Chapter 4: Swords or Pistols

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Chapter 4 Swords or Pistols?

• A Biological Guide to Fighting by
• Kelsey Barker, Jose Bonilla and Brittnae Stewart

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Introduction

• In nature, fighting is not always the answer.
• Knowing when to fight,
• when to run,
• or when to throw sand in
• your opponents face
• is the key to evolutionary
• success.

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Fight when you have nothing to lose

• Fig wasps 1
• Live inside figs. Males dont have wings, so the
  only time to mate is right after hatching.
• Two types of fig wasps

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Fight when you have nothing to lose Other
examples

• Gladiator frogs 1 Have sharp, retractable spine
  which they only use to fight other frogs. Aim is
  for eyes and eardrums.
• Reason for this is that they have a short life
  span and rarely live from one breeding season to
  the next, so there exists a lot of competition.

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Fight when you have nothing to lose Other
examples

• Annual fishes of Africa and South America 1
  live in puddles until they dry up.
• Once the puddles dry up, only their eggs survive.
• This creates a struggle to reproduce and
  facilitates aggressive male competition.

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Dont fight if you know youre going to lose

• African elephant 1
• Go into musth, anger and lust at the same time
• Females prefer older, stronger males
• The bigger an elephant is, or the more aggressive
  it acts, the higher the likelihood that it will
  win a fight
• Males often avoid each other during this time, so
  as to save themselves the struggle of fighting

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Dont fight if you know youre going to lose
Other examples

• Two-spotted spider mites 1 protects female
  until female molts, whenever fights start,
  smaller male usually retreats
• Flies measure length between eye stalks, the fly
  with the shorter stalk usually retreats

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Dont fight if you know youre going to lose
Other examples

• Lobsters engage in fights to establish dominance
  relationships, and they often remember who they
  have fought with

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Fight dirty when you can

• Xylocoris maculipennis (pirate bug) 1
• Can jab penis through another males body wall in
  order to inject sperm into other male
• This is possible, but unlikely. Scientists are
  still researching

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Fight dirty when you can Other examples

• Moniliformis dubis 1 (spiny-headed worm) finishes
  mating with female and caps off genitalia with
  cement chastity belt also does so with males
• Male African bat bedbugs 1 have false sperm
  receptors, so can trick males into depositing
  their sperm, thus making their rivals waste
  valuable sperm

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Feel free to sabotage others to further your
mating chances

• Three-spine stickleback 1
• Males steal eggs for own nest
• Makes male look better to others more females
  will want to leave their eggs with him
• Will lessen chances of other male to get more eggs

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Feel free to sabotage others to further your
mating chances Other Examples

• Bowerbirds 1 vandalize or destroy each others
  bowers

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Cheat Sheet for fighting

• Will this be your only chance to mate?
• If yes, proceed to question 2
• If you fight now, will it help you become
  successful in mating with more females?
• If yes, proceed to question 3
• Are you the biggest? Do you have a good chance
  of winning
• If yes, FIGHT!!!

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Remember, when youre fighting, bigger almost
always means better, running does not mean youre
a coward, watch closely for cheaters, and dont
be above cheating yourself
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Bibliography

• Judson, Olivia. Dr. Tatianas Sex Advice to All
  Creation. New York Henry Hold and Company,
  2002
• Kravitz, Edward, PhD. Fighting Lobsters and
  Fighting Flies Two Model Systems for the Study
  of Aggression. http//www.harvard.edu/bss/neuro/k
  ravitz/currentresearch.html May 25, 2005