Long-Legged Flies: A Concise Overview of These Unique Insects

Long-legged flies are fascinating insects that catch our attention with their distinct appearance. One common example is the crane fly, which resembles a giant mosquito due to its slender body and extremely long legs. Although they may look intimidating, these insects are actually harmless and often found around water sources.

Crane flies are part of the fly family Tipulidae and come in a wide range of sizes, from tiny to almost 1.2 inches long. They are known for their slow-flying nature and fragile legs. Though these flies have a proboscis, they do not bite and are in fact non-threatening to humans.

In North America, there are hundreds of species of crane flies, all with unique characteristics. Their single pair of wings is usually held out at a 45-degree angle to their body, while small, antennae-like appendages called halteres help maintain balance during flight. Knowing more about these intriguing insects can help us better appreciate the vast diversity of creatures in our natural environments.

Understanding Flies with Long Legs

Distinguishing Features

Flies with long legs can be easily identified by their distinct appearance:

  • Long, slender legs
  • Metallic colors such as red, tan, blue, gold, black, copper, and metallic green
  • Clear wings
  • Unique antennae

Common Species

There are various species of long-legged flies in North America, including:

  1. Dolichopodidae: Also known as “dancing flies,” these metallic insects are common throughout the continent.
  2. Tipulidae: Commonly known as “crane flies,” they often have a tan or black body with long legs.

Habitat and Range

Long-legged flies can be found throughout North America and thrive in diverse habitats:

  • Dolichopodidae: Predominantly found in wet, marshy areas, and forests with decomposing vegetation.
  • Tipulidae: Mostly live in moist environments, such as streams, ponds, and wetlands.
Species Habitat Range
Dolichopodidae Wetlands, forests North America
Tipulidae Streams, ponds, wetlands North America

These insects play a vital role in the ecosystem, preying on smaller insects and serving as a food source for larger animals.

Life Cycle and Behavior

From Egg to Adult

Long-legged flies, belonging to the family Dolichopodidae, undergo a complete metamorphosis which includes egg, larva, pupa, and adult stages. The time it takes to complete the life cycle varies depending on the species and environmental factors.

  • Eggs: Females lay their eggs in specific habitats, such as soil, leaf litter, or decaying organic matter.
  • Larvae: Also known as maggots, the larvae have several instars stages and consume a variety of organisms, including aphids, mites, and other small insects.
  • Pupae: After the final larval stage, the larvae form pupae, which act as a protective case during the critical transition to adulthood.
  • Adults: Adult long-legged flies emerge and begin to search for food and mates.

Feeding and Prey

Long-legged flies are predators, feeding on a variety of small insects such as:

  • Aphids
  • Mites
  • Gnats
  • Mosquitoes

Adults have been observed catching their prey in mid-air or plucking them off surfaces. They can also feed on nectar, while larvae typically consume other arthropods and decaying organic matter.

Reproduction

Males and females engage in mating behavior, often involving complex displays and rituals. Some key points about their reproduction include:

  • Females require a blood meal before laying eggs.
  • Eggs are typically laid in moist organic matter or soil.
  • One female can lay up to 200-400 eggs at a time.

Pros of long-legged flies:

  • Help control populations of pest insects.
  • Act as pollinators when they feed on nectar.
  • Contribute to maintaining a balanced ecosystem.

Cons of long-legged flies:

  • Can be a nuisance if found in large numbers.
  • Occasionally feed on beneficial insects.

Ecological Role and Benefits

Predators and Prey Relationships

Flies with long legs belong to the order Diptera and play a significant role in balancing ecosystems. They can be both predators and prey to other animals. For example, they feed on:

  • Aphids
  • Scales

These arthropods, in turn, become food for:

  • Birds
  • Bats
  • Larger insects

Pollination and Plant Support

Long-legged flies are essential for pollination, as they are attracted to plants with open structures and white flowers. This helps improve gardening efforts and, in turn, supports wildlife and native plant growth. Some benefits of pollination include:

  • Increased seed production
  • Enhanced fruit and vegetable growth
  • Improved meadow and garden ecosystems

Beneficial Insects in the Garden

Long-legged flies play an indirect role in supporting garden ecosystems. They help break down organic matter, releasing nutrients back into the soil. Moreover, they provide biological control of pests, thus contributing to overall garden health. Key pros and cons of having long-legged flies in the garden include:

Pros

  • Natural pest control
  • Adding balance to the ecosystem
  • Pollination support

Cons

  • Possible annoyance to humans
  • Potential parasite transmission (rare)

Comparison table

Characteristics Long-legged Flies Other Garden Insects
Role in garden Predators/Prey, Pollinators Varies (e.g., decomposers, pests, etc)
Contribution to ecosystem Support plant growth, control pests Varies (positive or negative effects)
Impact on water Bio-indicators of healthy streams Varies (indicate healthy or unhealthy water)
Relationship with native plants and animals Support native plant growth, serve as prey for various animals Varies (may help or hinder native species)

In conclusion, long-legged flies positively impact garden ecosystems by acting as both predators and prey, pollinating plants, and helping maintain balance in the garden.

Managing Flies with Long Legs

When They’re Pests

  • Crane flies belong to the family Tipulidae and are commonly mistaken for mosquitoes due to their appearance. However, unlike mosquitoes, these long-legged insects do not bite humans or pets [^1^].
    The crane flies’ larvae, known as leatherjackets, are known to cause damage to the roots of grasses, especially in damp meadows and lawns [^2^].Their habitat preferences often include fields, water margins, and woodlands.
  • Daddy long legs, or harvestmen, are not true flies but rather belong to the arachnid family. They are not known to cause significant harm to plants or humans, but their presence can be alarming to some [^3^].

When They’re Beneficial

  • The long-legged fly family (Dolichopodidae) is a group of metallic, brightly-colored flies that are predators of small insect pests such as aphids, thrips, and caterpillars [^4^]. They are commonly found near water sources, tree bark, and grassy areas.
  • Crane flies also have some beneficial qualities. Their larvae can be food for fish, aquatic insects, and birds, while adults can help pollinate flowers and aerate the soil [^5^].

Comparison Table:

Feature Crane Flies Long-Legged Flies (Dolichopodidae) Daddy Long Legs
Habitat Fields, meadows, water margins, and woodlands Near water, tree bark, grassy areas Everywhere
Pest status Damages roots of grasses (larvae) Predators of small insect pests Mostly harmless
Interaction with humans Do not bite, can help with pollination and soil aeration Do not bite, can be beneficial predators Do not bite, harmless
Main threats Larvae known as “leatherjackets” None None

In summary, while some long-legged flies can be pests, others can be beneficial to the environment. It’s important to properly identify the species before taking any action, especially when considering the use of insecticides or other control methods in your yard or landscape.

Authors

    by
  • Bugman

    Bugman aka Daniel Marlos has been identifying bugs since 1999. whatsthatbug.com is his passion project and it has helped millions of readers identify the bug that has been bugging them for over two decades. You can reach out to him through our Contact Page.

  • Piyushi Dhir

    Piyushi is a nature lover, blogger and traveler at heart. She lives in beautiful Canada with her family. Piyushi is an animal lover and loves to write about all creatures.

3 thoughts on “Long-Legged Flies: A Concise Overview of These Unique Insects”

  1. Thanks for the quick reply. I’ve been looking, and I can’t find any reference on what is native to here, but could you do me a favor and check out the wings? From what I’ve found from images is the Nephrotoma wings are a much closer match in general and the Crocata wings look to be exactly the same (as much as could be expected anyways). I’m very interested in this one. 🙂

    Reply
    • We concede the similar appearance, but we do not have the necessary qualifications to make an exact species identification on this.

      Reply
  2. I apologise for the double post but the other thing that has my attention is the black legs with the faint coloration only near the body.

    Reply

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