Migratory or Asian locust - Locusta migratoria L.
The Asian locust is a large insect, reaching a length (excluding wings) of 50—55 mm (females), with males being somewhat smaller; the folded wings of the locust noticeably extend beyond the end of the abdomen, making the locust appear even longer. It is a dirty green or brownish color, with brown spots on the forewings, and the hind wings are transparent, slightly greenish or yellowish. The upper jaws are blue, the hind shins are yellowish or red, and the hind thighs have black-blue or black spots on the inner side.
The natural habitats of this locust are reed thickets in river floodplains and marshy meadows.
In appearance, locusts are similar to grasshoppers, but at first glance, there is a significant difference: locusts have short antennae (see Fig. 84). Grasshoppers have thin, segmented antennae that are noticeably longer than half the body, mostly not shorter or barely shorter than the body, and often even longer. In locusts, the antennae are usually shorter than half the body and have no more than 25—30 segments. Upon closer examination, there are other differences as well. For instance, locusts lack auditory organs on the forelegs, and there are no mirrors on the forewings; the legs consist of no more than three segments.
In the second half or at the end of summer, a fertilized female locust lays eggs. Using the thick valves of a very short ovipositor, she pushes apart soil particles and burrows into it with her abdomen, which stretches significantly. Once she has pushed her abdomen into the soil "to the limit," the female slowly begins to pull it back out, laying eggs in the process. Simultaneously, she releases a foamy liquid (secretions from the accessory glands of the reproductive system). After laying, 55—115 fairly long, thin, pinkish eggs remain in the surface layer of the soil, usually arranged in four rows and enclosed in a foamy mass — the so-called "cocoon." Soil particles stick to the soft walls of the cocoon (from the outside, it looks like a long clump of earth), and in the upper part, above the eggs, there is a space filled only with foamy mass, the "plug."
The length of the cocoon reaches 50—75 mm, and the diameter is 7—10 mm. The top of the cocoon is covered with loose soil. The female lays two to three cocoons.
Immediately after laying the eggs, the development of the embryo begins, but it soon stops and resumes only in spring, after overwintering. The larvae of the Asian locust hatch late: in May, June, and sometimes even in July. The timing of hatching is significantly affected by the conditions in which the cocoons are located. For example, larvae hatching from cocoons laid in floodplains, riverbanks, and other areas flooded by water are delayed. Embryos can also die entirely if flooding occurs when their development is already close to completion (flooding at early stages of embryo development only delays development). Thus, the timing and duration of river flooding affect not only the hatching time of the locusts but also the number of hatched larvae. The larva that hatches from the egg does not resemble a typical orthopteran larva: it is worm-like and has a special temporary organ — a pulsating neck sac. With the help of this sac (pulsating, it pushes apart soil particles) and worm-like movements, the larva crawls to the surface of the soil. Here it immediately molts and, losing the neck sac and changing its body shape, transforms into a typical orthopteran larva — a first-instar larva (the worm-like larva and its molt are not included in age and molt counts). The further development of the larva lasts 40—50 days, during which it molts several times. With each molt, not only does the size of the larva increase, but its appearance also changes somewhat. For instance, as the larva ages, the number of segments in the antennae increases (in the first instar, there are usually no more than 13, while in the fifth, there are 23—26), and the rudiments of the wings become more pronounced. Finally, the last molt occurs, and the larva transforms into an adult insect.
It is characterized by outbreaks of mass reproduction.
As they mature, the larvae become very voracious. It has been calculated that the offspring of one female locust consumes as much food as would be sufficient for two sheep. With complete survival, its offspring can consume up to 75 kg of green mass. The Asian locust is a formidable pest not only of agricultural crops but also of natural pastures and hayfields.
During mass reproduction, the number of locusts reaches monstrous figures. One female lays an average of 250 eggs. In huge swarms, the insects take to the air and fly at a speed of 10–15 km/h, covering 80–120 km in a day. Where such a swarm appears, the number of locusts can reach several hundred per square meter.
In periods of natural disasters, the population of locusts increases to many millions of individuals.
During mass reproduction, all the merging swarms occupy very large areas, and the number of locusts (larvae of locusts are often called locusts or walking locusts) in them reaches monstrous figures. Winged locusts often leave their nesting sites and migrate in huge swarms to other locations.
When they descend somewhere to feed, the swarm rapidly destroys all herbaceous vegetation: bare ground is left, covered with remnants of plants and locust droppings. In the absence of food, the walking locust crawls out of its nesting site in monstrous swarms, destroying all vegetation in its path.
The raids of huge swarms of locusts have long been considered natural disasters, with many memories preserved of the devastation caused by migratory locusts that led to human famine. In ancient times, religion used the invasions of these pests to frighten believers. "Divine punishment for disobedience!" — priests of all times would say.
Locusts have many natural enemies. Many locusts are destroyed by rooks: in autumn and spring, they dig up cocoons, and in summer, they feed on larvae and adult locusts. Locusts are eaten by pheasants, and crows and ravens peck at them; the rose-colored starling is renowned as a locust destroyer. Larvae of gall beetles and hoverfly larvae parasitize in locust cocoons. All these enemies destroy a certain number of locusts, but during mass reproduction, their activity is, of course, hardly noticeable. It only becomes apparent when locusts are significantly thinned out in their nesting sites; predators and parasites then noticeably reduce their numbers, which are already small.
Distribution: Northern, Inner Tien Shan, Alai Valley
Melon grasshopper - Bakcha chigirke