Latrodectus hesperus
Encyclopedia
Latrodectus hesperus, the Western black widow spider
or Western widow, is a venomous spider species found in western regions of North America
. The female's body is 14–16 millimeters in length and is black, often with an hourglass
shaped red mark on the lower abdomen. This "hourglass" mark can be yellow, and on rare occasions, white. The male of the species is around half this size and generally a tan color with lighter striping on the abdomen. The population was previously described as a subspecies of Latrodectus mactans and it is closely related to the northern species Latrodectus variolus
. The species, as with others of the genus, build irregular webs.
The female's consumption of the male after courtship, a cannibalistic
and suicidal behaviour observed in Latrodectus hasseltii (Australia's redback),
is rare in this species. Male Western widows may breed several times during their relatively short lifespans.
The ultimate strength and other physical properties of Latrodectus hesperus silk were found to be similar to the properties of silk from orb weaving spiders that had been tested in other studies. The ultimate strength for the three kinds of silk measured in the Blackledge study was about 1000 MPa
. The ultimate strength reported in a previous study for Nephila edulis
was 1290 MPa ± 160 MPa
Black widow spider
Latrodectus mactans, the Southern black widow, is a highly venomous species of spider in the genus Latrodectus. They are well known for the distinctive black and red coloring of the female of the species and for the fact that she will occasionally eat her mate after reproduction. The species is...
or Western widow, is a venomous spider species found in western regions of North America
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...
. The female's body is 14–16 millimeters in length and is black, often with an hourglass
Hourglass
An hourglass measures the passage of a few minutes or an hour of time. It has two connected vertical glass bulbs allowing a regulated trickle of material from the top to the bottom. Once the top bulb is empty, it can be inverted to begin timing again. The name hourglass comes from historically...
shaped red mark on the lower abdomen. This "hourglass" mark can be yellow, and on rare occasions, white. The male of the species is around half this size and generally a tan color with lighter striping on the abdomen. The population was previously described as a subspecies of Latrodectus mactans and it is closely related to the northern species Latrodectus variolus
Latrodectus variolus
Latrodectus variolus, the Northern black widow spider or Northern widow, is a venomous spider species of the Latrodectus genus in the Theridiidae family...
. The species, as with others of the genus, build irregular webs.
The female's consumption of the male after courtship, a cannibalistic
Cannibalism
Cannibalism is the act or practice of humans eating the flesh of other human beings. It is also called anthropophagy...
and suicidal behaviour observed in Latrodectus hasseltii (Australia's redback),
is rare in this species. Male Western widows may breed several times during their relatively short lifespans.
The ultimate strength and other physical properties of Latrodectus hesperus silk were found to be similar to the properties of silk from orb weaving spiders that had been tested in other studies. The ultimate strength for the three kinds of silk measured in the Blackledge study was about 1000 MPa
Pascal (unit)
The pascal is the SI derived unit of pressure, internal pressure, stress, Young's modulus and tensile strength, named after the French mathematician, physicist, inventor, writer, and philosopher Blaise Pascal. It is a measure of force per unit area, defined as one newton per square metre...
. The ultimate strength reported in a previous study for Nephila edulis
Nephila edulis
Nephila edulis is a species of large spider of the Nephilidae family. It is referred to the common name edible golden silk spider or golden silk orb-weaver...
was 1290 MPa ± 160 MPa