BIOL 3300 Vertebrate Zoology: Ectotherms -

Herpetology

http://www.amphibian.com.au/

How does “sexy” and “macho” relate to fitness?

• Darwin’s contribution…

• Types of selection…

Mating systems and sexual selection?

• What conditions lead to polygynous and monogamous systems?

• Is there ever polyandry? When would it be beneficial?

What are the major types of mating systems?

• Dispersal of mating opportunities is IMPORTANT…

• If concentrated and short duration what approach?

• If concentrated and long duration what approach?

• If dispersed and long/short what approach?

What are the major types of mating systems?

• Scramble approach

What are the major types of mating systems?

• Scramble approach • Urodelans• Ambystoma maculata• Hynobids?

• Reptiles?

What are the major types of mating systems?

• Mate Searching

• What is the advantage of this type of amplexus in spotted newts?

• In reptiles?

What are the major types of mating systems?

• Mate Guarding

• Amplexus is a major form of this approach in amphibians

Atelopus chirriquiensis

What are the major types of mating systems?

• Mate Guarding

• In reptiles?

What are the major types of mating systems?

• Mate Guarding

• Multiple mates?

•CRBI homerange data…

What are the major types of mating systems?

• Sneakers

• Uta stansburiana…

An unusual game is being played out in the Coast Range of California. Three alternative male strategies are locked in an ecological "perpetual motion machine" from which there appears little escape. As in the rock-paper-scissors game where rock beats scissors, paper beats rock, and scissors beats paper, three morphs of lizards cycle from the ultra-dominant polygynous orange-throated males, which best the more monogamous mate gaurding blues; the oranges are in turn bested by the sneaker strategy of yellow-throated males, and the sneaker strategy of yellows is in turn bested by the mate guarding strategy of blue-throated males. Each strategy in this game has a strength and a weakness, and there is the evolutionary rub that keeps the wheels spinning. See B. Sinervo and C. M. Livley (1996) Nature 340:240-243.

What influences male success?• Difference between a lek and a chorus?

What influences male success?• Lithobates catesbeianus males may defend territories for months…

•What is the female interested in??

What influences male success?• Principle of Allocations

• What does this mean for males attempting to maximize fitness?

What influences male success?• Size Matters

• Refer to Table 14.1

Wood frog pic (calls?)Fig. 14-9 too

What influences male success?• Alternate approaches

• Interference• Sperm competition

African gray tree frogs chiromantis xeramplina

Sexual dimorphism?• What factors drive sexual dimorphism?

• Who should be bigger males or females?

Sexual dimorphism?• Gladiator frog pics!