Large Fly with a Stinger: Discover the Fascinating Robber Fly

The Robber Fly is a unique and intriguing insect in the world of predators. With a large size and a stinger-like proboscis, it is often mistaken for other types of flies but holds its own spot in the category of predatory insects. Displaying various appearances and colors, it is an adaptable hunter that plays an important role as a natural pest control, feasting on insects like grasshoppers, moths, and other flies.

Robber Flies exhibit some fascinating characteristics, such as their strong, bristled legs which assist in capturing prey mid-air source. They have also developed impressive camouflage techniques, with some species mimicking bees or blending in with their surroundings to better ambush their prey. In fact, there are around 7,000 species of Robber Flies worldwide, and 1,000 native to North America, making them a widespread and diverse group of insects source.

While their fierce predatory behavior might seem menacing, Robber Flies are not harmful to humans. As generalist predators, their focus remains on other insects, making them beneficial to our ecosystem by controlling the populations of potential pests. So, next time you spot a Robber Fly, don’t be alarmed – they are simply doing their part to maintain balance in nature.

Overview of Robber Flies

Classification and Scientific Name

Robber flies belong to the family Asilidae and are classified under the order Diptera, class Insecta, phylum Arthropoda, and kingdom Animalia (source).

Physical Characteristics

Robber flies exhibit various physical features including:

• Size: 0.2 – 2 inches
• Colors: Most are gray and black, some mimic other insects like bumble bees and wasps
• Bristles: Possess hairy or bristly bodies, and strong legs with bristles for prey capture
• Eyes: Large, widely-spaced compound eyes (source)

Habitat and Distribution

Robber flies are found all around the world. They are fierce predators, preying on a variety of insects like bees, wasps, dragonflies, spiders, beetles, and other flies. Specifically, there are about 7,000 species globally, with 1,000 native to North America (source).

Behavior and Biology

Prey and Predatory Tactics

Robber flies are predators known for their skillful hunting techniques. They primarily feed on:

• Bees
• Beetles
• Dragonflies
• Butterflies
• Leafhoppers
• White grubs

Using their long, strong legs, they catch their prey mid-flight and inject venomous saliva to immobilize it before consuming it source.

Comparison of Robber Fly and Horse Fly:

Reproduction and Life Cycle

The life cycle of robber flies includes egg, larva, pupa, and adult stages. Female robber flies lay eggs in the soil or decaying organic matter source. The larvae are also predators, feeding on the eggs and larvae of other insects. After pupation, the adult robber flies emerge and continue their predatory behavior.

Beneficial Insects and Pest Management

Robber flies are considered beneficial insects due to their predatory nature. They play a vital role in controlling various agricultural pests. For instance, they help control populations of Hymenoptera like bees and wasps source. The University of Florida recognizes their importance in pest management and encourages the use of these natural predators to reduce the need for chemical insecticides source.

Physical Appearance

Size and Colors

Robber flies are medium-sized to large insects, with adult sizes ranging from 3 mm to over 50 mm in length¹. They display varying colors, such as tan, black, brown, gray, and white². These flies often have contrasting, patterned, or spotted markings on their body.

Wings and Legs

These predators possess two wings to aid in their agile flight³. Their legs are equipped with prominent spikes, which help them capture prey effectively⁴. Some examples of their features include:

• Long, strong legs
• Bristled legs for prey capture
• Two wings for agile flight

Eyes and Face

Robber flies boast large, widely-spaced compound eyes, providing them with excellent vision for hunting⁵. Their face features a prominent proboscis, fashioned into a sharp tube or beak for injecting venom into their prey⁶. A comparison of Robber Fly features can be seen below:

Robber Fly Relatives

Other Flies

Robber flies belong to the order Diptera, which includes many other types of flies. Some common relatives of robber flies are:

• Sand flies: Small, biting flies known for transmitting diseases
• Black flies: Tiny flies with a painful bite, commonly found near rivers and streams
• Horse flies & Deer flies: Large biting flies from the family Tabanidae, known for their painful bites

It’s important to note that robber flies do not have the same biting behavior towards humans as their relatives.

Wasps and Bees

Robber flies share some similarities with wasps and bees of the order Hymenoptera, such as:

• Predatory behavior: Just like many wasp species, robber flies are fierce insect predators
• Mimicry: Some robber fly species display hair and color patterns to resemble bees or wasps for protection

However, some key distinctions between robber flies and hymenopterans include:

Ants, Larvae, and Lepidoptera

In the world of insects, robber flies (Asilidae family) also interact with ants and members of the Lepidoptera order, such as moths. They are known to prey on ants, as well as mature and larval forms of moths.

Some features of robber flies that can be helpful in distinguishing them from other insects like ants and Lepidoptera:

• Large, widely-spaced compound eyes
• A sharp, beak-like proboscis used for predation
• Two wings, instead of four like many other insects

The interaction between robber flies, ants, and moths exhibits the complexity and diversity of the insect world.

Impact on Humans and Environment

Biting and Stinging

Robber flies, despite their intimidating appearance, don’t usually bother humans. They are predatory insects that mainly target other insects, such as bees, wasps, and dragonflies¹. That being said, they might bite when mishandled². Their bite can be painful, but it’s not typically dangerous for people. To recognize a robber fly, look for these features:

• Narrow and tapering abdomen
• Large, widely-spaced compound eyes
• Prominent spikes on their legs
• Loud buzzing during flight

Role in Gardens and Ecosystem

Robber flies can actually be beneficial to gardens and ecosystems. They help keep populations of pest insects like aphids and other flies under control³. Additionally, they play a role in pollination, as they often visit flowers in search of prey. However, there are some drawbacks to their presence:

Pros:

• Control pesky insects
• Contribute to pollination
• Indicate a healthy ecosystem

Cons:

• Can potentially harm beneficial insects like bees
• Their bite can be painful if mishandled

Here’s a comparison table of robber flies and other flying insects:

Robber flies lay their eggs in soil or plants⁴. Their larvae pupate and emerge as adult robber flies, continuing the cycle. By understanding their biology and ecological role, you can better appreciate and coexist with these fascinating, albeit intimidating, insects.