Rare plant species are suggested to be less resistant to herbivores than common species. Their lower apparency and the fact that they often live in isolated populations, resulting in fewer herbivore encounters, might have led to the evolution of reduced defenses. Moreover, their frequently lower levels of genetic diversity compared with common species could negatively affect their resistance against enemies. However, the hypothesis that plant resistance depends on plant regional and local rarity, independently of habitat and competitive and growth strategy, lacks evidence. To test this hypothesis, we assessed the performance and preference of one belowground and three aboveground generalist invertebrate herbivores from different taxonomic groups as indicators of plant resistance. Herbivores were fed a total of 62 regionally and locally rare and common plant species from Switzerland. We accounted for differences in a plant’s growth and competitive strategy and habitat resource availability. We found that regionally and locally rare and common plant species did not generally differ in their resistance to most generalist herbivores. However, one herbivore species even performed better and preferred locally and regionally common plant species over rarer ones, indicating that common species are not more resistant, but tend to be less resistant. We also found that all herbivore species consistently performed better on competitive and large plant species, although different herbivore species generally preferred and performed better on different plant species. The latter indicates that the use of generalist herbivores as indicators of plant-resistance levels can be misleading.

Synthesis: Our results show that rare plant species are not inherently less resistant than common ones to herbivores. Instead, our results suggest that the ability of plants to allocate resources away from defense towards enhancing their competitive ability might have allowed plants to tolerate herbivory, and to become locally and regionally common.

Data were collected during two experiments to assess the performance (i.e. weight gain) and the preference of three above-ground and one below-ground invertebrate and generalist herbivores on multiple plant species varying in local and regional rarity, habitat resource-availability, growth and competitive strategies. Please, find all the details about the methodology in Bürli et al. (2023) "Are rare plant species less resistant than common ones to herbivores? A multi-plant species study using above- and below-ground generalist herbivores" published in Ecology & Evolution. DOI: 10.1002/ece3.10482 

To open the dataset (.csv), we suggest to use Libre Office Calc or Excel. To analyse the data, we suggest using R.