bee-flies

Third Grade Integrated NGSS
Life Cycles, Growth and Development

Identifying mimicry in nature using bees and flies.

THIRD GRADE - BEES AND FLIES

OBJECTIVE

· Comparing bees and flies.
· Exploring co-evolution.

VOCABULARY:

· adaptation

· mimicry

MATERIALS:

         Powerpoint Bees, bee eyesight and fly mimicry
         Boxes that can be dark
         Ultraviolet flashlights
         Variety of flowers—(check to make sure some of them look different in UV light)
         Bee lifecycle models
         Worksheet comparing bees and hoverflies

BACKGROUND:

Bees feed on flowers. Bees have powerful defense mechanisms such as painful sting and group defense. Most predators will avoid bees. Bees are the ideal model for other insects which also feed on flowers. Most bee mimics feed on nectar and are the pollinators of plants as well. Certain flies are bee mimics. By mimicking something else, they gain some protection and increase their chances of survival.Batesian mimicry involves a palatable, unprotected species (the mimic) that closely resembles an unpalatable or self-protected species. One example is this fly which looks like a bee. Birds know not to attack a bee as they will be stung.

There are three strategies for fooling predators;

1. To mimic a species that is distasteful or threatening to a predator.

2. To camouflage, blending into the background.

3. To use deceptive behavior whenever a predator is about to attack.

Most of the flies in the family Bombyliidae mimic wasps or bees (Batesian mimics of Hymenoptera). However, they have stout bodies and do not have narrowed waist. Their wings are easily recognized with distinctive vein pattern, usually dark in color, some with patterns or spots. When at rest, their wings are flat in outspread position.

Hover Flies (left) may sometimes confused with stinging bees or wasps because of their mimic color. Their bodies are medium to slender. On their abdomen there are the yellow-black wasps pattern and the narrow waist mimic pattern. Hover Flies visit flowers as bees and wasps. They are major pollinators of some flower plants. They are usually seen hovering or resting on flowers. How can you identify. On the figure to the right notice that the antennae are small, there is only pair of wings, and eyes are larger.

A real bee has long antennae, two pairs of wings and smaller eyes. In the picture on the right you can see the forewing and hindwing. Bees also have stingers whereas flies have larger mouth structures with no stingers.

PROCEDURE:

1. Go over the life cycle of bees. Use the model to point out the long antennae, 2 pairs of wings, and smaller compound eye.
Egg: The Queen bee lays between 1500 and 2000 pinhead-sized eggs each in its own cell. The queen is able to lay both fertilized eggs that produce both fertilized eggs that produce queens, sterile female workers and unfertilized eggs that produce male drones.

Larva: After 3 to days the eggs hatch into larvae which are fed by worker bees. A future Queen is fed “royal jelly” a substace secreted from glands in the heads of worker bees. A future worker is feed “bee bread” which is a mixture of pollen and nectar.

Pupa: At this stage the pupa does not eat, gegins losing its worm shape and starts to develop the eyes, wings, and legs of a n adult bee. This stage takes 6 days for a future queen and 11 days for a worker.

Adult: The adult bees have different jobs and life spans. Sterile femaile workers liver 20 to 40 days, tend to young bees and guard the hive entrance or are field workers that collect pollen, nectar and water. Drones live 30 to 90 days and their only role is to mate with the Queen.

2. Introduce the concept of mimicry in insects. Show the two pictures of difference mimics in the fly group. There are many species that will try to mimic the coloration of a bee or wasp.On the photography below (left) these are example of flies that look like bees or wasps. On the right are 5 real bees (long antennae) all the rest are flies.

3. ANSWER KEY FOR FIVE BEES: The bees are the two on the left in the top row (not the one on the right--the long thing is its tongue not antennae). The two on the left on the middle row and the one on the right on the bottom row).

4. Have the students make their own “real” bee and “mimic” fly. Use pipe cleaners, pom pom, glue, play dough, pencil and scissor. Make sure students realize the two models. Below the on the left is a bee (long antennae, 2 pairs of wings, and smaller eyes.
The one on the right is a fly with only 1 pair of wings and small antennae and larger eyes