Syrphid migration

Some flies migrate, just like some birds and butterflies, but it is rarely recorded. In fact, this might be the first record of a flower fly (or hover fly) migration for North America!

It took place on April 20th, 2017, at beautiful Montana de Oro State Park. I was walking with my dear friends Marianne and Gary Wallace  when Gary said “look at all those bees!” I looked, and realized that they were not bees, but flower flies, thousands of them. They were flying against the wind, in a northward direction, not stopping at all. I actually got some video of this migration; have a look.



The flies look like bullets going by. We didn’t have any collecting gear (duh, it’s a park), but we tried knocking some down, to no avail. They were moving fast and avoiding contact. I tried taking some stills, and this is my best (bad) photo:

Why would syrphids migrate? These flies feed on aphids as larvae, and aphids are found on tender new growth. California’s rainfall comes during a short time in the winter, and then things dry up. An hypothesis is that as the more southerly vegatation dies off from lack of water (and thus also the aphid supply dwindles) the flies move northward looking for green, still tender fields, well stocked with their aphid food.

This was something I never expected to see, but wanted to record so others could keep their eyes open for it in the future. I’ll be back next year looking for them at the same time of the year, hopefully to learn which species they are.

Barber-ian triumph

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 OLYMPUS DIGITAL CAMERAabundantly (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.

Moving to micro four-thirds

holding camera

My new Olympus OMD EM1 camera with 60 mm macro lens. Look how small it is!

Insect photography can be demanding, time-consuming, and expensive. It can also be heavy, lugging around a big SLR camera, a couple of lenses, flash, batteries, and other equipment necessary to capture high-quality images. Often, when I am in the field, I carry a heavy backpack of camera equipment plus my collecting gear on the first day, but subsequently leave the camera at home because it is just too much stuff.


Honey bee – sharp!

On a recent trip, miserable because of the heat of the tropics and the weight of my camera gear, I vowed I was finished with full-sized SLRs. I decided I would follow my technician Wendy Porras in moving to Olympus micro four-thirds (mft) technology. After all, these mirrorless cameras are half the weight, size, and price of a SLR, but have amazingly good image quality. The attached photo of honey bee won’t win any prizes, but you can see how sharp the images can be (an exceedingly important consideration for those of us photographing small flies). My new camera also has in-body image stabilization, which gives me a higher percentage of successful, non-blurry images.

Best of all, the camera is small enough to fit in a much smaller bag, and won’t be left behind when I need it in the field.

From now on, it is mft for me.

Diptera blitz continues

Uber-collector Wayne Mathis

Uber-collector Wayne Mathis

The 30 participants in the Zurqui all Diptera biodiversity inventory in Costa Rica have been pushing back our veil of ignorance about the fly fauna of tropical cloud forests. So far, we have spent two full days at the site (Zurqui de Moravia, 20 minutes north of San Jose), and one full day at our partner institution INBio. New species and even new genera of flies are being found everywhere we look. Some examples:

Collaborators Dr. Greg Curler and Sergio Ibanez have found a strange new type of psychodid (moth fly) that holds its wings unlike any other they have ever seen. Most moth flies hold their wings either flat over the body, or roof like over the body; this one inverts its wings over the body so that they make a trough. Significance? Who knows, but it is amazing that such a fundamentally different body form has been found. Last night, Curler hoisted some light traps up into the canopy of the forest to see what other strange things he could discover. Stay tuned for what he found.

Collaborator Dr. Wayne Mathis has been collecting for several days and has pushed our family list to 69 with this collection of diastatids (sorry, no common name), therevids, and anthomyzids, as well as boosting the list of shore flies (Ephydridae) to 26 species.

Netting bats at night has been particularly productive for inventorying bat flies. Dr. Carl Dick has added several genera and species to our list that would never have been included if we had only relied on Malaise traps and other standard insect collecting methods.

In a small raid of army ants, Anna Holden I collected some bizarre short winged phorid flies running around with the ants. These flies, genus Acontistoptera, have fully winged males that transport them in-flight among army ant colonies. We know this because the flightless females turn up in our Malaise trap samples along with their more mobile mates.


A tiny Acontistoptera female

Yesterday, we spent the day in the lab at our partner institution INBio, where our collaborators could interact with our Costa Rican staff and examine some of the ZADBI material in the collection. Collaborator Dr. Jeff Skevington looked at our 34 specimens of pipunculids (big headed flies) and pronounced almost every one of them a different species! Little duplication means that there are many more new things still to find.


This is just a taste of what has transpired over the last three days; I’ll get more reports from our scientists today. Lots of ideas have been exchanged, plans made for the future, and scientific papers outlined for publication. Two days still to go!

Diptera Blitz!

Villa Zurqui grounds

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

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

Short post from Costa Rica

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