Houdini Fly Alert for Mason Bee Raisers
We love mason bees for many reasons! They're early spring pollinators, a lot of fun to watch, and require very little maintenance compared to honey bees, making them perfect bees for busy gardeners and farmers.
Traditionally, spring mason bee care included three simple steps. Step one, Install the mason bee house—step two, release mason bee cocoons. Step three, sit back and relax while these super pollinators do their thing. However, the Houdini Fly, an invasive parasite of the mason bee, has added an important new step to our care routine!
What is the Houdini fly?
Cacoxenus indagator, more commonly called the Houdini fly, is a cleptoparasite. Cleptoparasites are thieves, meaning they steal food or prey from other animals. For bees, most cleptoparasites lay their eggs inside bee nests. Once the Houdini Fly eggs hatch, the larval parasites eat the pollen loaves intended for immature bees and sometimes will even eat the developing bees in the process.
The Houdini fly gets its name from its unique method of escaping from bee nests. Female Houdini flies lay their eggs in nest cells before the female mason bee can seal the nest with mud. The fly larvae quickly hatch and consume the pollen loaf before the mason bee larvae, causing the mason bee to starve. The flies then continue to grow in the nesting cavity undetected.
Following pupation, newly emerged adult flies have a brief window of time to escape from the nest before their bodies harden. Houdini flies use an anatomical adaptation called a "head blister" to perform their escape acts. The flies find a small crack in the nest's mud wall, insert their deflated head blisters, and then pump the blisters full of blood, which creates hydraulic pressure, causing the mud wall to fall apart. The flies repeat this process until they have created a small exit hole to squeeze their soft bodies through—it's not a quick process, but it's effective!
Click here to watch a video of the Houdini fly inflating it's head.
What do Houdini flies look like?
Adult Houdini Fly Characteristics
- Large, red eyes on the side of the head;
- Dull brown with horizontal stripes on abdomen;
- Wings fold over each other when resting;
- Smaller than a house fly, but larger than a fruit fly;
- Often found waiting on the outside of mason bee houses; and
- Slow, hovering flight pattern—not very skittish making them easy to squish.
Houdini Fly Larvae Characteristics
- Houdini fly larvae look like sticky white clusters inside the brood cell;
- Multiple larvae per brood cell;
- Often surrounded by curly orange/brown frass (poop).
