Nature watch, with Ron Freethy

LAST week I described the cold-blooded animals - the amphibians of Britain.

Molluscs and insects are also cold-blooded but when we describe their blood it is not in any way like that of vertebrates.

The blood of vertebrates is red and contains iron. The pigment is called haemoglobin. Molluscs have blue blood and their oxygen and carbon dioxide is carried in a copper pigment. Insects have colourless blood and it does not circulate around the body but is just a fluid which bathes the organs.

Insect blood does not carry oxygen and it breathes by a system of tubes. There is a hole called a spiracle in every segment of the body and this leads into tiny tubes called tracheoles. These tubes reach to every body cell.

This works very well for small animals but would not work for large creatures which would have to have a pump to push oxygen in one direction and carbon dioxide in the other. This is why insects are small compared to mammals and other vertebrates.

Many insects have ethylene glycol in their blood, which we know as anti freeze. This explains why insects like butterflies are able to cope with cold spells like that we experienced recently.

As we move into spring there are several creatures which emerge from hibernation, including the large black slugs which feed on nettles but eat many other things, much to the annoyance of gardeners. Toads and hedgehogs do a wonderful job as they feed on slugs. The common wasp also emerges in numbers in April and May and makes its nests of a paper which it produces from chewed wood. Not only do wasps sting us but they are also destructive and you need to get rid of them from houses. A wasp nest in the eaves means damaged timber. Many butterflies are able to handle spells of cold weather quite well and the peacock, which looks so colourful and delicate, is actually quite a tough cookie. They hibernate as adults and so they tend to be out and about early. Many moths are also active in all weather conditions. Actually, there are many more species of moth than there are butterflies. Some people say that if it flies in the daytime then it must be a butterfly but there are actually a lot of day-flying moths.

The best way to tell the difference between moths and butterflies is to look at their antennae. Those of butterflies are simple and shaped like clubs while those of moths are complex and feather like. This is because moths rely more on sound location and butterflies rely more on sight. The antennae of moths are like radar detectors.

Most people who enjoy the countryside tend to concentrate more on birds but in spring and summer there are many invertebrates awaiting discovery.

When roads take their toll

TRAVELLING along the countryside roads in the warmer months can be depressing because of the number of mammals and birds killed by fast-moving traffic.

Last weekend seemed particularly gruesome and on one journey between Burnley and Halifax along the country route I saw the bodies of three hares, numerous rabbits, 12 hedgehogs and a badger.

The latter reminded me of a year or two ago when I found a badger which had been recently killed, at the roadside near Burnley. I was walking and so I returned to my car and took the body to a taxidermist. There is a good skilled craftsman in the museum at Cliff Castle, near Keighley.

My badger is now part of a museum collection.

I was once shown a skull of a badger which showed just how powerful its jaws are.

There are huge muscles in this region of the skull and also a mechanism which enables the animal to lock its jaw. Once gripped by a badger, you stay gripped.

Many museums now obtain their specimens as a result of road casualties.

If you would like a list of these museums, send your name and address to this column and I will let you have some contacts.

Converted for the new archive on 14 July 2000. Some images and formatting may have been lost in the conversion.