1150 Marvels of the Universe 
A MARVEL OF INSTINCT 
BY HAROLD BASTIN. 
MANY caterpillars roll up the leaves of their food- 
plant, thereby forming retreats in which they take 
refuge when danger threatens. But although these 
insects well repay attention, they are completely out- 
classed in skill by certain small beetles—weevils, to 
be precise—which are grouped by naturalists in two 
families known as Rhynchitide and Attelabide. These 
weevils also roll up leaves, each species adopting a 
characteristic method; but, unlike the caterpillars, 
they do not spin silk threads to help them in their 
labours. Moreover, their habits are not inspired by 
any personal need for food or shelter, but by what 
is called—for want of a better term—parental instinct. 
In a word, the rolled leaves are to be regarded as 
for the female weevils 
) 
elaborately contrived nurseries ; 
lay their eggs among the folds, while the grubs, when 
they hatch, feed upon the partially-decayed leaf-tissue. 
One of these insects 
a pretty, coral-red species— 
is associated 
with the 
oak, while 
another, 
Photo by] (4. H. Bastin. 
A LEAF-ROLLING BEETLE. 
The second half of the leaf is now loosely 
scarcely less 
showy in 
appearance, wrapped around the first half. 
is to be sought among the foliage of hazel-bushes. For 
our present purpose, however, we will trace the habits 
of the small blue-black species known as Rhynchites 
betula—a double-barrelled name which refers to the 
insect’s characteristic rostrum, or snout, and to the 
fact that it is commonly found on the birch. Young 
birches, growing at the outskirts of plantations, are 
especially hable to harbour this little leaf-roller, although 
it is sometimes found upon other trees, including the 
alder. 
According to the common custom of insects, the male 
weevil takes little or no interest in the well-being of 
his offspring. The female does the leaf-rolling quite 
unaided. She sets about the work in a very systematic 
manner, and there can be no doubt that in her punc- 
tilious attention to detail lies the secret of her success. 
For it is no light task that she sets herself to accom- 
plish. A suitable leaf having been chosen, the insect 
Photo by) [A. H. Bastin. makes her way to a point at the edge, not far from the 
A LEAF-ROLLING BEETLE. leaf-stalk, and, working upon the upper surface, deliber- 
Botln eal eke mow Gigntance! Up: ately makes a curved cut from the edge to the midrib. 
