The Little Carpenter-Bee

Teacher’s Story

AKE a dozen dead twigs from almost any sumac or elder, split them lengthwise, and you will find in at least one or two of them, a little tunnel down the center where the pith once was. In the month of June or July, this narrow tunnel is made into an insect apartment house, one little creature in each apartment, partitioned off from the one above and the one below. The nature of this partition reveals to us whether the occupants are bees or wasps; if it is made of tiny chips, like fine sawdust glued together, a bee made it and there are little bees in the cells; if it is made of bits of sand or mud glued together, a wasp was the architect and young wasps are the inhabitants. Also, if the food in the cells is pollen paste, it was placed there by a bee; if of paralyzed insects or spiders, a wasp made the nest.

The little carpenter-bee (Ceratina dupla) is a beautiful creature, scarcely one quarter of an inch in length, with metallic blue body and rainbow tinted wings. In May, she selects some broken twig of sumac, elder or raspberry, which gives her access to the pith; this she at once begins to dig out, mouthful by mouthful, until she has made a smooth tunnel several inches long; she then gathers pollen and packs bee-bread in the bottom of the cell to the depth of a quarter-inch, and then lays upon it, a tiny white egg. She then brings back some of her chips of pith and glues them together, making a partition about one-tenth of an inch thick, which she fastens firmly to the sides of the tunnel; this is the roof for the first cell and the floor of the next one; she then gathers more pollen, lays another egg, and builds another partition.

Thus she fills the tunnel, almost to the opening, with cells, sometimes as many as fourteen; but she always leaves a space for a vestibule near the door, and in this she makes her home while her family below her are growing up.

The egg in the lowest cell of course hatches first; a little bee grub issues from it and eats the bee-bread industriously and grows by shedding his skin when it becomes too tight; then he changes to a pupa and later to a bee resembling his mother. But, though fully grown, he cannot get out into the sunshine, for all his younger brothers and sisters are blocking the tunnel ahead of him; so he simply tears down the partition above him and kicks the little pieces of it behind him, and bides his time until the next youngest brother tears down the partition above his head and pushes its fragments behind him into the very face of the elder which, in turn, performs a similar act; and thus, while he is waiting, he is kept more or less busy pushing behind him the broken bits of all the partitions above him. Finally, the youngest gets his growth, and there they all are in the tunnel, the broken partitions behind the hindmost at the bottom of the nest, and the young bees packed closely together in a row with heads toward the door. When we find the nest at this period, we know the mother because her head is toward her young ones and her back to the door. A little later, on some bright morning, they all come out into the sunshine and flit about on gauzy, rainbow wings, a very happy family, out of prison.

But if the brood is a late one, the home must be cleaned out and used as a winter nest, and still the loyal little mother bee stays true to her post; she is the last one to enter the nest; and not until they are all housed within, does she enter. It is easy to distinguish her for her poor wings are torn and frayed with her long labor of building the nest, until they scarcely serve to carry her afield; but despite this she remains on guard over her brood, for which she has worn out her own life.

The story of the little carpenter-wasps is similar to that of the bee, except that we have reason to believe they often use her abandoned tunnels instead of making new ones. They make their little partitions out of mud; their pupæ are always in long, slender, silken cocoons, and we have no evidence that the mother remains in attendance.