Experimental evidence for a hidden network of higher-order interactions in a diverse arthropod community

• Published in: Current biology Vol. 33; no. 2; pp. 381 - 388.e4
• Main Authors: Barbosa, Milton, Fernandes, Geraldo Wilson, Morris, Rebecca Jane
• Format: Journal Article
• Language: English
• Published: England Elsevier Inc 23.01.2023
• Subjects: Animals; ants; aphids; Arthropods; Baccharis; Baccharis dracunculifolia; Biota; Cerrado; experimental manipulation; galling insects; indirect interactions; Insecta; interaction modification; parasitism; parasitoid wasps; ants; parasitoid wasps; interaction modification; indirect interactions; experimental manipulation; galling insects; parasitism; Baccharis dracunculifolia; Cerrado; aphids
• DOI: 10.1016/j.cub.2022.11.057
• ISSN: 0960-9822; 1879-0445

Transcending pairwise interactions in ecological networks remains a challenge.1,2,3,4,5 Higher-order interactions (HOIs), the modulation of a pairwise interaction by a third species,6 are thought to play a particularly important role in stabilizing coexistence and maintaining species diversity.7,8,9,10,11,12 However, HOIs have so far only been demonstrated in models9,10,11,12,13,14 or isolated experimental systems including only a few interacting species.7,8,15 Their ubiquity and importance at a community level in the real world remain unknown. We hypothesized that a complex network of HOIs could be constantly modifying pairwise interactions and shaping ecological communities and that consequently the outcome of pairwise interactions would be a product of many influences from distinct sources. Using field experiments, we tested how multiple interactions within a diverse arthropod community associated with the tropical shrub Baccharis dracunculifolia D.C. (Asteraceae) were modified by the removal of ant species or live or hatched insect galls (a non-trophic engineering effect) of the dominant galler species. We revealed an extensive hidden network of HOIs modifying each other and the “visible” pairwise interactions. Most pairwise interactions were affected indirectly by the manipulation of non-interacting taxonomic groups. The pervasiveness of these interaction modifications challenges pairwise approaches to understanding interaction outcomes and could shift our thinking about the structure and persistence of ecological communities. Investigating coexistence mechanisms involving interaction modulation by HOIs may be key to elucidating the underlying causes of the stability and persistence of ecological communities. [Display omitted] •Higher-order interactions (HOIs) are interaction modulations by a third species•HOIs have so far only been demonstrated in models or simple empirical systems•We reveal an extensive network of HOIs in a diverse arthropod field community•This pervasiveness of HOIs challenges pairwise approaches in community ecology Barbosa et al. reveal with field experiments an extensive hidden network of higher-order interactions (HOIs) modifying the visible pairwise interactions in a diverse arthropod community. The pervasiveness of HOIs challenges pairwise approaches to understanding interaction outcomes and may shift our thinking on community structure and persistence.