Dobsonfly
Encyclopedia
A Dobsonfly is any insect
of the subfamily Corydalinae, part of the megaloptera
n family
Corydalidae
. There are over 220 species
of dobsonflies. Dobsonflies are found throughout the Americas
and Asia
, as well as South Africa
. Their closest relatives are the fishflies.
Both male and female dobsonflies can reach lengths up to five inches (12.5 cm), measured from the tips of their pincers to the tips of their four wings. Their wingspans can be twice as long as their body length. The wings are densely lined with intersecting veins. When not in use, the wings are folded along the length of their bodies. Dobsonflies have long, multi-segmented antenna
e.
Though both male and female dobsonflies have sharp mandibles, those of an adult male dobsonfly are actually so big – up to 1 inch (25 mm) – that they are unable to harm humans, as they have such poor leverage that they are incapable of breaking the skin. Their mandibles are used exclusively during mating, where males show them off and grasp the females during copulation. Female dobsonflies, however, retain the short, powerful pincers they had as larvae, so they can inflict painful bites, which can draw blood. Notwithstanding the males' inability to inflict harm, when threatened both sexes will raise their heads and spread their jaws menacingly. They are not venomous, but possess an irritating, foul-smelling anal spray as a last-ditch defense.
Dobsonflies spend most of their life in the larva
l stage, during which they are called hellgrammites, and are familiar to angler
s who like to use the large larvae as bait. Hellgrammites live under rocks at the bottoms of lake
s, stream
s and river
s, and prey on other insect
larvae with the short sharp pincers on their heads, with which they can also inflict painful bites on humans. The larvae reach to 2" to 3" in length, with gills all along the sides of their segmented bodies that allow them to extract oxygen from water.
After a few years of living and growing underwater, the larvae crawl out onto land and pupa
te. They stay in their cocoons over the winter and emerge only to mate
. Upon emerging, they live for only seven days. While not generally believed to eat during their adult stage, some captive female specimens have been observed with their heads burrowed into blackberries.
Adults can generally be found from late spring into the middle of summer, preferring to remain near bodies of water, particularly the ones where they grew up. Once they emerge as adults they mate, deposit their eggs near the water (often on overhanging vegetation), then die. They are primarily nocturnal, and like most aquatic insects
, are commonly attracted to bright lights.
Insect
Insects are a class of living creatures within the arthropods that have a chitinous exoskeleton, a three-part body , three pairs of jointed legs, compound eyes, and two antennae...
of the subfamily Corydalinae, part of the megaloptera
Megaloptera
Megaloptera is an order of insects. It contains the alderflies, dobsonflies and fishflies, and there are about 300 known species.The Megaloptera were formerly considered part of a group then called Neuroptera, together with lacewings and snakeflies, but these are now generally considered to be...
n family
Family (biology)
In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...
Corydalidae
Corydalidae
The family Corydalidae contains the megalopterous insects known as dobsonflies and fishflies. Making up about one dozen genera, they occur primarily throughout the Northern Hemisphere, both temperate and tropical, and South America....
. There are over 220 species
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
of dobsonflies. Dobsonflies are found throughout the Americas
Americas
The Americas, or America , are lands in the Western hemisphere, also known as the New World. In English, the plural form the Americas is often used to refer to the landmasses of North America and South America with their associated islands and regions, while the singular form America is primarily...
and Asia
Asia
Asia is the world's largest and most populous continent, located primarily in the eastern and northern hemispheres. It covers 8.7% of the Earth's total surface area and with approximately 3.879 billion people, it hosts 60% of the world's current human population...
, as well as South Africa
South Africa
The Republic of South Africa is a country in southern Africa. Located at the southern tip of Africa, it is divided into nine provinces, with of coastline on the Atlantic and Indian oceans...
. Their closest relatives are the fishflies.
Antenna (biology)
Antennae in biology have historically been paired appendages used for sensing in arthropods. More recently, the term has also been applied to cilium structures present in most cell types of eukaryotes....
e.
Though both male and female dobsonflies have sharp mandibles, those of an adult male dobsonfly are actually so big – up to 1 inch (25 mm) – that they are unable to harm humans, as they have such poor leverage that they are incapable of breaking the skin. Their mandibles are used exclusively during mating, where males show them off and grasp the females during copulation. Female dobsonflies, however, retain the short, powerful pincers they had as larvae, so they can inflict painful bites, which can draw blood. Notwithstanding the males' inability to inflict harm, when threatened both sexes will raise their heads and spread their jaws menacingly. They are not venomous, but possess an irritating, foul-smelling anal spray as a last-ditch defense.
Dobsonflies spend most of their life in the larva
Larva
A larva is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle...
l stage, during which they are called hellgrammites, and are familiar to angler
Fisherman
A fisherman or fisher is someone who captures fish and other animals from a body of water, or gathers shellfish. Worldwide, there are about 38 million commercial and subsistence fishermen and fish farmers. The term can also be applied to recreational fishermen and may be used to describe both men...
s who like to use the large larvae as bait. Hellgrammites live under rocks at the bottoms of lake
Lake
A lake is a body of relatively still fresh or salt water of considerable size, localized in a basin, that is surrounded by land. Lakes are inland and not part of the ocean and therefore are distinct from lagoons, and are larger and deeper than ponds. Lakes can be contrasted with rivers or streams,...
s, stream
Stream
A stream is a body of water with a current, confined within a bed and stream banks. Depending on its locale or certain characteristics, a stream may be referred to as a branch, brook, beck, burn, creek, "crick", gill , kill, lick, rill, river, syke, bayou, rivulet, streamage, wash, run or...
s and river
River
A river is a natural watercourse, usually freshwater, flowing towards an ocean, a lake, a sea, or another river. In a few cases, a river simply flows into the ground or dries up completely before reaching another body of water. Small rivers may also be called by several other names, including...
s, and prey on other insect
Insect
Insects are a class of living creatures within the arthropods that have a chitinous exoskeleton, a three-part body , three pairs of jointed legs, compound eyes, and two antennae...
larvae with the short sharp pincers on their heads, with which they can also inflict painful bites on humans. The larvae reach to 2" to 3" in length, with gills all along the sides of their segmented bodies that allow them to extract oxygen from water.
After a few years of living and growing underwater, the larvae crawl out onto land and pupa
Pupa
A pupa is the life stage of some insects undergoing transformation. The pupal stage is found only in holometabolous insects, those that undergo a complete metamorphosis, going through four life stages; embryo, larva, pupa and imago...
te. They stay in their cocoons over the winter and emerge only to mate
Mating
In biology, mating is the pairing of opposite-sex or hermaphroditic organisms for copulation. In social animals, it also includes the raising of their offspring. Copulation is the union of the sex organs of two sexually reproducing animals for insemination and subsequent internal fertilization...
. Upon emerging, they live for only seven days. While not generally believed to eat during their adult stage, some captive female specimens have been observed with their heads burrowed into blackberries.
Adults can generally be found from late spring into the middle of summer, preferring to remain near bodies of water, particularly the ones where they grew up. Once they emerge as adults they mate, deposit their eggs near the water (often on overhanging vegetation), then die. They are primarily nocturnal, and like most aquatic insects
Aquatic insects
Aquatic insects live some portion of their life cycle in the water. They feed in the same ways as other insects. Some diving insects, such as predatory diving beetles, can hunt for food underwater where land-living insects cannot compete.-Breathing:...
, are commonly attracted to bright lights.
Etymology
References to the names "dobson" and "hellgrammite" (both referring to the larvae) date back at least to the late 1800'shttp://biodiversitylibrary.org/page/25326868http://biodiversitylibrary.org/page/24481576, but to date there is only speculation as to the actual origin of these nameshttp://bugguide.net/node/view/4873.External links
- http://www.fcps.k12.va.us/StratfordLandingES/Ecology/mpages/dobsonfly.htm
- http://mbgnet.mobot.org/fresh/slide/dobson.htm
- http://insects.tamu.edu/fieldguide/bimg121.html
- http://tolweb.org/tree?group=Corydalus&contgroup=Corydalinae
- Dobson Fly page at "What's That Bug"
- Hellgrammite page at "What's That Bug"
- Corydalus cornutus, eastern dobsonfly on the UFUniversity of FloridaThe University of Florida is an American public land-grant, sea-grant, and space-grant research university located on a campus in Gainesville, Florida. The university traces its historical origins to 1853, and has operated continuously on its present Gainesville campus since September 1906...
/ IFASInstitute of Food and Agricultural SciencesThe University of Florida’s Institute of Food and Agricultural Sciences is a federal-state-county partnership dedicated to developing knowledge in agriculture, human and natural resources, and the life sciences, and enhancing and sustaining the quality of human life by making that information...
Featured Creatures Web site - Video of hellgrammites