Illustration of crane fly

Introduction

Tipulidae, often called crane flies in their adult stage, is the largest family of true flies. Crane flies form a highly diverse group of insects, both in number of species and in larval habitats, which extend from aquatic to terrestrial. The body plan or morphology of crane flies is rather simple. An elongate body, one pair of narrow wings, and long, slender legs characterize them. The body size ranges from 5 to 50 mm and can be described as mosquito-like. They are often mistaken for mosquitoes, but they belong to a group of harmless flies and can be distinguished from all other true flies by the transverse V-shaped groove on the dorsal part of the thorax.

In North America, more than 1,500 species of crane flies have been described and over 300 species are known from Pennsylvania. This number probably represents only about two-thirds of the estimated actual number for the state, and much more precise taxonomic studies are needed.

Crane flies undergo complete metamorphosis in their development with a brief egg stage, a relatively long larval feeding stage, a brief pupal resting stage, and finally a short adult breeding stage.

Crane flies serve several important roles in the ecosystem. Most importantly, adult and larval crane flies are food for many animals such as birds, fish, frogs, lizards, spiders and other insects.In addition, the larvae are detritus feeders that break down organic matter in various habitats such as streams and forest floors thereby enriching the soil, renewing and modifying the microhabitat for other invertebrate species. Some crane flies require special habitat conditions, and their presence or absence can be used as an indicator of environmental quality. Fishermen use larvae of some large crane flies as bait. Several species of crane flies are important agricultural pests; their larvae feed on seedlings of field crops and if abundant can be destructive to lawns, rangelands, rice fields, and golf courses.

Male of Epiphragma fasciapenne Female of Epiphragma fasciapenne Prepared Epiphragma fasciapenne
Male of Epiphragma fasciapenne
by Bruce Marlin
Female of Epiphragma fasciapenne
by Steve Marshall
Prepared Epiphragma fasciapenne
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Adults

Adult crane flies are sluggish fliers and are often abundant in moist woodlands and around water, usually near places where their larval life is spent. They occur mainly in spring and fall, but species of wingless, snow crane flies (Chionea) appear in the winter. Adult crane flies are most active in the cooler part of the day, usually around dusk. Adult males are more abundant at the beginning of the flight period while females are more numerous toward the end. Although individual adults have a relatively short life span of 10 to 15 days, the flight period for each species can last from 25-30 days. The main functions of the adult stage are mating and egg-laying. Feeding is less important, and probably water is the most pressing need. Species with elongated rostrum (Geranomyia, Elephantomyia, Toxorhina) have been reported visiting flowers, probably for nectars.

Limonia (Geranomyia) rostrata Limonia (Geranomyia) communis Limonia (Geranomyia) species
Limonia (Geranomyia) rostrata
by Richard Leung
Limonia (Geranomyia) communis
by Robin McLeod
Limonia (Geranomyia) sp.
by Lew Scharpf

Some large sized adult crane flies can be easily sexed in the field. The outline of the male caudal abdominal segments is expanded and round. In contrast the female has a tapering abdomen that terminates with an acute ovipositor. In addition, they can also be sexed by their flight pattern in the air. The males have an erratic flight pattern of undulations and spiral rotations. Females maintain a more direct, steady and straight flight path.

Tipula ultima - Male Tipula ultima - Female Pedicia albivitta - Male Pedicia albivitta - Female
Tipula ultima - Male
©2005 Chen Young
Tipula ultima - Female
©2005 Chen Young
Pedicia albivitta - Male
©2005 Chen Young
Pedicia albivitta - Female
©2005 Chen Young
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Larvae

The larvae are found in a wide variety of habitats, varying from strictly aquatic to terrestrial, even relatively dry soil. Their habitats include fresh water in fast-flowing streams, marshes, springs, meadows, seeps, tree holes, algal growth or mosses on rock faces near water, organic mud and decaying vegetable debris along the shores of streams and ponds, accumulated decomposed leaves and rotting wood on the forest floor, and occasionally soil in lawn and pastures.

Larvae by Marlin Rice
Photo taken by Marlin E. Rice

The typical shape of mature crane fly larvae is elongate, tapering gradually toward both ends. The skin is thin, tough, and usually covered with microscopic hairs. The head is fairly complete and can be retracted into the thorax. The posterior end has a single pair of spiracles surrounded by a disc of fleshy lobes (spiracular lobes), and membranous lobes (anal papillae) surround the anus. The shape, length, and number of these lobes vary among species and have proved to be taxonomically important and can be used to identify them. There is probably a close correlation of structure to habitats. Most crane fly larvae breath air through the posterior spiracles. Some can remain submerged in water for a limited time period when their habitats become flooded. The lobes surrounding the posterior spiracles often have a fringe of fine hairs that entrap a film of air when submerged. A few genera have truly aquatic larvae, which close the tracheal system completely and exchange of oxygen takes place by diffusion through the cuticle of tracheal gills.

Larvae are the growth stage and the majority of crane fly larvae are scavengers feeding on decomposing plant material and the associated microorganisms. Larvae of some aquatic species are predators on other small invertebrates, and several are herbivores on algae, moss or herbaceous plants.

Spiracular area of Tipula (Angarotipula) illustris larva, illustrated by Chen Young Spiracular area of Leptotarsus (Longurio) testaceus larva, illustrated by Chen Young Spiracular area of Dolichopeza (Oropeza) walleyi larva, illustrated by Chen Young
Spiracular area of
Tipula (Angarotipula) illustris larva,
illustrated by Chen Young
Spiracular area of
Leptotarsus (Longurio) testaceus larva,
illustrated by Chen Young
Spiracular area of
Dolichopeza (Oropeza) walleyi larva,
illustrated by Chen Young
     
Spiracular area of Tipula (Nippotipula) abdominalis larva, illustrated by Chen Young Spiracular area of Brachypremna dispellens larva, illustrated by Chen Young Spiracular area of Nephrotoma virescens larva, illustrated by Chen Young
Spiracular area of
Tipula (Nippotipula) abdominalis larva,

illustrated by Chen Young
Spiracular area of
Brachypremna dispellens larva,

illustrated by Chen Young
Spiracular area of
Nephrotoma virescens larva,

illustrated by Chen Young

Fishermen have long used both adult and larval crane flies as natural bait for fishing. They have experience in identifying several common aquatic and terrestrial crane flies and their larvae along streams. Artificial fly-fishing lures can be found that match several species of these crane flies.

Fishing Fly by John Henry Tipula (Pterelachisus) species
Fly by John Henry Tipula trivittata by Harriet Fell
Randome Image

Natural Predators

Being a group of clumsy fliers and sluggish maggots, adult and larval crane flies become easy prey for a wide variety of vertebrate and invertebrate predators. Many species of birds can be commonly seen returning to the nestlings with a mouth full of crane flies.

Photo by Chuck Musitano House Wren by Moses Martin Starlings feed on Tipula larva
Photo by Chuck Musitano Photo by Moses Martin Photo by Frode Falkenberg
Photo by David Jones Feed on crane fly by David Jones  
Photo by David Jones Photo by David Jones  
Gecko eating crane fly Frog eating crane fly  
Photo by C. E. Timothy Paine
Gecko feeds on Nephrotoma sp.
Photo by Scott Hasinger
Frog feeds on Tipula caloptera
 

 

 

Spiders, predacious insects, and even carnivorous plants also readily feed on adult crane flies.

Photo by Jim McClarin Photo by Herschel Raney Photo by Graham Checkley
Photo by Jim McClarin Photo by Herschel Raney Photo by Graham Checkley
     
Draining the cranefly Feed on crane fly Feed on winter cranefly
Photo by Ron Hautau Photo by Werner Eigelsreiter Photo by Randy Rhine
     
Ectemnius wasp preys on Nephrotoma ferruginea Empis deterra attacked Tipula submaculata Jumping spider feeds on Nephrotoma ferruginea
Photo by Thomas of Baltimore
Ectemnius wasp on
Nephrotoma ferruginea
Photo by Stephen Cresswell
Empis deterra on
Tipula submaculata
Photo by Steve Mattan
Jumping spider on
Nephrotoma ferruginea
     
Venus Fly trap feeding on crane fly Sundew Drosera filiformis feeding on cranefly Ant feeding on crane fly
Photo by Barry Rice Photo by Beatriz Moisset Photo by Anonymous
     
Protolophus singularis feeds on Tipula species.    
Photo by Marshal Hedin
Protolophus singularis feeds on Tipula sp.
   
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Phoretic Associations

Several species of pseudoscorpions and mites have been reported to attach themselves to crane flies. The majority of these associations are actually phoretic relationships, where the pseudoscorpions and mites are carried as hitchhikers by the crane flies. However, others are parasitic mites that feed on the body fluid of the crane flies.

Epiphragma fasciapenne with pseudoscorpion Tipula fuliginosa Tipula ultima with mites
Epiphragma fasciapenne with
pseudoscorpion. Photo by Jay Cossey
Tipula fuliginosa female with mite,
Photo by Tom Murray
Tipula ultima with mites,
Photo by Jay Cossey
     
Tipula borealis with mites Pseudolimnophila species with mite Tipula ultima with mite
Tipula borealis with mites,
Photo by Tony DiTerlizzi
Pseudolimnophila species with mite,
Photo by Tom Murray
Tipula ultima with mite,
Photo by Jay Cossey
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Parasitic Associations

Crane flies have also been found as victims of the parasitic fungus Entomophthora. Species in this genus such as Entomophthora muscae is the common pathogen that causes fungal disease in a wide range of adult flies and eventually kills them. The following image illustrates the typical posture of an infected crane fly (probably Tipula (Lunatipula) group) with spreading legs and wings, and the bloated abdomen filled with visible spores between the abdominal plates. This posture ensures that the fungal spores have the best possibility of dispersal and host infection. Because insect-pathogenic fungi usually require moisture to enable infection, this infection usually occurs during the wet or humid spring and fall of the year in our region.

Entomophthora fungus. By Judy Semroc.
Tipula sp. infected by Entomophthora fungus.
Photo by Judy Semroc

Recent field research by Carnegie Museum entomologists David Koenig and Chen Young has discovered an unusual parasitic relationship between a group of Big-headed flies (family Pipunculidae, genus Nephrocerus) and adult crane flies. Nephrocerus atrapilus and Nephrocerus daeckei were reared as endoparasitoids of three species of adult crane flies in the genus Tipula (Tipula duplex, Tipula mallochi, Tipula submaculata). Two additional Tipula species (Tipula furca, Tipula tricolor) were observed to host pipunculid larvae presumed to be species of Nephrocerus. Pipunculid larvae are known to parasitize leafhoppers, particularly Cicadellidae, Delphacidae and Cercopidae. This study presents the first report of hosts for Nephrocerus, and the first recorded instance of adult crane flies being parasitized by another true fly.

Nephrocerus species. By Stephen Cresswell. Tipula duplex. By Robin McLeod. Nephrocerus atrapilus. By Chen Young.
Nephrocerus species,
Photo by Stephen Cresswell
Tipula duplex female parasited by
Nephrocerus sp., Photo by Robin McLeod
Nephrocerus atrapilus,
Photo by Chen Young

Our study demonstrated the known host species belong to the subgenera Lunatipula and Yamatotipula within the genus Tipula. The majority of species of Tipula in our study area are univoltine, and they are common spring and summer elements in habitats of mixed deciduous woodlands of oak, hickory, maple, and black cherry. Our study also showed that female crane flies are preferred hosts for the Big-headed flies. The mode of infestation in this study is still unknown. Further observations on the life history of Nephrocerus are needed, especially of host location and oviposition behavior. The result of this study was published in the Proceedings of the Entomological Society of Washington 109(1):52-65. Two additional species of crane fly host were observed recently including Tipula valida (Westmoreland County, Pennsylvania) and Nephrotoma ferruginea (Suffolk County, New York, Garrett Herth).

Larva of Nephrocerus atrapilus. Illustrated by Chen Young. Puparium of Nephrocerus atrapilus. Illustrated by Chen Young.
Larva of Nephrocerus atrapilus,
Illustrated by Chen Young
Puparium of Nephrocerus atrapilus,
Illustrated by Chen Young

 

Nephrocerus atrapilus male lateral view. Photo by Jeff Skevington. Nephrocerus atrapilus male dorsal view. Photo by Jeff Skevington.
Nephrocerus atrapilus male lateral view.
Photo by Jeff Skevington
Nephrocerus atrapilus, dorsal view.
Photo by Jeff Skevington
   
Nephrocerus atrapilus female in lateral view. Photo by Jeff Skevington.
Nephrocerus atrapilus female in lateral view.
Photo by Jeff Skevington

 

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