Herpetology; Mating (4/22)

Class Announcements

• Instructor Introduction: Tyler, graduating president of biology club.
• Event Announcement: A baby shower event from 4 PM to 6 PM, coinciding with class time.
    - Activities:
      - Tours of the reptile room next door.
      - Availability of cake and desserts.
      - Games for attendees.
    - Importance:
      - Opportunity to meet members of the biology club.
      - Encouragement to join the biology club if not already a member.

Mating Systems and Mate Guarding

Definitions and Concepts

• Mating Systems: Refers to the social structures and systems within which mating occurs, including resource availability and individual behaviors.
• Mate Guarding: Involves a single male maintaining control over one or more females, influencing reproductive success.

Male and Female Territoriality

• Male guarding can involve:
    - Single male paired with a single female.
    - Males guarding multiple females if they are close or aggregated.
• Territoriality observed primarily in small insectivorous lizards during the breeding season.
    - Territories include essential resources:
      - Food.
      - Basking sites.
      - Display perches and retreat sites for cooling down.
• Home Range Dynamics:
    - Male territories typically larger than female home ranges.
    - As female home ranges increase, the density of females decreases.
    - Increased territory size can lead to more non-territorial males.
    - The sex ratio can shift towards a 1:1 male to female ratio in large territories due to males being unable to defend multiple females.

Leks and Choruses

• Leks: Aggregated display sites where males attract females.
    - Found in some amphibians and reptiles with long breeding seasons.
    - Characteristics of leks:
      - Do not contain significant resources for females.
      - Serve primarily as advertising grounds for males.
    - Examples of Leks in Amphibians:
      - Newts: Males grow large tail fins and congregate in ponds to display during breeding.
      - Frogs and Toads: Male calls are a primary method for attracting females, often involving aggressive calls among males.
      - Pacific Tree Frog: Male calling patterns during breeding illustrate communal display strategies.

Resource Defense in Breeding Behavior

• Resource Defense: Less common in reptiles and amphibians.
    - Males monopolize areas with resources attractive to females but often do not rely on physical characteristics.
• Example - Red-winged Blackbirds: Males call to establish territory, important for attracting females.
    - Females prefer areas with abundant resources (food, nesting sites).
• In salamanders, males that monopolize good oviposition sites gain reproductive advantages.
    - Males may also exhibit larger body sizes, indicating better territory defenders.
• Salamander Examples:
    - Hellbenders and Eastern Redback Salamanders: Use territories to attract females for egg-laying.

Unique Breeding Behaviors in Reptiles

• Lekking in Reptiles: Observed in some species, including crocodilians (e.g., American alligators).
    - More akin to resource defense due to the upheld territories needing usable resources.
• Iguanas: Males during breeding season utilize bright dewlaps to establish territories visually and through head-bobbing displays.
• Galapagos Marine Iguanas: Engage in aggressive competition within lek territories, where males with the most favorable attributes attract more females.

Notable Lizards and Breeding Strategies

• Side-blotched Lizards: Males defend rock piles, essential for basking and thermoregulation.
    - Experimental observations demonstrate adjustments to territory size based on resource availability.

Conclusion and Future Topics

• The lecture wraps up the mating systems chapter, with plans to cover conservation in the next class.
• Emphasis on continued engagement with material and upcoming topics to enhance understanding of ecology and biology concepts.