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R. Stoks 《Behavioral ecology and sociobiology》1999,47(1-2):70-75
Animals commonly choose between microhabitats that differ in foraging return and mortality hazard. I studied the influence
of autotomy, the amputation of a body part, on the way larvae of the damselfly Lestes sponsa deal with the trade-off between foraging or seeking cover. Survival of Lestes larvae when confronted with the odonate predator Aeshna cyanea was higher in a complex than in a simple microhabitat, indicating that this more complex microhabitat was safer. Within the
simple microhabitat, larvae without lamellae had a higher risk for mortality by predation than larvae with lamellae, showing
a long-term cost of autotomy. When varying the foraging value (food present or absent) and predation risk (encaged predator
or no predator) in the simple microhabitat, larvae with and without lamellae responded differentially to the imposed trade-off.
All larvae spent more time in the simple microhabitat when food was present than when food was absent. Larvae without lamellae,
however, only sporadically left the safe microhabitat, irrespective of the presence of the predator. In contrast, larvae with
lamellae shifted more frequently towards the risky microhabitat than those without lamellae, and more often in the absence
than in the presence of the predator. These decisions affected the foraging rates of the animals. I show for the first time
that refuge use is higher after autotomy and that this is associated with the cost of reduced foraging success. The different
microhabitat preferences for larvae with and without lamellae are consistent with their different vulnerabilities to predation
and demonstrate the importance of intrinsic factors in establishing trade-offs.
Received: 4 June 1999 / Received in revised form: 18 August 1999/ Accepted: 18 August 1999 相似文献
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Crickets can autotomize a limb in order to evade predation; however, this autotomy compromises their escape speed and, therefore,
their ability to avoid subsequent predation events. We recorded two measures of predator-avoidance behaviour in field crickets
(Gryllus bimaculatus) exposed to varying levels of predation threat, with the most extreme level leading to autotomy of a limb. Our first measure
of caution was time to emergence from cover, which was affected by perceived predation treatment, with both autotomized males
and females being significantly more cautious than intact individuals. For males (but not females), the presence of a calling
conspecific encouraged earlier emergence. Our second measure of caution was alteration of male calling behaviour. Autotomized
males remained silent for significantly longer time after disturbance than intact males, but there was no difference in call
rate once they had resumed calling, suggesting that behavioural changes were not merely a result of injury response but a
controlled modification of behaviour as a result of autotomy. These data suggest that autotomy in field crickets results in
altered calling behaviour, which was not significantly altered with different acoustic environments. 相似文献
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