THE NATURALIST.

Otago Witness, Issue 2215, 13 August 1896, Page 47

THE NATURALIST.

THE WATS OF MINUTE ANIMALS.

The habit of feigning death for the sake of protection can be observed among many of the lower animals — animals which differ widely in family, genus, and species. Indeed, this habit is to be observed in oreatnres miorosoopic in sfze and of exceedingly low organisation, bb well as in those as high in the soale of animal life as man himself; for even man does not hesitate, on oooaßions, to avail bimself of thiß natural subterfuge wben he thinks it will aid in the preservation of his life. "With the aid of the microscope one oan observeand study the natural history of theminnte animal world, which otherwise would remain aolo3ed and unread volume. This instrument has shown the writer beyond cavil, that creatures as low in the scale as actinophryans, very minute, mioroscopic animalcules, practise death-feigning when surprised by an enemy from which they cannot otherwise escape. Thus I have repeatedly seen aotinophryans fold their delioate, hair-like legs oroilia and sink to the bottom of their miniature lake (a drop of water) when approaohed by a water-louße, which preys upon them. They remain to all appearances absolutely without life until the water-louse swims away, when they unfold their oilia and go x back to their feeding grounds— a bit of water-weed or moss or decayed wood. A fresh-water worm is in the habit of making use of this stratagem when approached by the giant water-beetle. This little thread-like worm oan be found in almost every pond, as can also its natural enemy; the giant water-beetle ; so this interestlrg bit of natural histrionics may be witnessed by anyone who - will take the trouble to secure these creatures and place them in a jar of clear water. They are large enough to be seen with the naked eye : a lens, therefore, will not be neoesiary. The worm will be seen swimming with gentle undulations, when suddenly, in the twinkling of an eye, it will appear bereft of all motion, and, hanging in the water like a bit of thread, theßport and plaything of every current, will seem utterly lifeless. The cause of this sudden change is not far away, for, cleaving the water with arrow swiftness, its broad oar-like legs working with all the regularity of the oars in the weil-manned cutter of a man-o'-war, a giant water-beetle will make its appearanoe. As soon as it has disappeared from the immediate neighbourhood, however, the worm will " come to lite " and resume its swimming. Even an anemone, a creature of very low organisation indeed, has acquired this habit. On one ocoaßion, near St. Johns, Newfoundland, I noticed a beautiful anemone in a pool of sea weter. I reaohed down my hand for it, when, presto 1 it shrivelled and shrunk like a flash into an unsightly green lump, and appeared nothing more than a moss-covered nodule of rook. Very many grubs make use of this habit when they imagine themselves in danger. ]Tor Instance, the " fever worm," the larva of one of our common butterflies, is a noted death-feigner, and will "pretend dead" on the slightest provocation. Touch thiß grab with the toe of your boot, or with the tip of your finger, or with a stiok, and it will at onoe curl up, to all appearances absolutely without life. A gentleman recently told me that he saw the following example of letisimulation '{letttm, death, and aivivlare, to feign). One day, while sitting in bis front yard, he saw a caterpillar crawling on the ground at his feet. The grub crawled too near the edge of a little pit in the sandy loam, and fell over, dragging with it a miniature avalanche of sand. It immediately essayed to climb up the north side of the pit, and had almost reaohed the top when the treacherous soil gave way beneath its feet, and back it rolled to the bottom. It then tried the west side, and met with a like mishap. Not discouraged in the least by its failure, it then tried the east side, and reached the very edge, where it accidentally disturbed the equilibrium of a corncob poised upon the margin of the pit, dislodged it, and fell with it to the bottom. The caterpillar evidently thought that the cob was an enemy, for it at once rolled itself into a ball and feigned death. It remained quiescent for some time, but finally " oame to life," tried the south side with triumphant success, and went on its way rejoicing. This little creatnre evinoed consoious determination and a certain amount of reason ; for it never tried the .same side of the pit in its struggles to escape, but always essayed a different side from that where it bad encountered failure. " .The soaratjEeus, or " tumble-bug," is- a gifted letisimulaht.'ahd one with which experimentation can easily be carried on. It can bo seen any bright day in the latter part of July or in early August busily engaged in rolling its precious balls of manure, seemingly, here and there and everywhere along the roads and paths. This is not a pnrposeless pastime, however, on the part of this industrious little worker. [ There is a method in her seeming vacillation ; she is looking for a proper place in which to bury her treasure. The future welfare— nay, even the very existence —of her offspring depends on the judicious selection of a proper ! loil in which their cradle and their food (the ball of manure) is to be deposited until they emerge, 'youDg and vigorous " tumble-bugs." Touch this little mother with your foot, and at once her busy legs are drawn close to the sides of her body, her vibrating antennae or "feelers" are drawn beneath her head, and she sinks to the ground seemingly "as dead as a door nail." Step aside and wait a moment. Boon one of her antennas makes its appearanoe from beneath her head, followed in a second by the other; her ears are in these " feelers," and she is listening for dangerous sounds. Stamp your foot, and, presto! the antencse disappear, and she is again in the land of departed tumble-bug*. You may cause her to do this once or twice, but she soon discovers that the noise you make does not presage danger, and, her maternal instinct getting the better of her caution, she will busily resume the rolling of her ball. From some experiments I am confident tbat these beetles know their individual ballB ; tbat is, they are able to select their own property when placed among a number of balls. If, however, only one ball is given them, they will. accept it whether it be their own or not.— iippinoott's Magazine.