Category Archives: Tachinidae

Gardening for flies 4. Use Baccharis.

I recently witnessed and photographed an incredible assemblage of insects. They were on flowering female plants of Baccharis ‘Centennial’, a widely available hybrid of a plant commonly known around here as “coyote bush”. It was used extensively in what we call the 1913 Garden at the Natural History Museum of Los Angeles County, where I work.

For the last couple of weeks, the plants have been swarming with insects, including many Diptera. In fact, I was first alerted to the situation by Richard Hayden, our Head Gardener, who described a swarm of flies in the area. We went to check it out, and I had my first view of the seething mass of insects on and around the plants, apparently feeding on nectar.

The following photos are only a few of the flies on this swath of Baccharis in downtown L.A. I suggest using this plant in any insect-friendly landscape.

a female bibionid

little blood-red flower fly

thick-headed fly

Brazil expedition: day 3..

Actually we are farther in than 3 days. We are staying in a town called Monte Negro, and have 2 collecting sites: one about 10 km from here, and one about 50 km from here.

On day 3, we went to the 50 km site for the first time. It was seething with insects, from butterflies and uraniid moths to stingless bees and higher flies. We put up 3 of our Townes style Malaise traps, while my colleague, Dalton, and his 2 students put up a huge Gressitt-style, double headed trap. Instantly, this giant black trap became a drawing card for the local insect population. The trap was literally heaving with all the insects inside it and coating the outer surface. Rather than wait for the insects to possibly fly into the collecting bottles, Dalton swept them with an insect net. He made impossibly huge collections of tachinids, syrphids, strats, and myriads of smaller flies.

Dalton sweeping out his trap

I sat down beside the trap, and took a few photos without moving; you can see the diversity of fabulous larger flies here in the following photos.

syrphid fly

for Chris Raper - how is this for tachinid density?

tachinid fly

another tachinid fly

yet another tachinid fly

a final tachinid fly

It is unusual to see such overwhelming diversity, but sometimes it happens. We went back to the same site yesterday and all of our traps were stuffed full to the top, mostly with unwanted Lepidoptera. These we had to laboriously remove from the samples to find the more interesting (to us) material, a process that takes hours upon hours.

As for phorids, we found lots associated with ants, but the best phorid so far was in a Malaise trap sample. The attached photo isn’t the greatest, but it is the best I could do in the field with the fly less than 1 mm long. It is a male Brachycosta, the first I have seen.

tiny male of Brachycosta

Next post: a new discovery in ant decapitating fly behavior.

What Dipterology needs: a response

Chris Raper (see his blog at http://chrisraper.org.uk/blog/) had a thoughtful reply to my post. With his permission, I’m making it available here as a guest post for flyobsession.

Costa Rican tachinid

Some good points there Brian … how about also:

– We need to work through the millions of indet. and unmounted specimens help in museums around the world. Vast quantities of material exists on our doorsteps but lacks the time and experts to work through them. I know for a fact that the NHM & OUM have a lot of material that has been collected (often in malaise traps) and just sits on the shelves waiting for someone to work on them. The initial sorting can be done by volunteers or students, pinning can be done by out-sourcing but the taxonomic work needs to be done by the very few experts around the world.

– Digitisation of types – we need to make collections more accessible and harness the power of the internet by demanding that all major museums take high-res images of their collections (or types as a minimum) and make these available online free of charge. It might be too much to think that we could see enough to completely describe something (though with deep-focus/stacked imaging this is getting easier) but one of the most basic thing we need to do is to see whether the specimen in our hands looks like reliably-detted material. Just being able to Google for images of different genera would help me immensely and would reduce much of need for loaning valuable specimens or for expensive visits to foreign museums.

– More digitisation of all journals/articles and these to be made available free online. Projects like BHL are doing great work but they are not yet as comprehensive a collection of papers as they need to be. We all still keep far too many paper journals and PDF libraries on our hard-drives – just in case.

– We need to work together – using the internet / modern comms (forums/blogs) to help each other more and to mentor young entomologists and to develop/encourage enthusiastic amateurs (‘citizen scientists’) to pick-up groups and run with them. Online forums like diptera.info and bugguide.net are great for this but I feel that they are under-used or under-appreciated by many professional entomologists who feel that giving IDs to photos or working with amateurs is beneath them or a waste of time. Since setting up the UK Tachinid Recording scheme and providing a strong online presence (as well as seminars and workshops) we have managed to take tachinids from a fringe interest here to something that more and more entomologists are keen to try. We add between 1-2 new species to the British list and most of those from amateurs who have been encouraged by our scheme.

– There needs to be more money to pay for morphological taxonomy. In Europe there are many keen citizen scientists but they have to spend most of their time doing mundane jobs to pay the bills, when their time could better be used doing important taxonomic work. They can only be freed up if they can get contracts or salaried posts, working perhaps at home but attached to major institutions. We have much of the necessary manpower but at the moment it is badly under-funded and under resourced … even simple things like equipment and travel expenses are often down to the person to fund themselves and in hard economic times like these this is getting less and less possible.

I’m sure there are more things but those will do for a start