A pond accommodates many small creatures well worth noting. The following are the most likely to be discovered:
Boatman (Water Boatman).
A small insect seldom more than an inch long. Dark brown to black. Flat and thin. It lies on the surface of the water, apparently upside down. Has long legs which show a jerky action. May be recognised by the black triangular plate on the thorax.
Creamy white, with soft body, a never-failing attraction to fish, and indeed to every carnivorous pond dweller. There are some 150 different species. They thrive in an Aquarium and are most interesting to observe. As the caddis-worm has no natural protection, it builds a case, varying, as regards material, in the different species. Some use shells fastened together by silken threads, others cut leaves and pieces of stick to suitable lengths and weave them into a protective case. Again, small stones and even grains of sand may be selected. When the case is complete, the builder crawls in, tail first, and fixes a hook round the bottom end of its case. This prevents the creature from being dragged out— should it be seized by the head by an assailant. When building material is scarce, very amusing scenes occur, for the caddis-worms quarrel and fight for possession. Should an architect leave a partly constructed home, even for a few moments, the work will be set upon by all the local builders— destroyed, and the material carried off in triumph to assist in their own constructions.
During the third stage of its existence, the entrances to the tube are covered over with thick silk and the case is strongly attached to heavy stones, so that it may not be carried away by the current, etc. Finally, the pupa breaks through its case, climbs to the surface, and after a short rest flies away. The perfect insect is a moth-like creature with long antenna? and beautiful cream-coloured wings, which are covered with soft hair.
Although more often found in rivers, some clear ponds give them a home. They are to be seen best at night-time, when they leave their holes at the edge of the water to search for food. They are members of the lobster family and resemble them in shape, but not in size. Colour, a putty-grey with patches of flesh tint.
Thereareabout fifty different species of Dragon-flies to be found in our country. Unfortunately many are rare, and still more unfortunately Dragon-flies, as a whole, are becoming more scarce each year. These beautiful insects are harmless, and do an immense amount of good by destroying countless numbers of flies and other winged pests. The eggs are deposited in the water by the female, and in due course hatch. The larva is an extraordinarily ugly creature, very savage, and always hungry. From the head a claw-like projection is shot out and unfortunate animals are seized and conveyed to the mouth of this ‘ogre.’ Several moults take place during this stage, each of which produces some advancement towards the final stage. At last this is attained, and after drying its wings the perfect insect soars away into space.
It is not generally known that our common gnat is actually a member of the mosquito family. About a dozen species have been found in our country.
The mosquito does not sting. The pain suffered from these creatures is caused by the operation of piercing our flesh, and inserting the drinking-tube, through which the ‘brute’ sucks our blood. Only the female mosquito is responsible for this irritation and annoyance, as the male does not suck blood and is perfectly harmless.
The males spend their time on the wing, dancing in great companies, sometimes rising so high that they disappear from sight. The females are found singly and take no part in the atrial evolution, as they are fully occupied in searching for suitable places in which to lay their eggs. The eggs are deposited together upon the surface of the water—perhaps a pond—frequently in a water-butt —in fact, anywhere where standing water may be found. The eggs float, and in hatching the submerged end opens and the larva? drop into the water. These larva? breath through their tails, which they poke through the surface film, hanging head downwards and washing food into the mouth meanwhile. The creature remains in this stage from twelve to fourteen weeks, after which it turns into a pupa. This, in due course, liberates the perfect insect, which, if a male, flies away to join the dance, or if a female, to indulge in the more important duty of egg laying.
There are about a dozen different species of these animals to be found in our islands. They are all worm-like creatures.
The Medicinal Leech is the largest and sometimes reaches a length of 7 inches.
The Horse Leech is the most common, and may be found in the majority of streams and ponds. It is a blood-sucker and preys on soft-bodied creatures such as tadpoles, earthworms, snails, etc. This leech attains a length of 5 or 6 inches when fully extended, and swims by gently undulating its body. It also moves from place to place by looping—I.e. drawing itself along by means of the suckers situated at each end of the animal. Leeches are very voracious and consequently have very few enemies. Some leeches lay their eggs and leave them to hatch, whilst others carry the egg-case about with them. The majority of our other leeches are small and much has yet to be learned concerning their habits.
A beautiful insect with two pairs of transparent wings. It spends its early days as a submerged larva, eventually climbing up a stem and out into the world. In its perfect stage, this insect lias no mouth, and consequently cannot feed. However, as it dies a few hours after leaving the water this is no great handicap. Mayflies are seen on the wing during a ,few days only each year, after which they settle on the water and are promptly eaten by fish— an inglorious end for such dainty creatures.
The shell of this variety of mussel possesses none of the regularity of shape shown by the marine kind. The shell is domed, but the edges are curved, flattened, and irregularly shaped. Colour, slatish blue. Usually found buried in the mud with one tip projecting into the water.
This is a four-legged creature, long in body and with a long, lithe tail. Belongs to the batrachian family and has lungs. It can, therefore, live out of, as well as in water. Three kinds can be noted.
Great Crested Newt.
O f t e n called the Triton, has a dark coat, black or brown, relieved by whitish mottling on the sides. Bright orange underneath. The skin is rough and provided with numerous wartlike marks.
Green coat marked with blue. Underparts are yellowish-cream.
The male has an olive-green coat, mottled with black. Underparts bear yellow and reddish patches. The female has a brown coat. Underparts are yellowish, with pin-points of brown.
Ram’s Horn Snail.
Has a somewhat attractive shell, curled like a ram’s horn. A dull brown in colour.
Scorpion. Water Scorpion.
Much resembles the (Water) Boatman in its habits, but is usually smaller and broader. Its fore legs are shaped like a pair of pincers.
Water Beetle, Great Diving.
This beetle has a dome-shaped body, sometimes 1A inches long. Dark green, occasionally almost black, with a stripe of yellow running round its edge. Underneath, it is a greenish brown. Note that the male has a smooth back, while the female is fluted. The jaws are very prominent and a useful weapon. Never keep these beetles with other pond inhabitants, or even two or three of them together, if of different sizes.
Although there are several species of spiders that inhabit the water-film and the fringe of ponds, only one, Argyroncta aquatica, is really aquatic.
The other so-called water spiders content themselves with hunting along the margins of the ponds, with occasional excursions over the water-film in pursuit of insects.
Argyroncta aquatica, the true water spider, not only dives beneath the surface, but actually builds a dome-shaped nest among the submerged stems of plants. This nest is stocked with air which the builder carries down from the surface—a bubble at a time, until the house is full. The spider takes up a position in the doorway and patiently waits until some unfortunate creature swims within grabbing distance. The spider then thrusts out its front legs and end deavours to seize its victim. If successful the captive is drawn in an- the spider’s jaws quickly set to work. Often the distance is misjudged and the spider obtains only a partial grip on its prey. In the ensuing struggle, the spider is at a great disadvantage, for it is unwilling to leave the protection afforded by the nest. Consequently the prey often escapes. When this happens the spider shows every sign of temper and disappointment, and when in this mood, it makes an amusing study.
Whelk, Fresh-Water .
Very much like a marine whelk, but the shell is less regular in shape, more coarse at the lip, and the surface is greenish.
Winkle, Fresh -Water.
Larger than the marine variety, the shell has more pattern, is greenish and somewhat slimy.