dancing bees heather mahaney september 26 th, 2002
TRANSCRIPT
Dancing Bees
Heather Mahaney
September 26th, 2002
Discovery
• Karl von Frisch• Vienna• Nobel Prize 1973• The Dance Language
and Orientation of Bees
• Experiments began 1923
Methods
• Observation Hives– Large – 6 combs
– Small – 2 combs
– Shape – Flat
– Combs visible
– Temperature Regulation
– Wedges
Labeling
• Color Lacquer Dissolved in Alcohol
• 5 different colors
• 2 different spots on the thorax
• Duration – several weeks
• Method – mark bees while they are getting sugar water
Labeling
Artificial Feeding
• Watch glass filled with sugar water
• Colored paper under dish to resemble flower
• Attract by putting drops of sugar water in the hive entrance.
• Trail to artificial flower
• Only want bees from one hive
Challenges
• Spring Time– Natural food sources are good.– Hard to attract to artificial sources.
• Late Summer– Natural food sources are scarce.– Hard to keep other bees away.
Nutrition
• The hive needs both nectar and pollen to survive– Nectar – 120 kg– Pollen – 20 kg
• Must have correct balance
• Consume and Store
Food Sources
• Foragers monitor food sources within a 62 sq mile radius of the hive
• Choose the best food sources
• Constantly changing needs and resources
Foragers
• Each hive sends several thousand bees to collect food daily.– ¼ of total population
• No Scouts
• When a good source is found, other bees are recruited there to gather food.
Foraging
• Each bee can find flowers over 3.7 miles away.
• Travel at 5.5 mph
• 400,000 body lengths = 372 human miles
Foraging
• Covers a 62 sq mile distance around hive.
• Most foraging within ½ mile
• Large area = large variety of food sources
• Best shortly after blooming
Feeding
• Bee finds good food source
• Fills honey stomach
• Flies home
• Finds recipients
• Drops of honey water in mouth
• Bees drink through probiscus
• Dance
Dance - Measuring
• von Frisch used a protractor and drew lines with on the glass to measure angles
• Also used a rotating disk with gridlines 2cm apart placed parallel to the direction of the dance
• Measured length of circuits with a stop watch
• Motion picture
Dance – Process
• Bee distributes food
• Dances
• Distrubutes more food
• Dances again …
• Done in highly populated area
• Others follow with their antenna against her abdomen.
Dance - Types
• Tail-Waggle – greater than 100 m
• Transition: Round -Waggle – 25m to 100m
• Round – Food source within 10m
Round Dance
• Bee runs in a small circle
• Runs over 6 adjacent cells
• Reverses and returns
Tail - Waggle
• Run in a straight line
• Return in a semicircle
• Run again
• Return on the other side
Tail - Waggle
• Direction indicates direction of source
• Distance proportional to distance of source
• Buzzing
• Low sugar – little wagging, no buzzing
Surveillance
• Colonies effectively survey their foraging range for new patches of flowers.
• When sites are found, bees return to the hive and dance to recruit others.
• Upon discovery, bees dispatch quickly to the new site before competitors can find it.
Food Sources
• Colonies concentrate their resources on the riches food sources.
• When food is scare, bees are less selective.
• When food is plentiful, bees feed on only the best food sources.
Beeswax Combs
• Used for rearing and food storage.
• Initially build 20,000 cells
• Up to 100,000 cells by the end of the summer
• Create new combs when current combs are full and nectar is prolific
Pollen
• Colonies only store small amounts of pollen.
• 50kg of honey but only 1kg of pollen
• Pollen contains protein, constantly consumed over the summer when plentiful.
Water
• Colonies adjust their water intake due to environmental situations
• Colony needs water to regulate hive temperature on hot days
• Nurse bees need water to produce liquid food for larvae on cool days