Bolas spiders
Encyclopedia
Bolas Spiders are unusual orb-weaver spiders that do not spin the typical web
. Instead, they hunt by using a sticky 'capture blob' of silk
on the end of a line, known as a 'bolas
'. By swinging the bolas at flying male moths
or moth flies nearby, the spider may snag its prey rather like a fisherman snagging a fish on a hook. Because of this, they are also called angling or fishing spider (although the remotely related genus Dolomedes
is also called fishing spider). The prey is lured to the spider by the production of up to three pheromone
-analogues.
Traditional orb webs are not effective for capturing moths, because only their scales will stick, allowing the moth to escape. The ladder webs of Scoloderus
species appear to be adaptations in web design to increase moth capture. These webs extend vertically about seven times their width. When a moth slides down the web, it leaves a trail of scales until its body sticks to the web. However, these spiders do not seem to be closely related to bolas spiders. The nearest relatives seems to be the Cyrtarachneae (e.g. Pasilobus) of the Paleotropics. They also specialize on moths, and use threads that are beaded with sticky droplets. Celaenia
and Taczanowskia species in South America seem to use chemical attractants to catch moths, too, and may also be closely related to bolas spiders.
At least four Mastiphora species are known to sometimes, instead of preparing a single bola, to hang up to nine droplets on one horizontal line. This has not been observed to result in prey capture, but is remarkably similar to the midline of a Pasilobus web in which the low-shear joints of spanning threads have been broken.
Interestingly, the not closely related araneid genus Kaira uses a pheromone very similar to Mastiphora to catch moths, however it does not use a bola, but instead catches the insects with a basket formed from its legs.
.
About half of the known Mastophora species occur in South America
. The genus is distributed from southern Chile
to the extreme northern US (to 45° north latitude in Minnesota
). M. archeri, M. bisaccata, M. hutchinsoni and M. phrynosoma occur widely in the US east of the Great Plains
. M. cornigera occurs from Alabama
to California
, as well as in northern Mexico
.
Spiderlings and adult males hunt without a bola. This might be because the small globule these spiders could produce would dry out rapidly. Rather, they position themselves at edges of leaves and grab prey with their frontal pair of legs. Moth flies of the genus Psychoda are prominent prey in juvenile and adult male Mastophora. Adult spiders consume the bola after at most half an hour if the hunt was fruitless.
Female Mastophora catch an average of two moths per night, but as many as six or seven catches during a single night have been observed.
. A study by K.F. Haynes (University of Kentucky
) showed that the spider adapts to the change in prey availability: One prey species flies from the early evening until 10:30pm, the other only after 11:00pm. The first moth ignores the pheromone of the second, so the spider produces a mix of both pheromones early in the evening. However, since the second moth is repulsed by the other moth's pheromone, the spider ceases to produce the first pheromone later at night.
Males emerge as reproductively capable adults.
has been reared from eggs of the same species. Five species of hymenopteran parasitoids are known to attack Mastiphora eggs. Tromatobia notator parasitizes M. cornigera, M. bisaccata and M. phrynosoma; Gelis sp. parasitizes M. cornigera. The eupelmids Arachnophaga abstrusa, A. ferruginea and A. picea parasitize Mastophora species, M. hutchinsoni and M. cornigera, respectively.
Mastophora Holmberg, 1876
Ordgarius
Keyserling, 1886
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....
. Instead, they hunt by using a sticky 'capture blob' of silk
Spider silk
Spider silk is a protein fiber spun by spiders. Spiders use their silk to make webs or other structures, which function as nets to catch other animals, or as nests or cocoons for protection for their offspring...
on the end of a line, known as a 'bolas
Bolas
Bolas are a throwing weapon superficially similar to the surujin, made of weights on the ends of interconnected cords, designed to capture animals by entangling their legs...
'. By swinging the bolas at flying male moths
Moths
Moths may refer to:* Gustav Moths , German rower* The Moths!, an English indie rock band* MOTHS, members of the Memorable Order of Tin Hats...
or moth flies nearby, the spider may snag its prey rather like a fisherman snagging a fish on a hook. Because of this, they are also called angling or fishing spider (although the remotely related genus Dolomedes
Dolomedes
Dolomedes is a genus of large spiders of the family Pisauridae. They are also known as fishing spiders, raft spiders, dock spiders or wharf spiders. Almost all Dolomedes species are semi-aquatic, with the exception of the tree-dwelling D. albineus of the southwestern United States...
is also called fishing spider). The prey is lured to the spider by the production of up to three pheromone
Pheromone
A pheromone is a secreted or excreted chemical factor that triggers a social response in members of the same species. Pheromones are chemicals capable of acting outside the body of the secreting individual to impact the behavior of the receiving individual...
-analogues.
Description
Bolas spiders are small nocturnal animals (females up to 15 mm or 1/2", males about 2 mm or 1/16") with oddly 'lumpy' abdomens. Several Mastophora species (e.g. M. cornigera) look like bird droppings, which enables them to rest unnoticed at day in fairly exposed places. M. bisaccata resembles the shell of a snail that is abundant in the spider's habitat. While the bird dropping mimics rest on the upper surface of leaves, M. bisaccata rests on the undersides. If removed from the surface, Mastophora females produce a pungent odor, which is highly unusual for spiders (other than bolas spiders, only one species of Cyrtarachne is known to do this). They do not attempt to flee when handled. Some species of Cladomelea also rest exposed on leaves during the day. However, the Australian Ordgarius magnificus, which displays eye spots on its back that make it resemble the moth they hunt, ties leaves together with silk to form a retreat. The females of some bolas spiders look remarkably like a bird dropping, thanks to their large, globular abdomen and brownish cephalothorax. This is a form of defensive mimicry as the animals that prey on spiders pay little attention to bird droppings.Systematics
Bolas spiders are species of three related genera:- Mastophora (American Bolas, 48 species)
- Cladomelea (African Bolas, 4 species)
- OrdgariusOrdgariusOrdgarius is a genus of Australasian bolas spiders in the family Araneidae. Ordgar or Ordgarius is also an Anglo-Saxon masculine personal name .-Species:...
(Australasian Bolas, 12 species)
Traditional orb webs are not effective for capturing moths, because only their scales will stick, allowing the moth to escape. The ladder webs of Scoloderus
Scoloderus
Scoloderus is a genus of orb-weaving spider of the family Araneidae which feed largely on nocturnal moths. Scoloderus spiders make a "ladder" type nest with vertical extensions of sticky orbs above and below the circumference of the primary orb. When a moth strikes the web, it slides down the...
species appear to be adaptations in web design to increase moth capture. These webs extend vertically about seven times their width. When a moth slides down the web, it leaves a trail of scales until its body sticks to the web. However, these spiders do not seem to be closely related to bolas spiders. The nearest relatives seems to be the Cyrtarachneae (e.g. Pasilobus) of the Paleotropics. They also specialize on moths, and use threads that are beaded with sticky droplets. Celaenia
Celaenia
Celaenia is a spider genus in the family Araneidae.-Species:* Celaenia atkinsoni — Australia, Tasmania, New Zealand* Celaenia calotoides Rainbow, 1908 — New South Wales...
and Taczanowskia species in South America seem to use chemical attractants to catch moths, too, and may also be closely related to bolas spiders.
At least four Mastiphora species are known to sometimes, instead of preparing a single bola, to hang up to nine droplets on one horizontal line. This has not been observed to result in prey capture, but is remarkably similar to the midline of a Pasilobus web in which the low-shear joints of spanning threads have been broken.
Interestingly, the not closely related araneid genus Kaira uses a pheromone very similar to Mastiphora to catch moths, however it does not use a bola, but instead catches the insects with a basket formed from its legs.
Distribution
Members of this group are found in America, Africa, and Australasia. They do not occur in temperate EurasiaEurasia
Eurasia is a continent or supercontinent comprising the traditional continents of Europe and Asia ; covering about 52,990,000 km2 or about 10.6% of the Earth's surface located primarily in the eastern and northern hemispheres...
.
About half of the known Mastophora species occur in 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...
. The genus is distributed from southern Chile
Chile
Chile ,officially the Republic of Chile , is a country in South America occupying a long, narrow coastal strip between the Andes mountains to the east and the Pacific Ocean to the west. It borders Peru to the north, Bolivia to the northeast, Argentina to the east, and the Drake Passage in the far...
to the extreme northern US (to 45° north latitude in Minnesota
Minnesota
Minnesota is a U.S. state located in the Midwestern United States. The twelfth largest state of the U.S., it is the twenty-first most populous, with 5.3 million residents. Minnesota was carved out of the eastern half of the Minnesota Territory and admitted to the Union as the thirty-second state...
). M. archeri, M. bisaccata, M. hutchinsoni and M. phrynosoma occur widely in the US east of the Great Plains
Great Plains
The Great Plains are a broad expanse of flat land, much of it covered in prairie, steppe and grassland, which lies west of the Mississippi River and east of the Rocky Mountains in the United States and Canada. This area covers parts of the U.S...
. M. cornigera occurs from Alabama
Alabama
Alabama is a state located in the southeastern region of the United States. It is bordered by Tennessee to the north, Georgia to the east, Florida and the Gulf of Mexico to the south, and Mississippi to the west. Alabama ranks 30th in total land area and ranks second in the size of its inland...
to California
California
California is a state located on the West Coast of the United States. It is by far the most populous U.S. state, and the third-largest by land area...
, as well as in northern Mexico
Mexico
The United Mexican States , commonly known as Mexico , is a federal constitutional republic in North America. It is bordered on the north by the United States; on the south and west by the Pacific Ocean; on the southeast by Guatemala, Belize, and the Caribbean Sea; and on the east by the Gulf of...
.
Hunting
Every spider species produces the pheromone of only one specific moth species (or a small set) and is thus dependent on it. However, bola spiders will try and often succeed to catch any insect that is flying nearby, aided by their good eyesight. They also seem to detect prey by the sound of their approaching flight.Spiderlings and adult males hunt without a bola. This might be because the small globule these spiders could produce would dry out rapidly. Rather, they position themselves at edges of leaves and grab prey with their frontal pair of legs. Moth flies of the genus Psychoda are prominent prey in juvenile and adult male Mastophora. Adult spiders consume the bola after at most half an hour if the hunt was fruitless.
Female Mastophora catch an average of two moths per night, but as many as six or seven catches during a single night have been observed.
Mastophora hutchinsoni
The species Mastophora hutchinsoni preys exclusively on the males of a few moth species. Its major prey is Lacinipolia renigeraLacinipolia renigera
The Kidney-spotted Minor or Bristly Cutworm is a species of moth of the Noctuidae family. It is endemic to most of North America with the exception of Yukon and Alaska....
. A study by K.F. Haynes (University of Kentucky
University of Kentucky
The University of Kentucky, also known as UK, is a public co-educational university and is one of the state's two land-grant universities, located in Lexington, Kentucky...
) showed that the spider adapts to the change in prey availability: One prey species flies from the early evening until 10:30pm, the other only after 11:00pm. The first moth ignores the pheromone of the second, so the spider produces a mix of both pheromones early in the evening. However, since the second moth is repulsed by the other moth's pheromone, the spider ceases to produce the first pheromone later at night.
Variations
The manner in which the bolas is swung differ between the three genera. Mastophora holds the bolas stationary with a front leg until a moth approaches, and then cocks the leg and swings the bolas towards the prey with a rapid pendulum-like stroke. Ordgarius begins to whirl the bolas rapidly when detecting an incoming moth. Cladomelea akermani whirls the bolas immediately after it is prepared for about 15 minutes, even when there is no moth present. Ordgarius sometimes has smaller droplets above the terminal one, whereas the other genera produce only one terminal globule.Droplet anatomy
Droplets are about 2.5 mm in diameter. The internal structure is complex, consisting of a mass of curled or folded fibre embedded in a viscid matrix which is in turn surrounded by a less viscous layer. This results in the low viscosity liquid flowing past the moth's scales and reach the cuticle below, while the more viscous liquid forms a bond to the thread to sustain the moth's weight. The folded thread inside the ball permits elastic elongations which extend the spider's striking range.Reproduction
Bolas spiders mate in late summer. In late fall, the female spider attaches several egg-sacs suspended in the vicinity of her retreat; each one is larger than herself and contains a few hundred eggs.Males emerge as reproductively capable adults.
Natural enemies
A gryllacridid was observed feeding on the eggs of O. magnificus, and a sarcophagid parasitoidParasitoid
A parasitoid is an organism that spends a significant portion of its life history attached to or within a single host organism in a relationship that is in essence parasitic; unlike a true parasite, however, it ultimately sterilises or kills, and sometimes consumes, the host...
has been reared from eggs of the same species. Five species of hymenopteran parasitoids are known to attack Mastiphora eggs. Tromatobia notator parasitizes M. cornigera, M. bisaccata and M. phrynosoma; Gelis sp. parasitizes M. cornigera. The eupelmids Arachnophaga abstrusa, A. ferruginea and A. picea parasitize Mastophora species, M. hutchinsoni and M. cornigera, respectively.
Species
Cladomelea Simon, 1895- Cladomelea akermani Hewitt, 1923 (South Africa)
- Cladomelea debeeri Roff & Dippenaar-Schoeman, 2004 (South Africa)
- Cladomelea longipes (O. P.-Cambridge, 1877) (Congo)
- Cladomelea ornata Hirst, 1907 (Central Africa)
Mastophora Holmberg, 1876
- Mastophora abalosi Urtubey & Báez, 1983 (Argentina)
- Mastophora alachua Levi, 2003 (USA)
- Mastophora alvareztoroi Ibarra & Jiménez, 2003 (USA, Mexico)
- Mastophora apalachicola Levi, 2003 (USA)
- Mastophora archeri Gertsch, 1955 (USA)
- Mastophora bisaccata (EmertonJames Henry EmertonJames Henry Emerton was an American arachnologist.-Early life:Emerton was born at Salem, Massachusetts, on March 31, 1847. He was rather frail, and a young helper in his father's drug store, George F. Markoe, interested the boy in outdoor life...
, 1884) (USA, Mexico) - Mastophora brescoviti Levi, 2003 (Brazil)
- Mastophora carpogaster Mello-Leitão, 1925 (Brazil)
- Mastophora catarina Levi, 2003 (Brazil)
- Mastophora comma Báz & Urtubey, 1985 (Argentina)
- Mastophora conifera (Holmberg, 1876) (Argentina)
- Mastophora cornigera (Hentz, 1850) (USA to Nicaragua)
- Mastophora corpulenta (Banks, 1898) (Mexico, Honduras, Nicaragua, Brazil)
- Mastophora corumbatai Levi, 2003 (Brazil)
- Mastophora cranion Mello-Leitão, 1928 (Brazil)
- Mastophora diablo Levi, 2003 (Argentina)
- Mastophora dizzydeaniMastophora dizzydeaniMastophora dizzydeani is a species of spider named after baseball player Dizzy Dean. It uses a sticky ball on the end of a thread of webbing to catch its prey....
Eberhard, 1981 (Colombia, Peru) - Mastophora escomeli Levi, 2003 (Peru)
- Mastophora extraordinaria Holmberg, 1876 (Brazil, Uruguay, Argentina)
- Mastophora fasciata Reimoser, 1939 (Costa Rica, Venezuela)
- Mastophora felda Levi, 2003 (USA)
- Mastophora felis Piza, 1976 (Brazil)
- Mastophora gasteracanthoides (Nicolet, 1849) (Chile)
- Mastophora haywardi Birabén, 1946 (Argentina)
- Mastophora holmbergi Canals, 1931 (Paraguay, Argentina)
- Mastophora hutchinsoni Gertsch, 1955 (USA)
- Mastophora lara Levi, 2003 (Venezuela)
- Mastophora leucabulba (Gertsch, 1955) (USA to Honduras)
- Mastophora leucacantha (Simon, 1897) (Brazil)
- Mastophora longiceps Mello-Leitão, 1940 (Brazil)
- Mastophora melloleitaoi Canals, 1931 (Brazil, Argentina)
- Mastophora obtusa Mello-Leitão, 1936 (Brazil)
- Mastophora pesqueiro Levi, 2003 (Brazil)
- Mastophora phrynosoma Gertsch, 1955 (USA)
- Mastophora pickeli Mello-Leitão, 1931 (Brazil)
- Mastophora piras Levi, 2003 (Brazil)
- Mastophora rabida Levi, 2003 (Galapagos Is.)
- Mastophora reimoseri Levi, 2003 (Paraguay)
- Mastophora satan Canals, 1931 (Brazil, Uruguay, Argentina)
- Mastophora satsuma Levi, 2003 (USA)
- Mastophora seminole Levi, 2003 (USA)
- Mastophora soberiana Levi, 2003 (Panama)
- Mastophora stowei Levi, 2003 (USA)
- Mastophora timuqua Levi, 2003 (USA)
- Mastophora vaquera Gertsch, 1955 (Cuba)
- Mastophora yacare Levi, 2003 (Uruguay)
- Mastophora yeargani Levi, 2003 (USA)
- Mastophora ypiranga Levi, 2003 (Brazil)
Ordgarius
Ordgarius
Ordgarius is a genus of Australasian bolas spiders in the family Araneidae. Ordgar or Ordgarius is also an Anglo-Saxon masculine personal name .-Species:...
Keyserling, 1886
- Ordgarius acanthonotus (Simon, 1909) (Vietnam)
- Ordgarius bicolor Pocock, 1899 (New Britain)
- Ordgarius clypeatus Simon, 1897 (Amboina)
- Ordgarius ephippiatus Thorell, 1898 (Myanmar)
- Ordgarius furcatus (O. P.-Cambridge, 1877) (New South Wales)
- Ordgarius furcatus distinctus (Rainbow, 1900) (New South Wales)
- Ordgarius hexaspinus Saha & Raychaudhuri, 2005 (India)
- Ordgarius hobsoni (O. P.-Cambridge, 1877) (India, Sri Lanka, China, Japan)
- Ordgarius magnificusOrdgarius magnificusOrdgarius magnificus, the Magnificent spider, is a bolas spider in the family Araneidae. It is endemic to forests along the Australian east coast.-Description:Females are up to 14mm long and almost as wide; males reach only 2mm...
(RainbowWilliam Joseph RainbowWilliam Joseph Rainbow was an entomologist and arachnologist whose work includes the first catalogue of Australian spiders.-Life:...
, 1897) (Queensland, New South Wales) - Ordgarius monstrosus Keyserling, 1886 (Queensland)
- Ordgarius pustulosus Thorell, 1897 (Java)
- Ordgarius sexspinosus (Thorell, 1894) (India to Japan, Indonesia)