Cabbage Butterfly is a lepidoptera insect from the family of whites. Her second name – cabbage white is associated with the name of the family and genus. This kind of — Pieris brassicae was described by Linnaeus in 1758 as a member of the mace.
Origin and description
The name, both Latin and Russian, indicates that the main food plant for the larvae is cabbage. The wings of these Lepidoptera are white, which is also evident from the name. The cabbage has two more close relatives – the turnip and the rutabaga, they look similar, but the cabbage is larger. Its size can be compared with another whitefish, also a related species, — hawthorn, but there are no black marks on it.
Found almost throughout Eurasia, in some regions they migrate. In the northern latitudes, they become much more numerous in the middle of summer, due to migrations from the southern regions. Long-distance and mass migratory flights are not typical for this species, since there is a sufficient food base everywhere, but they can travel up to 800 km.
Fun fact: In August 1911, Professor Oliver visited a small island of about 2 acres in Norfolk. The whole space was covered with fluttering cabbages. They were caught by the sticky leaves of the insectivorous sundew plant. Each small plant captured 4 to 7 butterflies. When their professor saw them, almost all of them were still alive. He calculated that about 6 million individuals fell into the traps.
If the male starts courting a female who has already been fertilized, then she instantly plunges into the grass to hide from an annoying admirer. She closes her wings and stays still, relying on her underside camouflage. Usually a suitor can find her, due to the pheromones emitted, quite aggressively trying to impose herself.
At first she responds by swaying slowly from side to side. This is followed by a partial opening of the wings, which prevents contact. She raises her belly at a steep angle (perhaps simultaneously emitting a chemical deterrent) to signal her rejection of her mate, and the male flies away.
Fun Fact: Males emit a distinctive, scent-like odor pelargonium.
Appearance and features
Cabbage has white wings with black corners on the front. Females have a pair of black spots on the forewings, they are brighter, there is also a black teardrop-shaped stripe along the lower edge of the forewings. On the anterior margin of the first wing, some scales are black, it looks like a smoky stripe. So the black tips, closer to the very corner of the wing, become lighter. There is a black mark in the center of the upper edge of the lower wing, which is not visible when the insect is sitting, as it is covered by the front ones.
The undersides of the females' wings are pale greenish with dark pollen, and the forewings are mottled. Males have a more buffy underside. When the wings are folded, it serves as good camouflage. In this position, the hind wings almost cover the front ones. Their span is 5-6.5 cm. The antennae are black and white at the top. The head, thorax and abdomen are black with white hairs and whitish below.
Video: Cabbage Butterfly
The caterpillars are blue-green with three yellow stripes along the body and black dots. The pupa (2.5 cm) is yellow-green in color with gray-brown dots. It is girdled with a silky thread, which is attached to the leaf.
Whites are an aposematic species, which means they have warning colors to deter predators. Aposematic coloration is present in the larval, pupal, and adult stages. They also contain toxic mustard oil glycosides from food plants. Mustard oils contain sulfur compounds that impart a pungent odor to the larvae and their droppings. The unpleasant smell repels many birds and insects that might prey on them.
The insect has well-developed organs of vision and a rather acute sense of smell. Club-like thickenings on the antennae and forepaws serve as organs of touch. The female, before laying her eggs, sits on a leaf of a plant, carefully feels it, testing it for suitability, and only after that starts laying.
Where does the cabbage butterfly live?
This species of Lepidoptera is distributed throughout Europe, including the islands of the Mediterranean Sea and the subarctic regions of Scandinavia. Cabbage white is also found in Morocco, Algeria, Tunisia, Libya and throughout temperate Asia up to the Himalayan mountains. It does not occur naturally outside of these regions, but was accidentally introduced to Chile.
The appearance of cabbage has already been recorded in some regions of South Africa. Great concern was also caused by the fact that these arthropods were discovered in 1995 in Australia, and in 2010 in New Zealand. This pest of vegetable crops was found several times in the northeastern United States. It is not clear how the butterfly got there, it may have arrived illegally with a cargo.
The butterfly is well adapted to migrations, it is not difficult for it to replenish the population on the islands, as happens in England, where the cabbage flies from the mainland. They are often found on agricultural lands, in park areas, in vegetable gardens and on farms, they love open spaces. They can sit on fences, tree trunks, but always where there are food sources nearby for the next generation. In the mountains it rises to a height of 2 thousand meters.
On sunny days, adults fly from flower to flower, feeding on nectar, and on cloudy weather they sit on grass or low bushes, wings half open. So they warm up, part of the sun's rays, reflected from the wings, falls on the body.
What does the cabbage butterfly eat?
Winged creatures feed on the nectar of flowers. To do this, they have a proboscis coiled into a spiral. They can be seen on: dandelion, meadow calico, alfalfa and other flowers. Spring nectar sources are also tenacious and spurge, while summer broods prefer:
Butterflies lay their eggs on cruciferous plants, they are especially attracted to different varieties of cabbage. Plants with mustard oil glucosides are important for nutrition. These substances give the white cabbage a specific smell that repels enemies.
Interesting fact: Studies have shown that the type of plant on which clutches are made is determined by the previous experience of the insect. When selecting, they are guided by shades of green.
The caterpillars feed together, quickly absorbing leaves, leaving only veins, then move on to neighboring plants. They are one of the main pests and cause great damage to the cabbage family grown in fields and private gardens.
These are different varieties and derivatives of cabbage, especially Brussels sprouts, cauliflower, kohlrabi, as well as mustard, rapeseed, a total of 79 types of cruciferous, including bedbug, chickweed, and radish. Caterpillars are very fond of tender nasturtium leaves and mignonette.
Character and lifestyle features
Cabbage whites are among the first to appear as soon as the weather gets warmer. Even on cloudy days, when there are still few other insects, they can be seen fluttering over green spaces. They have a fairly powerful, undulating flight, and over obstacles such as bushes, trees, buildings, they easily fly over or tack between them.
As soon as the cabbage whites reach the place where there are flowers, they remain there for several days. In sunny weather, they make short but regular flights, stopping briefly every few seconds to drink nectar on undersized flowers.
Two generations of butterflies grow during the season. In the southern regions, the first generation in April-May, in the north & # 8212; a month later. In the second period, more individuals appear, it falls on the second half of the summer. Another generation is possible in the south.
Despite the fact that caterpillar larvae live on the plant they feed on, pupae of these insects can be found on tree trunks, fences, walls, at some distance from the host plant. Sometimes pupation occurs on the stem or leaf of the plant. Most often, the chrysalis is attached with a thread in a vertical position.
Interesting fact: Those pupae that are formed on the trunk or leaf of a forage plant are a solid dull green, while those that are formed on artificial grounds are a pale yellow tint, mottled with tiny black and yellow spots.
Social structure and reproduction
Whites are polygamous, but most of the females have one partner. 2-3 days after copulation, butterflies lay rather large pin-like ribbed eggs of pale yellow color (about 100 pcs.). For the first day, they become bright yellow and quite noticeable against the background of a green leaf. Ten days before larvae emerge from them, the eggs darken and the shell becomes transparent.
Interesting fact: If skittish butterflies see that other females have laid eggs on a plant, then there is no longer set aside theirs.
Most often, laying is done on the back of the leaf, so it is invisible to predators, not subject to solar insolation or precipitation.
During the development period, the larvae go through five instars through four stages of molting:
- The first is characterized by the fact that the larvae emerge from a light yellow egg with a soft, furry body and a dark head.
- At the second age, tubercles become visible on the body, on which hairs grow.
- At the third instar, they become very active, yellow-green in color with black dots and already cause great damage.
- The fourth instar is similar to the third, but the caterpillars are already larger, more active, the body shade is greenish-blue.
- At the fifth age, they become large (40-50 mm), with an elongated body, bright color. During this period, the food supply is especially important.
If the larvae do not receive the best possible food in sufficient quantities, then they may die before they become butterflies. In the pupal stage, summer individuals do not spend long, and after 2-3 weeks a new white-winged specimen is born. If pupation occurs at the end of summer or autumn, then they hibernate until spring.
Interesting fact: Studies have shown that female cabbage bugs more often feed on thistle and buddelea nectar. If their diet is dominated by legume nectar, then their larvae do not survive, as these crops do not contain nutrients that promote their development.
Natural enemies of the cabbage butterfly
About 80 percent of the larvae die from the rider Apanteles — Apanteles glomeratus, which injects its eggs into them. This happens at a time when the caterpillars are still small. The larvae of the predator hatch inside the body of the host, and slowly devour it, but at the same time the cabbage lady continues to live and consume food. When the ichneumon larvae grow up, they eat the host's vital organs and kill her and break through the skin.
Sometimes you can see the dry remains of a caterpillar shell surrounded by a cluster of up to 80 tiny yellow fluffy cocoons on a cabbage leaf. The next spring, the riders emerge from their cocoons and fly in search of new cabbage white caterpillars. Having found a potential prey, the female rider probes it with her antennae to estimate its size.
The size of the larva should be such that the offspring that will develop inside have enough food. An overgrown individual may turn into a pupa before the larvae of the parasitic insect develop there. Riders pierce the victim with an ovipositor and release one egg there. The female can make several such injections in one caterpillar.
Many pupae, when they have just formed and their integuments are still soft, are attacked by the parasitoid wasp Pteromalus puparum. She lays her eggs there. Up to 200 individuals of a predator can develop in one pupa. For three weeks, the larvae develop in the cabbage chrysalis. If this happens in the summer, then adult insects come out of it, in the autumn, they remain to winter inside.
The cabbage whitefish does not have a specific group of predators. They are preyed upon by a wide range of different birds. They are eaten by some mammals, rarely — reptiles, one insectivorous plant.
They are potential food for some:
Population and species status
These Lepidoptera have a large distribution area and are quite aggressive pests of cruciferous plants. If you do not fight them, then cabbages can lead to a 100% loss of crops of different types of cabbage, they can eat radishes, turnips, swedes, rapeseed. The fact that adults are prone to migration poses a threat to areas where they were previously few or not found before.
Damage from whitefish can lead to a significant decrease in the value of the crop. Outwardly, cabbage heads will look quite decent, but inside they are often damaged by larvae. Caterpillars often hide inside the cauliflower, which lowers its value. The high localization of larvae leads to the fact that one clutch eats the plant up to the skeleton, and moves on to another.
This pest is exposed to chemical methods of destruction. In small areas, caterpillars and insect eggs are harvested by hand. Although the population is constantly controlled and regulated by humans, the insect is considered a pest in many European countries, in China, Turkey, India, Nepal and Russia, where there is a significant annual crop loss on various vegetables.
In 2010, in New The Zeeland butterfly was first discovered. Within three years, it has multiplied and become a serious and unwanted invasive pest.
Fun Fact: To encourage children to join the effort to eradicate the cabbage moth, the New Zealand Department of Conservation offered schoolchildren a NZ$10 bounty for every moth caught during the school holidays. In two weeks, 134 copies were handed over. Employees of the department caught 3000 adults, pupae, caterpillars and egg clusters.
To combat the cabbage white, in addition to chemical and mechanical methods, biomethods were also used there. Special predatory wasps were released into the fields. This pest control company has been successfully completed. This success was due to the fact that the alarm was raised immediately and measures to combat cabbage were taken in the early stages. But in Australia and the USA, these Lepidoptera continue to breed and settle.
Interesting fact: Whites avoid laying eggs where they see other relatives. To deceive them, you can place white “flags” made of light fabric on pegs or wire among the plantations, which will imitate the pest's competitors.
The cabbage butterfly can fill your site very quickly. To prevent the reproduction of cabbage plants, it is necessary to fight cruciferous weeds, sweep or whitewash tree trunks and fences in autumn and spring to remove pupae. During the season, it is necessary to carefully inspect the plants and collect caterpillars, oviposition. It is undesirable to use chemical protection methods that can kill beneficial insects. The use of folk remedies is more justified: infusions of wormwood, tobacco, chamomile, etc.