''Hogna carolinensis'', commonly known as the Carolina wolf spider, is found across
North America
North America is a continent in the Northern Hemisphere and almost entirely within the Western Hemisphere. It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South America and the Car ...
. It is the largest of the
wolf spider
Wolf spiders are members of the family Lycosidae (). They are robust and agile hunters with excellent eyesight. They live mostly in solitude, hunt alone, and do not spin webs. Some are opportunistic hunters, pouncing upon prey as they find it or ...
s in North America,
typically measuring at 18–20 mm for males and 22–35 mm for females.
The Carolina wolf spider is mottled brown with a dark underside. Males have orange coloration on their sides. They live in either self-made burrows or ones they find. Like all wolf spiders, ''H. carolinensis'' does not make a web to catch prey. They hunt by ambushing prey from their burrows. These spiders are particularly known for the females carrying their
egg sac
Spiders ( order Araneae) are air-breathing arthropods that have eight legs, chelicerae with fangs generally able to inject venom, and spinnerets that extrude silk. They are the largest order of arachnids and rank seventh in total species dive ...
s on their bodies during the incubation period. The Carolina wolf spider also has a unique type of
venom
Venom or zootoxin is a type of toxin produced by an animal that is actively delivered through a wound by means of a bite, sting, or similar action. The toxin is delivered through a specially evolved ''venom apparatus'', such as fangs or a sti ...
that both paralyzes their prey and helps prevent microbes from their prey infecting them. ''H. carolinensis'' is able to
thermoregulate
Thermoregulation is the ability of an organism to keep its body temperature within certain boundaries, even when the surrounding temperature is very different. A thermoconforming organism, by contrast, simply adopts the surrounding temperature ...
quite well. This is particularly important for animals that inhabit desert ecosystems or other locations with large temperature swings.
Naming
''Hogna carolinensis'' is commonly known as the Carolina wolf spider. Historically, it was known as ''Lycosa carolinensis'', but refinement in
taxonomy
Taxonomy is the practice and science of categorization or classification.
A taxonomy (or taxonomical classification) is a scheme of classification, especially a hierarchical classification, in which things are organized into groups or types. ...
in the later half of the 20th century led to ''L. carolinensis'', among many other spiders, being reclassified to the current genus, ''Hogna''.
Description
The Carolina wolf spider is the largest wolf spider in North America. Adult females can reach 22–35 mm and adult males 18–20.
They are an overall light brown color, but have darker brown patterning on their backs.
Their undersides are a darker black and the males can have orange coloration on the sides of their abdomen.
The Carolina wolf spider has a few identifying characteristics. The orange coloration on the males is a good way to identify a male Carolina wolf spider.
Females carry the egg-sac with them during
incubation, so females can be identified in this way during the breeding season.
Additionally, the eyes of these spiders reflect light, which is an especially good identifier when encountering one at night.
Habitat and distribution
Distribution
Carolina wolf spiders are found throughout a large part of North America.
This includes, but is not limited to,
South Carolina
)''Animis opibusque parati'' ( for, , Latin, Prepared in mind and resources, links=no)
, anthem = " Carolina";" South Carolina On My Mind"
, Former = Province of South Carolina
, seat = Columbia
, LargestCity = Charleston
, LargestMetro = ...
,
Kansas
Kansas () is a state in the Midwestern United States. Its capital is Topeka, and its largest city is Wichita. Kansas is a landlocked state bordered by Nebraska to the north; Missouri to the east; Oklahoma to the south; and Colorado to the ...
,
all
Great Lake States, and the
American Southwest
The Southwestern United States, also known as the American Southwest or simply the Southwest, is a geographic and cultural region of the United States that generally includes Arizona, New Mexico, and adjacent portions of California, Colorado, N ...
.
Most research on Carolina wolf spiders, though they are present in many ecosystems, has been conducted on the desert-dwelling ones.
Habitat
The Carolina wolf spider is found all over the North American continent. Therefore, they are able to inhabit many types of geography and topology. Research suggests that these spiders prefer flatter and more open areas.
In fact, researchers noticed that the home range of spiders (distance they frequent from their burrow) would be cut off by sharp
topographical
Topography is the study of the forms and features of land surfaces. The topography of an area may refer to the land forms and features themselves, or a description or depiction in maps.
Topography is a field of geoscience and planetary sci ...
changes in desert areas.
Diet
Prey
Carolina wolf spiders usually feed on insects and other small
invertebrate
Invertebrates are a paraphyletic group of animals that neither possess nor develop a vertebral column (commonly known as a ''backbone'' or ''spine''), derived from the notochord. This is a grouping including all animals apart from the chordate ...
s.
They typically eat grasshoppers and crickets, among other arthropods.
Carolina wolf spiders will sometimes inhabit the areas around human homes, and will take advantage of available prey like cockroaches and other pests. Additionally, they have been observed with juvenile
Texas Banded Geckos as prey, implying they are also able to catch and consume small vertebrate species.
Hunting tactics
Carolina wolf spiders do not catch their prey within webs. They sit on the edge of their burrow or in some other good ambush location, and attack their prey when it gets near.
If the spider is not in its burrow when it catches its prey, it will feed on its prey before returning to the burrow.
If a Carolina wolf spider is in its burrow when it catches its prey, it will drag it down into the depth, holding on to the prey with its
chelicerae
The chelicerae () are the mouthparts of the subphylum Chelicerata, an arthropod group that includes arachnids, horseshoe crabs, and sea spiders. Commonly referred to as "jaws", chelicerae may be shaped as either articulated fangs, or similarly ...
(the “jaws”).
Burrows
Carolina wolf spiders tend to live in burrows. They either make their own burrow or find and inhabit one already made.
To construct their own burrow, the Carolina wolf spider digs out a small area, spins a web to act as a mat that will hold the structure. The spider then keeps digging out areas in this manner until they create a burrow that is a sufficient size.
Though they are diggers, Carolina wolf spiders do not have specialized digging anatomy, so it is sometimes easier to take over the burrow of other small organisms. Occasionally, spiders take over the burrow of their mother if she has died while her offspring are still spiderlings.
Carolina wolf spider burrows vary in size and shape. Some are tubes that are dug straight down while others have bends. Researchers think the variety in size and shape has to do, in part, with spiders digging the path of least resistance, though there is some correlation between spider and burrow size.
In addition to the burrows themselves, Carolina wolf spiders also create
turret
Turret may refer to:
* Turret (architecture), a small tower that projects above the wall of a building
* Gun turret, a mechanism of a projectile-firing weapon
* Objective turret, an indexable holder of multiple lenses in an optical microscope
* Mi ...
s around the entrance to their burrows using sticks, grasses, leaves, pebbles, small animal droppings, and mud.
The exact purpose of these turrets is not known, but they are hypothesized to be a lookout or early warning system for potential predators.
Carolina wolf spiders tend to dig and improve their burrows in the early part of their activity season.
More than offering a safe place for the spiders to live, these burrows are important
microclimate
A microclimate (or micro-climate) is a local set of atmospheric conditions that differ from those in the surrounding areas, often with a slight difference but sometimes with a substantial one. The term may refer to areas as small as a few squ ...
s for the Carolina wolf spiders.
As the burrows go deep in the ground, some as deep as 30 cm, they tend to be about 4 °C cooler than the temperature on the surface. This is especially important for the spiders that live in deserts and other places with hot climate.
The burrows are the main base for the Carolina wolf spider, and they typically have claim over the area that is about a meter out from their burrow.
They do not typically interact with others of their kind outside of mating and early offspring rearing, so burrows are dispersed randomly, no matter the environment, outside of the range of other spiders’ burrows.
It has been noted that when Carolina wolf spiders are brought in to lab conditions for observations, they do not burrow as well as out in the wild.
Reproduction and life cycle
Reproduction
![Wolf spider 1 sjh](https://upload.wikimedia.org/wikipedia/commons/1/14/Wolf_spider_1_sjh.JPG)
Carolina wolf spiders mate in late summer. The females carry the eggs, the sacs attached to their abdomen, during the approximately two week incubation period.
There tends to be two main egg carrying seasons, the first in late July and the second in late August.
While incubating the eggs, female spiders are often seen “sunning” the egg sacs. This is observed when the spider is sitting near the top of their burrow with their heads down and their abdomen and egg sac, sticking up. The Carolina wolf spider is
nocturnal
Nocturnality is an animal behavior characterized by being active during the night and sleeping during the day. The common adjective is "nocturnal", versus diurnal meaning the opposite.
Nocturnal creatures generally have highly developed sens ...
, therefore this behavior is observed during night hours. Researchers do not know why this behavior occurs, but they believe the warmth helps the eggs to hatch more quickly.
When the eggs hatch, there are about 200 spiderlings per sac.
Life cycle
Spiderlings are born near the end of summer and, barring exceptional circumstances like flooding, stay with their mother for the first 6 days of their life. During that time they learn different cues and behaviors from their mother and subsist on the remains of the yolk from where they emerged.
The spiders then disperse and find their own burrows or places to live.
As immature spiders, the spiderlings go through multiple
instar
An instar (, from the Latin '' īnstar'', "form", "likeness") is a developmental stage of arthropods, such as insects, between each moult (''ecdysis''), until sexual maturity is reached. Arthropods must shed the exoskeleton in order to grow or ass ...
s (growing stages) until they reach breeding age at about three years. During their third summer, the spiders will reproduce for the first time. Males die that same summer, but female spiders can live for multiple breeding seasons. As a result, adult male percentage peaks in June and adult female percentage peaks in July. During the year, Carolina wolf spiders are active from March to October, and they
hibernate
Hibernation is a state of minimal activity and metabolic depression undergone by some animal species. Hibernation is a seasonal heterothermy characterized by low body-temperature, slow breathing and heart-rate, and low metabolic rate. It most ...
from November through February.
Mating
Courtship
During courtship, a male will approach a female and make the first move: the male will enter into a courtship posture by extending his
forelegs
A forelimb or front limb is one of the paired articulated appendages (limbs) attached on the cranial (anterior) end of a terrestrial tetrapod vertebrate's torso. With reference to quadrupeds, the term foreleg or front leg is often used instead. ...
. The male will then extend his palps and vibrate his abdomen, repeating this a few times.
Then, depending on the movement of the female, the male will approach. If the female is moving around quickly, the male will too. The male will also mimic her movement speed if she is moving slowly.
Once the male is close enough to the female, he will carefully prod her with his forelegs. The female will react in one of two ways: she will either fight or not. If the female fights the male and does not kill him, he will keep pursuing her. If she fights and then pursues after the male, he will flee and try to escape her attack. If she does not fight at all and instead flees, the male will follow her in order to continue the courtship.
If no female is present, male/male courting can occur.
Copulation
If the female is amenable to mating, she will face the male and elevate the front legs on one side of her body, waiting for the male to copulate.
The male will then insert his palps several times into the female. After
copulation
Sexual intercourse (or coitus or copulation) is a sexual activity typically involving the insertion and thrusting of the penis into the vagina for sexual pleasure or reproduction.Sexual intercourse most commonly means penile–vaginal penetrat ...
, the male will quickly run away so he is not attacked and eaten by the female.
It has been observed in a lab setting that a female will court with a male if she has already copulated with a different male, but she will not pursue a second mating.
Female/female interaction
As these spiders are mostly solitary, there is not much interaction between females. When female Carolina wolf spiders do interact, their behavior can range from merely making foreleg contact to
cannibalism
Cannibalism is the act of consuming another individual of the same species as food. Cannibalism is a common ecological interaction in the animal kingdom and has been recorded in more than 1,500 species. Human cannibalism is well documented, b ...
. Typically, they will make threatening motions like extending their forelegs, spreading their chelicerae, or drumming their palpi at each other.
Social behavior
Though Carolina wolf spiders are not social, research has shown that the offspring that stay with and socialize with their mother after birth have better hunting skills and bigger brains.
Predators
Though excellent hunters, Carolina wolf spiders also find themselves subject to predation. As Carolina wolf spiders are widespread across the continent, they have myriad predators. Their predators include a variety of lizards, amphibians, wasps, and spider eating birds.
Carolina wolf spiders are prey to large
arthropod
Arthropods (, (gen. ποδός)) are invertebrate animals with an exoskeleton, a Segmentation (biology), segmented body, and paired jointed appendages. Arthropods form the phylum Arthropoda. They are distinguished by their jointed limbs and Arth ...
s, including
scorpion
Scorpions are predatory arachnids of the order Scorpiones. They have eight legs, and are easily recognized by a pair of grasping pincers and a narrow, segmented tail, often carried in a characteristic forward curve over the back and always end ...
s, as well as owls and
coyote
The coyote (''Canis latrans'') is a species of canis, canine native to North America. It is smaller than its close relative, the wolf, and slightly smaller than the closely related eastern wolf and red wolf. It fills much of the same ecologica ...
s.
One researcher witnessed a group of predatory ants enter a spider's burrow, consume the spider, and take over the burrow as their own.
Physiology
Locomotion
There is not a significant difference of the sprint speed, (i.e. the speed at which they will escape perceived threats) of the Carolina wolf spider between males and females.
There is, however, a difference in chances a males or a females will flee from a threat. Spiders will flee to try and get far enough from a predator in hopes that they will lose interest in them. Male Carolina wolf spiders flee significantly more than females. Researchers believe that this is due to Carolina wolf spider burrowing habits. Male spiders do not own burrows as often as females, so they are not able to find a safe escape in their burrows as frequently as their female counterparts. Interestingly, the speed of the spider and flee distance are positively correlated, meaning that the spiders that flee farther are able to run away faster, both mechanisms helping their
antipredatory reactions.
Senses
In addition to sight and olfactory senses, Carolina wolf spiders will react to vibrations they sense. They will either return to their burrow, if available, or they will flee.
Thermoregulation
Carolina wolf spiders are able to
thermoregulate
Thermoregulation is the ability of an organism to keep its body temperature within certain boundaries, even when the surrounding temperature is very different. A thermoconforming organism, by contrast, simply adopts the surrounding temperature ...
very well, which is especially important for those that inhabit desert ecosystems or other locations with large temperature swings. They are able to acclimate to any sized (within reason) temperature change in 1.5–3 days.
They do this by increasing their
oxygen consumption
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 well as ...
levels to very high amounts and then lowering it to the appropriate level for that temperature.
This adaptation is helpful because it reduces the shifts in food and water needs that in other spiders is associated with large temperature shifts.
In the short term, before they have thermoregulated, Carolina wolf spiders are able to keep cool by keeping their abdomens close to water and drinking large amounts of water.
These water sources are especially important because Carolina wolf spiders need outside sources of water as they are not able to derive water
metabolically
Metabolism (, from el, μεταβολή ''metabolē'', "change") is the set of life-sustaining chemical reactions in organisms. The three main functions of metabolism are: the conversion of the energy in food to energy available to run cell ...
.
Bites to humans and animals
The Carolina wolf spider is venomous, but is not meant as a defense system against threats. Instead it is thought that their venom, which is composed of lycotoxins, is used as a
paralytic agent
Neuromuscular-blocking drugs block neuromuscular transmission at the neuromuscular junction, causing paralysis of the affected skeletal muscles. This is accomplished via their action on the post-synaptic acetylcholine (Nm) receptors.
In clin ...
for their prey and as a method of defense against infection from any microbes that may be in their prey.
Lycotoxins change the ion and voltage gradients in their targets, especially targeting the
calcium ion
Calcium is a chemical element with the symbol Ca and atomic number 20. As an alkaline earth metal, calcium is a reactive metal that forms a dark oxide-nitride layer when exposed to air. Its physical and chemical properties are most similar to ...
, which is what makes it a paralytic.
Recent research on the toxins of the Carolina wolf spider has determined that this particular toxin creates a new subclass of spider venom due to its unique amino acid sequencing and the fact that it has important
antimicrobial
An antimicrobial is an agent that kills microorganisms or stops their growth. Antimicrobial medicines can be grouped according to the microorganisms they act primarily against. For example, antibiotics are used against bacteria, and antifungals ar ...
activity.
Culture
''H. carolinensis'' was voted as the state spider of South Carolina in 2000 after an initial suggestion by third grade student Skyler B. Hutto.
References
{{Taxonbar, from=Q2691059
Lycosidae
Spiders of the United States
Spiders described in 1805
Fauna of the Eastern United States
Symbols of South Carolina