title: Dipteran larvae and microbes facilitate nutrient sequestration in theNepenthes gracilispitcher plant host.
abstract: The fluid-containing traps ofNepenthescarnivorous pitcher plants (Nepenthaceae) are often inhabited by organisms known as inquilines. Dipteran larvae are key components of such communities and are thought to facilitate pitcher nitrogen sequestration by converting prey protein into inorganic nitrogen, although this has never been demonstrated inNepenthesPitcher fluids are also inhabited by microbes, although the relationship(s) between these and the plant is still unclear. In this study, we examined the hypothesis of digestive mutualism betweenN. gracilispitchers and both dipteran larvae and fluid microbes. Using dipteran larvae, prey and fluid volumes mimickingin situpitcher conditions, we conductedin vitroexperiments and measured changes in available fluid nitrogen in response to dipteran larvae and microbe presence. We showed that the presence of dipteran larvae resulted in significantly higher and faster releases of ammonium and soluble protein into fluids in artificial pitchers, and that the presence of fluid microbes did likewise for ammonium. We showed also that niche segregation occurs between phorid and culicid larvae, with the former fragmenting prey carcasses and the latter suppressing fluid microbe levels. These results clarify the relationships between several key pitcher-dwelling organisms, and show that pitcher communities facilitate nutrient sequestration in their host.
authors.affiliation: Department of Biological Sciences, National University of Singapore, 14 Science Drive 4, Singapore 117543, Republic of Singapore wengngai@u.nus.edu.
authors.forename: Weng Ngai
authors.identifier: 0000-0002-1188-1363
authors.initials: WN
authors.lastname: Lam
authors.affiliation: Department of Biological Sciences, National University of Singapore, 14 Science Drive 4, Singapore 117543, Republic of Singapore.
authors.forename: Kwek Yan
authors.identifier: 0000-0003-4754-8957
authors.initials: KY
authors.lastname: Chong
authors.affiliation: Department of Biological Sciences, National University of Singapore, 14 Science Drive 4, Singapore 117543, Republic of Singapore.
authors.forename: Ganesh S
authors.initials: GS
authors.lastname: Anand
authors.affiliation: Department of Biological Sciences, National University of Singapore, 14 Science Drive 4, Singapore 117543, Republic of Singapore.
authors.forename: Hugh Tiang Wah
authors.identifier: 0000-0002-3056-4945
authors.initials: HT
authors.lastname: Tan
mesh_terms: D064751:Ammonium Compounds / Q000378:metabolism; D000818:Animals; D004175:Diptera / Q000502:physiology*; D017753:Ecosystem; D007814:Larva / Q000502:physiology; D064307:Microbiota / Q000502:physiology*; D009584:Nitrogen / Q000032:analysis*; D010940:Plant Proteins / Q000378:metabolism; D052583:Sarraceniaceae / Q000382:microbiology* / Q000502:physiology*; D013559:Symbiosis
chemical_list: D064751:Ammonium Compounds; D010940:Plant Proteins; D009584:Nitrogen
keywords: Nepenthes gracilis; digestive mutualism; inquiline; phytotelm; plant–microbe interaction