Same but different: Diversity and complexity of an arthropod trophic network and comparative seed viability of an invasive and a native legume species

- Exotic species are a major cause of ecosystem degradation and biodiversity loss.
- The arthropod diversity on seeds of an exotic and a native legume was compared.
- The species richness was the same in the exotic and native species.
- The ecological networks were more complex and dense in the native legume.
- Seeds of native species had lower germination rates when damaged by seed-feeders.

Exotic species are species established outside of their natural range and include invasive species, which are the second most important cause of biodiversity loss worldwide and a high risk factor for fragile ecosystems. The exotic species Leucaena leucocephala, a high-risk invasive species, has been introduced to Andean tropical dry forests of Colombia. Here, we compare the complexity and structure of the arthropod trophic networks of the seeds of two legume species, Senegalia riparia (native) and L. leucocephala (exotic), and also evaluate seed germination potential after Bruchinae emergence in comparison with that of undamaged seeds. We found 16 species of arthropods associated with both legume seeds, but the native species had more parasitoids, causing its network to be more dense and complex than that of the exotic species. Four arthropod species connected the two networks. The native species seeds already used for beetle development had the lowest germination percentage, whereas those of the exotic species exhibited the highest. Comparing the structure of seed feeder communities and their effects on germination in exotic and native legumes is essential for understanding how exotic species relate to native communities and how anthropogenic changes affect species diversity, ecosystem dynamics, and community structure and interactions.