Evolutionary irony: evidence that 'defensive' plant spines act as a proximate cue to attract a mammalian herbivore.
Evolutionary irony: evidence that 'defensive' plant spines act as a proximate cue to attract a mammalian herbivore.
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进化的讽刺：有证据表明“防御性”植物刺是吸引哺乳动物草食动物的直接线索。
DOI：
10.1111/oik.02004
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发表时间：
2015
期刊：
影响因子：
--
通讯作者：
Dearing,MDenise
中科院分区：
文献类型：
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作者：
Kohl,KevinD;Miller,AaronW;Dearing,MDenise
许多植物产生结构性防御以阻止食草动物的进食。然而，许多先前的研究测试是否刺是有效地防御哺乳动物食草动物产生了模棱两可的结果。这些模棱两可的结果被假设是由于食草动物的反适应。我们研究了潜在的反适应人口的白色-throated woodratsNeotoma albigua，专门从事仙人掌通过调查喂养行为和偏好不同的仙人掌spinescence.Neotoma albigula表现出一种独特的行为，修剪仙人掌刺，这使得这些防御无效。引人注目的是，这些林鼠选择收集多刺的仙人掌，而不是实验性地去刺的仙人掌，这表明刺是吸引林鼠的近端线索。这种吸引力可能是由于与天然无刺仙人掌相比，多刺仙人掌的蛋白质含量更高，纤维含量更低。因此，仙人掌的“防御性”刺对专业食草动物无效，而是作为促进食草动物的营养质量的指标。我们的研究结果支持觅食的“经验法则”假设，即食草动物根据指示营养含量的明显视觉线索觅食，而不是采样植物的营养成分。我们建议，专业食草动物是独特的系统，在其中研究其他反适应结构防御和“经验法则”觅食策略。
Many plants produce structural defenses to deter feeding by herbivores. However, many previous studies testing whether spines are effective at defending against mammalian herbivores have produced equivocal results. These ambiguous results are hypothesized to be due to herbivore counter‐adaptations. We investigated potential counter‐adaptations in a population of white‐throated woodratsNeotoma albiguathat specialize on cactus by investigating feeding behavior and preference for cacti varying in spinescence.Neotoma albigulaexhibited a unique behavior of clipping cactus spines, which renders these defenses ineffective. Strikingly, these woodrats chose to collect spiny cacti over experimentally de‐spined cacti, demonstrating that spines act as a proximal cue that attracts woodrats. This attraction is likely due to the higher protein and lower fiber content of spiny cacti compared to naturally non‐spiny cacti. Thus, the ‘defensive’ spines of cacti are ineffective against a specialist herbivore and instead serve as an indicator of nutritional quality that promotes herbivory. Our results support the ‘rule‐of‐thumb’ hypothesis of foraging, which states that herbivores forage according to obvious visual cues that are indicative of nutritional content, rather than sampling nutrient composition of plants. We propose that specialist herbivores are unique systems in which to study other counter‐adaptations to structural defenses and ‘rule‐of‐thumb’ foraging strategies.