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--- 2018:groups:g8:start [2018/01/09 07:56] – [Introduction] mendes
+++ 2018:groups:g8:start [2024/01/09 18:45] (current) – external edit 127.0.0.1
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-<WRAP hide>
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-Option 1 below. Other options (ordered by difficulty) :
-**Plant defences limit herbivore population growth by changing predator–prey interactions.**
-Kersch-Becker et al 2017. Proceedings of the Royal Society B: Biological Sciences. 284: 20171120.
-[[http://rspb.royalsocietypublishing.org/content/royprsb/284/1862/20171120.full.pdf]]
-**Exposure to the leaf litter microbiome of healthy adults protects seedlings from pathogen damage.**
-Christian et al 2017. Proceedings of the Royal Society B: Biological Sciences. 284: 20170641.
-[[http://rspb.royalsocietypublishing.org/content/royprsb/284/1858/20170641.full.pdf]]
-**Zika virus activates de novo and cross-reactive memory B cell responses in dengue-experienced donors**
-Rogers et al. 2017. Science Immunology. 2: eaan6809.
-[[http://immunology.sciencemag.org/content/2/14/eaan6809]]
-</WRAP>
-</WRAP>
 **Group 8**
-====== Competition between brown bear and grey wolf ======
+====== Competition between brown bears and grey wolves ======
 Wiki site of the practical exercise of the [[http://www.ictp-saifr.org/mathbio7|VII Southern-Summer School on Mathematical Biology]].
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 ===== Introduction =====
-Different apex predators may share the same resources in a given environment. For instance, the grey wolf and the brown bear are predators of ungulates in North America and Europe. Tallian et al. evaluated a long dataset to understand how the presence of bears affects the killing rate of wolves and found that the time between consecutive kills made by wolves increased in the presence of bears, in both sites. The authors suggest some mechanisms to explain this:
+Different apex predators may share the same resources in a given environment. For instance, the grey wolf and the brown bear are predators of ungulates in North America and Europe. Bears usually dominate scavenged prey, which motivates the common assumption that wolves have to hunt more in the presence of bears to compensate the loss of resources. Tallian et al. evaluated a long dataset to understand how the presence of bears affects the killing rate of wolves and found , unexpectedly, that the time between consecutive kills made by wolves increased in the presence of bears, in both sites. The authors suggest some mechanisms to explain this:
   * bears reduce densities of neonate ungulates (i.e. exploitative competition)
   * wolves take longer between kills by attacking larger preys or by feeding on usurped kills under bears' presence (i.e. interference competition and/or kleptoparasitism)
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 {{ :2018:groups:g8:721303_1outlife041516.jpg |}}
 © Stan Tekiela
 ===== Assignment =====
-Think about the balance of exploitative and interference competition between bears and wolves. Are there only negative effects of bears to wolves’ kills? Is it possible one competitor to have a positive effect on the other competitor? How bears can increase the feeding rate of wolves? Think about considering the handling time differences in the absence and presence of bears.
+Propose and analyze a simple mathematical model to describe the coupled dynamics of populations of wolves and bears, taking into account the possibility of quite distinct details about their interaction.
-Propose a simple mathematical model to describe the coupled dynamics of populations of wolfs and bears. Your model should help to explore the questions above.
-===== Extension =====
+===== Questions and suggestions =====
-The authors suggest that the presence of both predators possibly impact prey less than the sum of their individual impacts. How does including prey's population dynamics explicitly can account for that effect? How the sympatric populations of predators affect differently from the predictions of the sum of allopatric populations?
+  * Be careful about the distinctions between kill rate, consumption rate and population growth rate.
+  * Consider the difference, in this system, between exploitative and interference competition. How can bears increase the feeding rate of wolves? Do bears affect the handling time of wolves?
+  * Are there only negative effects of bears on wolves’ kills, or are positive effects possible? In that case, what would be the consequence for the populations dynamics?
+  * The authors suggest that the presence of both predators possibly impact prey less than the sum of their individual impacts. Does your model confirm that possibility under some circumstances?
 ===== Reference =====