Does biological intimacy shape ecological network structure? A test using a brood pollination mutualism on continental and oceanic islands.

Autor: Hembry DH; Department of Environmental Science, Policy, and Management, University of California, Berkeley, California., Raimundo RLG; Departamento de Ecologia, Instituto de Biociências, Universidade de São Paulo, São Paulo, SP, Brazil., Newman EA; School of Natural Resources and the Environment, University of Arizona, Tucson, Arizona., Atkinson L; Department of Environmental Science, Policy, and Management, University of California, Berkeley, California., Guo C; Department of Integrative Biology, University of California, Berkeley, California., Guimarães PR Jr; Departamento de Ecologia, Instituto de Biociências, Universidade de São Paulo, São Paulo, SP, Brazil., Gillespie RG; Department of Environmental Science, Policy, and Management, University of California, Berkeley, California.
Jazyk: angličtina
Zdroj: The Journal of animal ecology [J Anim Ecol] 2018 Jul; Vol. 87 (4), pp. 1160-1171. Date of Electronic Publication: 2018 May 21.
DOI: 10.1111/1365-2656.12841
Abstrakt: Biological intimacy-the degree of physical proximity or integration of partner taxa during their life cycles-is thought to promote the evolution of reciprocal specialization and modularity in the networks formed by co-occurring mutualistic species, but this hypothesis has rarely been tested. Here, we test this "biological intimacy hypothesis" by comparing the network architecture of brood pollination mutualisms, in which specialized insects are simultaneously parasites (as larvae) and pollinators (as adults) of their host plants to that of other mutualisms which vary in their biological intimacy (including ant-myrmecophyte, ant-extrafloral nectary, plant-pollinator and plant-seed disperser assemblages). We use a novel dataset sampled from leafflower trees (Phyllanthaceae: Phyllanthus s. l. [Glochidion]) and their pollinating leafflower moths (Lepidoptera: Epicephala) on three oceanic islands (French Polynesia) and compare it to equivalent published data from congeners on continental islands (Japan). We infer taxonomic diversity of leafflower moths using multilocus molecular phylogenetic analysis and examine several network structural properties: modularity (compartmentalization), reciprocality (symmetry) of specialization and algebraic connectivity. We find that most leafflower-moth networks are reciprocally specialized and modular, as hypothesized. However, we also find that two oceanic island networks differ in their modularity and reciprocal specialization from the others, as a result of a supergeneralist moth taxon which interacts with nine of 10 available hosts. Our results generally support the biological intimacy hypothesis, finding that leafflower-moth networks (usually) share a reciprocally specialized and modular structure with other intimate mutualisms such as ant-myrmecophyte symbioses, but unlike nonintimate mutualisms such as seed dispersal and nonintimate pollination. Additionally, we show that generalists-common in nonintimate mutualisms-can also evolve in intimate mutualisms, and that their effect is similar in both types of assemblages: once generalists emerge they reshape the network organization by connecting otherwise isolated modules.
(© 2018 The Authors. Journal of Animal Ecology © 2018 British Ecological Society.)
Databáze: MEDLINE
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