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Submit an article to Indago - a peer reviewed journal
Submit an article to Indago - a peer reviewed journal
Submit an article to Indago - a peer reviewed journal

Tiger Flies (Fig. 1), scientifically called Coenosia are small inconspicuous grey flies. They belong to a family of flies called the Muscidae, generally referred to as “Houseflies” but they are not your stereotypical pesky housefly (Fig. 2) and are not likely to come into your house to irritate you like their cousins. You see, these little flies are actually fierce predators and typically hunt all kinds of insects.

One such species Coenosia attenuata, the “killer” or “hunter fly” is an important biological control agent in greenhouses and can be used to control plant pests such as fruit flies. They can also be quite entertaining, and can behave like tiny falconer’s birds (Suvák, 2008) perching on your finger, flying away and coming back with a tasty insect snack.

My interest in Coenosia however, started with a very weird new species of Coenosia from a farm near Oudtshoorn in the Western Cape. Trying to identify it yielded no known results, and it was described as C. macrotriseta Muller & Miller 2013. It is only known from the male, and had the strangest triple pair of head bristles (Fig. 3) I had ever seen, with enlarged swollen ends (Fig. 4). While comparing it to other museum specimens we found a similar existing species called C. globuliseta Pont, 1970 (from the Drakensberg) but this species, also only known from the male, had one pair of bristles (Fig. 5).

In 2017, we went on a general collecting trip to Mariepskop Mountain, Mpumalanga, a site for which the fly diversity is very poorly understood. We always try and put up Malaise traps (massive 6m flight interception traps) in areas that are potential flightpaths with the intention of optimizing our insect catches. I essentially rock-climbed through a deep ravine, risking life and limb to get the trap up in, what we thought, was “the most amazing position” (Fig. 6). The results were probably the worst collecting we had for the entire two weeks on the mountain, but at the very least made for a very nice photo (Fig. 6).

However, in the trap were three specimens. I knew immediately that what we had caught was another new species of curious tiger fly, Coenosia flagelliseta Muller 2019, again with strange swollen-end head bristles, however this time, the fly was even stranger in that it had whip-like hairs all over its body (tiger flies typically have straight bristles)(Fig. 7a). Even better, we also collected a female, the first for this strange group of flies. The female had a typical Coenosia appearance (Fig. 7b), and without any strange bristles. Interestingly upon dissection of the flies it was found that they had nectar in their gut, meaning the flies are also nectar feeding and potentially high-altitude pollinators in addition to their predatory behaviour.

In 2021, during a survey of the flies of Lesotho, high up in the alpine zone (at 3032 meters above sea level!) of the Maloti Mountains, during a week of collecting and rainfall that can only be described as “bucketing” we managed to do put up a Malaise trap and do some sweeping in-between the downpour (Fig. 8). This time we collected multiple males and females, another new species, with a mix of characters between the species occurring at Mariepskop and Oudtshoorn. We named it C. curiosa Muller & Midgley 2022, naming it after the curiosity this group of tiger flies have evoked in us (Fig. 9). This new species is also the first record for the genus in Lesotho, highlighting just how much work is left to do in our region.

As we continue to study these curious little creatures, it offers us a fascinating window into the complexity and diversity of insects, and especially flies in Africa. We deepen our understanding of the living systems around us, and how various interactions, from pollination to predation, contributes to the continued existence of our natural world.


Muller, B.S. (2022) How strange: Coenosia curiosa sp. nov. (Diptera: Muscidae), the first recorded Tiger fly from Lesotho, with revision of the Coenosia globuliseta-group. Zootaxa 5222 (4): 367–377.

Muller, B.S. (2019) A curious new Coenosia Meigen, 1826 (Diptera, Muscidae) from Mariepskop, Mpumalanga, South Africa. African Invertebrates, 60 (2), 239–253.

Muller, B.S. & Miller, R.M. (2013) Rediscovering the old from new: two curious species of Coenosia Meigen (Diptera: Muscidae) from South Africa. African Invertebrates 54 (2), 595–603.

Pont, A.C. (1980) Family Muscidae. In: Crosskey, R.W. (Ed.), Catalogue of the Diptera of the Afrotropical Region. British Museum (Natural History), London, pp. 721–761.

Suvák, M. (2008) “Coenosia attenuata can behave like a falconers bird”. Diptera.Info. Paul Buick., Retrieved 8 March 2023.

Figure Captions

Figure 1. Coenosia attenuata resting on a leaf, searching for its prey. Photo 1524389, (c) Katja Schulz, some rights reserved (CC BY) –

Figure 2. Musca domestica, the common housefly. USDAgov, Public domain, via Wikimedia Commons

Figure 3. Illustrated head of Coenosia macrotriseta. Based on Muller (2019) fig. 9.

Figure 4. Low vacuum scanning electron microscope photo. Based on Muller & Miller (2013) fig. 4a.

Figure 5. Illustrated head of Coenosia macrotriseta. Based on Muller (2019) fig. 10.

Figure 6. Malaise trap in ravine on top of Mariepskop. Based on Muller (2019), fig. 2.

Figure 7. a: Male of Coenosia flagelliseta showing the whip-like hairs (arrowed); b: female, with normal bristles.

Figure 8. Habitat where Coenosia curiosa was collected at Afriski Mountain Resort, Lesotho.

Figure 9. General appearance of Coenosia curiosa male, with the strange head bristles clearly visible.

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Burgert is a Senior Museum Scientist in the Department Terrestrial Invertebrates. His research interests are systematics, taxonomy, phylogeny and biogeography of true flies (Diptera), with special emphasis on Muscidae and Athericidae. He is also interested in Cybertaxonomy and literature mark-up, as well as Collections data quality assessment and use, which includes georeferencing, ecological niche modelling and collections information management. In 2014 Burgert obtained his Master’s degree for a thesis titled: Systematics of the shoot fly subgenus Atherigona s. str. (diptera: muscidae) of South Africa.

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