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

Abstract

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.

Host plant selection by Cerambycidae in two different strata in association with seasonality and physical wood characteristics in a tropical dry forest

“…There were effects of the stratum, wood density, wood decomposition rate and wood offered volume and the interactions between stratum with wood decomposition rate and stratum with wood offered volume on the abundance of cerambycids. This coincides with other works where they report that the stratum significantly influences the emergences of cerambycids (Berkov & Tavakilian, 1999;Lee et al, 2014;Li et al, 2017;Seibold et al, 2018). It was recorded in this work that there are significant differences between the emergence of the canopy and ground; for every three individuals that emerge from branches on the ground, 30 emerge in the canopy.…”

Beta diversity and oligarchic dominance in the tropical forests of Southern Costa Rica

“…Only three typical pioneer species are so frequent to be considered as oligarchs: A. tibourbou, Castilla tunu, and C. insignis . These species usually are present in the tree inventories of secondary but also in primary forests (Clark & Clark, ; Li, Aguilar & Berkov, ; Oliveira‐Filho, Curi, Vilela & Carvalho, ), with juvenile stages associated with canopy gaps (Clark & Clark, ). Only some tree species characteristic of primary forest (Cole et al., ; Webb, ) such as T. macrophyllum , Carapa nicaraguensis, and O. novogranatensis were able to recruit in significant numbers in these secondary forests.…”

Alien Scolytines on the Osa Peninsula, Costa Rica (Coleoptera: Curculionidae: Scolytinae)

“…Annual rainfall is approximately 6,000 mm, and the vegetation is representative of a tropical wet forest (Cornejo et al 2012). A rearing project (Apr 2013-Jun 2014) investigated community structure of saproxylic beetles (Li et al 2017;Morillo 2017). The data reported herein represent an extract from that project.…”

“…& Triana; Malvaceae), and the coffee family (Chimarrhis sp. ; Rubiaceae) (see Li et al 2017 for supplemental documents for tree details, including locations and diameters). Bait branches were cut during the transition to the rainy season (Apr-Jul 2013).…”