March

Seasonal snapshots of nature in close-up

This month's features:
- A ladybird (ladybug) in close-up
- Feathers
- Hazel catkins and pollen

Spring is a little way off in the north of England where the author lives, but there are definite signs that the winter is nearly over. The birds are singing and looking for nest material and the catkins are out on the hazel trees. So why not join me for a walk to see what can be found for study under the microscope or hand lens?

Before you put your boots on, please read the important notes on collecting.

A ladybird (ladybug) in close-up

The ladybird probably needs no introduction, as it is a common garden beetle certainly in the UK. They are members of the beetle family Coccinellidae and most species do a valuable job in keeping destructive aphids and mites in check. But, have you ever stopped to look at one under a 10X hand lens or low power stereo microscope?

Many species hibernate at the same location each winter and often enter sheds or houses to do so. In the recent milder weather they are becoming more active and easier to find. All insects are fascinating when studied in close-up. You don't need to be an entomologist just to admire the wonderful texture and detail of the shell, legs, spines and colour markings. The two images show a close-up of the head and underbody of a seven-spot ladybird.

There is no need to kill the ladybird to study it. They often obligingly 'freeze' on the spot when touched so can be viewed with ease. Flipping it on it's back will enable a closer look at the legs and underbody. Return the ladybird to a shrub outdoors when you have finished viewing it.

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Feathers

Occasionally you can find a pile of feathers and bones in the countryside, where a bird of prey or fox has had a meal of a bird. Feathers are always worth studying in close-up especially if you can compare the small downy feathers and the larger display feathers. There are a number of types of feather, which have specialised functions ie insulation, flight display and sensory reception.

The typical feather consists of a central shaft (rachis), with pairs of branches (barbs) forming a flattened and usually curved surface called the vane. The barbs possess further branches called the barbules, and adjacent barbules are attached to one another by hooks which stiffen the vane. In short, a marvel of nature's engineering!

Large feathers are easy to study under a hand lens or low power stereo microscope. Try using transmitted light, and also reflected light from various angles to fully appreciate their structure.

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Hazel catkins and pollen

A few trees start to produce flowers towards the end of winter, the hazel (Corylus) and alder (Alnus) are two of the earliest to flower. The male flowers of the hazel (catkins) have been out in the north of England for a few weeks, and are now bearing pollen. They are an attractive sight and provide welcome colour to the countryside at this time of year.

The catkins are worth studying under a low magnification, to examine the structure of the flower. The anthers when ripe (shown as yellow ovals in the image above ) will split to bear the pollen which in turn is an excellent subject for examination at higher powers under the microscope eg with a x10 to x40 objective. Just dab a little pollen with your fingertip on a slide and cover with a cover-slip. You will have to vary the focus to appreciate the structure because the depth of focus will be small.

Pollen structure can vary widely between species of flowering plant. We will investigate this in more detail later in the year when more plants are in flower.

Why not join me next month to study nature in close-up in Spring?

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Suggested reading

The large encyclopaedias such as Encyclopaedia Britannica, are often a good introduction to flowers, insects and birds. Most libraries should have plenty of books that deal with these subjects in more detail.

Natural History Book Services A comprehensive on-line service with search facilities.

Image details

Fractal cherry tree created using Fractal Vision v2.5 by Dick Oliver, Cedar Software.
Images were taken using a CCD camera attached to the eyepiece tube of a stereo microscope using a x1 paired objective with no eyepiece. Camera images were transferred to the PC using a Creative Video Spigot capture card.
Image manipulation using Photostyler v2.0 software.

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