Intraspecific variation in host plant traits mediates taxonomic and functional composition of local insect herbivore communities

Abstract

1. Host plant phenotypic traits affect the structure of the associated consumer community and mediate species interactions. Intraspecific variation in host traits is well documented, although a functional understanding of variable traits that drive herbivore community response is lacking. We address this gap by modelling the trait-environment relationship using insect traits and host plant traits in a multilevel model. 2. We compare herbivore assemblages from the canopy of the phenotypically variable tree Metrosideros polymorpha on Hawai'i Island. Multiple distinct varieties of M. polymorpha frequently co-occur, with variation in morphological traits. Using this system, we identify host and insect traits that underlie patterns of herbivore abundance and quantify the strength of host-insect trait interactions. 3. This work examines plant-insect interactions at a community scale, across 36 herbivore species in three orders. We find that co-occurring trees of varying phenotype support distinct communities. Leaf traits, including specific leaf area, trichome presence, and leaf nutrients, explain 46% of variation in insect communities. We find that feeding guild and nymphal life history are correlated with host plant traits, and we show that model predictions are improved by including the host and insect trait interaction. 4. This study demonstrates how insect herbivores traits influence community response to morphologically variable hosts. Environmental heterogeneity indirectly affected herbivore community structure via intraspecific variation in host plants, providing an important source of variation for maintaining diversity in the broader community.

Habitat traits and predation interact to drive abundance and body size patterns in associated fauna

“…On land, intraspecific variation within host plants drives variability in resource quality and availability and will often lead to more diverse consumer communities (e.g. Crutsinger et al., 2006 ; Tielens & Gruner, 2020 ). Plant intraspecific variation can also affect community abundance, as in seagrass, where increased genetic diversity had a positive effect on the abundance of associated invertebrate communities following a disturbance event (Hughes & Stachowicz, 2004 ).…”

Spatial Habitat Structure Assembles Willow-Dependent Communities across the Primary Successional Watersheds of Mount St. Helens, USA

“…Leaf area can influence associated insect and microbial community members [97,98]; thus, fresh leaves were collected from a subset of the tagged willows (n = 122). Roughly five to ten leaves (depending on size) were collected from each willow and either preserved in silica gel or laid onto individual paper sheets in a plant press.…”

Leaf traits linked to structure and palatability drive plant–insect interactions within three forested ecosystems

“…Integration of the modern literature illustrates how chemical traits influence leaf structure and overall palatability (Schädler et al, 2003). For example, tannins and phenols (secondary compounds) dissuade insect herbivory (Adams et al, 2009; Salminen and Karonen, 2011), while nitrogen and phosphorus might increase herbivory due to greater quality of food (Huberty and Denno, 2006; Tielens and Gruner, 2020). These relationships between plant defenses and insect herbivores are multidimensional with many direct and indirect pathways; as such, studies should focus on multiple traits (Agrawal and Fishbein, 2006; Farias et al, 2020) affecting insect herbivory, a strategy we deployed here.…”