A Little Bit More
Hoverfly (Helophilus sp.) © Solon Morse
Hover or flower flies are often called syrphid (SIR-fid) flies by entomologists. There are more than 4,000 species of syrphids worldwide with almost 1,000 in North America alone. If you’ve spent any time out in an open field or flower garden during the summer, it’s likely you’ve seen these flies hovering around you and the local wildflowers. At first they really do appear to be bees or wasps but once you know the difference, you can quickly distinguish them from stinging insects. Remember, flies have only 2 wings and bees and wasps have 4. Also, syrphids are especially adept at hovering, while bees and wasps are not! These delicate little flies are harmless – they don’t bite or sting - and as the unit poster points out, are an especially important pollinator.
Hover flies are probably the most skillful flyers of all insects. They’re able to hover suspended in space next to a flower, move to one side, or go forward, backward, up, or down, with ease. These feats of flight are even more impressive when one realizes that they’re often performing these feats in moving air currents. Most hover flies have short mouthparts that are used to sponge up the sugary liquids they seek. As a result, only flowers that have readily accessible nectar are visited. Only a few species can feed from flowers with nectar that is more difficult to obtain.
Immature syrphids look just like any other fly maggots. Many species of immature syrphids prey on aphids. Syrphid maggots crawl about on plants seeking aphids and use special hooks on their mouths to puncture their prey and then drain them of their internal fluids. Other species may lay their eggs in ant or termite nests and feed on the inhabitants there. Whether they’re feeding on aphids as immatures or pollinating plants as adults, it’s not hard to understand how important these little flies are to a healthy environment.
Definitions
mimicry: the resemblance of one organism to another
Activities
Science – Quiz
Objectives: Use the web to find answers to questions posed
Materials: Pencil, paper, and access to Electronic Naturalist web site
I’m posing some questions that are found in previous Electronic Naturalist units. Each answer can be found within a unit poster so students don’t have far to look for their answers. If students have been following the EN units right along, they may not even need to look online for their answers, they may already know them, and that’s fine too.
All answers to these questions are found in previous EN units – look on unit posters for your answer.
- Can you name a specific animal that does NOT have color vision?
- Toads hibernate underwater in the winter. True or false?
- Can you name a bird whose wings are especially well adapted for soaring?
- How many different species of bats are there north of Mexico?
- Opossum Shrimp are unusual shrimp. In what kinds of lakes would you look for these animals?
- Many kinds of seeds in the northern parts of North America need to be exposed to cold temperatures before what can take place?
- What group (order) of insects has more different kinds (different species) than any other?
- If you find an animal or plant and don’t know what it is, what user-friendly resource can you use to help you identify it?
- Some plants give off chemicals from their roots that restrict the growth of other plants. Can you name one of these chemical-producing plants?
- Bird feathers provide three main functions. Can you name one of these?
- Before you handle a catfish, what part of their anatomy should you know about before grabbing it?
- What kind of food are hover flies looking for?
Key Concepts
Life Cycles, Identification, Food Webs /Food Pyramids, Behavior and Regulation
Questions
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