Territoriality I

Competition

• It is unlikely that there will be any populations where all individuals are of equal competitve ability
• What resources might animals fight over?
  • Food
  • Mate
  • Shelter
  • Breeding/rearing young
  • Territory to attract mate

Territory vs Home Range

• What is a home range and how does it differ from a territory?
• Home range: Area in which an organism lives
• Territory: Defended area, ≤ home range

Mouthbrooding cichlid (Tilapia mossambica)

• No spaces between territories
• Retain maximum possible space within them

Are territories beneficial?

• Smith (1978) Rufous - collared Sparrow
• Territorial Males plus 'floaters'
• Mapped territories
• Colour-ringed population
• Found that when territorial males died, the younger non-territorial males moved in straight away
• Reproductive advantage to territoriality

Territory Defence

• How are territories typically defended?
  • Overy Aggression
    • Fighting
    • Threat Displays
  • Keep out signals
    • Scent marking
    • Singing

Is there a cost to territory defence?

• Territorial behaviour requires the expenditure of time & energy
• Yarrow's Spiny Lizard (Marler & Moore, 1989; 1991)

Yarrow's Spiny Lizard

• Testosterone inserted beneath skin, plus control group
  • Measured behaviour over time
• Gave food supplement to some testosterone lizards
  • Measured survival over time

When should a territory be defended?

• So, if territory defence is costly, when should it be defended?
• When it is economically viable to do so
  • When the benefits…