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Host specificity and interaction networks of insects feeding on seeds and fruits in tropical rainforests |
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| Authors: | Yves Basset Leonardo R Jorge Philip T Butterill Greg P A Lamarre Chris Dahl Richard Ctvrtecka Sofia Gripenberg Owen T Lewis Héctor Barrios John W Brown Sarayudh Bunyavejchewin Buntika A Butcher Anthony I Cognato Stuart J Davies Ondrej Kaman Petr Klimes Miloš Knížek Scott E Miller Geoffrey E Morse Vojtech Novotny Nantachai Pongpattananurak Pairot Pramual Donald L J Quicke Watana Sakchoowong Ruma Umari Eero J Vesterinen George Weiblen S Joseph Wright Simon T Segar |
| Institution: | 1. ForestGEO, Smithsonian Tropical Research Inst., Apartado, Balboa, Ancon, Panamá;2. Faculty of Science, Univ. of South Bohemia, Ceske Budejovice, Czech Republic;3. School of Biological Sciences, Univ. of Reading, Reading, Berkshire, UK;4. Dept of Zoology, Univ. of Oxford, Oxford, UK;5. Maestria de Entomologia, Univ. de Panamá, Panama City, Republic of Panama;6. National Museum of Natural History, Smithsonian Inst., Washington, DC, USA;7. Dept of National Parks, Research Office, Wildlife and Plant Conservation, Bangkok, Thailand;8. Dept of Biology, Faculty of Science, Integrative Ecology Laboratory, Chulalongkorn Univ., Phayathai Road, Pathumwan, Bangkok, Thailand;9. Dept of Entomology, Michigan State Univ., Natural Science Bldg., East Lansing, MI, USA
Contribution: Data curation (equal), Writing - original draft (equal), Writing - review & editing (equal);10. Forest Global Earth Observatory, Smithsonian Tropical Research Inst. and National Museum of Natural History, Washington, USA;11. Biology Centre of the Czech Academy of Sciences, Inst. of Entomology, Ceske Budejovice, Czech Republic;12. Forestry and Game Management Research Inst., Strnady, Jíloviště, Czech Republic;13. Biology Dept, Univ. of San Diego, Alcalá Park, San Diego, CA, USA;14. Dept of Forest Biology, Faculty of Forestry, Kasetsart Univ., Lat Yao Chatuchak, Bangkok, Thailand Contribution: Data curation (equal), Writing - original draft (equal), Writing - review & editing (equal);15. Dept of Biology, Faculty of Science, Mahasarakham Univ., Kantharawichai District, Maha Sarakham, Thailand;16. Dept of National Parks, Forest Entomology Group, Wildlife and Plant Conservation, Praholyothin Road, Chatujak, Bangkok, Thailand Contribution: Data curation (equal), Writing - original draft (equal), Writing - review & editing (equal);17. New Guinea Binatang Center, Madang, Papua New Guinea Contribution: Data curation (equal), Writing - original draft (equal), Writing - review & editing (equal);18. Dept of Biology and Biodiversity Unit, Univ. of Turku, Turku, Finland;19. Bell Museum and Dept of Plant and Microbial Biology, Univ. of Minnesota, Gortner Avenue, St. Paul, MN, USA;20. ForestGEO, Smithsonian Tropical Research Inst., Balboa, Ancon, Panamá;21. Agriculture and Environment Dept, Harper Adams Univ., Newport, Shropshire, UK |
| Abstract: | In the tropics, antagonistic seed predation networks may have different properties than mutualistic pollination and seed dispersal networks, but the former have been considerably less studied. We tested whether the structure of antagonistic tripartite networks composed of host plants, insects developing within seeds and fruits, and their insect parasitoids could be predicted from plant phylogenetic distance and plant traits. We considered subsets of the networks (‘subnetworks') at three rainforest locations (Panama, Thailand, Papua New Guinea), based on insect families, plant families or plant functional groups. We recorded 3197 interactions and observed a low percentage of realized interactions, especially in Panama, where insect host specificity was higher than in Thailand or New Guinea. Several factors may explain this, including insect faunal composition, incidence of dry fruits, high fruit production and high occurrence of Fabaceae at the Panamanian site. Host specificity was greater among seed-eaters than pulp-eaters and for insects feeding on dry fruits as opposed to insects feeding on fleshy fruits. Plant species richness within plant families did not influence insect host specificity, but site characteristics may be important in this regard. Most subnetworks were extremely specialized, such as those including Tortricidae and Bruchinae in Panama. Plant phylogenetic distance, plant basal area and plant traits (fruit length, number of seeds per fruit) had important effects on several network statistics in regressions weighted by sampling effort. A path analysis revealed a weak direct influence of plant phylogenetic distance on parasitoid richness, indicating limited support for the ‘nasty host hypothesis'. Our study emphasizes the duality between seed dispersal and seed predation networks in the tropics, as key plant species differ and host specificity tends to be low in the former and higher in the latter. This underlines the need to study both types of networks for sound practices of forest regeneration and conservation. |
| Keywords: | Barro Colorado Island functional group nasty host hypothesis plant phylogeny quantitative food web seed predation |