EPOW - Ecology Picture of the Week

Hoverfly (Metasyrphus sp., cf. M. americanus; or Sphaerophoria sp.)
Family Syrphidae, Order Diptera

Explanation:   What looks like an elongated bee or wasp, but is actually a harmless fly?  This is a species of hoverfly, a bee mimic (like another family of flies, the bee flies).  

Like its namesake helicopter, hoverflies indeed are often seen hovering, but over flowers.  Hoverflies belong to the very large family Syrphidae, which includes more than 950 species in North America north of Mexico alone.   

Hoverflies can be quite beneficial, as their larvae help eliminate insect pests such as aphids that otherwise harm ornamental plants and commercial crops.

Studies have discovered that hoverflies of this genus (Metasyrphus)  communicate using special chemicals or pheromones, in particular one called (Z)-9-Tetradecenyl acetate (C₁₆H₃₀O₂) and another called (Z)-7-Dodecenyl acetate (C₁₄H₂₆O₂).  These pheromones also are used by bolas spiders, other flies and insects, and some butterflies and moths.  Amazingly, the second one is also used by Asian elephants.  This suggests that organisms of vastly different types -- flies and elephants -- can develop the same biochemical solutions to similar ecological problems -- in this case, communication by chemicals!