Species employ multiple strategies to deal with stressful environments, but these strategies often incur costs. Aphids frequently utilize multiple predator avoidance strategies, including attracting mutualist ants for protection and dispersing by producing winged forms. While both strategies can be physiologically costly, the magnitudes of these costs have not been previously compared. In this study, we experimentally manipulated ant attendance in the field and measured the individual and interactive effects of ant attendance and wing formation on body size and reproduction of the ant-tended aphid Cinara schwarzii (Wilson) (Hemiptera: Aphididae). Aphid adult body size was smaller in the presence of ants (18%), but controlling for body size, there were no differences in embryo number or size. In contrast, wing formation did not affect adult body size but strongly reduced embryo number (46%) and size (8%). Although ant attendance reduced C. schwarzii wing formation, ant attendance and wing formation acted independently on aphid body size and reproduction. For comparison, we confirmed that the manipulation of ant presence had no effect on body size or reproduction of the untended co-existing congener Cinara solitaria (Gillette and Palmer) (Hemiptera: Aphididae). Complementing our empirical study, a meta-analysis of 78 responses from 24 publications showed that wing formation consistently and significantly reduces aphid body size and reproduction (37%), while the effects of ant attendance showed a mean positive effect (9%) that did not significantly differ from zero. Together, our empirical study and meta-analysis provide strong evidence for costs of wing formation but not ant attendance for aphids.

中文翻译：

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比较蚂蚁出勤和翅膀形成对蚜虫体型和繁殖的个体和综合影响

物种采用多种策略来应对压力较大的环境，但是这些策略通常会产生成本。蚜虫经常利用多种避免捕食者的策略，包括吸引有共性的蚂蚁进行保护，并通过产生翅来分散它们。尽管这两种策略在生理上都可能代价高昂，但这些成本的数量之前并未进行过比较。在这项研究中，我们在野外实验性地控制了蚂蚁出勤，并测量了蚂蚁出勤和机翼形成对蚂蚁蚜虫Cinara schwarzii个体大小和繁殖的个体和交互作用（威尔逊）（半翅目：蚜科）。在有蚂蚁的情况下，蚜虫成虫的体型较小（18％），但控制体型后，胚胎数目或大小没有差异。相反，机翼的形成并没有影响成年个体的体形，而是大大减少了胚胎数（46％）和体形（8％）。尽管蚂蚁的出勤减少了C. schwarzii的翅膀形成，但蚂蚁的出勤和翅膀的形成独立于蚜虫的体型和繁殖。为了进行比较，我们确认了对蚂蚁的存在没有任何影响，但对体形大小和并存的同类物种Cinara solitaria的繁殖没有影响。（吉列特和帕尔默）（半翅目：蚜科）。作为对我们的经验研究的补充，对来自24个出版物的78个回复的荟萃分析表明，机翼的形成持续且显着降低了蚜虫的体型和繁殖力（37％），而蚂蚁出勤的影响显示出平均正效应（9％）与零没有显着差异。总之，我们的经验研究和荟萃分析为机翼形成的成本提供了有力的证据，但没有为蚜虫提供辅助服务。