How we started working on “rare” bee-killing flies

The most beautiful phorid flies are in the genus Melaloncha, also known as bee killing flies. I have no small bias in this statement, however, since I worked on them for several years and grew to be very fond of them.

Melaloncha punctifrons, female

One of the allures of these flies was their rarity when I first started. In all of the collections I surveyed, I could find only a few specimens, about 100 in total. There were many new species among these specimens, however, so I knew that the 32 described species was only the tip of the iceberg. But how was I to uncover the rest of that iceberg?

Many parasitic phorid flies seem to be attracted to masses of their hosts. Logically, aggregations of hosts should create aggregations of parasitoids, so Giar-Ann Kung and I decided to try to make aggregations of stingless bees, the known hosts of these flies. Monty Wood, a fellow dipterist who works on tachinid flies, told me that when he sprayed a mixture of honey, Coca-Cola, and water onto undergrowth vegetation in an attempt to attract his flies often attracted huge aggregations of stingless bees instead. Therefore we tried spraying honey and water, and were almost immediately successful in attracting bees, and eventually flies. There was one other required condition, however: it had to be in the sunlight, or the flies would not be attracted. This is contrary to most phorids, which tend to be more active in shade.

Melaloncha acoma attacking stingless bee

Once we adopted the honey spray and sunlight combination, we started collecting large numbers of these flies, eventually collecting thousands of them. Sometimes, we were almost too successful in attracting the bees, producing gigantic aggregations that made it impossible to breathe or see anything, necessitating the use of jury rigged bee veils. These consisted of an insect net placed over the head and sealed around the neck with rubber bands. Eventually, though, the tiny stingless bees would get in, and we’d have to beat a retreat to get the annoying things out of our eyes, ears, and noses.

Me wearing a jury-rigged "bee veil" in Argentina, 2003

It was all worth it though, as we ended up catching 50-100 Melalonchaper day at good sites, and found almost 150 new species. I think there are still many more out there to find, so we keep spraying honey wherever we go in the tropics, and keep finding the beautiful, but deadly (to bees) bee-killing flies.

Melaloncha xanthocauda, femal

Melaloncha berezovskiyi, female

Melaloncha acoma, female

5 comments to How we started working on “rare” bee-killing flies

  1. John Hash says:

    It’s my hope that one day I’ll have collecting stories like this to tell. These blogs are great. And I don’t think anyone could argue against Melaloncha being the most beautiful!

  2. Anonomyia says:

    This is a great example of how sampling bias can lead to a highly distorted perception of biodiversity. A phenomenon I’ve noticed is that these perceptions often become self-fulfilling; a group regarded as rare becomes overlooked and easily dismissed; “oh, well, you never find those, so why spend the time on them?” Without devaluing the effort you put into these collections (and the bees up your nose) I think this also illustrates how adopting a collecting technique that is quite simple – though perhaps novel to the group in question – can revolutionize the rate at which individuals or species are encountered. I’m reminded of a previous post you had regarding netting smoke in order to capture other mini-dipts, a practice that to most eyes would appear pointless but is in fact very effective. Thanks for this post.

  3. Dave says:

    Nice post. I saw the smoke-effect first hand last autumn at a barbecue when my friend Matthias Buck netted two genera of ‘rare’ empidids around the campfire. I can’t wait to try it next summer at our Moose Pasture. I need to get off my butt and try inducing some sap oozing and a couple of other techniques too. I’m still slogging through the malaise trap samples from last summer and the idea of more discrete sampling is very appealing.

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