Intruder Pressure Affects Territory Size and Foraging Success in Asymmetric Contests in the Water Strider Gerris lacustris
Intruder Pressure Affects Territory Size and Foraging Success in Asymmetric Contests in the Water Strider Gerris lacustris
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入侵者压力影响水黾的领地大小和不对称竞争中的觅食成功
DOI：
10.1111/j.1439-0310.1996.tb01100.x
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发表时间：
2010
期刊：
影响因子：
1.7
通讯作者：
P. Jablonski
中科院分区：
文献类型：
--
作者：
P. Jablonski
非对称竞争中的进化稳定策略理论预测，个体在竞争中暴露于风险的倾向取决于个体的资源持有潜力（RHP）和竞争资源相对于对手的价值(V)。如果一个领土所有者与高RHP和高食物需求个体(V)的相遇频率增加，我们应该预期领土所有者的总体攻击性会降低，因此它的领土面积会缩小。这种减少应导致领土所有者消耗的食物量减少。利用Gerris湖中RHP和V的自然变化，我对这些预测进行了实验测试。具有生殖能力的雌性水黾（它们可能将大部分食物转化为卵）的平均猎物值(V)高于非生殖能力的雌性和雄性。由于雄性体型较小，它们的RHP低于雌性，因为RHP取决于体型。因此，生殖雌性是高RHP和高食物需求（高V）的个体。大多数不能生育的雌性保卫以食物为基础的领地。我在一个半自然的实验室环境中观察了两组水黾。正如预测的那样，与生殖雌性的相遇率与领地大小呈负相关，而领地大小与主人消耗的果蝇数量呈正相关。在领地所有者和有生育能力的雌性之间的相遇率较高的群体中，领地较小。在这个群体中，拥有领地的果蝇和没有领地的果蝇捕获了相同数量的果蝇。相比之下，在领地所有者和有繁殖能力的雌性相遇较少的一组中，领地更大，领地所有者比没有领地的水黾获得更多的食物。
The theory of evolutionarily stable strategies (ESS) in asymmetric contests predicts that the propensity of an individual to expose itself to risk during contests depends on the individual's resource-holding-potential (RHP) and on the value of the disputed resource (V) for the individual compared with that for an opponent. If encounters of a territory owner with individuals of high RHP and high food demands (V) increase in frequency, one should expect a decrease in total aggressiveness of the territory owner, and in consequence a decrease of its territory size. Such a decrease should result in a lower amount of food consumed by the territory owner. Using natural variability in RHP and V in Gerris lacustris, I experimentally tested these predictions. The average prey item has higher value (V) for reproductive female water striders (which probably transform most of their food into eggs), than for nonreproductive females and for males. Because males are smaller, they have lower RHP than females, as RHP depends on size. Thus the reproductive females are the class of individuals of high RHP and high food demands (high V). Most nonreproductive females defend food-based territories. I observed two groups of water striders in a seminatural laboratory setting. As predicted, there was a negative correlation between the rate of encounter with reproductive females and size of the territory, and a positive correlation between territory size and number of Drosophila flies consumed by the owner. Territories were smaller in the group with high rates of encounter between territory owners and reproductive females. Territory owners caught the same number of Drosophila flies as non-territorial individuals in this group. In contrast, in the group with fewer encounters between territory owners and reproductive females, territories were larger, and territory owners gained more food than non territorial water striders.