Tag Archive | Syrphidae

High-speed Arthropod Week day 4: halteres

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The flies of the family Syrphidae are some of the most accomplished of all insect aeronauts. Their agility, precision and speed are amazing to see, as they dart about flowers and freeze in motionless hovering flight.  Like all winged flies, syrphids have one pair of wings only,  (Diptera means “two wings”). Where the rear pair would be, there is a pair of knobbed appendages called halteres. These organs function to inform the fly of perturbations in two axes, allowing precise control of direction, speed and stability.

Without halteres, all flies become unable to maintain flight control. The precise means by which sensory information from the halteres is encoded and transmitted to the fly’s brain are not fully understood, but good physical models have been developed that implicate perception of strains associated with Coriolis forces on the beating halteres (if you hold a spinning bike tire and try to perturb it in planes perpendicular to the rotation, you will feel the Coriolis forces!).

OK, so enough physics! What do beating halteres look like? Have a look at this syrphid hovering and taking off.

It might not be super obvious, but it was surprising to me to note that the plane in which the halteres move differs by an angle of up to 30 degrees from that of the wings.

Syrphids also have high power relative to their mass, and this allows very rapid accelerations (making them difficult to catch).

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As mentioned in my other post on wing coupling, other flying insects couple their wings to achieve formidable aerial prowess. Of course, having a single pair of wings is not the only way to be a master of the skies, as dragonflies are undoubtedly one of the most agile and versatile fliers, hovering and accelerating in spectacular fashion.

Syrphids though, with their bright coloration and super high performance enabled by halteres, high power to weight ratio, and fascinating life history, are undoubtedly one of my favorite fly families.

I got lucky with a hoverfly!

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Y’all know I love me some syrphids! These awesome fliers are fun to watch and are very abundant in season. They are devilishly hard to catch in flight, but sometimes they oblige and hover motionless in the air, begging for a shot. Last evening at Hastings Park, I was shooting in an area filled with blooming thistle. This little gal did the hovering thing right in front of me, so I took a quick few shots.  With the Laphria I found Wednesday, this has definitely been my lucky week for flies! 

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Feed your Syrphid well!

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It is still National Pollinator Week in the USA, and I hope they are having a good one. Here in Vancouver, it is rainy and cold. But that is no reason not to engage in some pollinator photography! A couple weeks ago, I found a syrphid larva among the blackberry leaves we feed our stick insects.

I ended up keeping it in the cage, feeding it with bunches of aphids.

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The larva disappeared after a day of eating so well, so I presumed it had dropped to the soil to pupate. Sure enough, today we found him buzzing around the cage. I took the opportunity for some pictures, then sent him out (in a protected location) after a meal of honey.

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