ENT 104 Lecture 12

• Cues


  Information passively left in the environment by an animal, used by anyone (e.g. tracks, odors, sounds)
• Signals


  Information intentionally sent by one animal to another, usually within species
• Signals evolve from cues
• Threat signals evolve from the movement preceding an attack
• Bumble bee dances


  1. Inactive workers can use the activity in the nest (a cue) to tell how much foraging is occurring

  2. If a worker exaggerates wildly their activity in the nest after finding food for the first time, this is now a signal that has evolved from a cue
• Selection


  Works to increase the production of the cue (now a signal) and the sensitivity of the receiver
• Same signal can have many meanings
• Multiple meaning very common in social insects
• Honey bee communication signals

  • Chemical (pheromones)
  • Mechanical / acoustical (dances, shaking, buzzing, vibrating)

  
• Forager signals


  • Signals with information about food sources
  • Signals to coordinate activities
• Karl von Frisch


  • Studied color vision in bees, polarized light vision in bees, and the waggle dance in the 1930s-1940s

  
• Methods for studying waggle dance

  1. Bees can be trained to feeders over great distances

  2. Bees can be individually marked at the feeder

  3. Can check if bees dance after they find a rich food source by watching inside the hive for marked bees

  
• Bee vision


  Bees can see UV but not red, flowers look very different to bees
• Figuring out the meaning of the waggle dance

  1. Something must change as the distance grows

  2. Something must change as the direction changes
• Waggle dance angle


  Is vertical, needs a reference point like the sun to indicate direction
• Von Frisch was able to find food points by reading dances
• Bees do not use nectar concentration as the only measure of food site quality, the rate of energy transfer back to the colony is what matters
• The waggle dance is sent via sound, motion, smell, and substrate vibrations
• The waggle dance pheromone is a blend of several hydrocarbons
• Bees use optic flow to measure distance traveled
• There are many dances and other signals that together make up a dance language used to control foraging in honey bees