Crossopriza lyoni
Encyclopedia
Crossopriza lyoni is a widespread species
of cellar spiders that prefer to live in or around human structures
. They are commonly known as tailed cellar spiders, tailed daddy longlegs spiders, and sometimes box spiders. They all possess extremely long fragile legs that can reach up to 6 cm (2.4 in) long and a body length of that ranges from 2.5 to 7 mm (0.0984251968503937 to 0.275590551181102 in). Their abdomens are distinctly squarish when viewed from the side and their carapace is more or less circular when viewed from above. They also possess two kinds of sound-producing organs and have six eyes.
The original range
of C. lyoni is unknown. They have been introduced
into other parts of the world accidentally and are now pantropical
in distribution. They are a regulated species
in some countries and are often regarded as pests due to the large amounts of unsightly web
s they construct inside human homes. Some people, however, regard them as beneficial, as they are efficient predators of mosquito
es and other arthropod
s. They are harmless to humans.
Crossopriza
and the subfamily Holocneminae
. They belong to the cellar spider family (Pholcidae). They are commonly referred to as tailed daddy longlegs spiders, tailed cellar spiders, or (more rarely) box spiders. C. lyoni and other cellar spiders are also often confused with two other invertebrates - the harvestmen (order
Opiliones
) and the crane flies (family Tipulidae) - both of which are also known as 'daddy longlegs
'. However, they are not closely related to cellar spiders — the latter is a fly
; and the former, while also an arachnid, is not a spider
at all.
The species was first formally described in 1867 by the British
naturalist
John Blackwall
from a collection of spiders from Meerut, Agra
, and Delhi
. They came from Francis Lyon, a captain of the Royal Artillery
of the British Empire
stationed in India
. They were sent to his sister who presented them to Blackwall at the suggestion of a mutual friend. Blackwall named the spider after Captain Lyon and expressed a hope that others may follow Lyon's example in collecting specimens from foreign countries for the benefit of science. He classified the species under the genus Pholcus
. In 1892, the French
arachnologist Eugène Simon
erected the genus Crossopriza
and subsequently reclassified Pholcus lyoni to Crossopriza lyoni.
Blackwall also described a curious case of hermaphroditism in one adult specimen, in which the left side was male and the right side was female.
. Females of C. lyoni are about 3 to 7 mm (0.118110236220472 to 0.275590551181102 in) in length. Males are slightly smaller, at about 2.5 to 6 mm (0.0984251968503937 to 0.236220472440945 in) in length, and have prominent pedipalp
s. Both sexes possess extremely long fragile legs. Males have slightly longer legs than females. The first pair of legs in larger male individuals can can reach up to 6 centimetres (2.4 in) in length. The legs are gray to amber in color and covered with numerous small longitudinal brown spots. The 'knee joints' are brown, and the ends of the femur and tibiae are girdled with white. Males also possess a series of 20 to 25 spines (macrosetae
) on their femur. Their leg formula is I,II,IV,III - the front pair of legs being the longest and the third pair being the shortest.
The cephalothorax
is wider than it is long, greyish-white to pale amber in color. The carapace is subcircular. In the middle of the upper surface is a deep depression (called the thoracic fovea) and a darker longitudinal band of color. C. lyoni, like some other cellar spiders, only have six eyes. They are pearly-white in color and located at the tip of the cephalothorax in two groups of three.
The abdomen (the opisthosoma
) is gray with white lateral stripes and various dark and light patches on the sides and the upper surface. An irregular darker stripe runs lengthwise at the bottom surface. The abdomen is angular and somewhat box-shaped, with a small conical hump on the upper back.
They also possess two types of stridulatory organs. The first type is located at the posterior tips of their cephalothorax (the prosoma) in the form of two triangular protrusions. The spiders rub these structures with a matching pair of sclerotized
plates at the anterior portion of the abdomen, producing sound. These structures are more prominent in females. They also possess stridulatory files (in the form of a series of small ridges) on their chelicerae which are rubbed against the pedipalps to produce sound. The second type is more prominent in males.
C. lyoni can be distinguished from other members of the genus through several ways: by the characteristic boxy shape of their abdomens (C. cylindrogaster has a cylindrical abdomen); by the presence of two apophyses (jutting structures) in the chelicerae of males (C. pristina, C. semicaudata, and C. soudanensis all possess only one apophysis on each chelicera); or simply by geographic distribution (C. lyoni can be found globally and is the only species of Crossopriza in the New World
, while the other species like C. johncloudsleyi and C. nigrescens are restricted to Africa
or the Middle East
).
e. Because of the relative shortness of the male pedipalps in comparison to the sheer length of the legs of both males and females of the species, the spiders have to bring their bodies close together, giving the impression of 'snuggling'. This lasts for about 40 minutes. In rare instances, females may eat the males
after copulation.
The eggs are deposited by the females 5–6 days after copulation. After laying the eggs, females will bind them into a ball with tiny amounts of silk. They then clutch the resulting egg sacs with their mouthparts and carry them around (a behavior common among all cellar spiders). Eggs that somehow fall from the loose bundles do not hatch. The females still feed during this period, setting their burdens aside temporarily while they eat, then picking them up again. They also frequently adjust their grip. Instances of females eating some of their own eggs have been recorded. It is assumed that they only consume the infertile ones, as unfertilized eggs occur at high enough rates among C. lyoni.
5 to 54 spiderlings will eventually hatch from the eggs, 11 to 13 days after egg-laying. Spiderlings do not leave the eggs immediately. They hatch partially, but otherwise remain in the bundle their mothers carry for at least a day. They eventually leave it completely. They remain mostly inactive for 2 to 3 days after hatching until their first molt
. Spiderlings which are separated from their mothers mature more rapidly than those which remained nearby. They become adults approximately 80 days after hatching. C. lyoni has a lifespan of at least 194 days (around 6 and a half months).
C. lyoni are active hunters. Hanging upside down, they will quickly capture prey caught in their irregular cobweb
-like webs. If hungry enough, they also actively pursue prey that fly close to their webs. They do not use their fangs when hunting, throwing silk over prey instead and then wrapping them loosely using their hind legs. They will only bite them when they start to feed, which can sometimes be as long as six days after capture. They also actively clean their webs by removing carcasses regularly. When webs become too dirty, they build new ones.
Newly hatched spiderlings are just as active as adults. 2 to 4 days after their first molt, spiderlings can already overpower mosquitoes four times their own size. Spiderlings may share prey they caught themselves or prey caught by their mother. They may also engage in cannibalism
by preying on their own siblings.
C. lyoni, like other cellar spiders, will violently gyrate their bodies in small circles when threatened. They can do this very rapidly, blurring their outline and making them very difficult to see. This behavior earned cellar spiders one of their common names - 'vibrating spiders' - and is presumed to be an antipredator adaptation. If this does not work, they will drop from their webs to the ground, or flee awkwardly with their characteristic long-legged gait.
, preferring to live inside or near human-made structures. They usually build large irregular webs in corners of rooms, basements, cellars, and beneath ceilings. They are readily transported by human activity, especially as hitchikers in ships. As a result, C.lyoni has been introduced to most of the world, including Australia
, Asia
, Africa
, Europe
, North
and South America
, and some Pacific islands
.
Their place of origin is unknown but have been variously posited to be Africa (where their genus has the highest diversity) or somewhere in Asia.
in several countries.
While doing no appreciable damage to humans, they are sometimes regarded as pest
s due to the large amounts of unattractive webs they construct inside houses. Unlike most spiders which consume their old webs before building new ones, cellar spiders simply abandon their old webs. There are often hundreds of individuals representing different generations living in close proximity to each other in a given area.
Methods of controlling them can be as direct as simply using a broom
or a vacuum cleaner
to remove the webs. Preventive measures mostly focus on reducing the amounts of insect prey around the house. This includes changing exterior white lights to yellow or sodium vapor lights, colors which are less attractive to insects. Sealing small entry points can also prevent both insect and spider access into the house. Insecticide
s can also be used, but is usually only effective for a relatively short amount of time.
Some people regard C. lyoni spiders as beneficial. Adult C. lyoni can consume 12 to 20 mosquito
es (Aedes
sp.) a day, in addition to other insect pests. Their effects on containing the populations of mosquitoes (Aedes, Anopheles
, Culex
, etc.) and other disease-transmitting arthropod
s harmful to humans seems to be significant. In areas where mosquito-borne diseases (like dengue fever
) are present, it is recommended to avoid removing natural populations of C. lyoni. Studies have also shown that C. lyoni spiders that eat dengue virus
-infected mosquitoes do not seem to acquire the virus themselves.
A study in 2009 showed that the web
s of C. lyoni exhibit antibacterial properties
against Escherichia coli
, Pseudomonas aeruginosa
, Staphylococcus aureus
and others. Gram-positive bacteria were more vulnerable to the proteins from C. lyoni webs than Gram-negative bacteria.
C. lyoni and other pholcids are often the subject of a popular urban legend
about how they are the most venomous known animals except that 'their fangs are too small to penetrate human skin'. While they do possess potent venom
against insects and other spiders (some cellar spiders, for example, prey on deadly redback spiders in Australia
), their venom is not harmful to humans.
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 cellar spiders that prefer to live in or around human structures
Synanthrope
Synanthropes is a term applied to species of wild animals and plants of various kinds that live near, and benefit from, an association with humans and the somewhat artificial habitats that humans create around them . Those habitats include houses, gardens, farms, roadsides, garbage dumps, and so on...
. They are commonly known as tailed cellar spiders, tailed daddy longlegs spiders, and sometimes box spiders. They all possess extremely long fragile legs that can reach up to 6 cm (2.4 in) long and a body length of that ranges from 2.5 to 7 mm (0.0984251968503937 to 0.275590551181102 in). Their abdomens are distinctly squarish when viewed from the side and their carapace is more or less circular when viewed from above. They also possess two kinds of sound-producing organs and have six eyes.
The original range
Range (biology)
In biology, the range or distribution of a species is the geographical area within which that species can be found. Within that range, dispersion is variation in local density.The term is often qualified:...
of C. lyoni is unknown. They have been introduced
Introduced species
An introduced species — or neozoon, alien, exotic, non-indigenous, or non-native species, or simply an introduction, is a species living outside its indigenous or native distributional range, and has arrived in an ecosystem or plant community by human activity, either deliberate or accidental...
into other parts of the world accidentally and are now pantropical
Pantropical
In biogeography, a pantropical distribution one which covers tropical regions of all of the major continents, i.e. in Africa, in Asia and in the Americas. Examples include the plant genera Acacia and Bacopa....
in distribution. They are a regulated species
Invasive species
"Invasive species", or invasive exotics, is a nomenclature term and categorization phrase used for flora and fauna, and for specific restoration-preservation processes in native habitats, with several definitions....
in some countries and are often regarded as pests due to the large amounts of unsightly web
Spider web
A spider web, spiderweb, spider's web or cobweb is a device built by a spider out of proteinaceous spider silk extruded from its spinnerets....
s they construct inside human homes. Some people, however, regard them as beneficial, as they are efficient predators of mosquito
Mosquito
Mosquitoes are members of a family of nematocerid flies: the Culicidae . The word Mosquito is from the Spanish and Portuguese for little fly...
es and other arthropod
Arthropod
An arthropod is an invertebrate animal having an exoskeleton , a segmented body, and jointed appendages. Arthropods are members of the phylum Arthropoda , and include the insects, arachnids, crustaceans, and others...
s. They are harmless to humans.
Taxonomy and nomenclature
Crossopriza lyoni are classified under the genusGenus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
Crossopriza
Crossopriza
Crossopriza is a genus of cellar spiders classified under the subfamily Holocneminae, family Pholcidae.It contains the following species:* Crossopriza cylindrogaster Simon, 1907 — West Africa...
and the subfamily Holocneminae
Holocneminae
Holocneminae is a subfamily of cellar spiders .It contains the following genera:*Artema Walckenaer, 1837*Aymaria Huber, 2000*Cenemus Saaristo, 2001*Ceratopholcus Spassky, 1934*Crossopriza Simon, 1893...
. They belong to the cellar spider family (Pholcidae). They are commonly referred to as tailed daddy longlegs spiders, tailed cellar spiders, or (more rarely) box spiders. C. lyoni and other cellar spiders are also often confused with two other invertebrates - the harvestmen (order
Order (biology)
In scientific classification used in biology, the order is# a taxonomic rank used in the classification of organisms. Other well-known ranks are life, domain, kingdom, phylum, class, family, genus, and species, with order fitting in between class and family...
Opiliones
Opiliones
Opiliones are an order of arachnids commonly known as harvestmen. , over 6,400 species of harvestmen have been discovered worldwide, although the real number of extant species may exceed 10,000. The order Opiliones can be divided into four suborders: Cyphophthalmi, Eupnoi, Dyspnoi and Laniatores...
) and the crane flies (family Tipulidae) - both of which are also known as 'daddy longlegs
Daddy longlegs
-Biology:* Opiliones, an order of arachnids also commonly known as harvestmen* Crane fly, winged insects belonging to the family Tipulidae* Pholcidae, a family of spiders also commonly known as cellar spiders...
'. However, they are not closely related to cellar spiders — the latter is a fly
Diptera
Diptera , or true flies, is the order of insects possessing only a single pair of wings on the mesothorax; the metathorax bears a pair of drumstick like structures called the halteres, the remnants of the hind wings. It is a large order, containing an estimated 240,000 species, although under half...
; and the former, while also an arachnid, is not a spider
Spider
Spiders are air-breathing arthropods that have eight legs, and chelicerae with fangs that inject venom. They are the largest order of arachnids and rank seventh in total species diversity among all other groups of organisms...
at all.
The species was first formally described in 1867 by the British
British people
The British are citizens of the United Kingdom, of the Isle of Man, any of the Channel Islands, or of any of the British overseas territories, and their descendants...
naturalist
Naturalist
Naturalist may refer to:* Practitioner of natural history* Conservationist* Advocate of naturalism * Naturalist , autobiography-See also:* The American Naturalist, periodical* Naturalism...
John Blackwall
John Blackwall
John Blackwall was a British naturalist.Blackwall lived at Hendre House near Llanrwst in north Wales from 1833 until his death...
from a collection of spiders from Meerut, Agra
Agra
Agra a.k.a. Akbarabad is a city on the banks of the river Yamuna in the northern state of Uttar Pradesh, India, west of state capital, Lucknow and south from national capital New Delhi. With a population of 1,686,976 , it is one of the most populous cities in Uttar Pradesh and the 19th most...
, and Delhi
Delhi
Delhi , officially National Capital Territory of Delhi , is the largest metropolis by area and the second-largest by population in India, next to Mumbai. It is the eighth largest metropolis in the world by population with 16,753,265 inhabitants in the Territory at the 2011 Census...
. They came from Francis Lyon, a captain of the Royal Artillery
Royal Artillery
The Royal Regiment of Artillery, commonly referred to as the Royal Artillery , is the artillery arm of the British Army. Despite its name, it comprises a number of regiments.-History:...
of the British Empire
British Empire
The British Empire comprised the dominions, colonies, protectorates, mandates and other territories ruled or administered by the United Kingdom. It originated with the overseas colonies and trading posts established by England in the late 16th and early 17th centuries. At its height, it was the...
stationed in India
India
India , officially the Republic of India , is a country in South Asia. It is the seventh-largest country by geographical area, the second-most populous country with over 1.2 billion people, and the most populous democracy in the world...
. They were sent to his sister who presented them to Blackwall at the suggestion of a mutual friend. Blackwall named the spider after Captain Lyon and expressed a hope that others may follow Lyon's example in collecting specimens from foreign countries for the benefit of science. He classified the species under the genus Pholcus
Pholcus
The spider genus Pholcus contains the Daddy long-legs spider P. phalangioides.Confusion often arises because the name "Daddy longlegs" is also applied to two other unrelated arthropods: the Harvestman and the Crane Fly....
. In 1892, the French
French people
The French are a nation that share a common French culture and speak the French language as a mother tongue. Historically, the French population are descended from peoples of Celtic, Latin and Germanic origin, and are today a mixture of several ethnic groups...
arachnologist Eugène Simon
Eugène Simon
Eugène Simon was a French arachnologist. His many taxonomic contributions include categorizing and naming many spiders, as well as creating genera such as Anelosimus, Psellocoptus and Phlogius....
erected the genus Crossopriza
Crossopriza
Crossopriza is a genus of cellar spiders classified under the subfamily Holocneminae, family Pholcidae.It contains the following species:* Crossopriza cylindrogaster Simon, 1907 — West Africa...
and subsequently reclassified Pholcus lyoni to Crossopriza lyoni.
Blackwall also described a curious case of hermaphroditism in one adult specimen, in which the left side was male and the right side was female.
Description
C. lyoni are sexually dimorphicSexual dimorphism
Sexual dimorphism is a phenotypic difference between males and females of the same species. Examples of such differences include differences in morphology, ornamentation, and behavior.-Examples:-Ornamentation / coloration:...
. Females of C. lyoni are about 3 to 7 mm (0.118110236220472 to 0.275590551181102 in) in length. Males are slightly smaller, at about 2.5 to 6 mm (0.0984251968503937 to 0.236220472440945 in) in length, and have prominent pedipalp
Pedipalp
Pedipalps , are the second pair of appendages of the prosoma in the subphylum Chelicerata. They are traditionally thought to be homologous with mandibles in Crustacea and insects, although more recent studies Pedipalps (commonly shortened to palps or palpi), are the second pair of appendages of the...
s. Both sexes possess extremely long fragile legs. Males have slightly longer legs than females. The first pair of legs in larger male individuals can can reach up to 6 centimetres (2.4 in) in length. The legs are gray to amber in color and covered with numerous small longitudinal brown spots. The 'knee joints' are brown, and the ends of the femur and tibiae are girdled with white. Males also possess a series of 20 to 25 spines (macrosetae
Seta
Seta is a biological term derived from the Latin word for "bristle". It refers to a number of different bristle- or hair-like structures on living organisms.-Animal setae:In zoology, most "setae" occur in invertebrates....
) on their femur. Their leg formula is I,II,IV,III - the front pair of legs being the longest and the third pair being the shortest.
The cephalothorax
Cephalothorax
The cephalothorax is a tagma of various arthropods, comprising the head and the thorax fused together, as distinct from the abdomen behind. The word cephalothorax is derived from the Greek words for head and thorax...
is wider than it is long, greyish-white to pale amber in color. The carapace is subcircular. In the middle of the upper surface is a deep depression (called the thoracic fovea) and a darker longitudinal band of color. C. lyoni, like some other cellar spiders, only have six eyes. They are pearly-white in color and located at the tip of the cephalothorax in two groups of three.
The abdomen (the opisthosoma
Opisthosoma
The opisthosoma is the posterior part of the body in some arthropods, behind the prosoma . It is a distinctive feature of the subphylum Chelicerata...
) is gray with white lateral stripes and various dark and light patches on the sides and the upper surface. An irregular darker stripe runs lengthwise at the bottom surface. The abdomen is angular and somewhat box-shaped, with a small conical hump on the upper back.
They also possess two types of stridulatory organs. The first type is located at the posterior tips of their cephalothorax (the prosoma) in the form of two triangular protrusions. The spiders rub these structures with a matching pair of sclerotized
Sclerite
A sclerite is a hardened body part. The term is used in various branches of biology for various structures including hardened portions of sponges, but it is most commonly used for the hardened portions of arthropod exoskeletons....
plates at the anterior portion of the abdomen, producing sound. These structures are more prominent in females. They also possess stridulatory files (in the form of a series of small ridges) on their chelicerae which are rubbed against the pedipalps to produce sound. The second type is more prominent in males.
C. lyoni can be distinguished from other members of the genus through several ways: by the characteristic boxy shape of their abdomens (C. cylindrogaster has a cylindrical abdomen); by the presence of two apophyses (jutting structures) in the chelicerae of males (C. pristina, C. semicaudata, and C. soudanensis all possess only one apophysis on each chelicera); or simply by geographic distribution (C. lyoni can be found globally and is the only species of Crossopriza in the New World
New World
The New World is one of the names used for the Western Hemisphere, specifically America and sometimes Oceania . The term originated in the late 15th century, when America had been recently discovered by European explorers, expanding the geographical horizon of the people of the European middle...
, while the other species like C. johncloudsleyi and C. nigrescens are restricted to Africa
Africa
Africa is the world's second largest and second most populous continent, after Asia. At about 30.2 million km² including adjacent islands, it covers 6% of the Earth's total surface area and 20.4% of the total land area...
or the Middle East
Middle East
The Middle East is a region that encompasses Western Asia and Northern Africa. It is often used as a synonym for Near East, in opposition to Far East...
).
Ecology and life cycle
A single male C. lyoni is able to copulate with several females. Mating is accomplished with the male inserting both his pedipalps into the genital orifice of the female and transferring a previously prepared packet of sperm into her spermathecaSpermatheca
The spermatheca , also called receptaculum seminis , is an organ of the female reproductive tract in insects, some molluscs, oligochaeta worms and certain other invertebrates and vertebrates...
e. Because of the relative shortness of the male pedipalps in comparison to the sheer length of the legs of both males and females of the species, the spiders have to bring their bodies close together, giving the impression of 'snuggling'. This lasts for about 40 minutes. In rare instances, females may eat the males
Spider cannibalism
Spider cannibalism is a special case of cannibalism in which a female spider kills and eats a male of the same species before, during, or after copulation. Rarely, these roles are reversed...
after copulation.
The eggs are deposited by the females 5–6 days after copulation. After laying the eggs, females will bind them into a ball with tiny amounts of silk. They then clutch the resulting egg sacs with their mouthparts and carry them around (a behavior common among all cellar spiders). Eggs that somehow fall from the loose bundles do not hatch. The females still feed during this period, setting their burdens aside temporarily while they eat, then picking them up again. They also frequently adjust their grip. Instances of females eating some of their own eggs have been recorded. It is assumed that they only consume the infertile ones, as unfertilized eggs occur at high enough rates among C. lyoni.
5 to 54 spiderlings will eventually hatch from the eggs, 11 to 13 days after egg-laying. Spiderlings do not leave the eggs immediately. They hatch partially, but otherwise remain in the bundle their mothers carry for at least a day. They eventually leave it completely. They remain mostly inactive for 2 to 3 days after hatching until their first molt
Ecdysis
Ecdysis is the moulting of the cuticula in many invertebrates. This process of moulting is the defining feature of the clade Ecdysozoa, comprising the arthropods, nematodes, velvet worms, horsehair worms, rotifers, tardigrades and Cephalorhyncha...
. Spiderlings which are separated from their mothers mature more rapidly than those which remained nearby. They become adults approximately 80 days after hatching. C. lyoni has a lifespan of at least 194 days (around 6 and a half months).
C. lyoni are active hunters. Hanging upside down, they will quickly capture prey caught in their irregular cobweb
Cobweb
-Animals:* Cobweb or spider web, silken web made by spiders* Cobweb spider or tangle web spider, any of the many spiders in the family Theridiidae* Cobwebbing, a pattern of fine lines on the face of a horse, zebra or other equid: see horse Primitive markings...
-like webs. If hungry enough, they also actively pursue prey that fly close to their webs. They do not use their fangs when hunting, throwing silk over prey instead and then wrapping them loosely using their hind legs. They will only bite them when they start to feed, which can sometimes be as long as six days after capture. They also actively clean their webs by removing carcasses regularly. When webs become too dirty, they build new ones.
Newly hatched spiderlings are just as active as adults. 2 to 4 days after their first molt, spiderlings can already overpower mosquitoes four times their own size. Spiderlings may share prey they caught themselves or prey caught by their mother. They may also engage in cannibalism
Cannibalism (zoology)
In zoology, cannibalism is the act of one individual of a species consuming all or part of another individual of the same species as food. Cannibalism is a common ecological interaction in the animal kingdom and has been recorded for more than 1500 species...
by preying on their own siblings.
C. lyoni, like other cellar spiders, will violently gyrate their bodies in small circles when threatened. They can do this very rapidly, blurring their outline and making them very difficult to see. This behavior earned cellar spiders one of their common names - 'vibrating spiders' - and is presumed to be an antipredator adaptation. If this does not work, they will drop from their webs to the ground, or flee awkwardly with their characteristic long-legged gait.
Distribution and habitat
C. lyoni are synanthropicSynanthrope
Synanthropes is a term applied to species of wild animals and plants of various kinds that live near, and benefit from, an association with humans and the somewhat artificial habitats that humans create around them . Those habitats include houses, gardens, farms, roadsides, garbage dumps, and so on...
, preferring to live inside or near human-made structures. They usually build large irregular webs in corners of rooms, basements, cellars, and beneath ceilings. They are readily transported by human activity, especially as hitchikers in ships. As a result, C.lyoni has been introduced to most of the world, including Australia
Australia
Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...
, 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...
, Africa
Africa
Africa is the world's second largest and second most populous continent, after Asia. At about 30.2 million km² including adjacent islands, it covers 6% of the Earth's total surface area and 20.4% of the total land area...
, Europe
Europe
Europe is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally 'divided' from Asia to its east by the watershed divides of the Ural and Caucasus Mountains, the Ural River, the Caspian and Black Seas, and the waterways connecting...
, North
North America
North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...
and South America
South America
South America is a continent situated in the Western Hemisphere, mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere. The continent is also considered a subcontinent of the Americas. It is bordered on the west by the Pacific Ocean and on the north and east...
, and some Pacific islands
Pacific Islands
The Pacific Islands comprise 20,000 to 30,000 islands in the Pacific Ocean. The islands are also sometimes collectively called Oceania, although Oceania is sometimes defined as also including Australasia and the Malay Archipelago....
.
Their place of origin is unknown but have been variously posited to be Africa (where their genus has the highest diversity) or somewhere in Asia.
Relations with humans
C. lyoni are a regulated invasive speciesInvasive species
"Invasive species", or invasive exotics, is a nomenclature term and categorization phrase used for flora and fauna, and for specific restoration-preservation processes in native habitats, with several definitions....
in several countries.
While doing no appreciable damage to humans, they are sometimes regarded as pest
Pest
Pest may refer to:*Pest , an animal or plant detrimental to humans or human concerns*Pest, an archaic term for pestilence, originally the Black Death*Pest , an ice hockey player specialising in aggravating opponents...
s due to the large amounts of unattractive webs they construct inside houses. Unlike most spiders which consume their old webs before building new ones, cellar spiders simply abandon their old webs. There are often hundreds of individuals representing different generations living in close proximity to each other in a given area.
Methods of controlling them can be as direct as simply using a broom
Broom
A broom is a cleaning tool consisting of stiff fibers attached to, and roughly parallel to, a cylindrical handle, the broomstick. It is thus a variety of brush with a long handle. It is commonly used in combination with a dustpan....
or a vacuum cleaner
Vacuum cleaner
A vacuum cleaner, commonly referred to as a "vacuum," is a device that uses an air pump to create a partial vacuum to suck up dust and dirt, usually from floors, and optionally from other surfaces as well. The dirt is collected by either a dustbag or a cyclone for later disposal...
to remove the webs. Preventive measures mostly focus on reducing the amounts of insect prey around the house. This includes changing exterior white lights to yellow or sodium vapor lights, colors which are less attractive to insects. Sealing small entry points can also prevent both insect and spider access into the house. Insecticide
Insecticide
An insecticide is a pesticide used against insects. They include ovicides and larvicides used against the eggs and larvae of insects respectively. Insecticides are used in agriculture, medicine, industry and the household. The use of insecticides is believed to be one of the major factors behind...
s can also be used, but is usually only effective for a relatively short amount of time.
Some people regard C. lyoni spiders as beneficial. Adult C. lyoni can consume 12 to 20 mosquito
Mosquito
Mosquitoes are members of a family of nematocerid flies: the Culicidae . The word Mosquito is from the Spanish and Portuguese for little fly...
es (Aedes
Aedes
Aedes is a genus of mosquito originally found in tropical and subtropical zones, but now found on all continents excluding Antarctica. Some species have been spread by human activity. Aedes albopictus, a most invasive species was recently spread to the New World, including the U.S., by the used...
sp.) a day, in addition to other insect pests. Their effects on containing the populations of mosquitoes (Aedes, Anopheles
Anopheles
Anopheles is a genus of mosquito. There are approximately 460 recognized species: while over 100 can transmit human malaria, only 30–40 commonly transmit parasites of the genus Plasmodium, which cause malaria in humans in endemic areas...
, Culex
Culex
Culex is a genus of mosquito, and is important in that several species serve as vectors of important diseases, such as West Nile virus, filariasis, Japanese encephalitis, St. Louis encephalitis and avian malaria....
, etc.) and other disease-transmitting arthropod
Arthropod
An arthropod is an invertebrate animal having an exoskeleton , a segmented body, and jointed appendages. Arthropods are members of the phylum Arthropoda , and include the insects, arachnids, crustaceans, and others...
s harmful to humans seems to be significant. In areas where mosquito-borne diseases (like dengue fever
Dengue fever
Dengue fever , also known as breakbone fever, is an infectious tropical disease caused by the dengue virus. Symptoms include fever, headache, muscle and joint pains, and a characteristic skin rash that is similar to measles...
) are present, it is recommended to avoid removing natural populations of C. lyoni. Studies have also shown that C. lyoni spiders that eat dengue virus
Dengue virus
Dengue virus in one of four serotypes is the cause of dengue fever. It is a mosquito-borne single positive-stranded RNA virus of the family Flaviviridae; genus Flavivirus...
-infected mosquitoes do not seem to acquire the virus themselves.
A study in 2009 showed that the web
Spider web
A spider web, spiderweb, spider's web or cobweb is a device built by a spider out of proteinaceous spider silk extruded from its spinnerets....
s of C. lyoni exhibit antibacterial properties
Antibacterial activity
The shelf life of a product can be extended either by adding artificial preservatives or by taking hygienic measures during the manufacturing process. As the consumer trend today is towards preservative-free foods with a long shelf-life, industry is being forced to rethink its manufacturing methods...
against Escherichia coli
Escherichia coli
Escherichia coli is a Gram-negative, rod-shaped bacterium that is commonly found in the lower intestine of warm-blooded organisms . Most E. coli strains are harmless, but some serotypes can cause serious food poisoning in humans, and are occasionally responsible for product recalls...
, Pseudomonas aeruginosa
Pseudomonas aeruginosa
Pseudomonas aeruginosa is a common bacterium that can cause disease in animals, including humans. It is found in soil, water, skin flora, and most man-made environments throughout the world. It thrives not only in normal atmospheres, but also in hypoxic atmospheres, and has, thus, colonized many...
, Staphylococcus aureus
Staphylococcus aureus
Staphylococcus aureus is a facultative anaerobic Gram-positive coccal bacterium. It is frequently found as part of the normal skin flora on the skin and nasal passages. It is estimated that 20% of the human population are long-term carriers of S. aureus. S. aureus is the most common species of...
and others. Gram-positive bacteria were more vulnerable to the proteins from C. lyoni webs than Gram-negative bacteria.
C. lyoni and other pholcids are often the subject of a popular urban legend
Urban legend
An urban legend, urban myth, urban tale, or contemporary legend, is a form of modern folklore consisting of stories that may or may not have been believed by their tellers to be true...
about how they are the most venomous known animals except that 'their fangs are too small to penetrate human skin'. While they do possess potent venom
Venom
Venom is the general term referring to any variety of toxins used by certain types of animals that inject it into their victims by the means of a bite or a sting...
against insects and other spiders (some cellar spiders, for example, prey on deadly redback spiders in Australia
Australia
Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...
), their venom is not harmful to humans.
See also
- List of Pholcidae species
- Pholcus phalangioidesPholcus phalangioidesThe cellar spider or daddy longlegs , also known as the skull spider due to its cephalothorax looking like a human skull, is a spider of the family Pholcidae. Females have a body length of about 9 mm; males are slightly smaller. Its legs are about 5 or 6 times the length of its body...
, another widespread synanthropic cellar spider - Spider cannibalismSpider cannibalismSpider cannibalism is a special case of cannibalism in which a female spider kills and eats a male of the same species before, during, or after copulation. Rarely, these roles are reversed...
External links
- Pholcidae - the longest legs in the web maintained by Bernard A. Huber and the University of BonnUniversity of BonnThe University of Bonn is a public research university located in Bonn, Germany. Founded in its present form in 1818, as the linear successor of earlier academic institutions, the University of Bonn is today one of the leading universities in Germany. The University of Bonn offers a large number...
- Pholcidae ~ Cellar Spiders from Valerie's Austin Bug Collection