This is how insects and co. Ensure reproduction

the essentials in brief

• Pollination describes the sexual reproduction of plants
• diverse forms, basic distinction between self-pollination and cross-pollination
• all plants need help with pollination, mostly from insects or wind
• Not only do bees pollinate plants, too Bumblebees, Butterflies, moths, beetles, flies etc.
• many plant species specialize in pollination by certain insects

What is pollination?

As with humans and with many animals, there are also two different sexes in plants Pollination come together - the male pollen is transferred to the female ovule (stigma) in different ways transfer. This is where the pollen germinates and grows through the flower pen. This is where the embryo sac cell is located, in which the male and female cells finally fuse with one another. After successful fertilization - because this is what it is - the seed-containing fruits are then formed. The reproduction was successful.

Digression

Is there a difference between pollination and fertilization?

Types of pollination

Kiwi flowers are dioecious (here: female flowers)

Basically, the biologist differentiates between monoecious and dioecious plants:

• monoecious plants: female and male flowers are on the same plant (hermaphrodite), appear either at the same time or at different times
• dioecious plants: there are male and female plants, each specimen forms only flowers of one sex

Depending on the frequency of a plant species, the type of pollination is decided, whereby there are two different options. Monoeous species are capable of self-pollination (provided the different-sex flowers are at the same time dioecious, however, always rely on cross-pollination by animals - mostly insects - or wind reliant.

Self-pollination

Self-pollinators are able to develop male and female genes and thus pollinate themselves - they are therefore not dependent on a second plant of the same species. Therefore, it is always a monoecious plant that has both male and female flowers. However, these plants also need insects, wind or other aids to transfer the pollen to the female flowers.

The advantage of self-pollination is that whole colonies can grow very quickly from a single plant specimen. Therefore, this ability is often found in pioneer plants - i. H. in species that colonize fallow land first - or in early bloomers. Typical self-pollinators are therefore peas, beans and barley. That too snowdrop or the anemone belong to this group.

Cross-pollination

Bees are probably the best-known pollinators

Cross-pollinators, on the other hand, are unable to fertilize themselves. Here the male pollen of one plant has to pass to the female ovary of another - otherwise a fusion of the genetic makeup is not possible. In contrast to self-pollination, cross-pollination has the advantage that the genetic diversity is greater and thus the ability of the species to adapt to its environment is greater. Cross-pollinators are always found in dioecious plants, but also in many monoecious species fall into this group - for example, when these male and female flowers are at different times carry.

Some species are even able to do both, can pollinate both themselves and other specimens of their own variety. Regardless of whether it is self-pollinated or cross-pollinated, all plants rely on outside help for this process. The pollen must either

• Insects like bees, bumblebees, butterflies, beetles
• Animals of different species passing randomly (and taking the pollen with them)
• Birds (e.g. B. Hummingbird) and nectar-sucking bats
• Elements like wind or water

be transmitted. Most plant species prevent self-pollination, as this is evolutionarily less successful than cross-pollination. Ergo, self-pollination is a kind of embarrassment solution when a suitable pollinator is not available.

Insect pollination

Butterflies also pollinate flowers

Many plants rely on the diligent help of various insect species for pollination. "Insect-flowered" species can be recognized by their typical flower characteristics such as

• bright, colorful flower colors (especially red, pink, yellow, purple or blue)
• very fragrant flowers
• special flower shapes

These characteristics serve to attract the pollinating insects. Many plant species have specialized in pollination by certain insects, so that for example

• Nectar composition
• Flower shapes
• Flowering time and duration

are precisely adapted to the flight times, hatching times and needs of the pollinator insects.

It is well known that bees pollinate plants. However, many people are less aware that not only bees take on this important task - bumblebees, butterflies, moths, beetles, flies and other insects are also active. Scientific research has shown that in many cases pollination is less than that of bees rather it takes place through other species - or it is more successful if different insect species are on the flowers frolic. For this reason, the frequently quoted word that after the bee became extinct, there would soon be no more plants and four years later humans would also die, is simply wrong. Quite apart from the fact that Einstein (to whom the quote is attributed) never made this claim.

Digression

Why do we talk about bee deaths? Will the honey bee no longer exist soon?

Wind pollination

The evolutionarily oldest form of pollination is wind pollination: In the primeval forests, in which initially only Conifers stood - deciduous trees did not emerge until much later - the wind blew the pollen to the female Blossoms. For this reason, all conifers are still pollinated by wind today - many other species such as birch, poplar, alder and hazelnut bushes only developed this shape afterwards. Typical characteristics of wind-pollinated plants are:

• pendulous, long catkin-flowers
• these are always male and carry millions of pollen
• these are often recognizable as pollen
• female flowers are inconspicuous
• have no petals or similar ornamentation
• and have only a few ovules
• no nectar is produced

Other typical representatives of wind-pollinated species are grasses, sedges, Rushes as well as nettles.

frequently asked Questions

What is water pollination?

Water pollination (also water bloom or Hydrophilicity) is the name given to the pollination of aquatic plants by water. Its movements ensure that the pollen is transported from one flower to the other. This phenomenon only occurs in a few aquatic plants that you can recognize by their inconspicuous flowers. Examples of this are the great mermaid (Najas marina), the common seaweed (Zostera marina) or the various types of waterweed (Elodea).

How can you help bees and other insects?

As wide a variety of flowers as possible attract pollinating insects into the garden

Anyone who opposes the bee or If you want to kill insects, you can do it with a few simple means: no pesticides or other toxins in the Use the garden, manage the garden as close to nature as possible and offer hiding places (dead wood, piles of stones, Sandy areas, Insect hotel(€ 11.33 at Amazon *) etc.), sow or plant many flowering plants (with unfilled flowers!) - especially umbellifers are popular with insects, but also flowering shrubs, provide plenty of flowering plants early and late in the year (flowering period from March and from July to October inside).

Why is it not a good idea to buy wild bees and reintroduce them artificially?

Basically, this idea sounds tempting: You simply buy wild bees of certain species and settle them in your garden - and you do something about bee deaths. Unfortunately, it is not that simple, as many nature conservation organizations emphasize. Because by artificially settling wild bees, you do not promote biodiversity, but endanger it.

For what reason? Because the bought bees displace native species (and thus their gene pool)! This is true even if it is the same species, because different populations from different regions also have different genetic information - and are also adapted to their respective home through evolution.

Are there also plants that can do without pollination at all?

No plant can do without pollination. However, there are many plants that can do without pollination by insects at all. An estimated 60 percent of all flowering plants worldwide need bees & Co. for their reproduction - other helpers such as the wind take care of 40 percent. In our food crops, this applies to cereals such as wheat, rye and barley, but also to legumes such as peas and beans. Without insect pollination, however, our table would be set less abundantly, as most types of fruit (such as apples, pears, cherries or strawberries) are dependent on cross-pollination.