Spent a hot and frustrating afternoon chasing hyperactive bee-flies around the garden, as they visited the forget-me-knots and lady’s smock flowers around the pond. Never really got the picture I was hoping for, but made an interesting discovery - take a look at the middle picture (double-click on image for a larger version). There’s a step change in the thickness of this insect’s long, straight proboscis (see top picture) and where this step-change occurs the narrow, pointed tip splits apart into a Y-shape when it withdraws from the flower. I’m guessing that when the two halves are brought back together again this reforms a narrow tube that draws up nectar by capillarity, and that this splitting-and-reforming operation prevents the formation of airlocks in the hollow proboscis. A high shutter speed reveals what the human eye can never see, even though it means that the photos have a very shallow plane of focus.
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I know how you felt from the time I decided to try to capture a drone fly in mid hover. Well done on the photos you did get and on the discovery about the proboscis. Fascinating.
ReplyDeleteAfternoon well spent, I'd say.
ReplyDeleteCapturing mid flight like that is some achievement, and the discovery.
Very interesting post.
Thanks for your comments, Midmarsh John and holdingmoments. They're such elusive insects - sometimes they seemed to disappear in the fraction of a second that it took for the decision to press the shutter button to travel from my brain to my finger - I had a lot of frames with flowers but no insect when I downloaded the images.
ReplyDeleteFascinating observation on the plumbing of the proboscis. What delicate long legs they have too - such poise when feeding.
ReplyDeleteThey mostly seem to use the legs for hanging onto the flower, Rambling Rob, to gain a purchase on the petals to they can push their proboscis to the bottom of the corolla tube.
ReplyDeleteThat is one amazing piece of observation! You ought to post that to the diptera.info and dipterists forum groups. I'm sure they'll be very interested. I have the Stubbs & Drake book 'British Soldierflies and their Allies' but the proboscis movement you witnessed isn't mentioned anywhere in the section on Bombyliids!!
ReplyDeleteThanks for the advice Steve, I'll do that. I'd be interested to know more about this. Both sites look fascinating - I wasn't aware of either.
ReplyDelete