Questions remain about differentiating greenbottle flies (Lucilia spp.) from muscid lookalikes (Neomyia) in iNaturalist photos. I wrote previously that the distribution of the tomentum (silver reflection caused by microtrichia) would help; below are some further photos to aid in this process.

Male Neomyia

Male Lucilia

Female Neomyia

Female Lucilia 

In each instance, you can see that the tomentum in Lucilia extends much farther dorsally on the frons than in Neomyia.

There was also the tougher question about separating Lucilia cuprina from L. sericata in photos. This is more difficult, because the main character used by the calliphorid expert, Terry Whitworth, is on the back of the head, usually out of sight in photos. There are supporting characters, however, on the dorsum (top) of the thorax. If you look at the humeral callus (“h”, below) and the notopleuron (the triangular area marked “n”), there are a  few tiny setulae along the posterior margins. In L. sericata, there are usually around 6, in L. cuprina 2-3. If you can see that kind of detail in an iNaturalist photo, then you can make a call; otherwise, I suggest leaving them as “Lucilia sp.”

sericata thorax

cuprina thorax

The phorid genus Megaselia Rondani is possibly one of the biggest genera of insects. I say “possibly” because we still don’t know if we should consider all the species currently classified as Megaselia as belonging to a single group. Recently molecular work by Sibylle Häggqvist seems to indicate that most of Megaselia is monophyletic (forms a natural group), but much more work needs to be done.

Just for fun, I made a graph of the described species of phorids, showing the number of species per genus.  This is a representation of how big Megaselia is within the Phoridae. Note that this is the number of DESCRIBED species, and does not take into account all the unknowns. 

For the phorid researchers: does this treemap surprise you? It did me, a little.  I thought Megaselia would be even more dominant. Presumably, once we get to do all the world’s fauna, Megaselia will end up being closer to half of the family.

Or maybe not.

In the recent “City Nature Challenge” (an iNaturalist event co-hosted by our museum, LACM), the question was indirectly asked of me “how do you separate the common greenbottle flies,  classified in the calliphorid genus Lucilia, from the muscid lookalikes in the genus Neomyia that can also be green.” Especially, how would you tell them apart from the photos in iNaturalist, which are often not of stellar quality. My answer is to look them in the face. In both genera, the distribution of tomentum (microscopic extensions of the fly’s cuticle; not ‘hairs’ or setae, which are socketed) is different. The tomentose parts of the frons reflect light as silver or white, so this is often easy to see in photos.

You can see in Lucilia, on the left, that the tomentosity extends much farther up the frons, especially medially (in the middle) than in Neomyia, on the right, which has a dark, tomentosity- free section of the head.

You can see that the attached photo from iNat is a Lucila.

My old friend and colleague Kevin Barber is visiting us in Los Angeles to help out with our Diptera collection and to do a little collecting. Kevin works on a family called Anthomyzidae, which are slim, long-winged flies usually associated with plants upon which they innocuously feed. Two species that he is looking for are known from Morro Bay (California), so we took him up to the Central Coast to find them.

I am happy to report that he found them both!

One is a species called Stiphrosoma vittatum with prominent stripes on its body, whereas the other is an undescribed Anthomyza species. Both were found together in a streamside forest near Cambria, CA, where the indicator plant that Kevin was seeking, Equisetum telmateia, grows abundantly (thanks to local bird expert Jim Royer who suggested the site). One more day of collecting remains, and Kevin’s goal is to collect many more specimens, especially of the Anthomyza, of which so far he found only two specimens.

Finding such otherwise unknown or poorly known species of tiny (up to 3 mm long) flies is tougher than finding a needle in a haystack: at least you know where the haystack is! I am constantly amazed at the skill and knowledge of taxonomic experts like Kevin Barber.

Take note! Besides what is posted here, there are a couple of other active fly blogs coming from the LACM.

The ZADBI web page (tropicalflies.net) has results from our tropical inventory project.

The BIOSCAN project has a lively blog by Lisa Gonzalez about our urban bioinventory project. I hope you read and enjoy them both!

Villa Zurqui grounds

Fifteen dipterists from around the world, plus grad students, parataxonomists, and other interested biologists, are converging on Zurqui de Moravia next week as part of our ZADBI (Zurqui All Diptera Biodiversity Inventory) project: our attempt to inventory all the flies at a single tropical site. Although we are collecting with a battery of traps and general techniques, we are relying on the years of field experience our collaborators possess to ferret out the hard-to-find species from our site.

Wayne (left) and Sergio

Although the blitz does not officially commence until Monday, our first early arrivals were Wayne Mathis and wife Diane, who set off from our beautiful hotel, Villa Zurqui, this morning and came back this afternoon with about 13 species of ephyrdrids, plus one new family for the project, Diastatidae. Awesome start, Wayne!

Today, Sergio Ibanez & son Diego arrived from Mexico as part of the psychodid (moth fly) duo (along with Greg Curler, who will be coming soon). Tomorrow, we’ll all go to Zurqui and see what else we can find.

PS: see our project web site phorid.net/zadbi

My group and I arrived in Costa Rica yesterday. We are still getting our bearings, but today we got at least a little time in the field. No doubt we will continue to find strange and exciting new behaviors and species of phorid flies. As I write this, there is pounding rain outside, hopefully not flooding the two light traps (see previous post). Tomorrow, I should have time and energy to publish a longer blog on what we have found so far

Meanwhile, take a look at this Microdon flower fly from a Malaise trap sample. This is from an area around the town of Guapiles, where we are also staying. I’m not an expert on this group, but this is a pretty amazing looking fly to me. Maybe one of the syrphid experts will comment?

a syrphid fly that caught my eye