Challenging the foraging-mode paradigm: a case study of lizards

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# Challenging the foraging-mode paradigm: a case study of lizards
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.author[
### Dylan Padilla Herp group 2023 <svg viewBox="0 0 512 512" style="position:relative;display:inline-block;top:.1em;fill:skyblue;height:1em;" xmlns="http://www.w3.org/2000/svg"> <path d="M502.3 190.8c3.9-3.1 9.7-.2 9.7 4.7V400c0 26.5-21.5 48-48 48H48c-26.5 0-48-21.5-48-48V195.6c0-5 5.7-7.8 9.7-4.7 22.4 17.4 52.1 39.5 154.1 113.6 21.1 15.4 56.7 47.8 92.2 47.6 35.7.3 72-32.8 92.3-47.6 102-74.1 131.6-96.3 154-113.7zM256 320c23.2.4 56.6-29.2 73.4-41.4 132.7-96.3 142.8-104.7 173.4-128.7 5.8-4.5 9.2-11.5 9.2-18.9v-19c0-26.5-21.5-48-48-48H48C21.5 64 0 85.5 0 112v19c0 7.4 3.4 14.3 9.2 18.9 30.6 23.9 40.7 32.4 173.4 128.7 16.8 12.2 50.2 41.8 73.4 41.4z"></path></svg> <a href="mailto:dpadil10@asu.edu" class="email">dpadil10@asu.edu</a> | <svg viewBox="0 0 512 512" style="position:relative;display:inline-block;top:.1em;fill:skyblue;height:1em;" xmlns="http://www.w3.org/2000/svg"> <path d="M326.612 185.391c59.747 59.809 58.927 155.698.36 214.59-.11.12-.24.25-.36.37l-67.2 67.2c-59.27 59.27-155.699 59.262-214.96 0-59.27-59.26-59.27-155.7 0-214.96l37.106-37.106c9.84-9.84 26.786-3.3 27.294 10.606.648 17.722 3.826 35.527 9.69 52.721 1.986 5.822.567 12.262-3.783 16.612l-13.087 13.087c-28.026 28.026-28.905 73.66-1.155 101.96 28.024 28.579 74.086 28.749 102.325.51l67.2-67.19c28.191-28.191 28.073-73.757 0-101.83-3.701-3.694-7.429-6.564-10.341-8.569a16.037 16.037 0 0 1-6.947-12.606c-.396-10.567 3.348-21.456 11.698-29.806l21.054-21.055c5.521-5.521 14.182-6.199 20.584-1.731a152.482 152.482 0 0 1 20.522 17.197zM467.547 44.449c-59.261-59.262-155.69-59.27-214.96 0l-67.2 67.2c-.12.12-.25.25-.36.37-58.566 58.892-59.387 154.781.36 214.59a152.454 152.454 0 0 0 20.521 17.196c6.402 4.468 15.064 3.789 20.584-1.731l21.054-21.055c8.35-8.35 12.094-19.239 11.698-29.806a16.037 16.037 0 0 0-6.947-12.606c-2.912-2.005-6.64-4.875-10.341-8.569-28.073-28.073-28.191-73.639 0-101.83l67.2-67.19c28.239-28.239 74.3-28.069 102.325.51 27.75 28.3 26.872 73.934-1.155 101.96l-13.087 13.087c-4.35 4.35-5.769 10.79-3.783 16.612 5.864 17.194 9.042 34.999 9.69 52.721.509 13.906 17.454 20.446 27.294 10.606l37.106-37.106c59.271-59.259 59.271-155.699.001-214.959z"></path></svg> <a href="https://dylanpadilla.netlify.app/" class="uri">https://dylanpadilla.netlify.app/</a>
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# Acknowledgements

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Shai Meiri

Mark O'Shea

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Gustavo Burin

Camila Tabares

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# Outline

- History of the foraging-mode paradigm

- Relationship with the life history

- Current state of knowledge

- What is new

- What comes next

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# The foraging-mode paradigm

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# The foraging-mode paradigm

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Active foragers

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Sit-and-wait foragers

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# Hypotheses about how an organism’s foraging mode relates to its life history

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# Functional reproductive volume

Strategy 1: Sit-and-wait foragers;

Strategy 2: active foragers

Vitt and Congdon (1978)

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# Sit-and-wait lizards evolved greater reproductive effort than did active-foraging lizards

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Vitt and Congdon (1978)

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Vitt and Price (1982)

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Mesquita et al. (2016)

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# The relationship between foraging mode and life-history traits is currently unsupported

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# Data source and description of variables

- Hatchling mass
- Offspring number
- Female mass
- Scaled-mass index

\[Reproductive\; output=Hatchling\; size \times Offspring\; number \]

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# Ancestral reconstruction of foraging mode

- We used a set of continuous-time, discrete-state Markov chain models to sample the character histories from their posterior probability distribution

- We fitted three different models to our data, using the function `make.simmap` from the [`phytools` 📦](https://cran.r-project.org/web/packages/phytools/index.html) of <svg viewBox="0 0 581 512" style="height:1em;position:relative;display:inline-block;top:.1em;" xmlns="http://www.w3.org/2000/svg"> <path d="M581 226.6C581 119.1 450.9 32 290.5 32S0 119.1 0 226.6C0 322.4 103.3 402 239.4 418.1V480h99.1v-61.5c24.3-2.7 47.6-7.4 69.4-13.9L448 480h112l-67.4-113.7c54.5-35.4 88.4-84.9 88.4-139.7zm-466.8 14.5c0-73.5 98.9-133 220.8-133s211.9 40.7 211.9 133c0 50.1-26.5 85-70.3 106.4-2.4-1.6-4.7-2.9-6.4-3.7-10.2-5.2-27.8-10.5-27.8-10.5s86.6-6.4 86.6-92.7-90.6-87.9-90.6-87.9h-199V361c-74.1-21.5-125.2-67.1-125.2-119.9zm225.1 38.3v-55.6c57.8 0 87.8-6.8 87.8 27.3 0 36.5-38.2 28.3-87.8 28.3zm-.9 72.5H365c10.8 0 18.9 11.7 24 19.2-16.1 1.9-33 2.8-50.6 2.9v-22.1z"></path></svg>, v. 1.0.1

- We estimated the prior distribution on the root node of the tree (`pi = 'estimated'`) and sampled the transition matrix, `Q`, from its posterior distribution (`Q = 'mcmc'`).

- We selected the most likely model of evolution based on the Akaike information criterion (AIC)

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# Effects of maternal mass and foraging mode on reproductive output

- We used PGLS to model the relationship among maternal mass, foraging mode and reproductive output through the `gls` function from the [`nlme` 📦](https://cran.r-project.org/web/packages/nlme/index.html) of <svg viewBox="0 0 581 512" style="height:1em;position:relative;display:inline-block;top:.1em;" xmlns="http://www.w3.org/2000/svg"> <path d="M581 226.6C581 119.1 450.9 32 290.5 32S0 119.1 0 226.6C0 322.4 103.3 402 239.4 418.1V480h99.1v-61.5c24.3-2.7 47.6-7.4 69.4-13.9L448 480h112l-67.4-113.7c54.5-35.4 88.4-84.9 88.4-139.7zm-466.8 14.5c0-73.5 98.9-133 220.8-133s211.9 40.7 211.9 133c0 50.1-26.5 85-70.3 106.4-2.4-1.6-4.7-2.9-6.4-3.7-10.2-5.2-27.8-10.5-27.8-10.5s86.6-6.4 86.6-92.7-90.6-87.9-90.6-87.9h-199V361c-74.1-21.5-125.2-67.1-125.2-119.9zm225.1 38.3v-55.6c57.8 0 87.8-6.8 87.8 27.3 0 36.5-38.2 28.3-87.8 28.3zm-.9 72.5H365c10.8 0 18.9 11.7 24 19.2-16.1 1.9-33 2.8-50.6 2.9v-22.1z"></path></svg>, v. 3.1.153

- The slope of the linear relationship can be interpreted as reproductive effort—proportion of mass allocated to reproduction—which enabled us to avoid statistical issues associated with the analysis of ratios

- Models in which maternal mass was standardized (M) enabled us to deal with outliers, thus increasing the robustness of our conclusions

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# Sit-and-wait foraging is the most likely ancestral state

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# Foraging mode is conserved among lizards

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# The evolution of reproductive effort in lizards was driven by an *interaction* between maternal mass and foraging mode

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# Our analysis provides evidence that widely-foraging lizards have evolved greater reproductive effort, but only in heavier species

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# Addressing issues associated with the scatter in the data

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Mean effect size of the interaction was \[-0.259\]

Proportion of time that the p-value was significant \[57.4\%\]

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# Food consumption may play an important role as follows:

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Promoting follicular growth

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Increasing energy stores to initiate reproduction

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Reducing age at first reproduction

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# Concluding remarks

- The early shift in foraging mode—from sit-and-wait foraging to widely foraging—in the evolutionary history of lacertilians was likely accompanied by the evolution of a greater reproductive effort, specifically in large-bodied species of lizards

- Importantly, our study captured the effects of foraging plasticity on the reproductive effort of lizards. For instance, lizards that adopt a mixed-foraging strategy produced the greatest reproductive effort

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Find the paper here 👉

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