Caterpillars are insect larvae that belong to the Lepidoptera order. These little creatures are very vulnerable and can easily become someone's prey, so they have to protect themselves in order to turn into one of the most beautiful insects after some time.
Building
Most have cylindrical, multi-segmented bodies with three pairs of true legs on the thorax and several pairs of short and thicker false limbs on the abdomen. There are six pairs of small eyes (stem) on the head, which function when detecting light, but not when forming an image. They have short, segmented antennae and strong jaws. Many caterpillars in the order Lepidoptera are called worms, such as the silkworm (silkworm) and the army worm (Spodoptera frugipeda).
What do they eat
Caterpillars are known for their insatiable appetite. They usually feed on the leaves of various plants, although some may eat insects or other small animals. Leaf-eating species can cause significant damagefruit trees, agricultural crops, ornamental plants, deciduous trees and shrubs. For example, caterpillars of the cabbage borer (Trichoplusia ni) can eat three times their body weight daily. In addition to the damage these caterpillars cause by eating cabbage leaves and related crops, the feces they produce, known as frass, can stain leaves and make plants unsalable. Examples of insect-eating caterpillars are Feniseca tarquinius, which preys on woolly aphids, and Alesa amesis, which feeds on insect nymphs of the order Homoptera.
Features of individual species
Some caterpillars have special respiratory structures that allow them to survive in aquatic habitats. For example, the larvae of some pyralid mollusks (family Pyralidae) are aquatic, and several representatives of the genus Hyposmocoma (family Cosmopterigidae) have an amphibious caterpillar stage. Some caterpillars weave silk sheaths that provide protective hiding places. They are often woven with leaves, pebbles, and more, making them look like part of their natural surroundings.
Defense strategy
All kinds of butterflies and moths start life as caterpillars. This is a very vulnerable form of the insect, so it needs protection.
Their appearance varies greatly, especially the coloration, which plays a major role in the ability to protect themselves from predators. In many cases, their coloring should mimic the appearanceenvironment, and it changes as it grows. For example, the young larvae of many swallowtail butterflies (Papilio) are white and brown and resemble bird droppings on leaves, but over time their appearance changes in such a way that the colors eventually become camouflage, allowing them to blend in with the leaves and stems of plants.. In some caterpillars, coloration is noticeable or enhanced by the presence of features such as false organs of vision, which can deceive or frighten predators.
Other defense strategies used by caterpillars include the release of foul-smelling substances, the use of sounds, the generation of vibration signals, and the sequestration of chemicals in tissues that are toxic to predators. Caterpillars of the great nocturnal peacock eye (Saturnia pyri) send out ultrasonic warning signals to deter predators. The caterpillar of the sicklewing butterfly (Drepana arcuata) produces vibration signals to defend its territory from intruders of the same species; she taps her jaws on the surface of the leaf and scratches it with hairy feet.
Monarch butterfly (Danaus plexippus) larvae rely on a defense system associated with their unique ability to feed on milkweed (Asclepias) plants. These plants produce compounds known as cardenolides, which are usually toxic to animals. Monarch butterfly larvae are not affected by the poison, and they are able to isolate the compound in their tissues. Because the venom remains with the insects in subsequent developmental stages, they are toxic to vertebrate predators, both as larvae and as adults.butterflies.
Classification
There are different types of caterpillars. This is primarily due to the diversity of the Lepidoptera themselves. Interestingly, the color of the larva does not always match the color of the adult. One classification of caterpillar varieties is based on what they eat.
- The group of polyphages is represented by their completely unscrupulous representatives who can eat any plants. These include night butterflies, for example, wine hawk hawk, ocellated hawk hawk, blind hawk hawk, kaya bear, moths, peacock-eye and others.
- The group of monophages includes caterpillars that feed on only one particular type of plant. These are cabbage, apple moth, silkworm and some others.
- The group of oligophages includes those who feed on a certain type of plant, they represent one family or type. These include: swallowtails, pine scoop, polyxena and others.
- Xylophages are caterpillars that feed on wood or bark. This group is represented by leafworms, wood borers and others.
Different stages of the life cycle
The caterpillar is the second phase of the butterfly's life cycle. Other phases: egg (first phase), chrysalis (third phase) and butterfly (fourth/last phase). The time it takes for a butterfly to complete its life cycle can take anywhere from one month to a calendar year.
Egg phase
She is the first incaterpillar life cycle. Eggs can be of various shapes, they can be round, cylindrical, oval, etc. Eggs are usually laid on the leaves of plants. Females may also leave eggs on stems. Their location on the leaves makes it easier to get food at the next stage of development (caterpillars). The eggs are protected by a hard outer covering known as the chorion. The thin layer of wax that coats it helps prevent the eggs from drying out. This phase usually lasts for several weeks. However, eggs that were laid during the winter months are dormant during the cold season. The larvae hatch from them only with the onset of the spring season.
Second stage of development
Caterpillars are very voracious creatures. They go through various phases of growth during their development. Apolysis is the process by which the caterpillar sheds its cuticle, the outer layer of protein and chitin. By the time the last growth phase is reached, wing development begins.
The legs of the caterpillars are of two types, that is, real and false. If there are only three pairs of the first, then there can be six on the body of the second
The second and third thoracic segments of the caterpillar's body have wing discs. Their development is associated with the trachea. They grow rapidly in the last stage of this phase. The hemolymph gradually pushes the wings through the epidermis.
Pupa phase
This is an intermediate stage between a larva and an adult butterfly. When the caterpillars turn into pupae, they stop feeding and look for the substrate for the last molt. Asapproaching the pupal stage, the hormone metamorphosis is produced, which ensures a change in the phases of development. Wings undergo rapid mitosis, so a lot of nutrients are required at this stage. To protect themselves from predators, pupae make certain types of sounds.
Adult
The fully developed form of the caterpillar is known as the adult. Butterfly wings that appear during the pupal stage take some time to dry out; The whole process takes about 3-4 hours. For the correct flight of the adult, the wings must be deployed.
Why caterpillars grow so fast
Growing fast is an important part of the survival strategy, because at this stage of their life cycle many species are extremely vulnerable to predators, so short pupation times give them the best chance of survival. However, there are species that remain caterpillars for long periods of time, some hibernate, and sometimes remain in a tree trunk for several years.
Interesting facts
- Stigmas (stigmas), holes in the lateral parts of the abdomen and chest are involved in the process of breathing of caterpillars.
- The total number of muscles present in the body of caterpillars is 4000. The head segment alone contains 248 muscles.
- Caterpillars have poor eyesight. The stems, which are six tiny eyes present on both sides of the head, help capture images.
- Some types of caterpillarspoisonous in nature; they can fire poisonous acids to protect themselves.
- The smallest caterpillar is a member of the moth family. Some of them are no more than one millimeter in size.
- The largest caterpillar is considered to be the peacock-eye atlas (Attacus atlas). Her body length can reach 12 centimeters in length.
- The most beautiful is the caterpillar of the black swallowtail with white, orange and black stripes.
- In the process of growth, some species change color, pattern, number of hairs on the body and even shape.
- The only period when most of them stop feeding is the time before pupation, when their bodies have already begun metamorphosis - the transformation of a caterpillar into a butterfly. However, some species may not feed for several months during the winter.
