Aphid — gardeners and gardeners often encounter it – it causes damage to plants, causing a decrease in yields, and therefore they usually wage an uncompromising struggle with it. But still, it is worth taking a closer look at this insect and finding out if it has any interesting features, how it lives in general – especially since it will also help in the fight.
Aphids are a superfamily belonging to the class of insects. It has not been reliably revealed when and from whom insects originated – there is not a sufficient array of fossils of those times to reveal this. There are only the most reliable and widespread hypotheses, but they can be refuted over time. So, it was previously believed that they descended from centipedes, but now the point of view is much more common that they are closest to crustaceans and originated either from a common ancestor or directly from crustaceans.
The most ancient crustaceans were found in the Early Cambrian deposits over 510 million years old, insects – only in layers formed a hundred million years later. This makes it more likely that insects originated from crustaceans than from a common ancestor, although it cannot be ruled out that their oldest remains simply were not found or were not preserved at all.
Phylogenetic reconstructions are also consistent with this version. It is considered most likely that the insects evolved in the late Silurian period. But when exactly the aphid occurred is unknown. The fact is that its fossil remains are preserved very rarely, perhaps the only option is if they ended up in amber. But this method has limitations, since the oldest amber is 120 million years old. Ultimately, there are too few such finds to draw conclusions, but at least they allow us to establish the time when aphids already definitely inhabited our planet – the beginning of the Paleogene period.
It is also possible that they became one of species that appeared after the Cretaceous-Paleogene extinction, and that they arose much earlier. An analysis of the available data and the morphology of the aphids themselves does not allow us to lean towards one of these options: insects constantly continue to give rise to new forms, both developed and seemingly primitive.
For example, dragonflies and cockroaches appeared in the Carboniferous, Hymenoptera in the Triassic, butterflies in the Cretaceous, higher Diptera only in the Neogene, and lice in the Pleistocene, that is, quite recently by the standards of paleoanthology. Aphids are able to quickly change and adapt when new plants appear – this is favored by their breeding system with the accompanying rapid variability of generations. As a result, they formed an extensive superfamily, including ten families and thousands of species.
Its scientific description was compiled by P. Latreille in 1802, the name in Latin is Aphidoidea. But it should be noted that there are other classification options: sometimes, in addition to the indicated one, one more Phylloxeroidea superfamily is distinguished, and sometimes two – the last one is Adelgoidea. There is also a variant in which Aphidoidea becomes a megafamily, including a number of superfamilies. The researchers did not come to a common point of view.
Appearance and features
In shape, the body of the aphid is close to round, in most species the length is not more than 3 mm, although there are also especially large ones, reaching sizes up to 8 mm. The shape of the head is trapezoidal, with compound eyes and antennae standing out in front, serving as an organ of touch. Vision is very good, but the aphid does not distinguish colors, usually only a few shades. It itself can have a different color – most often it is green, so as not to stand out on the plant on which it feeds, but it can also be different: brown or dark gray, the same color as the branches, white, red. The aphid has a thin proboscis, with the help of which it draws juices from plants: it is sharp and is able to pierce a leaf or stem so that you can get to the juice.
The aphid's body is covered only by a soft and almost transparent shell – unlike insects protected by a chitinous cover, it is practically defenseless when attacked by a predator. Breathing holes are located on the anterior segments. Although the aphids have long legs, they usually move with difficulty and rather slowly. Representatives of some species crawl on plants, others can jump, pushing off with their front legs, but it is easiest for those who have wings. Such individuals can fly over fairly long distances, so that their offspring quickly disperse around the area. Interestingly, only females can have wings. Aphids without wings densely populate a small area, and it is with them that gardeners and gardeners have to fight. It exceeds the size of the insect itself: the adult aphid of this species reaches 5-6 mm, and the proboscis can exceed 10 mm.
Where do aphids live?
She is able to live almost anywhere where there are plants. The most preferable climatic conditions for it reign in the temperate zone – the insect does not like severe cold, but it also hardly tolerates heat. However, some species have adapted well to life in the tropics. In the subtropical climate zone, the greatest diversity of species is observed at all. Aphids prefer areas with average humidity, equally dislike both excessively wet and arid areas – but they are also found in them, just less often.
These insects are able to live in a variety of environments – in the steppes, meadows, fields, forests, parks, and finally, in gardens. If the summer is cold and rainy, there are very few aphids, but as soon as favorable conditions come, they multiply rapidly. Her eggs die at temperatures below 25-30 degrees, but even in the conditions of the north with its cold winters, aphids manage to survive under snow litter, in anthills or other shelters, where it is much warmer than outside.
Very often it can be seen near anthills – she develops a symbiotic relationship with their inhabitants. The ecological niche of aphids is very wide, you can encounter it both above the ground – it climbs onto plants and sucks juice from them, and in the air and in the soil – some species suck juices from the roots.
What do aphids eat?
It feeds on the juices of plants, and a variety of them. Some species have special preferences, but most aphids can drink juices from a wide variety of plants, and this applies to both grasses and shrubs and trees. Almost any non-horticultural or garden plant can be attacked by aphids, therefore it is more sense not to list them all, but on the contrary, from a list of species that she does not like – even their proximity can scare her away. Of the most accessible plants for gardeners, it includes garlic, onions and Dalmatian chamomile. There is another way to deal with aphids – to allocate a place on the site specifically for them and plant there those plants that attract them more than others.
- tuberous begonia;
- viburnum .
As a result, these plants are given to be torn apart by aphids, and it is assumed that pests will not be distracted by others. But for this they need to be planted at a distance, so a lot of space is required. In addition, the aphid population should be controlled and not allowed to multiply too much – poisonous chemicals may be required. Therefore, a similar, but slightly different method is sometimes used – the plants that attract aphids are planted in a ring around those that they must protect, and when the aphids breed on them, they mow down these plants and destroy its entire colony.
Features of character and lifestyle
The aphid feeds for most of its life. From morning to evening, she can suck the juices out of the plant, from time to time crawling onto a neighboring leaf, because in the former they have dried up. It is very voracious, mainly due to the fact that it constantly breeds, and this requires a lot of nutrients. Sometimes aphids enter into a symbiotic relationship with ants, taking advantage of their love of sweets. Aphids produce sweet secretions, and ants take care of them for this: they transfer them to other plants when necessary, protect them, care for their eggs and build shelters that protect from the weather.
When predators attack aphids, ants protect them to the last and often even die, hoping to wait for the approach of relatives. To make this happen less often, aphids can even be placed in an anthill, where it is much easier to ensure their safety, but you have to feed them. The very process of obtaining sweet secretions is called milking, because outwardly it is very similar to milking a cow – the ants massage the belly of the aphid, and it allocates a portion of viscous secretions, after which the ants immediately eat them.
A day from one aphid so you can get a very large amount of moisture, sometimes it is comparable to its weight. The shortest-lived species of aphids die a couple of days after birth, others can live for several weeks. In a cool climate, the life span increases to two months.
Interesting fact: Treatment of plants with poisons or bacterial solutions against aphids should be done in clear sun. If the weather is cloudy, then the leaves curl up, and inside them some pests can survive, and even a small number is enough to fill the entire area again very quickly. Therefore, it is necessary to treat all the areas where the aphid has settled, and it is better to agree in advance with the neighbors, if they have it too.
Social structure and reproduction
Aphids live in large colonies, while they can arise from one individual and reproduce incredibly. It happens like this: a fertilized male lays eggs, most often choosing inconspicuous and well-hidden places for this. Masonry may be near the roots of plants or in the bark of trees, in anthills. There, the eggs spend the winter, and when the heat comes, new individuals appear from them. These are wingless females capable of reproduction through parthenogenesis, that is, without the participation of males. Once in a favorable environment, they do it very quickly. In the next generations of some species of aphids, females are already born with embryos inside, and soon they themselves produce offspring.
This further speeds up the process and the aphids begin to multiply exponentially. A female can give birth to several dozen larvae every week, and they grow very quickly and begin to breed 2-3 days after birth for short-lived species, or 1-2 weeks for long-lived ones. All this time only wingless females appear. But if the colony of aphids grows excessively, and it begins to lack food in the area, winged females begin to be born. They fly away from the colony and establish new ones, still multiplying by parthenogenesis. Such a female is able to fly 20-30 kilometers.
Some species are dioecious: before the appearance of winged females, they live on some plants, after that they stop breeding on them, and move to others. Finally, in the fall, they return to their original place again. During the spring and summer, 10-20 generations of aphids manage to change, and if you do not fight it, then each time it becomes an order of magnitude larger. Finally, when the weather worsens with the onset of autumn, males and females appear that are able to reproduce sexually. In this case, fertilization occurs, and larvae will not be born, as before, but a clutch will be made that can survive the cold. There are far fewer of them – all that is required is to produce founding females in this way, which will begin to reproduce by parthenogenesis in the spring, and the whole process will begin anew.
Natural enemies of aphids
Insects feed on aphids and birds. Of insects, these are:
- some riders;
- praying mantises;
- ground beetles;
Of all these, the most harmless to the garden, and at the same time the most effective against aphids, are lacewings and ladybugs. For both, it can become the main source of food, and the eggs of these insects can be bought in specialized stores. After the population is hatched out of them, it will be possible to forget about aphids. Plants that attract these insects also help: umbrella, legumes and spicy. For example, common dill, clover or mint will lead them into the garden. And when buying eggs for breeding, you should also not forget about these plants, otherwise the brood may simply fly away, and the aphids will remain. Ground beetles can be attracted by nightshades, hoverflies flock to daisies, and for earwigs, you can put flower pots in the garden and put shavings in them. Small birds also fight aphids, but are not as effective, and can also damage gardens themselves.
Interesting fact: Parasitic wasps prefer to lay their eggs in green-colored insects, and ladybugs are more likely to prey on red ones. Aphids adapt to them – if there are more parasitic wasps nearby, then red ones are born, and if there are more ladybugs, green ones.
Now you know how to get rid of aphids in the area. Let's see how the insect reproduces.
Population and species status
There are a huge number of aphids of different species, their total population cannot be calculated. They live almost everywhere where people can live, and parasitize plants, including cultivated ones. Therefore, their status is a pest, which can be freely exterminated using various means for this, if possible, not threatening other living organisms. And although the aphid is an insect very weak and vulnerable, so it is easy to destroy them, but the problem in the fight against it is its rapid reproduction. The second problem is ants. Even if it seems that all the aphids in the area have been destroyed, it may turn out that some individuals have been covered by ants, and then they will multiply again in a matter of days.
There are several ways to deal with this pest:
- poisons – they act quickly and effectively, some also work against ants. The disadvantage is that during flowering their use kills bees, there are a number of other restrictions, depending on which preparation is used – they must be observed so that the poison does not get into the plants used for food;
- bacteria that infect aphids. The main plus is complete safety, since such bacteria are aimed specifically at aphids and harm only them. But their action does not last long, so the treatment will have to be carried out often;
- other means, such as the proximity of plants that repel aphids, the treatment of plantings with soap, wormwood, onion peel, needles – may be effective to a greater or lesser extent, depending on what kind of aphid attacked the plantings.
Aphids are a vulnerable insect with a large number of enemies, but all this is compensated by rapid reproduction, due to which a dozen new ones take the place of each dead individual . But do not forget that the aphid is not only a pest, it also has a useful role: it sucks out excess sugar from plants, which has a beneficial effect on photosynthesis, and its sweet secretions make the soil more fertile.