The chemical ecology of tropical forest diversity: Environmental variation, chemical similarity, herbivory, and richness

Abstract

Species richness in tropical forests is correlated with other dimensions of diversity, including the diversity of plant–herbivore interactions and the phytochemical diversity that influences those interactions. Understanding the complexity of plant chemistry and the importance of phytochemical diversity for plant–insect interactions and overall forest richness has been enhanced significantly by the application of metabolomics to natural systems. The present work used proton nuclear magnetic resonance spectroscopy (1H‐NMR) profiling of crude leaf extracts to study phytochemical similarity and diversity among Piper plants growing naturally in the Atlantic Rainforest of Brazil. Spectral profile similarity and chemical diversity were quantified to examine the relationship between metrics of phytochemical diversity, specialist and generalist herbivory, and understory plant richness. Herbivory increased with understory species richness, while generalist herbivory increased and specialist herbivory decreased with the diversity of Piper leaf material available. Specialist herbivory increased when conspecific host plants were more spectroscopically dissimilar. Spectral similarity was lower among individuals of common species, and they were also more spectrally diverse, indicating phytochemical diversity is beneficial to plants. Canopy openness and soil nutrients also influenced chemistry and herbivory. The complex relationships uncovered in this study add information to our growing understanding of the importance of phytochemical diversity for plant–insect interactions and tropical plant species richness.

Essential Oils of Aromatic Plant Species from the Atlantic Rainforest Exhibit Extensive Chemical Diversity and Antimicrobial Activity

“…The chemical profiling of the EOs confirmed the roles of inter- and intra-specific genetic variation and environmental conditions in determining the metabolic diversity of rainforest plants [ 12 ]. In the EOs from 50 species, we identified 113 distinct metabolites.…”

“…The biome is also one of the primary biodiversity hotspots in the world, with approximately twenty-thousand species [ 11 ]. The plants in the Atlantic Rainforest exhibit high inter- and intra-specific genetic variation, which, coupled with the distinct environmental conditions, allows them to produce hundreds of thousands of distinct specialized metabolites [ 12 ]. The chemical diversity of the EOs from rainforest plants remains scarcely characterized.…”

Canopy height, rather than neighborhood effects, shapes leaf herbivory in a tropical rainforest

“…Neighboring species richness and diversity were calculated from composition data. The 10‐m radius was used because it was sufficient to capture the great majority of neighborhood effects on plant–herbivore interactions in tropical forests (Forrister et al, 2019; Lasky et al, 2014; Massad et al, 2022). To represent the neighbor composition, the abundance of conspecific trees (the conspecific neighbor abundance) and the total abundance of neighboring trees (the total neighbor abundance) within the 10‐m radius range of the focal tree were recorded.…”

“…Neighboring species richness and diversity were calculated from composition data. The 10-m radius was used because it was sufficient to capture the great majority of neighborhood effects on plant-herbivore interactions in tropical forests (Forrister et al, 2019;Lasky et al, 2014;Massad et al, 2022).…”

Effects of climate change on plant resource allocation and herbivore interactions in a Neotropical rainforest shrub

“…P. generalense leaves persist on the plant for an average of 1.5-2 years (Marquis, 1990). Piper plants host many insect herbivores, including Piper specialists, such as Eois (Geometridae) caterpillars, Memphis (Nymphalidae) caterpillars, Curculionidae, and Chrysomelidae, as well as generalists, such as Orthoptera and Erebidae (Dyer et al, 2010;Massad et al, 2022). P. generalense plants experience damage throughout the year by a variety of insect herbivores, including Coleoptera, Diptera, Hymenoptera, Lepidoptera, and Orthoptera, as well as leafcutter ants (Atta cepha lotes; Marquis, 1987Marquis, , 1990.…”