Aggressive Chemical Mimicry of Prey Pheromones

9722828猎物信息素的攻击性化学模拟捕食者对几个猎物物种的进化专门化有潜在的优势和劣势。这样的捕食者可以进化成在寻找、处理和利用猎物方面变得非常高效，但捕食者变得依赖这些特定猎物的可用性，这在猎物稀缺的年份可能代价高昂。博拉斯蜘蛛Mastophora hutchinsoni是一种非常专业的捕食者。成年雌蛾会释放化学诱饵，模仿其捕食者的性信息素，这是一种攻击性化学模仿。蜘蛛利用其受害者的固有寻找配偶的行为，这些受害者是雄蛾。当猎物接近蜘蛛时，它会用一根短线末端的粘性球攻击蜘蛛。这种捕获装置被称为Bolas，代表着蜘蛛用一条前腿摆动的高度缩小的网。两种蛾，一种在夜间活动，另一种在深夜活动，占这种捕食者猎物的90%以上；另外只有两种蛾被捕获过。为了吸引配偶，这两个主要猎物物种的雌蛾会释放成分不重叠的化合物混合物。蜘蛛可以产生所有这些成分的主要混合物，但初步结果表明，这将使引诱剂在引诱蜘蛛的两个主要猎物物种之一时的效率大大降低。如果蜘蛛能够根据猎物丰度的可预测和不可预测的变化来调整其引诱剂的混合物，它将是一个更有效的捕食者，并可以最大限度地减少猎物专业化的一个主要劣势。在这项研究中，我们建议使用化学、电生理和行为方法的组合来确定这种博拉斯蜘蛛是否在行为上表现出灵活性或模仿信号来提高其狩猎效率。需要解决的具体问题包括：(1)蜘蛛发出的信号是否随着一夜的变化而变化，以适应其主要猎物物种可预测的不同性行为模式？(2)发出的信号是否随季节变化而与其猎物物种丰度的可预测变化相对应？(3)狩猎策略和发出的信号是否随着不可预测的猎物可用性而发生可塑性变化？对这一系统的研究将有助于理解化学通信开发演变过程中所涉及的权衡，以及行为可塑性在最小化专业化成本方面的作用。

9722828 Aggressive Chemical Mimicry of Prey Pheromones Evolutionary specialization of a predator on a few prey species has potential advantages and disadvantages. Such a predator can evolve to become highly efficient at finding, handling, and utilizing its prey, but the predator becomes dependent on availability of these particular prey, which could be costly in years of prey scarcity. The bolas spider Mastophora hutchinsoni is an extremely specialized predator. The adult female emits chemical attractants that mimic the sex pheromones of its moth prey, a form of aggressive chemical mimicry. The spider exploits the inherent mate-finding behavior of its victims, which are male moths. When prey approach the spider, it strikes them with a sticky ball at the end of a short thread. This capture device, called a bolas, represents a highly reduced web that the spider swings with one of its forelegs. Two moth species, one active early at night and the other late at night, account for more than 90% of this predator's prey; only two other moth species are ever captured. To attract mates, female moths of the two principal prey species release blends of chemical compounds that do not overlap in their components. The spider could produce a master blend of all these components, but preliminary results indicate this would make the attractant much less efficient in luring one of the spider's two principal prey species. If the spider could adjust its attractant blend to predictable and unpredictable variation in prey abundance, it would be a much more efficient predator and could minimize a major disadvantage of prey specialization. In this research, we propose to use a combination of chemical, electrophysiological, and behavioral approaches to determine if this bolas spider shows flexibility in its behavior or mimetic signal to improve its hunting effectiveness. Specific questions to be addressed include the following: (1) Does the spider's emitted signal change over the cou rse of a night to correspond with the predictably different diel patterns of sexual activity of its principal prey species? (2) Does the emitted signal vary seasonally to correspond with predictable changes in abundance of its prey species? (3) Do hunting tactics and the emitted signal vary plastically with unpredictable prey availability? Studies of this system will lead to an understanding of tradeoffs involved in the evolution of exploitaiton of chemical communication and the role of behavioral plasticity in minimizing the costs of specialization.