Migratory locust is the most dangerous pest insect. When attacked by a large flock, it is able to completely destroy the entire crop, leaving behind a bare desert with no signs of vegetation, as after a natural disaster.
Insect description
The Locust family (lat. Acrididae) includes more than 1 thousand species of insects, of which 400 inhabit Asian-European countries, including Russia (regions of Central Asia, Kazakhstan, the Caucasus, the south of Western Siberia and the European part). The most harmful and widespread species is the Asian locust, or migratory (Locusta migratoria).
In external description, it is similar to ordinary grasshoppers, only larger. As can be seen in the photo, the Asian migratory locust is a large insect reaching 6 cm in length, has a green-brown or olive body color and well-developed wings that help to overcome great distances (up to several thousand kilometers) at a speed of 10-15 km / h. The body structure is typical of orthoptera and consists of 3 segments: head, chest and abdomen. Locusts move on the ground with jumping legs, making high jumps.
There are small antennae on the head, as well as powerful jaws and a curved sharp keel located on the pronotum. The wings are divided: the anterior ones are more dense, of a brown color, the hind ones are transparent yellow-green, more delicate in structure.
Lifestyle & Nutrition
In the development of migratory locusts, 2 main phases are distinguished: single and herd. It is in the latter that this insect poses a danger, emptying crops and destroying all plants that come in its way. Due to its omnivorous nature, it is able to actively eat, eating up to 0.5 kg of plant mass per day each! Eats locusts leaves, flowers, branches, stems and fruits, preferring morning and evening hours, resting in the heat.
During the summer season, 1 female, together with the offspring, eats as much as 2 sheep consume. Flocks of locusts sometimes number up to 1 million insects, so the attack of such hordes on the fields leads to the death of the crop. The most favorite locust treats are reed, as well as gourds and garden plants.
Reproduction: egg-laying
The answer to the question of how long the migratory locust lives depends on many external factors that affect the life cycle of the insect: nutrition, climate, etc. It is believed that it can live from 8 months. up to 2 years.
In the single phase, the locust exists as a large insect of green color, which is also called the "green filly". She is harmless and leads an inactive lifestyle. This is the period when females mate with males and after 30-40 days lay eggs, which occurs in the 2nd half of summer.
When laying eggs, the female envelops them with a foamy liquid secreted from the glands, which quickly hardens in air. At the same time, it forms several capsules (egg capsules) with a lid, 50-100 eggs are placed inside each. In total, the total masonry can be 300-350 pieces. During the summer season, each female can form up to 3 generations of offspring.
The place for the egg capsule is chosen in loose, preferably sandy and rather moist soil. Popular places for masonry are floodplains of rivers and banks of water bodies surrounded by sedge and reed. In the beginning of autumn, with the advent of cold weather, all adult individuals (females and males) die. In the winter months, the masonry does not freeze even in severe frost.
Locust development: from larva to imago
For the development of the insect in question, 3 stages are characteristic (egg - larva - imago), i.e. this is an incomplete transformation. Migratory locusts in the form of larvae appear only at the beginning of next spring, bypassing the pupal stage. This happens after warming the soil to the desired temperature, usually in May.
Larvae are similar to adult insects, only smaller. As they develop, they molt several times (4-5), gradually increasing in size, which occurs within 35-40 days. Foods for the younger generation are plants rich in protein: wheat grass, reed, wild cereals.
In a single phase, an insect can exist, eating calmly all summer and then laying eggs for laying a new generation. Absolutely harmless green fillies have a slight bulge ("hump") on their backs and lead an inactive lifestyle.
Herd form, flock formation
A signal for the formation of a flock of Asian migratory locusts is the lack of protein food, which happens on average every 10-12 years (the interval between epiphytoties). The herd phase of the existence of locusts is characterized by the reproduction of insects in extreme quantities, when the larvae, even having grown wings, sharply grow to 6-6.5 cm in length. They straighten their back, acquiring a gray-brown spotted color, and begin to gather in swifts - columns, massively destroying all the plants around.
After the 4th-5th molt, all insects in the flock gain wings and begin their “nightmare” flight in search of food. A flock of locusts can fly without respite for 12 hours, covering distances of hundreds of kilometers, and with a fair wind up to 1 thousand km! When planting, insects with their severity even break tree branches.
Locust invasion
During a mass flight, millions of insects produce a terrifying thundering sound that arises from the total crackling of their wings. Insects feed in a flock almost without interruptions, trying to normalize the protein balance in the body. They completely eat all crops (wheat, barley, rye, corn and oats), gnaw all bushes and trees, pastures and grass in the fields. On their way, they gobble up the growth of melons and legumes, leaves on root crops, etc.
They are able to travel 50-300 km in the surrounding area per day. And along the way, many insects in the flock turn into predators, devouring their own kind, and not just plants.
Flock communication
Large communities of migratory locusts could not survive for long if they did not communicate with each other. In a flock for communication, they use sound and visual signals, touch, apply chemical irritants in the form of odors. In order to make sounds, special organs have formed in insects. So, the locust makes a chirping, or sound of stridulation, which is caused by rubbing the paws or wings of other parts of the body with a certain frequency and rhythm, for which they have denticles (80-90 pieces) located at the edges.
Other sounds are produced by insects using membranes located on the abdomen - these are clicks and pops, and they can also bang their heads on stems, leaves or the ground. Scientists suggest that echolocation is also used to coordinate the movement of large flocks. Migratory locusts, having strayed into huge swifts, sometimes numbering up to a million individuals, migrate in a certain area, flying from one field to another and destroying everything around.
