July
Seasonal snapshots of nature in close-up
This month's features in our summer
issue :
The author of these walks regularly suggests that readers
carry a 10X hand lens on a walk to admire nature in
close-up...... particularly at this time of year, when the
countryside is full of flowers in bloom and insects to study.
This month, none of the subjects studied in close-up
require a microscope at all, just that 10X hand lens ...... and
if you have a camcorder or still camera with a rarely used 5-10X
macro capability why not take it with you on a walk and take some
close-ups! Two articles in 'Further Reading' provide more
information on buying and using a hand lens.
Please read the important
notes on collecting.
Everyone admires flowers, whether in the garden, ornamental park
or in the wild. The beauty of the larger flowers such as roses
and tulips can be appreciated without any magnification aid. But
those smaller flowers that are barely 5-10mm across often have
wonderful shapes, colours and textures that can be overlooked
unless you look closely with a lens.
For example, the Forgetmenot (Myosotis)
shown at the top of the page is a common flower in both wild and
urban areas, and is in flower around the author's garden pond at
the moment. The flowers are only 8mm across, but in close-up they
are beautiful! A 10X lens will reveal the wonderful detail shown
left (note the aphid on the flower).
Another
small flower that is attractive in close-up is the Speedwell (Veronica).
There are a number of wild species with delicate blue flowers,
but the garden varieties such as the one right from the author's
garden are also worth studying. Note that whereas the anthers of
the forgetmenot are almost enclosed within a tube formed by the
fused petals, the speedwell's anthers are not enclosed. (The
anthers are the pollen- bearing structures on the stamen, the
stalk which carries them).
Many larger flowers also have
easily overlooked detail in their flower structure. The Foxglove
(Digitalis) for example, which is in flower in the
author's area at the moment, is a tall plant with spikes of
pink-purple bell-shaped flowers 4-5cm long. If a flower is split
open, the patterning on the inside of the flower (right) and the
detail on the unopened anthers which carry the pollen can be seen
(left).
Studying the structure of flowers can give
you a valuable insight into the botanical distinctions between
plants of different families, and may create an interest in
identifying wild flowers. For example, the clover (Trifolium)
the low growing flower in grassland and the lupin (Lupinus)
a tall plant with spikes of typically blue flowers, bear no
obvious resemblance. However, inspection of the flowers with and
without a lens will show that they have a similar structure,
because they are both members of the pea family (Leguminosae).
At this time of
year the larvae of butterflies and moths can be seen on their
respective food plants. The larvae are often attractive and worth
studying in close-up. Hundreds of the larvae (caterpillar) shown
left were eating their way through the leaves of the dwarf willow
(Salix sp) in the author's garden. Only the midribs of
the leaves were left by the time they had finished!
A typical caterpillar has three pairs of true
legs at the front, which are just visible in the image, and five
pairs of stumpy or fleshy prolegs at the back. The last pair are
known as claspers. All the prolegs have numerous minute hooks,
with which the caterpillar keeps a firm hold on the food plant.
Another common sight
in the author's area at this time of the year is frothy masses on
the stems of plants. You may have noticed them many times
yourself, but have you ever stopped to examine what is inside
this froth? It is produced by the nymph (see Footnote 1) of the
froghopper which is also known as the spittlebug or cuckoo spit.
The nymph can be seen in the froth on the image right. It is
facing downwards, and the yellow abdomen and one of the two
reddish eyespots on the head are visible.
The nymph produces the froth by secreting a
fluid through the anus that is mixed with a secretion from the
abdominal glands. Air bubbles are introduced through a special
valve on the abdomen to create the froth (or spittle) that
protects the larva from predators and desiccation.
Froghoppers are bugs, and the adults which are
less than 15mm long, have some resemblance to a frog and are
powerful leapers. Although 'bug' is often used loosely to
describe any insect, it more correctly describes a distinct order
of insects (see Footnote 2) whose characters include piercing
mouthparts through which the insect sucks juices from the plants
or animals on which the bug feeds.
Go back to Walk
Contents
Footnotes on the froghopper section
1) A nymph is a sexually immature form usually similar to the
adult and occurs in a number of insect groups. In contrast, a
larva is also an immature stage before the adult (not just in
insects) but it bears no resemblance to the adult. For example,
the caterpillar is the larva of the butterfly and moth.
2) Froghoppers belong to the insect order Homoptera. This
order is considered by some taxonomists a sub-order of the order
Hemiptera and a separate order by others. The family to which the
froghoppers belong, the Cercopidae, is referred to as the
Aphrophoridae in some older textbooks. Confused? .... so is the
author!
Suggested reading
Read an article 8X
Everything in the July issue of Micscape by Maurice
Smith. This illustrated article gives advice on what hand lens to
buy, what to look at and even how to take video or still pictures
through it!
Read an article in the Micscape library on Using
your camcorder as a microscope by Maurice Smith.
This provides an illustrated introduction on how to use your
camcorder for close-up filming.
Flowers
The structure of plants and their flowers should be
covered in an introductory guide to botany or a good illustrated
identification guide to wild flowers of your region.
Encyclopaedias should also give a good introduction to the
structure of flowering plants.
Insects
There are a wide range of books on insects, particularly
the more popular groups like butterflies and moths. A good
example of a general guide is Collins Guide to the
Insects of Britain and Western Europe by M Chinery. ISBN
0 00 219137-7.
Note that general guides of this type only indicate
representative species or those most likely to be found for
groups such as beetles and flies, because of the large number of
species in some insect groups.
Image details
The flower images were taken using a CCD camera with a 50mm
SLR camera lens and extension tubes attached and the screen
magnifications are between 5-7X . The close-up of the Myosotis
is magnified 20X and was taken with the CCD camera attached to a
stereo microscope with no eyepiece using a 1X objective.
Camera images were transferred to the PC using a Creative Video
Spigot capture card.
Image manipulation using Photostyler v2.0 software.
Go back to Walk Contents
Return to Walk
Index
The author Dave Walker
is a UK based amateur naturalist keen to encourage people to
explore nature in close-up.
© Onview.net Ltd, Microscopy-UK, and all contributors 1995 onwards. All rights
reserved. Main site is at www.microscopy-uk.org.uk with full mirror at www.microscopy-uk.net.