Warning color: colorful coat
The prototype of the little ladybug in “Insects” is the familiar ladybug. One of its important distinguishing features is the red base color and seven black spots on the elytra. I don’t know if you have ever thought about it: when the ladybug is foraging and flying in the fields and jungles, the red and black elytra markings form a sharp contrast with the green background. Isn’t it afraid of being spotted by predators?
In fact, this body color that contrasts sharply with the background is precisely a defensive method for ladybugs, which is called “warning color.” Warning colors are the bright colors and markings of certain odorous or poisonous creatures. It allows the enemy to be easily identified, so as not to be attacked, just like shouting to the enemy: “Seeing that I am equipped with a colorful poison, you hurry up and stay away from me.” Many animals in nature, such as snakes and frogs. , Moths, bugs and ladybugs all have such defense mechanisms. Related studies have found that the degree of red coloration of coleopteran insects is positively correlated with the alkaloid content in their bodies. That is to say, the greater the proportion of red on the elytra, the higher the alkaloid content in the body and the greater the toxicity. Therefore, in the long evolutionary process, some predators formed the habit of not feeding on red ladybugs.
Escape: Thirty-six strategies, walking is the best strategy
In the film, in order to avoid the hunting of the praying mantis, the little ladybug staged scenes of life and death in the tropical rain forest. Escape is an important defensive measure for most animals, and ladybirds are no exception. Almost all kinds of adult ladybirds have strong flying ability.
Ladybirds are a member of a large family of beetles, with horny forewings and membranous hindwings. The horny forewings are usually called “elytra” and have completely lost their flight function. Their main function is to protect the hind wings and weak abdomen. In addition to defending against attacks from natural enemies (mainly various predatory insects and spiders), elytra can also prevent rain, mucus and dirt from being contaminated, as well as various microorganisms.
The membranous hindwings are the main power system for ladybird flight and are usually folded and hidden under the elytra. Before taking off, the ladybug will first tighten the muscles at the base of the elytra and unfold the elytra to expose the folded hind wings. Studies have shown that ladybirds use a venous hydraulic mechanism to unfold and fold their hind wings. When the hind wings are unfolded, the ladybug pumps body fluid into the veins, and the hind wings can be rapidly unfolded within 0.1 second. When flying, the vibration frequency of the rear wing can reach 85 times per second, and the maximum flying speed is about 60 kilometers per hour.
Feign death: fall on the spot
If the vigilance color fails to warn certain predators, the ladybug will use the trick of “feign death” to escape. In the film, the little ladybug is upturned and motionless, while the ants look at each other around it and dare not step forward. Similarly, the suspended little ladybug also uses this trick to escape the “killing disaster” of being preyed by the lizard.
Feign death is a conditioned reflex of animals facing threats. False death is the most common in Insecta, such as ladybugs, beetles, leaf beetles, weevils, bugs and moth larvae. When these insects face threats, their leg muscles will rapidly contract and their bodies will fall from the leaves, thus achieving the purpose of avoiding natural enemies. In addition, fish, amphibians, reptiles, birds and mammals also have the habit of suspended animation, but unlike insects, they mainly take advantage of the habit of some predators only attacking moving targets or not feeding on dead bodies. .
Reflex bleeding: toxic and smelly
Seeing this, don’t think that suspended animation is a job without technical content—just lying there, in fact, this skill will be used in conjunction with other defense methods, which is far more complicated than we thought. In the film, a brave ant stepped forward to test the pseudo-dead little ladybug. When the ant touched the little ladybug a few times, the little ladybug’s abdomen released a kind of gas. It’s not that the ladybug is “gassing”, it’s defense through reflex bleeding.
Most of the adult ladybug’s leg joints and the spines on the back of the larva have the ability to reflex bleeding, that is, secrete a yellow hemolymph. This hemolymph not only has a pungent odor, but also is toxic to some predators, so it can effectively prevent the hunting of natural enemies. Researchers analyzed the hemolymph secreted by ladybugs and found that most of the hemolymph contains alkaloids that are toxic to other insects or arthropods.
Mimicry: Look at its seventy-two changes
In addition to the above several defense strategies, ladybirds can also defend themselves by mimicking. Mimicry refers to the phenomenon of ecological adaptation in which one organism imitates another organism in the form and behavior of another organism, thereby benefiting one or both parties. It is a special behavior formed by organisms in the long-term natural evolution process. This defense mechanism is widely present in many creatures in nature, such as octopus, chameleon, leaf, mantis and dead leaf butterfly, etc. are all mimicry masters in nature.
The larvae of some ladybirds can avoid attacks from natural enemies by simulating the shape of their prey. For example, the larvae of M. monsiensis are the main natural enemies of mealybugs. In order to obtain the honeydew secreted by mealybugs, ants will drive or attack the ladybugs, and the larvae of M. monsiensis will secrete a white wax silk all over the body. , Which makes them look very similar to mealybugs, so they can feast on mealybugs.
Each creature has its own way of defense when facing threats. The little ladybug can not only escape, but also avoid danger and survive through mechanisms such as alertness, suspended animation, reflex bleeding, and mimicry. This is also an important reason why ladybirds can find a place on the fiercely competitive earth.