banner


Line
Languages:                                
English / engels    
Dutch / nederlands

Line

[All pictures of garden wildlife on this page are thumbnails. Click on any thumbnail for a large format to be displayed.]

Mites and Ticks (Acari)

Mites are closely related to spiders. They also have 8 legs. They differ from spiders in one respect: they crawl out of their eggs with six legs only. Only after the first skinning the fourth pair of legs appear. Spiders are born with all eight legs. Besides mites are small, almost invisible to the naked eye. Many species are parasites to all kind of animals: from man to insects. Some mites are very small animals that hunt for insects mainly, such as plant lice. These small red animals are probably the best known mites known to most people.

These well-known red mites hunt for plant lice and other small insects.

Ticks usually are parasites living mainly on birds and mammals. Below you see pictures of tick nymphs. To the left a freshly hatched nymph, for like all mites the first instar has 6 legs only. To the right a later instar, which is complete and equipped with 8 legs. The tick is a small animal indeed, but that does not mean it isn't dangerous. On the contrary, ticks can be very dangerous indeed! They suck blood from mammals, including humans. Normally they bite you and hang on to you for one or two weeks, before letting go. But in the mean time they can give you some serious diseases. In Holland and Belgium the only disease they are spreading at the moment is Lyme's disease. This is a very severe illness, unless treated early with heavy medication. So when you detect a tick somewhere on your body check the spot regularly for weeks. When it's getting red, and white and red ringlets appear, do see your doctor immediately. In 1999 Hans was bitten 12 times (one bite resulted in Lyme's disease), in 2000 only 8 times with no serious consequences. Ticks bite animals all their life long starting from the moment of birth. The female adult ticks are considerably larger than the nymphs and more colourful. Below to the right two adult females and one adult male, which is entirely dark.

Ixodes ricinus Tick larva

Two pictures of the larvae of the Tick (Ixodes ricinus). To the left a newly hatched, to the right an older animal.


Below two pictures of adult ticks. Even though ticks have four pairs of legs, they only use the last three pairs to walk on. As they do not have antennes, the first pair of legs is used as sensors. They are packed with sensitive nerves and these are used to find victims, mates etc. The use of the first pair of legs as antennae is clearly visible in the picture to the left below. The female probably 'smelled' me and was ready to let go and fall upon me.

To the left: the first pair of legs is used like a pair of antennae. To the right: two females and one male waiting for a host.

Below to the left another nymph. To show you exactly how small the nymph is, there is a match next to it for reference. The smallest nymphs, those just hatched, have three pairs of legs only. Six legged mites are often called larvae instead of nymphs. Only after they have bitten their first victim, they cast their skin for the very first time and with that the fourth pair of legs appears and from that moment on they are called nymphs. To the right a male. The adult male lacks the red of the female. That is because it doesn't bite anymore. Being a larva or nymph the male sucks blood just like the female does, but once it is adult it stops eating alltogether. Like a female it waits on a stem for a hot blooded animal to pass by and just like the female it crawls on this animal when it is brushing against the plant. But instead of sucking blood it searches for females to mate.

To the left a small nymph, to the right an adult male.

Ticks are dangerous animals to people and there has been an explosion of them in the garden. Hence the question whether they have any natural enemy. They seem too small to be attractive for birds and we have never seen one in a spider's web. But then one day, I was turning over some stones to see what could be found underneath and got lucky. I saw a tick walking happily towards me, when it was noticed by a Red Ant. Immediately the ant started to bite the tick severely. Soon another ant showed up. Both ants were biting the poor tick incessantly. The tick soon stopped protesting. When it was completely quiet, the two ants transported the tick right into the nest. Even though I felt sorry for the tick, I was glad to know at least one natural enemy of the bugger...

Tick attacked by Red Ants.

Many ticks use warm blooded animals for host, especially birds and mammals. Many other mites however are parasites to other animals as well and can be found on insects. Many bees, especially bumble bees, suffer from these bloodsucking mites. Just take a look at the Bumble Bee below. It is covered by at least four mites. The mites will of course weaken the animal's condition and thus can be very harmful to the animal.

This Bumble Bee suffers from mites.

Many mites can hardly be seen without a microscope, for most are very small indeed. This is especially true for gall mites. Most are less than 1mm long. Yet it is very easy to determine whether they are there are not. Because where they sit on a plant, the plant reacts by showing an abnormal growth or swelling at that place. Such a swelling or growth is called a gall. Best known are the round, reddish balls on the leaves of oak. Galls may appear on the twig of a plant as well. Sometimes galls get quite big, in particular those on twigs. These galls are made up of very small leaves and twigs growing like a mistletoe. These bigger galls on twigs are called witches' brooms. Not only mites can cause galls. There are many other creatures capable of causing galls: gall flies, gall wasps, certain beetles, some moths and barklice. Even some fungi may cause galls! In many cases one can determine which creature caused the gall by looking at the gall itself! And that is a good way of identfying many small creatures, without the need to trace them down and put them under the microscope. Below a typical witches' broom. It can be seen on Broom regularly and when appearing often in considerable numbers. The galls are not very big, around 2 cm, but striking. They are caused by a very small mite: Aceria genistae.

Aceria genistae

This witches' broom on broom is caused by a tiny mite: Aceria genistae.



Line
        © Copyright 1998-2024 gardensafari.net (Hania Berdys)