EPOW - Ecology Picture of the Week

The Vanishing Phantom Crane Fly

Phantom Crane Fly (cf. Bittacomorphella sp.)
Order Diptera, Family Ptychopteridae, Subfamily Bittacomorphinae
Democratic Republic of the Congo, Africa

Explanation:  This week's vanishing act stars a nearly-invisible member of the order of flies.  This is a phantom crane fly ... and its nearly-unseeable appearance is only one of its strange quirks.  

I was on a trek into the heart of the Congo River Basin -- into the huge, remote, and almost inaccessible Salonga National Park -- slogging through swamp forests and on overland trails created by ornery forest elephants.  The dense forest canopy overhead was like a dim green translucent curtain, and the forest floor was dank and very dark. 

Somehow, we noticed something very strange in the dark recess of a pile of decaying leaves on the ground.  It was like a small bundle of the thinnest of white wires, quickly and incessantly pulsating.  

It was so dark, and the visage was so slight of form, that I could not make out what it was.  I took several flash photos and only later was able to make out the tiny, quivering body and legs ... of this phantom crane fly.  

Phantom crane flies are ancient life forms but only two subfamilies and three genera still exist.  I can find no information on phantom crane flies in the heart of the Congo River Basin of central tropical Africa, but perhaps they had been collected during Belgian and other specimen-collecting, natural history expeditions in the 19th and early 20th century.  

This subfamily of phantom crane fly has the odd coloration pattern of highly contrasting black and white ... perhaps as way to break up its body outline and camouflage itself from predators, but I know of no specific studies on this.

Phantom crane flies, particularly of this subfamily, have the peculiar habitat of wafting into the air by pulsing their legs, which seem to serve as a form of secondary wings.  When aloft, usually all you see is the white of their legs, like the bizarre image I saw under the leaf litter, beating against the air.  Floating and pulsing aloft, the insect seems to fade in and out of visibility -- thus giving rise to its phantom epithet.  

But wait, it gets stranger.

I can find no information on one we discovered.  Look closely.  It seems to have no wings, yet it is an adult form.  Perhaps it had shed its wings before laying eggs?  Or is an undescribed potentially wingless form?  Regardless, this might be species as yet unknown to science.  

Nearly invisible among the sticks and decaying leaves of the
jungle floor is this phantom crane fly.  Is is an undescribed species?

There were several present, partially represented
in the various photos here, and all of them seem wingless.

The closest identification I can make is that it seems similar to the genus Bittacomorphella, but the legs are far longer compared to the body length and ... again ... there are no wings apparent.  But perhaps that is appropriate ... to an unknown phantom crane fly to be sporting invisible wings ...  

Information:
     Podenas, S.  2007.  First phantom crane flies (Diptera, Ptychopteridae) from Baltic amber (Eocene).  Proceedings of the Academy of Natural Sciences of Philadelphia 156:195-198.