''Chaoborus'' is a genus of
midges in the family
Chaoboridae
Chaoboridae, commonly known as phantom midges or glassworms, is a family of fairly common midges with a cosmopolitan distribution. They are closely related to the Corethrellidae and Chironomidae; the adults are differentiated through peculiarit ...
. The
larva
A larva (; plural larvae ) 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.
...
e are known as glassworms because they are
transparent
Transparency, transparence or transparent most often refer to:
* Transparency (optics), the physical property of allowing the transmission of light through a material
They may also refer to:
Literal uses
* Transparency (photography), a still, ...
. They can be found commonly in
lake
A lake is an area filled with water, localized in a basin, surrounded by land, and distinct from any river or other outlet that serves to feed or drain the lake. Lakes lie on land and are not part of the ocean, although, like the much large ...
s all over the world and can be up to . The adults are sometimes called phantom midges or lake flies.
Appearance
Glassworms are almost entirely transparent, except for pairs of black kidney-shaped structures in the front and the back of the body. These dots are the air sacs. They use these air sacs to migrate up and down in lakes. Glassworms breathe through the end of their
abdomen
The abdomen (colloquially called the belly, tummy, midriff, tucky or stomach) is the part of the body between the thorax (chest) and pelvis, in humans and in other vertebrates. The abdomen is the front part of the abdominal segment of the to ...
and have two small
eyes at the front of their bodies.
Behavior
''Chaoborus'' adults do not bite mammals or suck
blood
Blood is a body fluid in the circulatory system of humans and other vertebrates that delivers necessary substances such as nutrients and oxygen to the cells, and transports metabolic waste products away from those same cells. Blood in the cir ...
. Larvae live in open waters and even sediments, where there may be little
oxygen
Oxygen is the chemical element with the symbol O and atomic number 8. It is a member of the chalcogen group in the periodic table, a highly reactive nonmetal, and an oxidizing agent that readily forms oxides with most elements as ...
for them to breathe. In some lakes they can be found as deep as . In these deep
anoxic waters
Anoxic waters are areas of sea water, fresh water, or groundwater that are depleted of dissolved oxygen. The US Geological Survey defines anoxic groundwater as those with dissolved oxygen concentration of less than 0.5 milligrams per litre. Anoxic ...
they can avoid predation more easily than near the surface. They get around the fact that a normal air filled
invertebrate trachea
The trachea, also known as the windpipe, is a cartilaginous tube that connects the larynx to the bronchi of the lungs, allowing the passage of air, and so is present in almost all air-breathing animals with lungs. The trachea extends from the la ...
l system would fail at these depths by having it reduced to just two air sacs. They are predaceous, and catch their prey with their modified
prehensile
Prehensility is the quality of an appendage or organ that has adapted for grasping or holding. The word is derived from the Latin term ''prehendere'', meaning "to grasp". The ability to grasp is likely derived from a number of different orig ...
antennae. They look somewhat like
mosquito
Mosquitoes (or mosquitos) are members of a group of almost 3,600 species of small flies within the family Culicidae (from the Latin ''culex'' meaning " gnat"). The word "mosquito" (formed by ''mosca'' and diminutive ''-ito'') is Spanish for "li ...
larvae, on which they
prey
Predation is a biological interaction where one organism, the predator, kills and eats another organism, its prey. It is one of a family of common feeding behaviours that includes parasitism and micropredation (which usually do not kill ...
and frequently destroy in large numbers. ''Chaoborus'' are considered opportunistic eaters, as their main diet consists of
copepods and
cladocerans
The Diplostraca or Cladocera, commonly known as water fleas, are a superorder of small crustaceans that feed on microscopic chunks of organic matter (excluding some predatory forms).
Over 1000 species have been recognised so far, with many more ...
, though they are believed to prefer copepods. However, they tend to select whatever prey enters its strike zone as it is not known for chasing prey. Prey selection also varies between species as head and mandible size dictate maximum prey size.
![Lake flies, Lake Malawi (2499202894)](https://upload.wikimedia.org/wikipedia/commons/e/e7/Lake_flies%2C_Lake_Malawi_%282499202894%29.jpg)
Their main predator is fish, which can cause a behavioral response due to light factors influenced by their presence. This fish factor causes an increase in the average depth the individuals can be found. This vertical migration behavior is believed to be a chemical reaction, rather than a visual or mechanical. In the
African Great Lakes
The African Great Lakes ( sw, Maziwa Makuu; rw, Ibiyaga bigari) are a series of lakes constituting the part of the Rift Valley lakes in and around the East African Rift. They include Lake Victoria, the second-largest fresh water lake in th ...
of
Malawi
Malawi (; or aláwi Tumbuka: ''Malaŵi''), officially the Republic of Malawi, is a landlocked country in Southeastern Africa that was formerly known as Nyasaland. It is bordered by Zambia to the west, Tanzania to the north and northeas ...
and
Victoria
Victoria most commonly refers to:
* Victoria (Australia), a state of the Commonwealth of Australia
* Victoria, British Columbia, provincial capital of British Columbia, Canada
* Victoria (mythology), Roman goddess of Victory
* Victoria, Seychelle ...
(but not
Tanganyika
Tanganyika may refer to:
Places
* Tanganyika Territory (1916–1961), a former British territory which preceded the sovereign state
* Tanganyika (1961–1964), a sovereign state, comprising the mainland part of present-day Tanzania
* Tanzania Main ...
where this genus is absent, perhaps because of chemical factors), huge swarms of ''Chaoborus'' midges occur and are collected by local people to make
''kungu'' cakes, biscuits or burgers, a local delicacy rich in
protein
Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, res ...
.
[Morris, B. (2004). Insects and Human Life, pp. 73—76. ][van Huis, A.; H. van Gurp; and M. Dicke (2012). The Insect Cookbook: Food for a Sustainable Planet, p. 31. ] David Livingstone
David Livingstone (; 19 March 1813 – 1 May 1873) was a Scottish physician, Congregationalist, and pioneer Christian missionary with the London Missionary Society, an explorer in Africa, and one of the most popular British heroes of t ...
(1865) claimed that they "tasted not unlike caviare".
[
]
Life cycle
''Chaoborus'' spends the majority of its life in the larval stage. In this larval stage, there are 4 growth instars before reaching adulthood. Most ''Chaoborus'' species are univoltine, or live for only one year, though some populations have been recorded as having a two-year generation time
In population biology and demography, generation time is the average time between two consecutive generations in the lineages of a population. In human populations, generation time typically ranges from 22 to 33 years. Historians sometimes use this ...
. Timing of pupation depends on local environmental conditions, though generally occurs after any ice has thawed and temperatures in the water begin to rise again.
Collection
The simplest way to collect glassworms is by a plankton net
A plankton net is equipment used for collecting samples of plankton in standing bodies of water. It consists of a towing line and bridles, nylon mesh net, and a cod end. Plankton nets are considered one of the oldest, simplest and least expensi ...
. They can be found in almost all water, but most abound in fish-free quarry ponds during winter. Glassworms are very easy to store if the water is kept cold and aerated. They are very tolerant to bad water conditions, including chlorine
Chlorine is a chemical element with the symbol Cl and atomic number 17. The second-lightest of the halogens, it appears between fluorine and bromine in the periodic table and its properties are mostly intermediate between them. Chlorine i ...
. They are sometimes collected and sold as fish food
Aquarium fish feed is plant or animal material intended for consumption by pet fish kept in aquariums or ponds. Fish foods normally contain macronutrients, trace elements and vitamins necessary to keep captive fish in good health. Approximatel ...
.
Species
These 44 species belong to the genus ''Chaoborus'':
* '' Chaoborus albatus'' Johnson, 1921 i g b
* '' Chaoborus americanus'' (Johannsen, 1903) i c g
* '' Chaoborus annandalei'' Edwards, 1930 c g
* '' Chaoborus anomalus'' Edwards, 1930 c g
* '' Chaoborus antillum'' Knab, 1913 c g
* '' Chaoborus asiaticus'' (Giles, 1901) c g
* '' Chaoborus astictopus'' Dyar & Shannon, 1924 i c g b (clear lake gnat)
* '' Chaoborus australis'' Sahnnon & Ponte, 1928 c g
* '' Chaoborus bolviensis'' Lane & Heredia, 1956 c g
* '' Chaoborus brasiliensis'' (Theobald, 1901) c g
* '' Chaoborus brevisector'' Edwards, 1930 c g
* '' Chaoborus ceratopogones'' (Theobald, 1903) c g
* '' Chaoborus cooki'' Saether, 1970 i c g b
* '' Chaoborus cornfordii'' (Theobald, 1903) c g
* '' Chaoborus crystallinus'' (De Geer, 1776) i c g
* '' Chaoborus depereti'' Meunier, 1915 c g
* '' Chaoborus edulis'' Edwards, 1930 c g
* '' Chaoborus elnorae'' Shannon & Ponte, 1928 c g
* '' Chaoborus festivus'' Dyar & Shannon, 1924 i c g b
* '' Chaoborus flavicans'' (Meigen, 1830) i c g b
* '' Chaoborus flavidulus'' Edwards, 1930 c g
* '' Chaoborus freemani'' Verbeke, 1958 c g
* '' Chaoborus fryeri'' Verbeke, 1958 c g
* '' Chaoborus fuscinervis'' Edwards, 1930 c g
* '' Chaoborus indicus'' (Giles, 1904) c g
* '' Chaoborus longicercus'' Colless, 1986 c g
* '' Chaoborus maculipes'' Stone, 1965 i c g b
* '' Chaoborus magnificus'' Lane, 1942 c g
* '' Chaoborus manilensis'' (Schiner, 1868) c g
* '' Chaoborus microstictus'' Edwards, 1930 c g
* '' Chaoborus nyblaei'' (Zetterstedt, 1838) c g
* '' Chaoborus obscuripes'' (Wulp, 1859) i c g
* '' Chaoborus ornatipennis'' Colless, 1986 c g
* '' Chaoborus pallidipes'' (Theobald, 1911) c g
* '' Chaoborus pallidus'' (Fabricius, 1781) c g
* '' Chaoborus punctilliger'' Colless, 1986 c g
* '' Chaoborus punctipennis'' (Say, 1823) i c g b
* '' Chaoborus queenslandensis'' (Theobald, 1905) c g
* '' Chaoborus sampsera'' Ogawa & Judd, 2008 c g
* '' Chaoborus souzai'' Lane, 1939 c g
* '' Chaoborus stonei'' Lane, 1942 c g
* '' Chaoborus trivittatus'' (Loew, 1862) i c g b
* '' Chaoborus unicolor'' Lane, 1942 c g
* '' Chaoborus vagus'' Colless, 1986 c g
Data sources: i = ITIS,[ c = Catalogue of Life,][ g = GBIF,][ b = Bugguide.net]
References
{{Taxonbar, from=Q2707905
Culicoidea genera
Chaoboridae