A FEW INTERESTING FLIES

      Every summer in Lancaster County, Pennsylvania, I enjoy seeing three kinds of small, harmless flies- large bee flies, long-legged flies and hover flies.  They are intriguing, little critters, but one has to know when and where to look for them.  

     These flies have a few traits in common.  As adults, they all have swept-back wings to fly in search of food and mates.  Their larvae are predators on other types of invertebrates.  And adult flies are attractive.

     Every April, I see several cute, little bee flies standing camouflaged on soil paths in local woodlands.  They quickly fly up at my approach and hover in the air, close by.  They are covered with dull-brown "fur" and each one has a straight beak that sticks out in front and can not be retracted.  They look a bit like tiny, furry hummingbirds. 

     Adult bee flies ingest flower nectar and pollen from early-blooming woodland plants, including bloodroot, spring beauties, trout lilies and several other kinds of flowering plants.  But bee fly larvae are predators on other kinds of insect larvae, including species of solitary bees, wasps and beetles.  Female bee flies follow female solitary bees home.  When the solitary bee leaves its nest, the bee fly female lays an egg or two at the entrance to the bee's nest.  The bee fly larvae hatch and crawl into the bee home, eat the nectar and pollen stored for the larval bees, and then consume the bee larvae themselves.  The bee fly larvae pupate in the bee home and emerge in early summer as adult bee flies ready to sip flower nectar. 

     I also enjoy seeing the quarter-inch long, iridescent-green and copper long-legged flies perched in summer on shrubbery foliage.  These flies do have six long legs for their small bodies, and large eyes to spot prey.  These flies are quick to fly from potential danger, and to capture tiny invertebrates.  And both the adults and larvae are predatory, feeding on a variety of aphids, mites, gnats and adult mosquitoes.  Their larvae live hidden in damp soil, where they also pupate.  

     The lovely, one-inch hover flies are also beneficial in that they pollinate flowers when they sip those blooms' nectar, and their larvae are predatory, feeding on destructive aphids and leaf hoppers.  

     The handsome hover flies mimic bees and wasps for their own protection.  I like seeing several of them at once hovering before blossoms, before landing on them to sip their nectar and ingest pollen.  Hover flies' abdomens have alternate black and yellow rings to imitate bees and wasps so that birds and other predators will leave them alone. 

     All these pretty flies bring more life, color and interest to woods, meadows and lawns in Lancaster County, as elsewhere.  This spring and summer, look for them when outside enjoying the weather and nature.  But one must look closely to spot bee flies and long-legged flies.       

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