Beijing Key Laboratory for Forest Pest Control, Beijing Forestry University, Beijing, 100083, China.
BMC Ecol Evol. 2021 May 28;21(1):101. doi: 10.1186/s12862-021-01824-7.
Elongated rostra play an important role in the egg-laying of weevils, and its emergence plays a key role in the adaptive radiation of weevils. Eucryptorrhynchus scrobiculatus Motschulsky and E. brandti Harold co-occur on the same only host Ailanthus altissima, while their oviposition sites are different. In order to understand the adaptation between the rostra of the two weevils and their oviposition sites, the structural differentiation of the rostra in E. scrobiculatus and E. brandti was compared.
The present study reveals that: (1) The rostra length of E. scrobiculatus and E. brandti was found to be correlated with body size, larger weevils have a correspondingly longer rostrum. The increase of rostra length may be a byproduct of larger weevils. (2) There were significant differences in the external shape of the two rostra, especially the shape of the mandibles of the mouthparts at the apex of the rostra used to excavate an oviposition cavity. (3) There was no difference in the size of the abductor muscles that control the extension of the mandibles, but there were significant differences in the size of the adductor muscles that control the contraction of the mandibles.
These structural differences reflect the functional potential ovipositional tactics of rostra, which is considered to be a response to the ecological demands of egg deposition, and also provide new insights into the coexistence of two weevil species in the same host A. altissima.
伸长的喙在象鼻虫产卵中起着重要作用，其出现对象鼻虫的适应性辐射起着关键作用。麻皮蝽 Motschulsky 和麻皮蝽 Harold 共同出现在同一宿主臭椿上，但它们的产卵地点不同。为了了解这两种象鼻虫的喙与其产卵部位之间的适应关系，比较了麻皮蝽和麻皮蝽 Harold 喙的结构分化。
本研究揭示：（1）发现麻皮蝽和麻皮蝽 Harold 的喙长与体型大小相关，体型较大的象鼻虫喙相应地更长。喙长的增加可能是体型较大的象鼻虫的副产品。（2）两种喙的外部形状存在显著差异，特别是用于挖掘产卵腔的喙顶端口器的下颚的形状。（3）控制下颚伸展的外展肌大小没有差异，但控制下颚收缩的内收肌大小有显著差异。
这些结构差异反映了喙的潜在产卵功能策略，这被认为是对产卵生态需求的响应，也为两种象鼻虫在同一宿主臭椿上共存提供了新的见解。
