Evolutionary dynamics of specialisation in herbivorous stick insects

Understanding the evolutionary dynamics underlying herbivorous insect mega-diversity requires investigating the ability of insects to shift and adapt to different host plants. Feeding experiments with nine related stick insect species revealed that insects retain the ability to use ancestral host plants after shifting to novel hosts, with host plant shifts generating fundamental feeding niche expansions. These expansions were however not accompanied by expansions of the realized feeding niches, as species on novel hosts are generally ecologically specialized. For shifts from angiosperm to chemically challenging conifer hosts, generalist fundamental feeding niches even evolved jointly with strong host plant specialization, indicating that host plant specialization is not driven by constraints imposed by plant chemistry. By coupling analyses of plant chemical compounds, fundamental and ecological feeding niches in multiple insect species, we provide novel insights into the evolutionary dy...

要理解食草昆虫巨大多样性背后的进化动力学，需探究昆虫向不同宿主植物转移并适应的能力。对9种近缘竹节虫物种开展的取食实验表明，昆虫在转移至新宿主后仍保留利用祖先宿主植物的能力，且宿主植物转移会引发基础取食生态位扩张。但这些扩张并未伴随实际取食生态位的扩张，因为新宿主上的物种通常具有生态特化性。对于从被子植物向化学防御复杂的针叶树宿主的转移，广食性基础取食生态位甚至与强烈的宿主植物特化共同进化，这表明宿主植物特化并非由植物化学特性施加的限制所驱动。通过结合对植物化合物、多种昆虫物种的基础及生态取食生态位的分析，我们为进化动...