Data from: What shapes cerambycid beetle communities in a tropical forest mosaic? Assessing the effects of host tree identity, forest structure, and vertical stratification

Due to anthropogenic activities, tropical rain forests face many challenges in sustaining biodiversity and maintaining global climates. This study explores how forest successional stage, tree composition, and stratum affect communities of saproxylic cerambycid beetles—concealed feeders that play important roles in forest nutrient cycling. Forty trees in five families (Fabaceae, Lecythidaceae, Malvaceae, Moraceae, and Sapotaceae) were sampled in a mosaic of old-growth and secondary forest on the Osa Peninsula, Costa Rica. Bait branches yielded 3549 cerambycid individuals in 49 species. Species richness was almost identical in old-growth and secondary forest, and both yielded specialists, but abundance was higher in old-growth forest. Overall community structure was most strongly influenced by host plant species; within most plant families it was also impacted by forest successional status. Moraceae was the exception, presumably because the focal tree species was abundant in both old-growth and secondary forest. Several host and old-growth specialist species reached high densities within patches of old-growth forest, but seldom colonized apparently suitable trees within secondary forest. This suggests that even small areas of old-growth forest can act as refuges, but that secondary forest may act as a barrier to dispersal. The vulnerability of specialized saproxylic insects to land use change will be linked to the ability of their preferred hosts to disperse to and persist in successional habitats; rearing studies may provide the most accurate method to monitor community changes over time.

受人类活动影响，热带雨林在维持生物多样性与稳定全球气候方面面临诸多挑战。本研究探讨了森林演替阶段、树木组成与林层结构如何影响蛀木天牛（saproxylic cerambycid beetles）的群落结构——这类隐蔽取食类群在森林养分循环中发挥着重要作用。研究于哥斯达黎加奥萨半岛的原始林与次生林镶嵌景观中，对隶属于5个科（豆科Fabaceae、玉蕊科Lecythidaceae、锦葵科Malvaceae、桑科Moraceae、山榄科Sapotaceae）的40株树木进行了采样。诱捕枝条共采集到49种天牛，总计3549头个体。原始林与次生林的物种丰富度几乎一致，两者均存在专性寄主类群，但原始林内的天牛个体丰度更高。整体群落结构最主要的影响因素为寄主植物种类；在多数植物科中，森林演替状态也会对其产生影响，桑科（Moraceae）是唯一例外，推测是因为该科的目标树种在原始林与次生林中均分布广泛。若干专性寄主类群与原始林专性类群在原始林斑块内达到了较高的种群密度，但极少在次生林内看似适宜的树木上定殖。这表明即便小片原始林也可作为蛀木天牛的庇护所，而次生林或会成为其扩散的障碍。专性蛀木昆虫对土地利用变化的脆弱性，与其偏好寄主向演替生境扩散并持续存活的能力息息相关；人工饲养研究或许是长期监测群落动态的最精准方法。