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Fast growth and large size generally increase survivorship in organisms with indeterminate growth. These traits frequently covary, but where they do not, trade-offs often exist in the behavioral choices of organisms. Juvenile bicolor damselfishStegastes partitusthat settle on coral reefs at larger sizes generally experience enhanced survivorship but have slower juvenile growth rates. We hypothesized that differences in behavior may mediate this trade-off. To test whether it is trait-related behaviors or the traits themselves that enhance early survival, we combined individual behavioral observations with otolith (ear stone)-based daily growth measurements for juvenileS. partitusin the Florida Keys. Foraging, sheltering, and chasing behaviors of 256 fish were measured during 5 different months (2008–2009), and patterns of differential survival were similar to those from a 6-year (2003–2008) recruitment time series. We found a trade-off between sheltering and foraging that significantly explained patterns in size-at-settlement: damselfish that settled at larger sizes spent less time sheltered and more time feeding high in the water column. Juvenile growth rates were unrelated to any of the sheltering–foraging behaviors but instead were inversely related to adult conspecific density. Damselfish that settled near higher densities of conspecifics were subjected to increased territorial chasing. Chasing intensity interacted with settlement size such that large juveniles who were chased more frequently exhibited slower growth rates, whereas smaller settlers did not experience this energetic cost. Thus, the dominant survival strategy ofS. partitusis to settle at a large size and spend more time foraging high in the water column while dodging conspecifics at an energetic cost to their growth rates. Size-at-settlement is determined during the larval period and after settlement, this trait is key to subsequent behaviors and the strength of trait-mediated survival. Understanding how somatic growth, body size, and survival are intertwined in early life is necessary to help explain population dynamics.
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This content will become publicly available on June 26, 2026
The interplay between foraging choices and population growth dynamics
Population growth models typically incorporate attributes observable at the population scale, often overlooking the trade-off between individual-level reproductive and behavioral traits and their influence on population size. Individuals’ survival and reproductive abilities are expected to dynamically evolve depending on the population size, which is affected by the aggregation of individual decisions. Reconciling individual-level incentives with population-level dynamics requires an integrative framework that explicitly addresses the intertwined relationships between population growth and individual decision-making processes. We formulate a multiscale modeling framework that integrates the logistic population growth model with an optimal foraging model to study the interplay between individual-level behavioral incentives and population growth dynamics. Specifically, we explicitly model individuals’ decision-making process, which shapes their reproductive fitness and, ultimately, influences population growth. Moreover, we incorporate the concept of resource limitations from the logistic growth model to account for dynamic incentives that depend on population size. Our results yield insights into the multiscale processes, such as the selection pressure of behavioral choices and the cost-benefit of social activities that influence population robustness beyond mere size and aggregated reproductive traits. We found that populations exhibiting similar limiting sizes may undergo significantly different transient dynamics. This variation may be induced by environments imposing distinct behavioral cost-benefit trade-offs that require individuals to exert different levels of foraging effort to maintain reproductive viability.
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- PAR ID:
- 10637842
- Editor(s):
- Ndiribe, Charlotte
- Publisher / Repository:
- PLOS
- Date Published:
- Journal Name:
- PLOS One
- Volume:
- 20
- Issue:
- 6
- ISSN:
- 1932-6203
- Page Range / eLocation ID:
- e0325942
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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