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Gita R. Kolluru Gregory F. Grether Heidy Contreras 《Behavioral ecology and sociobiology》2007,61(5):689-701
Food availability is expected to influence the relative cost of different mating tactics, but little attention has been paid
to this potential source of adaptive geographic variation in behavior. Associations between the frequency of different mating
tactics and resource availability could arise because tactic use responds directly to food intake (phenotypic plasticity),
because populations exposed to different average levels of food availability have diverged genetically in tactic use, or both.
Different populations of guppies (Poecilia reticulata) in Trinidad experience different average levels of food availability. We combined field observations with laboratory “common
garden” and diet experiments to examine how this environmental gradient has influenced the evolution of male mating tactics.
Three independent components of variation in male behavior were found in the field: courtship versus foraging, dominance interactions,
and interference competition versus searching for mates. Compared with low-food-availability sites, males at high-food-availability
sites devoted more effort to interference competition. This difference disappeared in the common garden experiment, which
suggests that it was caused by phenotypic plasticity and not genetic divergence. In the diet experiment, interference competition
was more frequent and intense among males raised on the greater of two food levels, but this was only true for fish descended
from sites with low food availability. Thus, the association between interference competition and food availability in the
field can be attributed to a genetically variable norm of reaction. Genetically variable norms of reaction with respect to
food intake were found for the other two behavioral components as well and are discussed in relation to the patterns observed
in the field. Our results indicate that food availability gradients are an important, albeit complex, source of geographic
variation in male mating strategies. 相似文献
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Most models of habitat selection assume that individual animals choose and either reuse or abandon sites based on a constant
reassessment of site quality. When survival is a function of the presence of conspecifics, however, the benefits of returning
to traditional sites may override resource assessment. Many animals form roosting aggregations at what appear to be traditional
sites. At our study site in Nicaragua, the harvestman Prionostemma sp. forms diurnal roosting aggregations on a small subset of the available spiny palm trees. With respect to physical characteristics
and microclimate, the spiny palms used by the harvestmen resembled a random sample of those available, yet the same subset
of trees was used in two different years (2001, 2003). This suggests that the location of aggregation sites is traditional,
not a product of habitat limitation. Individual harvestmen were not faithful to particular roost sites, however, which raises
the question of how the tradition could be maintained over time. In this paper, we present evidence, derived from a series
of small-scale field experiments, that the harvestmen mark roosting sites chemically and enter marked sites preferentially
when searching for places to roost. We also show that the harvestmen are sensitive to changes in site quality (the presence
of spines) but will continue to use degraded traditional sites when no intact spiny palms are nearby. This system provides
an example of how animal traditions could be maintained over multiple generations without learning. Site-labeling can be viewed
as an external form of social memory. 相似文献
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Protective mimicry has been studied extensively for over a century. Mimicry in a competitive context, however, has remained largely neglected. It has been overlooked in mimicry classification schemes, and few systems have been rigorously studied. We define "competitive mimicry" as mimicry that enables access to a defended resource or aids in defense of a resource. We explain how competitive mimicry fits with existing mimicry classification schemes and outline criteria for identifying competitive mimicry systems. For each form of competitive mimicry, we describe the effects of the mimic on the model and receiver, predict the evolutionary dynamics of the system, and present examples. We then identify key directions for the study of competitive mimicry. 相似文献
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Gregory F. Grether Abrahm Levi Carmen Antaky Debra M. Shier 《Behavioral ecology and sociobiology》2014,68(10):1629-1638
Situations in which animals preferentially settle in low-quality habitat are referred to as ecological traps, and species that aggregate in response to conspecific cues, such as scent marks, that persist after the animals leave the area may be especially vulnerable. We tested this hypothesis on harvestmen (Prionostemma sp.) that roost communally in the rainforest understory. Based on evidence that these animals preferentially settle in sites marked with conspecific scent, we predicted that established aggregation sites would continue to attract new recruits even if the animals roosting there perished. To test this prediction, we simulated intense predation by repeatedly removing all individuals from 10 established roosts, and indeed, these sites continued to attract new harvestmen. A more likely reason for an established roost to become unsuitable is a loss of overstory canopy cover caused by treefalls. To investigate this scenario, without felling trees, we established 16 new communal roosts by translocating harvestmen into previously unused sites. Half the release sites were located in intact forest, and half were located in treefall gaps, but canopy cover had no significant effect on the recruitment rate. These results support the inference that communal roost sites are potential ecological traps for species that aggregate in response to conspecific scent. 相似文献
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