Morphology and evolution

Sexual selection

Studies of sexual selection have tended to concentrate on obvious morphological traits (think about fancy tails, crests, horns, antlers etc).  However, traits that show no obvious sexual dimorphism may nevertheless still be under sexual selection. One of the most important avenues to competing for a mate is tiny: sperm!

  • Male roos fight with each other from youngsters, which helps them build up the strength they need to fight over females as adults.  We examined the relative size of forelimb muscles in male and female kangaroos, and revealed strong sexual selection in males.
  • Ms Meg Lane is currently investigating the links between male muscularity and sperm traits (e.g. how fast they can swim).  This is in roos too, before you get excited.

Antipredator behaviour

Flight initation distance (FID) and vigilance has been used by many researchers to explore how organisms assess risk and there are many papers out there attesting to the value of this simple metric. We have now produced several papers on escape behaviour in animals ranging from tortoises to frogs, birds, mammals, tadpoles and grasshoppers.

An extreme way of avoiding being dinner is to sacrifice part of your body to escape predation: many taxa will voluntarily drop an appendage when caught or threatened by a predator, a process called ‘autotomy’ (self-cutting), often along a breakage plane to aid rapid shedding of the leg, tail, antenna etc. Autotomy has fascinated us as, although the benefit (survival) seems huge, there are also costs. Losing a leg can make you slower; losing a tail can rob you of fat stores, or alter your locomotion.

See wWEB blogs on this topic

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