Trophobiotic interactions between ants and honeydew-providing hemipterans are widespread and are one of the key mechanisms that maintain ant super-abundance in ecosystems. Many of them occur inside ant nests. However, these cryptic associations are poorly understood, particularly those with hoppers (suborder Auchenorrhyncha). Here, we study tree-dwelling ant and Hemiptera communities in nests along the Mt. Wilhelm elevational gradient in Papua New Guinea and report a new case of this symbiosis between Pseudolasius Emery, 1887 ants and planthoppers. Furthermore, we provide a worldwide review of other ant-hopper interactions inside ant-built structures and compare their nature (obligate versus facultative) and distribution within the suborder Auchenorrhyncha. The novel interactions were observed in nests located at the tree trunk bases or along the whole trunks. Only immature planthopper stages were found inside nests, so full species identifications were not possible. However, nymph morphology and molecular data (18S and COI genes) indicated four related species of the family Flatidae (infraorder Fulgoromorpha) associated with Pseudolasius. Ant-planthopper occurrences were relatively rare (6% of all trophobiotic interactions) and peaked at mid-elevation (900 m above sea level). Pseudolasius was the only genus associated with planthoppers in the communities, with most cases monopolised by a single species, P. breviceps Emery, 1887. In contrast, all other ant genera tended various scale insects (Sternorrhyncha: Coccoidea). This apparent partner-specificity is rare: Worldwide, there are only about ten reported cases of obligate symbiosis in ant nests, distributed in five of the thirty-three Auchenorrhyncha families. Those trophobioses are randomly dispersed across the Auchenorrhyncha phylogeny, and thus likely originated multiple times independently. Further research on both adult and nymph hopper life history is needed to answer how these symbioses, notably rare in hoppers compared with other hemipterans, are maintained.
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RBINS Staff Publications 2018
Tidal channels are essential morphological structures that mediate hydrological connectivity and maintain coastal resilience. Previous studies on vegetation-induced channel development primarily focused on the stages of initial establishment or later elaboration, characterized by slow and localized changes. However, the impact of rapid shifts in landscape vegetation on the initiation of tidal channels, such as main or tributary channels, remains poorly understood, particularly in micro-tidal system. In this study, we investigated this relationship through satellite imagery analysis and biogeomorphic modeling of a rapidly expanding micro-tidal marsh in the Yellow River Delta, China, which has experienced an invasion by Spartina alterniflora over the past decade. The satellite imagery demonstrated that Spartina alterniflora invasion has increased drainage density and reduced overland flow path length. Our modeling results showed that local flow acceleration between vegetation patches was insufficient to rapidly initiate channels under micro-tidal conditions. As the patchy marsh coalesced and expanded into a contiguously vegetated marsh, it altered landscape-scale flow patterns, diverting from homogenous platform flow to concentrated channel flow. This shift prominently promoted the initiation of tributary channels in the landward marsh zone. The simulated scenarios of vegetation removal highlighted a marked increase in flow divergence from adjacent platforms due to changes in landscape-scale vegetation configuration. This alteration in flow pattern amplified local hydrodynamics, consequently intensifying local channel incision. Our findings emphasize that the channel initiation is significantly influenced by landscape-scale vegetation configuration under micro-tidal conditions, beyond the localized interactions between plants and flow.
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RBINS Staff Publications 2025
