Tuesday, May 31, 2011

Honey Bee, Honey Bee, What Do You See? Part 1

 

A forager hard at work
Spring has sprung! Now that America is warming up and flowers all over the country are bursting into bloom, you may begin to notice honey bees outside in the sunny spring weather. These bees are called foragers (worker bees who leave the hive to visit flowers). Let's explore how these forager bees perform their important job.

When a forager bee leaves her hive, she moves off in search of 4 things: nectar (to make honey), pollen (to feed to the baby bees - called brood - as their source of protein), water (to use in air-conditioning the hive), and tree sap or resin (to make into propolis, a sticky, brown substance which disinfects the hive and strengthens the honeycomb). She uses her senses of smell and vision to locate these 4 things. However, a honey bee's senses of smell and vision are different than ours.
 

Honey bees don't have noses; instead, they smell through their antennae. Honey bees have an excellent sense of smell - believe it or not, honey bees have even been trained to detect bombs!


You can see 1 of the 3 tiny simple eyes on this
honey bee's forehead, and the 2 large compound
eyes on the sides of her head

Honey bees also see differently than we do. We only have two eyes, but honey bees have 5 eyes: two compound eyes on the sides of their heads and three simple eyes (called ocelli) on their foreheads. Each compound eye is made up of thousands of lenses called ommatidia (kind of like thousands of tiny eyes all in one), and are the eyes actually used for seeing. The simple eyes are used to detect differences in light and shadow, which is helpful when the bee is navigating between plants. Honey bees are also very sensitive to rapid movements. This is called flicker fusion potential. A honey bee probably wouldn't have much fun at the movie theater because the film would just look like lots of still photographs appearing on the screen one after another. The film would have to be sped up quite a bit to look like it was actually moving! 


Honey bees can see the short-wavelength ultraviolet light
(left), but we can see the long-wavelength red light (right)

Honey bees can't see the color red, but they can detect a color we can't: ultraviolet. On the color spectrum, the color red is made up of very long wavelengths which our eyes can detect, but honey bees can see the shorter ultraviolet wavelengths on the other side. However, honey bees do sometimes visit red flowers, because many flowers, including red ones, have ultraviolet markings (called nectar guides) on them that the bees can see. Here is an interesting video about honey bee vision.

On the left is our view of the flower; the picture
on the right shows us what the honey bees see!
Notice the ultraviolet nectar guides (they appear
red in this picture) on the flower on the right.

In the next part of this series we'll talk about how honeybees use their eyes to be so effective at pollinating our crops!

 

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