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 ===== Introduction =====
-Ants and plants are engaged in mutualistic interactions where plants provide resources to ants, such as food (in the form of extra-floral nectar or food bodies) and shelter (such as hollow stems and domatia) in exchange for protection against natural enemies. Ants protect plants from natural enemies by capturing herbivores and removing other natural enemies, such as competing and parasitic plants.
+Many ants and plants engage in mutualistic interactions where plants provide resources to ants, such as food (in the form of extra-floral nectar or food bodies) and shelter (such as hollow stems and [[https://en.wikipedia.org/wiki/Domatium|domatia]]) in exchange for protection against natural enemies. Ants protect plants from natural enemies by capturing herbivores and removing other natural enemies, such as competing and parasitic plants.
 {{:2020:groups:g8:ant-plant-fungus.jpg?nolink&300 |}}
-Two species of ants coexist (//Allomerus octoarticulatus// and //A. decemarticulatus//) in French Guinea with two distinct strategies regarding the protection they provide to their host plant. Their host plant (//Hirtella physophora//) provide the ants with nesting cavities, so-called domatia, in exchange of protection from herbivory (left photos of domatia and trapping from Annals of Botanic Office and Forest Floor Narrative).
+Two species of ants coexist (//Allomerus octoarticulatus// and //A. decemarticulatus//) in French Guinea with two distinct strategies regarding the protection they provide to their host plant. Their host plant (//Hirtella physophora//) provide the ants with nesting cavities, so-called domatia, in exchange for protection from herbivory (left photos of domatia and trapping from Annals of Botanic Office and Forest Floor Narrative).
 The two strategies are:
-i) The typical strategy of foraging on leaves, actively searching for herbivores.
+i) The typical strategy of foraging on leaves, stems and trunk, actively searching for herbivores.
 {{:2020:groups:g8:trap.png?nolink&300 |}}
-ii)The innovative strategy of using galleries for prey capture: The hollow porous tubes are filled with ants ready to ambush. Unsuspecting insects that land on the trap and quickly become overwhelmed by the voracious invertebrates. Also the fungus improves nutrient uptake by the host plant.
+ii) The innovative strategy of using galleries for prey capture: the ants cut plant 'hairs' (trychomes) and bind them with a fungi that they grow to build galleries over the plant bark (Dejean et al 2005). The hollow porous tubes are filled with ants ready to ambush. Unsuspecting insects land on the trap and quickly become overwhelmed by the voracious invertebrates. Also the fungus used to build the galleries improves nutrient uptake by the host plant.
-However, because of a limited worker force in their colonies, the prey capture behaviour of the ants results in a trade-off between plant protection (i.e. the ants patrol the foliage and attack intruders including herbivores) and ambushing prey in the galleries, which has a cascading effect on the fitness of all of the partners.
+However, because of a limited worker force in their colonies, the prey capture behaviour of the ants results in a trade-off between the strategies of patrolling the foliage and ambushing prey in the galleries, which has a cascading effect on the fitness of all of the partners. The quantification of partners' traits and effects showed that the two ant species differed in their mutualistic investment ratios.
-The quantification of partners' traits and effects showed that the two ant species differed in their mutualistic investment ratios.
+Less investment in the galleries (i.e. in fungal cultivation) translated into more benefits for the plant in terms of less herbivory and higher growth rates and vice-versa. However, the greater vegetative growth of the plants did not produce a positive fitness effect for the better mutualistic ant species in terms of colony size and production of reproductive individuals nor was the mutualism compensated by the wider dispersal of its queens.
-Less investment in the galleries (i.e. in fungal cultivation) translated into more benefits for the plant in terms of less herbivory and higher growth rates and vice-versa. However, the greater vegetative growth of the plants did not produce a positive fitness effect for the better mutualistic ant species in terms of colony size and production of sexuals nor was the mutualism compensated by the wider dispersal of its queens.
+In a nutshell: this tripartite relationship is fascinating! The plants receive nutrients and protection from the ants, while the ants get a place to live. The ants help to disperse and propagate the fungus, while the fungus helps hold the trapping structure together. The fungus also gets a place to live provided by the plants, and in turn, efficiently transfers nutrients from ant waste into the plant.
-In a nutshell: this tripartite relationship is fascinating! The plants receive nutrients and protection from the ants, while the ants get a place to live. The ants help disperse and propagate the fungus, while the fungus helps hold the trapping structure together. The fungus also gets a place to live provided by the plants, and in turn, efficiently transfers nutrients from ant waste into the plant.
 ===== Assignment =====
-Write a model to investigate mutualistic investment, its potential trade-offs and their consequences for the longevity of ant species coexistence in this tripartite interaction involving a myrmecophyte (plant), two ant species which compete to occupy its domatia and a fungus they cultivate.
+Propose a mathematical model to investigate mutualistic investment, its potential trade-offs and their consequences for the persistence of ant species coexistence in this tripartite interaction involving a myrmecophyte (plant), two ant species which compete to occupy its domatia and a fungus that ants cultivate.
-===== Questions & Suggestions =====
+===== Suggested questions =====
-) We know that a consequence of competing strategies is exclusion of the worse strategy. Although the better ant mutualism is the one that provides more benefits to its host plant, its lower host–plant exploitation does not give this ant species a competitive advantage. Can your model support local coexistence of the ant species? Does the model eventually lead to the exclusion of the less competitive species?
+  - Is the coexistence of the two ant species possible?
+  - Will the scenario proposed by Orivel //et al.// lead to competitive exclusion, as proposed by the authors ?
+  - Is there an optimal proportion of the two strategies in the worker force? (A proportion that leads to the greatest ant population, or leads to the greatest growth rates...)
-) From the experimental data in the recent article of Orival //et al.//, can you estimate (some) parameters of your model?
+Further well-grounded questions from the group are welcome.
 ===== References =====
-Orivel Jérôme, Malé Pierre-Jean, Lauth Jérémie, Roux Olivier, Petitclerc Frédéric, Dejean Alain and Leroy Céline. **Trade-offs in an ant–plant–fungus mutualism** 284 Proc. R. Soc. B. 2019.<[[http://doi.org/10.1098/rspb.2016.1679]]>.
+Jérôme Orivel, Pierre-Jean Malé, Jérémie Lauth, Olivier Roux, Frédéric Petitclerc, Alain Dejean and Céline Leroy. **Trade-offs in an ant–plant–fungus mutualism** 284 Proc. R. Soc. B. 2019.[[http://doi.org/10.1098/rspb.2016.1679]].
-Leroy, C., Séjalon‐Delmas, N., Jauneau, A., Ruiz‐González, M.‐X., Gryta, H., Jargeat, P., Corbara, B., Dejean, A. and Orivel, J. **Trophic mediation by a fungus in an ant–plant mutualism.** Journal of Ecology, 99: 583-590. 2011. <[[https://doi.org/10.1111/j.1365-2745.2010.01763.x]]>.
+Leroy, C., Séjalon‐Delmas, N., Jauneau, A., Ruiz‐González, M.‐X., Gryta, H., Jargeat, P., Corbara, B., Dejean, A. and Orivel, J. **Trophic mediation by a fungus in an ant–plant mutualism.** Journal of Ecology, 99: 583-590. 2011. [[https://doi.org/10.1111/j.1365-2745.2010.01763.x]].
-Dejean, Alain; Solano, Pascal J., Ayroles, Julien; Corbara, Bruno and Orivel, Jérôme  Arboreal. **Ants build traps to capture prey**. Nature volume 434, pg. 973 (2005). <[[https://www.nature.com/articles/434973a]]>.
+Dejean, Alain; Solano, Pascal J., Ayroles, Julien; Corbara, Bruno and Orivel, Jérôme  Arboreal. **Ants build traps to capture prey**. Nature volume 434, pg. 973 (2005). [[https://www.nature.com/articles/434973a]].