[1] A genus of Longicorns, or Long-horned Beetles.—Translator’s Note. [↑]
[2] Cf. The Life of the Grasshopper, by J. Henri Fabre, translated by Alexander Teixeira de Mattos: chaps, i. to v.—Translator’s Note. [↑]
Chapter xiii
THE GEOTRUPES: NEST-BUILDING
In September and October, when the first autumn rains soak the ground and allow the Sacred Beetle to split his natal casket, the Stercoraceous Geotrupes and the Mimic Geotrupes found their family-establishments: somewhat makeshift establishments, in spite of what we might have expected from the name of these miners, so well styled earth-borers. When he has to dig himself a retreat that shall shelter him against the rigours of winter, the Geotrupes really deserves his name: none can compare with him for the depth of the pit or the perfection and rapidity of the work. In sandy ground, easily excavated, I have dug up some that were buried over a yard deep. Others carried their digging farther still, tiring both my patience and my implements. There you have the skilled well-sinker, the inimitable earth-borer. When the cold sets in, he will be able to descend to some stratum where the frost has lost its terrors.
The family-lodging is another matter. The propitious season is a short one; time would fail, if each individual grub had to be endowed with one of those mansions. Nothing could be more satisfactory than for the insect to devote the leisure which the approach of winter gives it to digging a hole of unlimited depth: this makes the retreat doubly safe; and for the moment its energies, [[204]]which are not yet suspended, have no other outlet. But at laying-time these laborious undertakings are impossible. The hours pass swiftly. In four or five weeks a numerous family has to be housed and victualled, which puts the sinking of a deep pit that requires time and patience quite out of the question.
In any case, precautions will be taken against the dangers of the surface. Once its family is settled, the unprotected adult insect is obliged to establish its winter quarters at great depths, whence it will emerge in spring accompanied by its young ones, like the Sacred Beetle; but neither the egg nor the grub needs this costly refuge in the wet season, being well protected by the parents’ industry.
The burrow dug by the Geotrupes for the benefit of her grub is hardly deeper than that of the Copris or the Sacred Beetle, notwithstanding the difference of the seasons. Eleven or twelve inches, roughly speaking, is the most that I find in the fields, where nothing occurs to restrict the depth. My cages, with their limited thickness of soil, are less trustworthy in this respect, since the insect has no option but to use the layer of earth at its disposal. Many a time, however, I perceive that this layer is not fully traversed down to the floor of the box, thus furnishing a fresh proof of the slight depth needed.
In the open fields as in the confinement of my cages, the burrow is always dug under the heap of dung that is being exploited. No outward sign betrays its presence, concealed as it is beneath the voluminous droppings of the Mule. It is a cylindrical passage, the same width as the neck of a claret-bottle, straight and perpendicular in a homogeneous soil, bent and winding irregularly in [[205]]rough ground where a root or stone may bar the way and necessitate an abrupt change of direction. In my cages, when the layer of earth is insufficient, the pit, at first vertical, bends at right angles on touching the wooden floor and is continued horizontally. There is no precise rule therefore in the boring. The accidents of the soil determine the shape.