**Group 5**

====== Alternative reproductive tactics in cichlid fish ======


Wiki site of the practical exercise of the [[http://www.ictp-saifr.org/?page_id=4634|III Southern-Summer School on Mathematical Biology]].

Here you will find the exercise assigment and the group's products. 

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===Final Presentation===
{{:2014:groups:g5:presentation-5.pdf|GROUP 5 PRESENTATION}}
===== Group =====
  * Chaquea, Jose Dario; //Universidad de los Andes, Depart. Biomedical Engineering, Colombia//
  * Couto, Thiago Belisario D'Araújo; //National Institute of Amazonian Research, Brazil//
  * Giese, Adriana Carolina; //Centro Nacional Patagónico, Argentina// 
  * Simões Yamaki, Tania Patricia; //University of Campinas, Physics Institute, Brazil//
  * Tonhatti, Carlos Henrique; //University of Campinas, Institute of Biology, Brazil//
  
  

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===Assistants===

  * Bernardo Niebuhr
  * Diogo Melo
  * Fernando Rossine
 

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===== Assignment =====

{{ :2014:groups:g5:lapro_shell.jpg?200|Lamprologus callipterus carrying a shell}}

Alternative reproductive strategies within the same species is a widespread phenomenon in fish. In the cichlid 
fish //[[http://en.wikipedia.org/wiki/Lamprologus_callipterus|Lamprologus callipterus]]//, large males
collect and guard shells in which females enter and release their eggs. There is strong sexual size dimorphism
in this species and the male are too large to enter the shell. Females, 
on the other hand, remain primarily in the shell during the whole reproductive period. Since the males 
monopolize resources, this behavior is referred as the [[http://en.wikipedia.org/wiki/Bourgeoisie|bourgeois]] tactic.

{{:2014:groups:g5:lapro_all.png?350 |Figure 1. Nest of //Lamprologus callipterus// with large male, female inspecting shell and small male. From Wirtz-Ocaňa //et al.// (2013)}}

Only males large enough to carry shells are able to adopt this strategy. 
Alternatively, smaller males may attempt to release their sperm in a guarded shell, while the large male 
is away (parasitic tactic) (([[http://jhered.oxfordjournals.org/content/92/2/100.full|Michael Taborsky. “The Evolution of Bourgeois, Parasitic, and Cooperative Reproductive Behaviors in Fishes.” Journal of Heredity 92(2) (March 1): 100–110, 2001]])). If the male is small enough, it may even enter the shell, go to its innermost 
part and remain there during the fertilization period (([[http://onlinelibrary.wiley.com/doi/10.1046/j.1439-0310.2003.00944.x/full| Tetsu Sato, Mitsuru Hirose, Michael Taborsky,and Seishi Kimura. “Size-Dependent Male Alternative Reproductive Tactics in the Shell-Brooding Cichlid Fish Lamprologus callipterus in Lake Tanganyika.” Ethology 110(1): 49–62, 2004]])). 

The male size distribution of populations of this species is clearly bimodal, allowing the distinction of two separate groups of individuals: large (also called nest males) and small (dwarf males). 
Wirtz-Ocaňa and collaborators (2013) have 
shown that male size is paternally inherited in this species. Large male father large individuals and dwarf males father small individuals (([[http://onlinelibrary.wiley.com/doi/10.1002/ece3.570/full| Sabine Wirtz-Ocaňa, Dolores Schütz, Gudrun Pachler, and Michael Taborsky. “Paternal Inheritance of Growth in Fish Pursuing Alternative Reproductive Tactics.” Ecology and Evolution 3(6): 1614–1625, 2013]])).




{{ :2014:groups:g5:two_strategies.jpg?450 |}}

Parasitic dwarf male (smallest individual) is shown inside the shell with the female. Nest
male is shown in the outside. [[http://www.sciencedirect.com/science/article/pii/S0169534797013189 | From Taborsky (1998)]].


==== Questions ====
Different questions can be investigated by modeling this system. It is important to keep mind which are the relevant features on the problem being studied. A possibility is to think about a population model that explains in which conditions each reproductive strategy is more appropriate and in which conditions there is long-term coexistence of both strategies in a population.

==== References ====