title: An invasive slug exploits an ant-seed dispersal mutualism.
abstract: Plant-animal mutualisms, such as seed dispersal, are often vulnerable to disruption by invasive species. Here, we show for the first time how a non-ant invasive species negatively affects seed dispersal by ants. We examined the effects of several animal species that co-occur in a temperate deciduous forest-including native and invasive seed-dispersing ants (Aphaenogaster rudis and Myrmica rubra, respectively), an invasive slug (Arion subfuscus), and native rodents-on a native myrmecochorous plant, Asarum canadense. We experimentally manipulated ant, slug, and rodent access to seed depots and measured seed removal. We also video-recorded depots to determine which other taxa interact with seeds. We found that A. rudis was the main disperser of seeds and that A. subfuscus consumed elaiosomes without dispersing seeds. Rodent visitation was rare, and rodent exclusion had no significant effect on seed or elaiosome removal. We then used data obtained from laboratory and field mesocosm experiments to determine how elaiosome robbing by A. subfuscus affects seed dispersal by A. rudis and M. rubra. We found that elaiosome robbing by slugs reduced seed dispersal by ants, especially in mesocosms with A. rudis, which picks up seeds more slowly than M. rubra. Taken together, our results show that elaiosome robbing by an invasive slug reduces seed dispersal by ants, suggesting that invasive slugs can have profound negative effects on seed dispersal mutualisms.
authors.affiliation: Department of Ecology and Evolutionary Biology, University of Toronto, 25 Harbord Street, Toronto, ON, M5S 3G5, Canada. shannon.meadleydunphy@mail.utoronto.ca.
authors.forename: Shannon A
authors.initials: SA
authors.lastname: Meadley Dunphy
authors.affiliation: Department of Ecology and Evolutionary Biology, University of Toronto, 25 Harbord Street, Toronto, ON, M5S 3G5, Canada.|Department of Biology, University of Florida, 411 Carr Hall, Gainesville, FL, 32611, USA.
authors.forename: Kirsten M
authors.initials: KM
authors.lastname: Prior
authors.affiliation: Department of Ecology and Evolutionary Biology, University of Toronto, 25 Harbord Street, Toronto, ON, M5S 3G5, Canada.
authors.forename: Megan E
authors.initials: ME
authors.lastname: Frederickson
mesh_terms: D000818:Animals; D001000:Ants / Q000502:physiology*; D030023:Asarum / Q000502:physiology*; D020387:Food Chain; D049851:Gastropoda / Q000502:physiology*; D058865:Introduced Species; D009864:Ontario; D012377:Rodentia / Q000502:physiology*; D058614:Seed Dispersal; D012639:Seeds; D013559:Symbiosis
keywords: Aphaenogaster rudis; Arion subfuscus; Invasion; Mutualism; Myrmecochory
references.citation: Oecologia. 2009 Sep;161(3):529-37
references.pmid: 19579034
references.citation: Ecology. 2015 Mar;96(3):654-61
references.pmid: 26236862
references.citation: PLoS One. 2009;4(5):e5480
references.pmid: 19436714
references.citation: Oecologia. 2004 Feb;138(3):448-54
references.pmid: 14673638
references.citation: Am J Bot. 2001 Feb;88(2):234-41
references.pmid: 11222246
references.citation: Nature. 2001 Oct 11;413(6856):635-9
references.pmid: 11675787
references.citation: Oecologia. 2001 Sep;129(1):87-97
references.pmid: 28547071
references.citation: Oecologia. 1996 Jun;106(4):500-506
references.pmid: 28307450
references.citation: J Econ Entomol. 2005 Dec;98(6):1774-84
references.pmid: 16539093
references.citation: Trends Ecol Evol. 2006 Apr;21(4):208-16
references.pmid: 16701087
references.citation: Proc Biol Sci. 2015 Feb 7;282(1800):20142846
references.pmid: 25540283
references.citation: Am Nat. 2012 Jan;179(1):124-31
references.pmid: 22173465
references.citation: Oecologia. 2010 Jul;163(3):681-93
references.pmid: 20364390
references.citation: Oecologia. 1991 Nov;88(3):435-443
references.pmid: 28313808
references.citation: Genetica. 2005 Nov;125(2-3):155-71
references.pmid: 16247689
references.citation: PLoS One. 2013 Jul 03;8(7):e68788
references.pmid: 23844239
references.citation: Oecologia. 2003 May;135(4):576-82
references.pmid: 16228256
references.citation: PLoS One. 2013 Sep 25;8(9):e75243
references.pmid: 24086477
references.citation: PLoS One. 2013 Aug 13;8(8):e71871
references.pmid: 23967257