Host plant specificity of the monarch butterfly Danaus plexippus: A systematic review and meta-analysis

The preference-performance hypothesis explains host specificity in phytophagous insects, positing that host plants chosen by adults confer the greatest larval fitness. However, adults sometimes oviposit on plants supporting low larval success because the components of host specificity (adult preference, plant palatability, and larval survival) are non-binary and not necessarily correlated. Palatability (willingness to eat) is governed by chemical cues and physical barriers such as trichomes, while survival (ability to complete development) depends upon nutrition and toxicity. Absence of a correlation between the components of host specificity results in low-performance hosts supporting limited larval development. Most studies of specificity focus on oviposition behavior leaving the importance and basis of palatability and survival under-explored. We conducted a comprehensive review of 127 plant species that have been claimed or tested to be hosts for the monarch butterfly Danaus plexipp...偏好-适合度假说（preference-performance hypothesis）阐释了植食性昆虫的宿主专一性，其核心主张为：成虫所选择的寄主植物能够为幼虫提供最优的适合度。然而，成虫有时仍会在幼虫存活率低下的植物上产卵——这是由于宿主专一性的组成要素（成虫寄主偏好、植物适口性与幼虫存活能力）并非二元属性，且彼此间未必存在相关性。其中，适口性（即昆虫的取食意愿）受化学信号与表皮毛等物理屏障调控，而幼虫存活能力（完成发育的能力）则取决于寄主植物的营养状况与毒性水平。当宿主专一性的各构成要素间缺乏关联时，便会出现低适合度寄主仅能支持有限幼虫发育的情况。当前多数关于宿主专一性的研究均聚焦于产卵行为，使得植物适口性与幼虫存活能力的重要性及其内在机制长期未得到充分探索。为此，我们针对127种被宣称或已被验证可作为君主斑蝶（Danaus plexipp）寄主的植物开展了全面综述……