Abstract

Multiple phenotypic traits often interact with each other to determine an individual’s fitness. Behavioral and extended phenotypic traits, such as architectural constructions, can contribute to fitness in an integrated way. The goal of this study was to understand how the interaction between behavioral and extended phenotypic traits can affect foraging success. We tested this question using black widow spiders, where spiders that are aggressive in a foraging context tend to build more gumfooted silk lines that aid in prey capture, while non-aggressive spiders build webs with fewer gumfooted lines. We repeatedly assessed behavior and web structure to quantify relationships between these traits, and then allowed spiders to forage for live prey on their own web or the web of a conspecific that differed in structure. Thus, we assessed how varying combinations of behavior and web structure affect foraging success, and if correlational selection might act on them. We confirmed that aggressiveness and number of gumfooted lines are positively correlated and found that capture success increased with both aggressiveness and the number of gumfooted lines. Yet, we did not find any evidence for correlational selection: aggressiveness and number of gumfooted lines appeared to affect foraging success independently of each other. These findings highlight that a correlation between traits that contribute towards the same ecological function does not necessarily imply correlational selection. Taking advantage of the experimental convenience afforded by extended phenotypic traits can provide insight into the functional consequences of phenotypic variation within and between individuals.

中文翻译：

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觅食行为和扩展表型独立影响蜘蛛觅食的成功

摘要

多种表型特征经常相互影响，以确定一个人的健康状况。行为和扩展的表型特征，例如建筑构造，可以以综合的方式促进健康。这项研究的目的是了解行为和扩展表型性状之间的相互作用如何影响觅食的成功。我们使用黑寡妇蜘蛛测试了这个问题，其中在觅食环境中具有攻击性的蜘蛛往往会形成更多的足底丝线，以帮助捕获猎物，而没有攻击性的蜘蛛会建立具有较少足底线的网。我们反复评估了行为和网状结构以量化这些特征之间的关系，然后让蜘蛛在自己的网状结构或结构不同的同种网状结构上觅食活食。从而，我们评估了行为和网络结构的不同组合如何影响觅食的成功，以及相关选择是否可能对其起作用。我们证实侵略性和齿足线的数量呈正相关，并发现捕获成功率随侵略性和齿足线的数量而增加。然而，我们没有找到任何相关选择的证据：侵略性和齿足线的数量似乎彼此独立地影响觅食的成功。这些发现突出表明，促成相同生态功能的性状之间的相关性不一定意味着相关性选择。