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Alternative reproductive strategies in the ruff, Philomachuspugnax: a mixed ESS? FREDRIK WIDEMO Section of Animal Ecology, Department of Zoology, Uppsala University and Department of Zoology, Norwegian University of Science and Technology, Trondheim.

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Alternative reproductive strategies in the ruff, Philomachuspugnax: a mixed ESS?FREDRIK WIDEMOSection of Animal Ecology, Department of Zoology, Uppsala Universityand Department of Zoology, Norwegian University of Science and Technology, Trondheim

Widemo, Fredrik. (1998). Alternative reproductive strategies in the ruff, Philomachus pugnax: a mixed ESS?. Animal Behaviour, 56(2), 329-336. doi: 10.1006/anbe.1998.0792. Summary by Jordan Gash, Daniel Vakili, and Matthew Yamamoto

ruff philomachuspugnax

Ruff(Philomachuspugnax)

The ruff is a lekking wader which breeds throughout

northern Eurasia

From PCAS Feathers e-newsletter, July 2008

what is a lek

What is a Lek?

“In classical leks, individuals gather within sight of each other to court and compete. Physical contest in these situations is frequent, and plays a major role in the mating rituals of certain shorebird and gamebird species”.(Wikipedia)

Adapted From Libb Thims

male ruff bird reproductive strategy are you a satellite or independen t

Male Ruff Bird Reproductive Strategy:Are you a Satellite or Independent?

Independent

-Resident - Alpha male within a lek circle, the one who attracts the females

-Marginal - Independent, seeks to be 

Alpha male, a threat to the Resident.

Satellite

-Gains access to Resident’s lek by 

submitting to him:

aka. letting the Resident peck his 

head.(termed “coupling”). This further

attracts females to that Resident’s lek  

-Gets the females that the Resident doesn’t

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The Study

Is this a mixed ESS?

- An evolutionarily stable strategy cannot be replaced by an alternate strategy easily, and should be consistent over time.- Observe a population of ruffs during the breeding  seasons of 1990–1997- Analyze reproductive success >between the Resident and Satellite strategies>between coupled and non-coupled Residents- Relationship and interaction of the two

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Some major results-Females were found inside the territories of coupled Residents much more often than expected by chance-The presence of females increased Resident-Satellite couplings, and absense of females resulted in decreased coupling.-More pecking at the Satellite attracted more females

-Positive correlation

between number of 

females in a lek

and number of satellites

Adapted from Fredrik Widemo

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Some major results

-Residents copulate more when coupled with Satellites-Satellites copulate almost exclusively when coupled with a resident.-From 1990 to 1996, Percent of copulations performed by Residents (~83-91%) and Satellites(~8-13) remained stable, evidence of the stability of both reproductive strategies.

Adapted from Fredrik Widemo

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Speculation: Why does this happen?

-Questions of equal fitness between residents and satellites

- Is it a ritualized fight? Coalition? Agreed hierarchy?

- Are the satellites just attracted to Residents the same way females 

are?

-The Satellite strategy

may represent a

low-cost, low-benefit

strategy, for both

groups.

Adapted from Spark Notes, types of natural selection

critical review
Interesting Points:

The presence of females increased Resident-Satellite couplings, and absense of females resulted in decreased coupling

More Pecking at the Satellite by the Resident attracted more females

Females have a strong impact on the coupling of Residents and Satellites such that the presence of females brings about quicker, longer lasting, and higher retention rates of couplings.

Limitations:

1. It is still unclear for the exact reasoning of Satellites and Females to visit a Resident’s Lek.

2. The evolutionary benefits of having multiple reproductive strategies among male ruffs is still unclear.

3. Couldn’t calculate overall male lek attendance for Satellites and marginals.

Critical Review