The Content Of The Article:
- Recognize hoverflies
- Reproduction and development
- way of life
- Meaning as beneficials
- Preferred forage plants
- Locate and promote hoverflies
- Natural enemies
Hoverfly (Syrphidae), also known as standing flies or flies, are often confused with wasps, which are very similar in appearance. However, they belong to the insect order of the two-winged (Diptera) and are a suborder of the flies (Brachycera). In central Europe circa 450 different species of hoverflies occur.
The animals stand out in the gardens of many hobby gardeners mainly by their special flying skills. With a high degree of constancy they can, similar to the hummingbird, remain in one place even when the air is moving. The wings then swing with up to 300 beats per second. The insects also owe their name to this extraordinary flight behavior.
Their early emergence in the spring and their enormous propagation and feeding potential make the hover flies to the most important natural enemies of aphids or blood lice. Especially in fruit growing, they are therefore used specifically as beneficials.
Since there are many different types of hoverflies, the insects also vary accordingly in color, shape and size.
The body of the animals can be both stocky and long and slim. The insects are in possession of short feelers. Among the individual species there are animals with and without hair. The hoverfly mouthparts are redesigned into so-called licking tools, as with most fly groups.
Frequently, adult hoverflies are mistakenly mistaken for the similar-looking wasps or even bees due to their yellow-black colored abdomen. But who looks closely, recognizes that it is about five to ten millimeters long insect is a fly. The great similarity to the comparatively dangerous biting insects serves in nature as a warning signal and protects hoverflies from potential predators. In biology, this phenomenon is called "mimicry". But unlike wasp and Co., the hoverfly is not in possession of a spine.
Another distinguishing feature between hoverflies and wasps is that they have only one pair instead of two wing pairs. Besides, her waist is not constricted. The hind wings are converted into stubby swinging cups (holders). The safest way to recognize hoverflies is by their type of zigzagging and the ability to stand in the air like a hummingbird - wasps, on the other hand, can only fly straight ahead.
Hoverflies usually lay their eggs directly on plants that are attacked by aphids
The whitish yellow, pin-shaped eggs of the larvae are about one millimeter long and have a smooth surface. They are usually deposited individually or in groups directly into the colony of lice. The 10 to 20 millimeters long larvae also differ greatly in their appearance. Most larvae are pointed at the front and have no head capsule. This is a distinguishing feature to the caped butterfly caterpillars. Due to the lack of legs, the larvae of hoverflies are not very mobile. Depending on the species they have a greenish, brownish, black or translucent body. The drop-shaped, brown pupae of hoverflies can be up to ten millimeters long, they are often found on leaves and shoots.
Reproduction and development
The developmental cycle of animals also differs from species to species. Hibernation occurs as a larva or a pupa in, for example, hedges, cracks or cracks in walls or house walls. Some species, such as the marsh hoverfly, even migrate south like migratory birds when it gets colder outside. One or more generations can occur per year. For species with only one year's generation, a summer or winter rest follows. In hoverflies with up to five generations missing a summer break.
Hoverflies usually find a suitable partner over the external appearance. For example, male animals have enlarged compound eyes for this purpose. The males then plunge in a kind of Rüttelflug on the female and mate the Chosen in flight.
way of life
For hoverflies almost exclusively plants and flowers are interesting as food sources
Since hoverflies are generally not interested in our food, you will most likely not find the little animals at the coffee table on the terrace or in your home. Instead, the insects visit flowers and plants whose nectar and pollen they feed on. As already mentioned, hoverflies do not form states, but lay their eggs close to the food sources of the larvae. The females have a very pronounced search behavior when laying eggs, which affects the colonies of aphids. Female hoverflies lay between 50 and 100 eggs.The predatory larvae then develop from them.
Meaning as beneficials
Adult hoverflies feed on the nectar, pollen and honeydew of the selected plants. Since they only have a short trunk, they depend on a rich supply of easily accessible flowers. The predatory larvae, on the other hand, mainly live on blood and aphids. Up to their pupation they suck out several hundred lice. For this reason, the young hoverflies are specifically used as beneficial insects in the garden and in the greenhouse. Elderberry (Sambucus), viburnum (viburnum), cereals and many types of herbs are often affected by lice infestation.
Since hoverflies are among the first predatory insects in spring, they can be used very early against lice such as the apple grass louse (Rhopalosiphum insertum). Later in the year, beneficial insects help to regulate economically important aphid species such as the floury apple aphid (Dysaphis plantaginea) or the apple wrinkled louse (Dysaphis spec.).
Preferred forage plants
Hoverflies are particularly fond of umbelliferae, such as bear claw (Heracleum), meadow chervil (Anthriscus sylvestris) and wild carrot (Daucus carota subsp. Carota). Giersch (Aegopodium podagraria), wild garlic (Allium ursinum), marsh marigold (Caltha palustris), hawthorn (Crataegus) and privet (Ligustrum) are also popular fodder plants. If you plant blackthorn (Prunus spinosa), creeping buttercup (Ranunculus repens), raspberry (Rubus idaeus), sal willow (Salix caprea) or coltsfoot (Tussilago farfara) in your garden, you will also successfully attract the beneficial insects.
Locate and promote hoverflies
Who wants to locate and promote the useful helpers in his garden, there are several options available. And attracting hoverflies is worthwhile, as the insect larvae eat up a large number of aphids during their development of about two weeks.
There are many different types of hoverflies. To see here: the Hainschwebfliege (Episyrphus balteatus)
On the one hand, the beneficial insects can be attracted with the help of the plants mentioned above. As flowering visitors, the hoverflies, however, rely on a broad and enduring flowering offer. Do not mulch margins too often. Shrubs and hedges are used by the animals as wintering quarters and as a reserve in the event of scarce food supply.
Furthermore, avoid the use of insecticides as hoverflies - especially their larvae - are very sensitive to it. In addition to direct control, the use also leads to indirect damage as a result of reduced food supply. With special nesting aids that are offered online or in specialist shops, you can successfully settle the insects in your garden. Gardening enthusiasts with craftsmanship can also build the nesting sites for hoverflies themselves.
The most significant natural enemies of hoverflies are parasitic wasps (Ichneumonidae), white-legged wasps (Chalcidoidea) and long-eared wasps (Proctotrupoidea). Even birds, dragonflies and other predatory flies can be fatal to them. And last but not least the person who confuses them with wasps and not infrequently kills.