Wasp Larra - Black Thunderstorm Bears

Burrowing or sand wasps (Crabronidae) - a family of about 9,000 species worldwide. Hymenoptera insects build nests in sandy soil; paralyzed prey is brought to feed the larvae. The genus Larra specializes in bear hunting. Wasp Larra lays an egg on a living incubator. Its offspring, before pupation, feeds on the orthoptera. Representatives of the species Larra anathema on a special account among gardeners. They are always happy to support an ally in the fight against a dangerous pest.

Morphological description of the species

Wasp Larra anathema (Larra anathema) belongs to the largest subfamily of sand wasps. The size of females is 16-22 mm, males 15-17 mm. The head, chest, limbs and antennae are black. The two anterior segments of the spindle-shaped abdomen are red, the rest are black. The head is free, expanded in the transverse direction. Large eyes are located on the sides. The size and structure of the organs of vision provide the ability to monitor what is happening in different directions. On the forehead between the complex eyes, the triangle has simple eyes. Antennae are organs of touch and smell.

Information. The thin waist connecting the chest and abdomen allows the wasps to bend at any angle to sting the enemy.

The wasps have membranous wings with a sparse network of veins. Both pairs are darkened, almost black. At rest, the wings fold horizontally on the back. The abdomen consists of 6 segments. In females it ends with a sting, which in the usual state is pulled inward. The limbs of the walking type, tibia and tarsi are covered with rows of teeth and bristles.

Distribution area

Larra of Anathema is distributed throughout the world. Insects are found in Central and Southern Europe, North Africa, Central Asia, the Caucasus and Crimea. Larra wasps live in South and North America.

Information. Species Larra anathema is the only representative of the genus Larra in Crimea. The number of insects in the region is reduced, they are listed in the Red Book.

Lifestyle

The years of digging wasps begin in June and end in August. Under natural conditions, they settle in the floodplains of the rivers, in a meadow or on the banks of water bodies. These places are popular among the Orthoptera of the bear family (Cryllotalpidae). They are found on agricultural land, where they are an entomophage. Adults feed on nectar, prefer plants euphorbia, kermek, thyme. They are found on asteraceae and umbrella crops. For wasps, a shallow peduncle is important, from which it is easy to get nectar. Males are more often caught during feeding, females devote most of their time to hunting.

An insect observation enthusiast can spot the female Larra anathema on a hot sunny day, running on the ground. She makes short dashes until she finds the entrance to the underground passages of the bear. These are massive brown insects that damage plants in the garden. Their strong jaws and gluttony suffer from cereal crops, sunflowers, potatoes, cabbage, legumes and melons. Farmers make a lot of efforts to remove pests. The large black wasp Larra anathema can help in the fight against the bear.

The natural enemy of the pest pursues underground and expels it to the surface, where it is paralyzed by several precise blows of the sting.A characteristic feature of digging wasps is injections into the chest area. At this point, the integument is soft, unprotected. Paralysis of the bear is temporary. While she lies calmly, the female lays an egg under the base of the anterior extremity of the orthoptera. The future owner of the larva returns to the underground passage, where he will live another 2-3 weeks.

Interesting fact. The behavior of the Larra genus is not characteristic of the rest of the Crabronidae family. Usually burrowing hymenoptera arrange passages with chambers in the soil, where paralyzed insects are dragged. They leave eggs on the body of the victims, which turn into larvae. Larra females do not build nests, and their poison is able to paralyze prey only for a short period of time - 5-6 minutes.

Propagation Features

Sand wasp Larra insects with complete transformation. They go through 4 stages of development, gradually transforming from an egg to a larva, pupa, and imago. The female, using sticky secretions, attaches the egg to a deep fold near the forelimb (usually the left). This ends parental care. From a pearl-white oblong egg, laid by a female on a bear’s imago, a larva appears after 5 days. It is an endoparasite, lives and develops on the surface of the host body.

Before turning into a pupa, the larva passes 5 ages, sheds 6 times. The egg incubation time depends on the ambient temperature. In hot weather, it takes 4-5 days for the larva to appear, in cool, up to 7 days. At the first age, the offspring of wasps has a white worm-like body with soft integuments. The larva sucks the host hemolymph. The rate of its development also depends on environmental conditions. Under favorable conditions, it goes through all stages of the change of ages in 12 days. At low temperatures, the larva grows slowly; it pupates to pupation only after a month.

During this time, it becomes larger several times, the integuments of the body darken to gray. By the age of 5, the larvae of the bear die. The wasp progeny builds a cocoon from soil particles and saliva next to the remains of the host. In a shelter with thin walls, the pupa hibernates. Development continues in the spring, with the onset of sustainable heat. Young imagoes of Larra anathema appear in early summer. One generation is developing in a year.

Protection and limiting factors

The development of natural habitats, the use of chemical pesticides leads to a decrease in the population of the larra genus. In Crimea, the species Larra anathema is listed in the Red Book in the second category, as it is declining in number. To create conditions for the restoration of the number of entomophages, the creation of reserves is recommended in the habitats. Hymenoptera Larra anathema is protected in the Crimean reserves Opuksky, Kazantipsky and Karadagsky, as well as in the national park "Tarkhankutsky."