C. M. Bakker 《Behavioral ecology and sociobiology》2009,63(8):1141-1148
Many animals live in groups most of their life. One function of this behaviour is an increased predator protection whereas
larger groups provide better protection than smaller ones. A causal explanation is that due to a higher number of shoal members
the individual risk of being predated will decrease (“dilution effect”). Additionally, shoaling leads to increased predator
confusion. This “confusion effect” can be strengthened by an increased group density, which often correlates with group size.
Many studies found that individuals prefer the larger of two groups. However, whether this preference is due to a larger group
size or because of an increased density of the larger group remained unclear. To disentangle these factors we gave three-spined
sticklebacks (Gasterosteus aculeatus) the choice between shoals of (1) different group size and density, (2) different group size, but equal density and (3) equal
group sizes, but different densities. As expected, test fish preferred the larger and denser shoal over the smaller, less
dense one. This preference was lost when shoal size differed but density was kept constant. When shoal size was equal but
density differed, test fish preferred the less dense shoal. However, this was only the case when test fish chose between two
relatively dense shoals. On the other hand, when overall density was low, test fish did not discriminate between shoals of
different densities. This result may be explained in terms of predator avoidance. The results show that shoaling preferences
might not always be influenced by a higher number of group members but also by the density and cohesiveness of the respective
groups.
An erratum to this article can be found at 相似文献
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G. M. Gouchie L. F. Roberts R. J. Wassersug 《Behavioral ecology and sociobiology》2008,62(11):1821-1829
We examined the behavioral and developmental responses of Xenopus laevis larvae to their mirror images in three experiments. The mirrors allowed us to visually simulate increased density, without
the tadpoles’ behavior being confounded by chemical cues from additional tadpoles. In the first experiment, we demonstrated
that Xenopus tadpoles have a right eye preference for mirrors, contrary to the left eye preference of all other anuran species studied
to date. This lateralized eye use disappeared, however, as tadpoles approached metamorphosis. Next, we examined how mirrored
aquaria walls affected tadpole growth and development. We found that tadpoles raised in aquaria with partially mirrored walls
showed depressed growth compared to tadpoles raised without mirrors, despite the fact that Xenopus larvae normally thrive when raised in visual contact with conspecifics. The tadpoles raised with mirrors had, though not
significantly, proportionally larger bodies relative to their tail length (d = 0.51). This suggests that a phenotypically plastic response in body proportions was induced in these tadpoles solely by
the sight of other tadpoles. The third experiment established that X. laevis tadpoles are more active in front of a mirror; i.e., they turn more often and spend more time in front of mirrored surfaces.
We consider this increased activity to be an aberrant behavior of the tadpoles, which were attempting to school with their
own images. We suggest that this extra activity reduced the amount of energy available for growth, accounting for the depressed
growth seen in our second experiment. 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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