Thread subject: Diptera.info :: Very small fly on Squash Leaf

Posted by Stephen on 14-08-2006 19:06
#1

This very small fly was at rest on a squash leaf. Length was 3.8 mm. Open area near woodland, West Virginia, USA. Taken yesterday.

ID help appreciated!

Posted by Stephen on 14-08-2006 19:10
#2

Second image.

Posted by Nikita Vikhrev on 14-08-2006 19:31
#3

Even in far and mysterious New World it is still good old Lonchptera of Lonchopteridae.
Nikita

Posted by Stephen on 15-08-2006 12:10
#4

Nikita, Thanks very much for the ID!

Just for fun, I looked up and found there are four species of Lonchoptera in North America: L. borealis, L. furcata, L. occidentalis, and L. uniseta.

I found a 1934 article on North American Lonchopteridae. That author also named 4 species, though he listed dubia rather than furcata. Using his key I came up with L. occidentalis for my picture, though I realize a 1934 key may not be best to use!

Thanks again, Nikita!

Edited by Stephen on 15-08-2006 12:13

Posted by Jan Willem on 15-08-2006 12:36
#5

Hi Stephen,

According to www.faunaeur.org, Lonchoptera impicta is also known from the Nearctic Region (I have no more details:().
L. furcata is a synonym of L. bifurcata!

Jan Willem

Posted by Tony Irwin on 15-08-2006 13:40
#6

Hi Stephen
Not all 1930's keys are useless - after all, the species haven't evolved that much since then. ;)
However, you are right to be wary of Curran's key. He (or the typesetter) appears to have confused the terms occipital, orbital and frontal. The key is of an odd construction, with a double lead to couplet 4. And he chose an abnormal male for the type of borealis - never a good move, though it happens suprisingly frequently!
Anyway I can't identify the specimen in your photo from Curran's key or his descriptions.

Edited by Tony Irwin on 15-08-2006 13:46

Posted by Stephen on 15-08-2006 14:12
#7

Nikita, Jan, Tony, Thanks for your help on this one!

Poking around a little further about Lonchoptera impicta in the Nearctic, I found an
abstract of a 2005 paper
by Canadian John Klymko, proposing that L. borealis is a junior synonym of L. impicta.

Usually neartica.com is great for giving lists of currently accepted Nearctic species, but this proposed change is too recent I suppose. I'm not sure what the mechanism is for nearctica.com updating its lists.

Anyhow, gentlemen, thanks again for your help!

Edited by Stephen on 15-08-2006 14:16

Posted by crex on 15-08-2006 15:01
#8

John Klymko seems to know a lot about Lonchoptera. Drop him an email with a link to this thread!? B)

Posted by Stephen on 31-08-2006 12:30
#9

John Klymko comments, "The photo you have taken is of Lonchoptera bifurcata (= L. furcata, = L. dubia) It is recognized by the combination of pale post-ocular bristles (the bristles on the head that occur all along the back of the eye), pointed wingtips, and more than one bristle on the leading face of the fore tibia. L. impicta/L. borealis would also have pale pale post oculars and more than one tibial bristle, but would have rather rounded wings. All other described Nearctic species have dark post-oculars, a single tibial bristle, and pointed wings.

Notice the photo is of a female (you can see the tip of the rather
blunt ovipositor (males would have a phallus bent up under the
abdomen). L. bifurcata is a largely parthenogenic species, with only
seven males ever being taken in North America (there are populations
in Iceland and the UK where males occur regularly). L. bifurcta can be
pale tan (as in photos) to black (though the postoculars remain pale), tan most common in summer, black most common in winter. In West Virginia it may well be the only species of Lonchoptera, I have seen many specimens from the south east and don't recall seeing any other species.

L. bifurcata is definitely the most common Lonchoptera species in the
Nearctic, particularly in disturbed habitats (lawns, ditches etc). It
has been my experience that the other species are found in more
natural settings, such as riverbanks and swamps, where they to can be
quite common."

Thanks to one and all for help with this fly!