Rare ladybug spider: miniature but very brave

Black eresus (Eresus kollari) is a poisonous spider with a unique appearance. It is also sometimes called "black fathead". This species belongs to the Eresidae family. Spider bites are dangerous for both people and pets. It is necessary to take into account that black eresus is listed in the Red Book, so killing the arachnid is strictly not recommended.

Eresus black or black fathead, appearance

What does an eresus spider look like: photo

Eresus: ladybug spider.

Skilled braiders

Like all web spiders, Argiope Brünnich prepares traps stretched between blades of grass and low branches of bushes. The networks of this species of arachnids are circular, in the center they have a zigzag-like pattern, characteristic of the weaving of all brothers in the genus Argiope and called stabilimentum. Despite the small size of the hunter, his traps are very durable, capable of holding a grasshopper, which is 2-3 times larger than the predator. Argiope Brünnich spends only an hour creating nets that are woven at sunset, in the approaching twilight.

Description of the Erasus spider

Name: Eresus or Black fathead Lat.:
Eresus kollari

Class: Arachnida - Arachnida Order: Spiders - Araneae Family: Eresidae - Eresidae

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The size of the female individual is from 8 to 18 mm. The body is compact and round with short thick legs. The color is velvety black. Small light hairs are present. Males have a body length of 6 to 8 mm. The color is very bright. The cephalothorax is black with sparse light hairs. The hairs form the basis of white narrow rings.

The belly has a rounded shape. In the upper part it is painted bright red. In this area there are 4 black spots, similar in appearance to a button. The bottom and sides are black. The hind two pairs of paws may be spotted with red.

Larvae

Coccinellid larvae belong to the campodeoid type - they are mobile, have an elongated body and three pairs of long thoracic legs. The appearance of the larvae of members of the family is very diverse. The larvae of most Palaearctic species belong to the so-called coccinelloid type, which is characterized by a fusiform body shape, a large head and long legs.

The head of the larvae is rounded and quadrangular, approximately the same width and length. Its sides are rounded to one degree or another or straight. There are antennae on the head. Two-segmented and single-segmented antennae are characteristic of specialized genera that feed on pseudoscale insects. Variations in the structure of the antennae are represented by a combination in different combinations of different lengths of the basal and apical segments (genus Hyperaspis

,
Nephus
).
The mandibles of the larvae are triangular or sickle-shaped, protruding or slightly protruding. Mandibles according to their structure can be divided into 2 types. The first - multi-toothed, triangular in shape, with an absent retinacula - are characteristic of species ( Subcoccinella
) with a herbivorous lifestyle. Mandibles of the second type are characteristic of Coccinellinae; they are sickle-shaped, have 1-2 sharp teeth at the apex, and the retinacula is developed. There are three simple eyes on the sides of the head. The abdomen is 10-segmented, without caudal filaments at the end. The legs are long, wider than the body. The dorsum has various structures, armed with setae, or covered with white waxy threads.

The prothorax is much longer and narrower than the mesothorax and metathorax. The dorsum of the prothorax has 2 or 4, rarely 6 scutes - square, rounded-square or elongated, placed longitudinally. The dorsum of the mesothorax and metathorax have 2 scutes of an oval oblong, less often round shape, located across the segments. On their outer edges the scutes are covered with various setae.

Legs are elongated. The abdomen is formed by 10 segments, the last of which is shifted to the ventral side and has the shape of a sucker. The tergite of segment IX is most often rounded at its apex, sometimes with a cone-shaped or triangular outgrowth. The integumentary formations on the abdomen of larvae are extremely diverse and can be used as important taxonomic characters. They are represented by: warts, outgrowths of various shapes and bristles.

The larvae go through four instars. Larvae of the first instar are small in size, length from 0.5 to 1.2-1.7 mm. At the fourth instar, the length of the larvae is 5-8 mm, and some - 17-18 mm. Larvae of the first instar usually have a single color - dark or gray with white, yellow, orange or red spots. At older ages, the larvae acquire bright and varied colors. Bright coloring is characteristic, as a rule, of species that feed on aphids and live openly in their colonies. There is a relationship between color and their behavior: the more active the larva, the brighter its color (genus Coccinella, Coccinula, Anatis

,
Harmonia axyridis
,
Aiolocaria mirabilis
, with a contrasting combination of rich black color with orange spots and stripes). Single-colored, often dark larvae are characteristic of ladybugs that feed on pseudoscale insects. The color of the larvae is subject to age and individual variability.

Beetles and larvae of most species are entomophagous predators. Only a few species eat plant foods.

Diet and lifestyle

The Eresus spider leads a secretive lifestyle and rarely appears on the surface of the earth. They can occupy the beetles' home, but they are also capable of digging a deep hole themselves. The nest is a web-like tube located in the ground. Basically, the black eresus lives in a hole. Females are in the shelter all the time. Only young individuals and adult males emerge from the burrows during the mating period.

Webs are a network for the victim. Future food gets caught there and gets stuck, which the female catches and prepares for consumption. Arthropods feed on:

• insects;
• beetles;
• flies;
• butterflies;

• centipedes;
• woodlice;
• scorpions;
• lizards.

Black Widow

The top 10 most dangerous spiders in the world continues with this small-sized representative of arthropods. The length of its body is only 1.5-2 centimeters. And although the females of these representatives of arthropods are twice as large as the males, they are also quite difficult to distinguish in natural conditions. Nevertheless, these are the most dangerous spiders, located almost at the top of the corresponding rating.

The Black Widow is in constant “mourning.” Only sexually mature adults have red hourglass markings on their abdomen. Young spiders have a light color. Their body is sometimes white or yellowish-white. The color becomes darker only with age. The body of these spiders acquires a black color only in the second or third month of life.

This most dangerous spider (see photo below) did not receive its “mourning” name by chance. The females of this arthropod are distinguished by cannibalism towards males.

The habitat of these spiders, as a rule, is Central Asian deserts and steppes. They are less common in the Caucasus, as well as in the Crimea.

The black widow, ranking third out of the 10 most dangerous spiders, prefers to hunt in recesses under stones, placing its snares at a small height from the ground. She also watches for victims in cracks and various openings, over squat plants and even in the thick of grape vines.

Representatives of these spiders go hunting at night. During the day, they prefer to hide in their shelters. The food for the black widow is usually insects. However, these spiders are not averse to dining on woodlice and their own relatives.

The bite of a black widow is dangerous to humans. This is especially true for older people and children. The poison, spreading throughout the body, causes severe muscle spasms. Also, after a black widow spider bite, weakness and headache, shortness of breath and increased salivation, vomiting, a feeling of anxiety and tachycardia appear. You can neutralize the poison by burning the bite site with a match. To eliminate the possibility of an allergic reaction, it is also advisable to take the victim to the hospital.

Life cycle

Eresus spider black.

Males leave their burrows in search of a mate. The courtship period takes place over several hours. The males are dancing. At the same time, they form a protein liquid, which leads the female to a catalytic state. The pedipalps transport seminal fluid into the genital opening.

If there are several males, a duel begins. For 2 months after fertilization, males live in burrows with females. The female is engaged in the manufacture of a cocoon. There can be about 80 eggs in a cocoon.

The female weaves insect skin, grass, and leaves into the cocoon to disguise it. During the day she warms him under the bright rays of the sun, and at night she takes him to shelter. The lifespan of a female is 1.5 years, and a male is 8 months.

Reproduction

Puberty occurs at the age of 1-2 years.
Sexually mature males go in search of potential mates after the spring urge. Having discovered a female, they settle near her shelter and patiently wait for the right moment to form a pair. As a rule, it appears in late summer or early autumn, when dry, warm weather sets in. Ritual fights take place between males for the right to acquire family ties. The female allows the winner to sneak into her shelter and stay there until next spring. Mating occurs after the arrival of spring warmth.

The male makes his way under the female’s abdomen and, using pedipal fingers, transfers the spermatophore to her genitals, located in front of the spinnerets. While the female is in a cataleptic state, the gentleman tries to leave her home. Otherwise it may be eaten.

Soon after mating, the female weaves a cocoon up to 10 mm in size and lays 60 to 80 eggs in it. She presses him to the cephalothorax with her forelimbs and almost constantly maintains this position.

Incubation lasts 2-3 weeks. The hatched spiders gather near the mother's mouth and feed on pre-digested food. A caring mother, due to the large production of digestive enzymes, gradually turns into a nutritious pulp and dies.

They spend the winter in her hole, and in the spring they scatter in different directions. Males, as a rule, go further than females.

Eresus bites

The venom of the Eresus spider is considered strong and dangerous. The spider kills its prey in seconds. For humans, the bite is very painful, but not fatal. The spider stings painfully and injects a large portion of poison.

Black fathead.

Symptoms of a bite are:

• sharp pain;
• swelling;
• numbness of the bite site;
• strong pain.

ONE OF A KIND

Spiders of the eresid family live mainly in the tropics. The black fathead, also known as black eresus, is the only European species. Its range covers vast territories from the Iberian Peninsula to Novosibirsk. The spider can be found in central Russia, Crimea, the Caucasus, the southern part of the Urals and Central Asia, but is very rare everywhere.

The cephalothorax of eresids in both males and females is black and velvety. The head part is raised high above the chest and looks square from above. The eight eyes are arranged in three rows, with one pair, set back and to the sides, being significantly larger than the others. The body is covered with a dense layer of short feathery hairs, which is why the spider looks velvety. The legs are powerful, also black, with white rings in the male.