Gallers as leaf rollers: ecosystem engineering in a tropical system and its effects on arthropod biodiversity

다국어 초록 (Multilingual Abstract)

Gall‐inducers can be considered ecosystem engineers when they modify leaf morphology and create shelters for secondary users, altering properties of ecological communities.
In this study, we evaluated whether shelter structures created by leaf‐galling contribute to changes in the diversity and composition of the community at plant and leaf scales, the effects of leaf roll occupation on the choice of secondary colonisers and the influence of leaf shelters on herbivory levels on host plants.
The arthropod abundance, richness, and biomass were higher in leaf shelters compared to intact leaves. These effects were observed at similar magnitudes at both plant and leaf scales. The composition of arthropods differed between plants with leaf‐rolled galls and plants with galls removed and between unoccupied leaf rolls and intact leaves. Artificial leaf rolls increased arthropod abundance, richness, and biomass by almost 100.0% compared to intact leaves. However, occupied artificial leaf rolls had a decrease in abundance, richness, and biomass of arthropods by almost 60.0% compared to unoccupied leaf rolls. Finally, plants with galls removed exhibited higher levels of leaf herbivory than plants with leaf‐rolled galls.
Our findings demonstrated the strong and positive indirect effects of gall induction facilitating shelter creation and the indirect effects of shelters on the diversity, species composition, and on leaf herbivory, and should be replicated in other systems involving plants and their respective gallers.

We showed that gallers can also act as leaf rollers, facilitating ecosystem engineering when curled and galled leaves act as shelters.
The leaf‐rolled galls created by the nematode Ditylenchus sp. are subtle and ephemeral structures, but with strong effects in community organization.
These structures increased the abundance, richness, and biomass of arthropods on plant and leaf scales, as well as influencing the species composition and herbivory levels on Miconia ligustroides.