Wolf Spider: Characteristics, Habitat, Reproduction, Behavior

The wolf spider ( Lycosa tarantula ) is a spider belonging to the Lycosidae family. It was described by Linnaeus in 1758. This species is one of the largest on the European continent. They are quite shy so when they feel threatened they quickly flee to their shelters.

Initially they were called tarantulas, however, with the discovery of the South American mygalomorphic spiders (much larger), they adopted the common name of wolf spiders, due to their active hunting methods.

Both the females and the males before their sexual maturation are located in small burrows. The maturation of these spiders can last up to 22 months, dividing their post-embryonic development into discrete periods clearly distinguishable by the appearance of the molts.

When the reproductive period is limited and the males and females are not sexually mature for the same period, the number of mature animals determines whether or not there is polygamy.

The external genitalia, the copulatory bulb of the male and the epigynum of the female, are fully developed during the last molt. The complete maturation of individuals occurs in late spring (late May and early July).

In nature there can be a high density of these animals, registering up to 40 burrows in an area of ​​400 m 2 , where adult females, young females and undeveloped males are distributed.

Wolf spiders can exhibit a random distribution within the territories they occupy, during the early stages of their development. When they are juveniles, they tend to be located in an aggregate way in those places that offer them the best conditions. However, upon reaching adulthood, the spatial arrangement varies significantly.

The burrows of the females are separated by constant distances, which indicates a certain degree of territoriality and protection of the “burrow” resource. In addition to this, food availability is guaranteed within a protected territory.

They attack their prey at distances between 30 and 40 cm from their burrow, to which they return later, by integrating the route thanks to the collection of visual information and through other receptor organs.

General characteristics

They are large spiders. Their bodies (without taking into account the length of the legs) can reach sizes of up to 3 cm in females and in males a maximum of 2.5 cm. Females tend to live longer than males because they spend most of their lives in the burrow.

The coloration of these arachnids is quite variable. Males are usually light brown in color, while females are dark brown. The legs in both sexes have dark side band patterns that are more noticeable in females.

They have eyes arranged in a typical 4-2-2 configuration. An anterior row made up of a pair of medial anterior eyes (SMA), a pair of medial lateral eyes (ALE), and a posterior row made up of a large pair of medial posterior eyes (PME) and a pair of lateral posterior eyes (PLE) .

In the juvenile stages, males and females are indistinguishable, however, they are sexually recognizable after the penultimate molt (subadults), when the tarsus of the pedipalps in males increase in size and the female external genitalia (epigynum) are clearly distinguishable.

Visual characteristics

These spiders are able to use the visual structure of the substrate in which they operate to return to their burrow using path integration. Only the anterior lateral eyes are capable of perceiving the visual change of the substrate in which they operate.

The anterior lateral eyes (ALE) are responsible for measuring the angular component of the displacement in conditions in which there is no polarized light or a relative position with respect to the sun . In this way, Lycosa tarantula can determine the distance and route back to the burrow.

In natural lighting conditions, the directionality of movement is associated with the anterior medial eyes (AME), which are the only ones that detect polarized light.

The role of the posterior medial eyes seems to be related to that of the anterior lateral eyes and the detection of movement, being one of the spiders with better vision.

Habitat and distribution

Lycosa tarantula is distributed in much of southern Europe, in the basin of the Mediterranean Sea. It is currently found in southern France (Corsica), Italy, the Balkans, Turkey, Spain, and much of the Middle East.

It generally occupies dry environments with low humidity and sparse vegetation. Some distribution areas have scattered bushes and abundant undergrowth.

They build vertical galleries or burrows that can reach 20 to 30 cm deep. The outer region of the burrow generally consists of small branches, leaves, and stones that are held together with silk.

During the winter they use these shelters to protect themselves from the low temperatures. Similarly, they protect most of the day from solar radiation.

Taxonomy

Lycosa tarantula currently has two recognized subspecies. Lycosa tarantula carsica (Caporiacco, 1949) and Lycosa tarantula cisalpina (Simon, 1937).

Recently, the molecular phylogeny of the wolf spider group for the western Mediterranean basin establishes a closely related group of species called the “ Lycosa tarantula group ”. The group establishes genetic, morphological and behavioral kinship relationships.

The group includes the species Lycosa tarantula , Lycosa hispanica and Lycosa bedeli .

Another spider of the family Lycosidae with which Lycosa tarantula is often confused is Hogna radiata , which is smaller in size and has a distinctive coloration pattern on the cephalothorax.

State of conservation

As in most arachnids, the population status of these spiders has not been evaluated and it is not known if there are decreasing trends in their populations.

It is possible that the intervention of the habitat and the elimination of these animals affect their numbers, however, it is necessary to establish research on their conservation status.

Reproduction

Some populations studied show a polygamous breeding behavior, however, the frequency of multiple mating is low.

The reproductive success of females may be biased, as a small number of males can monopolize the copulation. Reproductive events also depend on the spatial and temporal distribution of both males and females.

In the reproductive season, males tend to mature faster because they are smaller and consequently undergo fewer molts.

On the other hand, Lycosa tarantula males are wandering, that is, they do not have a permanent den as in the case of females and therefore suffer a higher degree of mortality. Therefore, mortality and maturation related to sex are factors that influence the availability of a partner.

Females can be very scattered and can be difficult for males to locate. It has been observed that females can influence reproduction through selection of males.

Once the male locates an interested female, he initiates a brief courtship consisting of a series of elaborate steps and movement of the pedipalps.

Cocoon construction and parental care

Cocoon development occurs between three and four weeks after mating.

Generally, if it is the female’s first reproductive period, she will only build a cocoon of eggs. If it survives into the next year, you can make a new cocoon that will hang from the ventrodistal region of the abdomen until the eggs hatch.

Each cocoon can contain more than one hundred eggs. Once the young emerge from the cocoon, like most of the spiders of the Lycosidae family, they position themselves on the mother’s prosoma and abdomen.

Once they are independent and ready to hunt, the young disperse in the environment, establishing their own shelters.

Females with more than one reproductive season tend to lay smaller egg sacs with fewer eggs than younger females.

The latter is linked to the less frequent feeding of the longest-lived females and a phenomenon known as reproductive senescence. The following video shows the egg bag of a female of this species:

Nutrition

The activity of these spiders is mainly nocturnal. Females can be observed at night ambushing possible prey around their burrow or exploring near it.

In general, females mark a perimeter with silk about 20 cm in diameter around the burrow, which helps them detect prey passing near their burrow. The males on the other hand, being ground dwellers, hunt their prey more actively.

Much of the diet of these spiders is based on other invertebrates such as crickets, cockroaches and lepidoptera. In addition, they can be cannibals, consuming juvenile wolf spiders or males with reproductive intentions in the case of females.

Males may have a higher nutritional value than many of the prey available in the female’s environment.

The males have adapted their behavior to avoid the females at night. It is believed that they detect pheromones that the female leaves imprinted on the silk around the burrow. In nature, the feeding rate of females is higher than that of males. In the following video you can see how a wolf spider hunts a cricket:

Behavior

The males after maturing sexually (after the last molt), leave their shelters to become ground dwellers. This type of strategy is known to a wide variety of cursory spiders. On the other hand, females remain in and around their burrow throughout their lives.

The males leave the burrow a week after maturation, in order to look for females to reproduce. During some nights they can be observed spending the night in an abandoned burrow or even with a female, if he is successful in finding her and being accepted by her.

No competitive relationships between males have been observed as a guarantee measure for reproductive success. The females of this species can mate with several males in a single reproductive season, in the same way the males can be observed mating with up to six females.

Females tend to be more aggressive with males at night than during the day, in the same way, females are more effective hunters during this period.

Because of this, males often visit females during the day when they are least likely to be cannibalized by the female.

Cultural relations

In some regions of Italy and Spain where this spider is distributed, it was considered a dangerous spider.

However, poisonings with these spiders are rare and not serious. Its venom is considered similar to that of a bee and the systemic reaction is rather identified as a localized allergic reaction.

In 17th century European popular culture, a Lycosa tarantula bite produced a picture of convulsive hysteria known as tarantism, which is combated only by performing a highly elaborate dance with musical accompaniment known locally as the tarantella.

The person affected by the bite of a tarantula was subjected to a series of dances that varied according to the response of the affected person and if the spider responsible for the accident was female or male.

The tarantulated person, danced with the help of other people, attached to a rope tied to a beam on the roof of the house. The music stopped when the patient showed symptoms of fatigue, at which time he was comforted with plenty of fluids, broths, and water.

The dance lasted for a maximum period of 48 hours, until all the symptoms related to tarantism disappeared.

References

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  4. López Sánchez, A., & García de las Mozas, A. (1999). Tarantella and tarantismo in lower Andalusia (historical sketch). Journal of Education Sciences. 16 , 129-146.
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  8. Moya ‐ Laraño, J., Pascual, J., & Wise, DH (2004). Approach strategy by which male Mediterranean tarantulas adjust to the cannibalistic behavior of females. Ethology , 110 (9), 717-724.
  9. Ortega-Escobar, J. (2011). Anterior lateral eyes of Lycosa tarantula (Araneae: Lycosidae) are used during orientation to detect changes in the visual structure of the substratum. Journal of Experimental Biology , 214 (14), 2375-2380.
  10. Ortega-Escobar, J., & Ruiz, MA (2014). Visual odometry in the wolf spider Lycosa tarantula (Araneae: Lycosidae). Journal of Experimental Biology , 217 (3), 395-401.
  11. Reyes-Alcubilla, C., Ruiz, MA, & Ortega-Escobar, J. (2009). Homing in the wolf spider Lycosa tarantula (Araneae, Lycosidae): the role of active locomotion and visual landmarks. Naturwissenschaften , 96 (4), 485-494.
  12. Ortega-Escobar, J., & Ruiz, MA (2017). Role of the different eyes in the visual odometry in the wolf spider Lycosa tarantula (Araneae, Lycosidae). Journal of Experimental Biology , 220 (2), 259-265.

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