Larvae promote a decline in the harvesting of myrmecochorous seeds by Myrmica rubra ants
Non-granivorous ant species that contribute to seed dispersal (myrmecochory sensu stricto) are assumed to benefit from the larval consumption of elaiosomes, the lipid-rich appendages of myrmecochorous seeds. It is, however, questionable whether this ant–plant interaction is truly mutualistic, since some ant partners do not show a clear-cut fitness gain and may cease the harvesting of myrmecochorous seeds over time. In particular, the role of ant larvae as potential consumers of seed elaiosomes is not yet fully understood. In this study, we investigated how the number of larvae influences the foraging responses of the red ant Myrmica rubra to Viola odorata myrmecochorous seeds and to Drosophila melanogaster prey. Ant workers retrieved less elaiosome-bearing seeds than prey and the harvesting of seeds remained low, even in the presence of larvae. Furthermore, while the ant colonies continued to collect prey over successive foraging events, the retrieval of myrmecochorous seeds decreased, most particularly in colonies containing a large number of larvae. Brood exposure to diaspores also declined, with very few larvae coming into contact with seeds. Our results suggest that the role of larvae as elaiosome consumers should be reconsidered and that larvae may provide workers with cues about the poor palatability of V. odorata diaspores, thereby altering the stability of this ant–plant interaction.
KeywordsCommon red ant Sweet violet Ant–plant interactions Myrmecochory Foraging Brood number
This work was supported by a Belgian PhD Grant from the F.R.I.A. (Fonds pour la formation à la Recherche dans l’Industrie et dans l’Agriculture) attributed to A. Bologna. Dr Claire Detrain is Research Director from the Belgian National Fund for Scientific Research (F.N.R.S).
- Cammaerts M (1977) Recrutement d’ouvrières vers une source d’eau pure ou sucrée chez la fourmi Myrmica ruba L. Biol Behav 2:287–308Google Scholar
- Culver DC, Beattie AJ (1980) The fate of Viola seeds dispersed by ants. Am J Bot 67:710–714. https://doi.org/10.1002/j.1537-2197.1980.tb07701.x CrossRefGoogle Scholar
- Handel SN (1978) The competitive relationship of three wood land sedges and its bearing on the evolution of ant dispersal of Carex pedunculata. Evolution 32(151):163. https://doi.org/10.1111/j.1558-5646.1978.tb01105.x Google Scholar
- Horvitz CC (1981) Analysis of how ant behaviors affect germination in a tropical myrmecochore Calathea microcephala (P.&E.) Koernicke (Marantaceae): microsite selection and aril removal by neotropical ants, Odontomachus, Pachycondyla, and Solenopsis (Formicidae). Oecologia 20:47–52. https://doi.org/10.1007/BF00344651 CrossRefGoogle Scholar
- Horvitz CC, Beattie AJ (1980) Ant dispersal of Calathea (Marantaceae) seeds by carnivorous ponerines (Formicidae) in a tropical rain forest. Am J Bot 67:321–326. https://doi.org/10.1002/j.1537-2197.1980.tb07657.x CrossRefGoogle Scholar
- Lambinon J, Verloove F (2012) Nouvelle flore de la Belgique, du G.-D. de Luxembourg, du nord de la France et des régions voisines. 6th Ed. Jardin Botanique- Plantentuin, MeiseGoogle Scholar
- Lengyel S, Gove AD, Latimer AM, Majer JD, Dunn RB (2009) Ants sow the seeds of global diversification in flowering plants. Public Libr Sci One 4:e5480Google Scholar
- Rico-gray V, Oliveira PS (2007) The ecology and evolution of ant–plant interactions. University of Chicago Press, ChicagoGoogle Scholar
- Warren RJ II, Giladi I (2014) Ant-mediated seed dispersal: a few ant species (Hymenoptera:Formicidae) benefit many plants. Myrmecol News 20:129–140Google Scholar