Limits...
Evolving nutritional strategies in the presence of competition: a geometric agent-based model.

Senior AM, Charleston MA, Lihoreau M, Buhl J, Raubenheimer D, Simpson SJ - PLoS Comput. Biol. (2015)

Bottom Line: Our results indicate that a transition between two alternative strategies occurs at moderate to high levels of competition.Our models imply that competition combined with reproductive skew in social groups can play a role in the evolution of diet breadth.We discuss how the integration of agent-based, nutritional and evolutionary modelling may be applied in future studies to further understand the evolution of nutritional strategies across social and ecological contexts.

View Article: PubMed Central - PubMed

Affiliation: Charles Perkins Centre, The University of Sydney, Sydney, New South Wales, Australia; School of Biological Sciences, The University of Sydney, Sydney, New South Wales, Australia.

ABSTRACT
Access to nutrients is a key factor governing development, reproduction and ultimately fitness. Within social groups, contest-competition can fundamentally affect nutrient access, potentially leading to reproductive asymmetry among individuals. Previously, agent-based models have been combined with the Geometric Framework of nutrition to provide insight into how nutrition and social interactions affect one another. Here, we expand this modelling approach by incorporating evolutionary algorithms to explore how contest-competition over nutrient acquisition might affect the evolution of animal nutritional strategies. Specifically, we model tolerance of nutrient excesses and deficits when ingesting nutritionally imbalanced foods, which we term 'nutritional latitude'; a higher degree of nutritional latitude constitutes a higher tolerance of nutritional excess and deficit. Our results indicate that a transition between two alternative strategies occurs at moderate to high levels of competition. When competition is low, individuals display a low level of nutritional latitude and regularly switch foods in search of an optimum. When food is scarce and contest-competition is intense, high nutritional latitude appears optimal, and individuals continue to consume an imbalanced food for longer periods before attempting to switch to an alternative. However, the relative balance of nutrients within available foods also strongly influences at what levels of competition, if any, transitions between these two strategies occur. Our models imply that competition combined with reproductive skew in social groups can play a role in the evolution of diet breadth. We discuss how the integration of agent-based, nutritional and evolutionary modelling may be applied in future studies to further understand the evolution of nutritional strategies across social and ecological contexts.

No MeSH data available.


Model Results in Different 2-Food Environments.The effects of increasing competition, c (Equation 3), on the mean level of nutritional latitude, K, (and the 2.5th and 97.5th percentile; dashed line) that is stable under differing nutritional environments containing 2 foods. Data are based on 30 model runs. Data from levels of competition, above which the population could not consistently survive (i.e., extinction, given by a bold grey line), have been removed. A geometric visualisation of each environment is given; see Fig. 2 legend for details.
© Copyright Policy
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4376532&req=5

pcbi.1004111.g003: Model Results in Different 2-Food Environments.The effects of increasing competition, c (Equation 3), on the mean level of nutritional latitude, K, (and the 2.5th and 97.5th percentile; dashed line) that is stable under differing nutritional environments containing 2 foods. Data are based on 30 model runs. Data from levels of competition, above which the population could not consistently survive (i.e., extinction, given by a bold grey line), have been removed. A geometric visualisation of each environment is given; see Fig. 2 legend for details.

Mentions: We next considered competition in a 2-food environment, containing one balanced and one imbalanced food, the latter of which varied in the degree of nutritional imbalance (Fig. 3). With a mildly imbalanced food, absent or weak competition selected for a lower K (and lower variance; Fig. 3A) than in 3-food environments (Fig. 2). Thus, selection for low nutritional latitude was stronger in this 2-food environment than in the 3-food environments. That being said, in the 2-food environment with a mildly imbalanced food and low c, K was stable, before transitioning to high K under moderate to high c (Fig. 3A), as was the case in 3-food environments (Fig. 2). In the 2-food environment that contained a balanced and a severely imbalanced food, nutritional latitude showed a quite different profile from that previously observed. Increasing c in this environment selected for low nutritional latitude (and very low variance in K), reaching a minimum value of K = 0.06 at c = 0.625 (Fig. 3B).


Evolving nutritional strategies in the presence of competition: a geometric agent-based model.

Senior AM, Charleston MA, Lihoreau M, Buhl J, Raubenheimer D, Simpson SJ - PLoS Comput. Biol. (2015)

Model Results in Different 2-Food Environments.The effects of increasing competition, c (Equation 3), on the mean level of nutritional latitude, K, (and the 2.5th and 97.5th percentile; dashed line) that is stable under differing nutritional environments containing 2 foods. Data are based on 30 model runs. Data from levels of competition, above which the population could not consistently survive (i.e., extinction, given by a bold grey line), have been removed. A geometric visualisation of each environment is given; see Fig. 2 legend for details.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4376532&req=5

pcbi.1004111.g003: Model Results in Different 2-Food Environments.The effects of increasing competition, c (Equation 3), on the mean level of nutritional latitude, K, (and the 2.5th and 97.5th percentile; dashed line) that is stable under differing nutritional environments containing 2 foods. Data are based on 30 model runs. Data from levels of competition, above which the population could not consistently survive (i.e., extinction, given by a bold grey line), have been removed. A geometric visualisation of each environment is given; see Fig. 2 legend for details.
Mentions: We next considered competition in a 2-food environment, containing one balanced and one imbalanced food, the latter of which varied in the degree of nutritional imbalance (Fig. 3). With a mildly imbalanced food, absent or weak competition selected for a lower K (and lower variance; Fig. 3A) than in 3-food environments (Fig. 2). Thus, selection for low nutritional latitude was stronger in this 2-food environment than in the 3-food environments. That being said, in the 2-food environment with a mildly imbalanced food and low c, K was stable, before transitioning to high K under moderate to high c (Fig. 3A), as was the case in 3-food environments (Fig. 2). In the 2-food environment that contained a balanced and a severely imbalanced food, nutritional latitude showed a quite different profile from that previously observed. Increasing c in this environment selected for low nutritional latitude (and very low variance in K), reaching a minimum value of K = 0.06 at c = 0.625 (Fig. 3B).

Bottom Line: Our results indicate that a transition between two alternative strategies occurs at moderate to high levels of competition.Our models imply that competition combined with reproductive skew in social groups can play a role in the evolution of diet breadth.We discuss how the integration of agent-based, nutritional and evolutionary modelling may be applied in future studies to further understand the evolution of nutritional strategies across social and ecological contexts.

View Article: PubMed Central - PubMed

Affiliation: Charles Perkins Centre, The University of Sydney, Sydney, New South Wales, Australia; School of Biological Sciences, The University of Sydney, Sydney, New South Wales, Australia.

ABSTRACT
Access to nutrients is a key factor governing development, reproduction and ultimately fitness. Within social groups, contest-competition can fundamentally affect nutrient access, potentially leading to reproductive asymmetry among individuals. Previously, agent-based models have been combined with the Geometric Framework of nutrition to provide insight into how nutrition and social interactions affect one another. Here, we expand this modelling approach by incorporating evolutionary algorithms to explore how contest-competition over nutrient acquisition might affect the evolution of animal nutritional strategies. Specifically, we model tolerance of nutrient excesses and deficits when ingesting nutritionally imbalanced foods, which we term 'nutritional latitude'; a higher degree of nutritional latitude constitutes a higher tolerance of nutritional excess and deficit. Our results indicate that a transition between two alternative strategies occurs at moderate to high levels of competition. When competition is low, individuals display a low level of nutritional latitude and regularly switch foods in search of an optimum. When food is scarce and contest-competition is intense, high nutritional latitude appears optimal, and individuals continue to consume an imbalanced food for longer periods before attempting to switch to an alternative. However, the relative balance of nutrients within available foods also strongly influences at what levels of competition, if any, transitions between these two strategies occur. Our models imply that competition combined with reproductive skew in social groups can play a role in the evolution of diet breadth. We discuss how the integration of agent-based, nutritional and evolutionary modelling may be applied in future studies to further understand the evolution of nutritional strategies across social and ecological contexts.

No MeSH data available.