Micronutrients are key to insect diversity and abundance in tropical rainforests.

Soil insect communities in tropical rainforests are among the richest and most complex, but the mechanisms that structure them remain largely unknown. Identifying whether nutrient availability plays a relevant role in the assembly of these communities poses several challenges due to the varied nutritional requirements of insects. The study published in the scientific journal Ecosphere shows that the availability of micronutrients such as sodium, potassium, magnesium and calcium is a determining factor in the structure of soil insect communities in tropical rainforests . This work was led by CREAF researcher Miquel Ferrín , during his thesis work, supervised by researcher Guille Peguero from the Biodiversity Research Institute of the University of Barcelona (IRBio) and Josep Peñuelas , CSIC researcher at CREAF, with the collaboration of an international team of scientists.

The study focused on the importance of nutrient availability in relation to the abundance, richness, and composition of soil insect communities in tropical rainforests.

The researchers sampled 72 sites in two tropical rainforests in French Guiana , collecting more than 18,000 insect specimens and identifying 2,634 operational taxonomic units (OTUs) using metabarcoding techniques—the technique of identifying species through mass-analyzed "genetic barcodes." In parallel, they analyzed the concentration of 19 nutrients in the soil and leaf litter.

“This work reminds us that, in ecology, small details—like micronutrients—can have large effects,” says Miquel Ferrín, first author of the study.

The team observed that species richness increases with potassium and calcium concentrations , while sodium increases both the richness and abundance of some groups such as Orthoptera and cockroaches. In contrast, macronutrients such as carbon, nitrogen, and phosphorus—so essential for plants—did not show a significant influence in most cases. This makes it necessary to expand the theoretical framework for the variation and limitations of C:N:P ratios in organisms and ecosystems, incorporating elemental composition and relative species concentrations, thus encompassing the multidimensionality of the biogeochemical niche.

The study also highlights the importance of analyzing responses at a fine taxonomic level, since different insect orders respond in contrasting ways to nutrient availability.

This research represents a step forward in understanding the ecological mechanisms that regulate soil-dwelling fauna. Ecological research should consider micronutrient availability as a key factor in community structure.

It also has important implications for the conservation of soil biodiversity , which is often ignored but essential for the functioning of ecosystems and the sustainable management of tropical forests, especially in the context of climate change and alterations in biogeochemical cycles.

"This study helps us better understand how seemingly minor factors, such as micronutrients, can have a profound impact on the biodiversity at our feet, which is essential for maintaining the fertility of our soils," highlights Guille Peguero, IRBio researcher and co-author of the study.

Note prepared by the IRBio-UB communications department.

Reference article : Ferrín, M., Asensio, D., Gargallo-Garriga, A., Grau, O., Llusià, J., Màrquez, L., Murienne, J., Peguero, G., Peñuelas, J., et al. (2025). Micronutrients are drivers of abundance, richness, and composition of soil insect communities in tropical rainforests. Ecosphere, 16 (5), e70200. https://doi.org/10.1002/ecs2.70200