Insect Week Spotlight: Robber Flies (Also Known as Assassin Flies)
Robber flies—also commonly known as assassin flies—are highly skilled aerial predators found throughout North America, including right here in the Dallas-Fort Worth Metroplex. With a distinctive, bristly body, strong legs, and large compound eyes, these insects are easily identified once you know what to look for.
Robber flies belong to the Asilidae family and are most commonly seen in hot, sunny environments, often perched on fences, outdoor furniture, or tall vegetation as they wait for potential prey.
What Robber Flies Eat
Robber flies are carnivorous and rely on other insects for food. Their diet includes:
Wasps
Flies
Bees
Moths
Grasshoppers
Butterflies
Occasionally, even other robber flies
They capture their prey mid-flight, using their legs to grab and immobilize it. Once captured, the robber fly uses a specialized mouthpart to inject digestive enzymes into the prey, liquefying the internal tissues for consumption.
This feeding method is highly effective and allows them to consume a wide variety of insects in a relatively short time.
A Closer Look at Their Behavior
Robber flies are solitary and territorial. They do not form colonies and generally prefer to hunt alone. Their ability to track, intercept, and subdue other insects in mid-air makes them one of the most capable insect predators in our region.
Though they may look aggressive, robber flies are not considered dangerous to humans or pets. However, if handled or provoked, they can deliver a painful bite. This is rare and typically only occurs through accidental contact.
Ecological Role: Helpful or Harmful?
Robber flies are sometimes considered beneficial due to their role in controlling populations of pest insects such as houseflies and wasps. However, they also feed on beneficial pollinators like honeybees and butterflies, which complicates their ecological impact.
Their presence in a yard or garden may indicate an abundance of insect activity in the area, as they tend to inhabit places where prey is readily available.
Why Robber Flies Matter
At Paragon Pest Control, we believe that pest management starts with understanding the broader environment. Robber flies are not typically a species we treat for directly, but they serve as an important reminder of how interconnected our ecosystems are—and why careful, informed pest control practices matter.
During Insect Week, we’re highlighting lesser-known insects like the robber fly to help homeowners recognize and better understand the species they might encounter around their homes.