Nature Watch, with Ron Freethy THOSE who enjoy pond dipping can often find more in the winter than in the summer.

This is because many aquatic insects spend most of their life in water and only emerge in order to breed.

Stoneflies, mayflies and dragonflies, for example, have very brief periods as adults.

They fly in order to find a mate and then they die.

Dragonflies and caddis flies spend periods of at least a year, and in the case of some species much longer, as larvae living in fresh water.

They are very sensitive to pollution. Whenever you find these creatures during your pond dip you can be certain that the water is reasonably clean.

Many crustaceans spend all of their lives in water and one of the most fascinating species is the water flea which is called daphnia.

It is called a water flea because as it swims its movements are jerky and it seems to jump.

In unpolluted waters daphnia are very common indeed and they are fed upon by fish.

The daphnia itself is a filter feeder and sieves tiny plants from the water.

The water flea is just visible to the naked eye and its movements can be observed just by using any white plastic container. The water flea is a vital part of the food chain which can be traced back to the energy of sunlight: sunlight -- aquatic plants -- daphnia -- fish -- birds.

In some cases the food chain leads to human beings: sun -- tiny plants -- daphnia -- trout -- humans.

All this proves how important it is to make sure that our rivers, ponds and canals are kept free from pollution.

Anyone can enjoy pond dipping and it costs virtually nothing.

Begin now because February is a great time for pond dipping.

A word of warning, though.

All of us, but young people in particular, should take care when working near water.

The very young should be supervised and everybody should be vigilant.