The Leaf-Cutter Bee
NE beautiful day in late June when I was picking some roses, I saw a bee, almost as large as a honey-bee but different in shape and darker in color, alight on a leaf and moving with nervous rapidity, cut a circle out of a leaf with her jaws "quicker'n a wink;" then taking the piece between her fore-feet and perhaps holding it also with her jaws, she flew away, the green disk looking as large in proportion to her size as a big base drum hung to the neck of a small drummer. I waited long for her to come back, but she came not; meanwhile I examined the leaves of the rose bush and found many circlets, and also many oblong holes with the ends deeply rounded, cut from the leaflets.
I knew the story of the little bee and was glad I had seen her cut a leaflet with her jaw shears, which work sidewise like real shears. I knew that somewhere she had found a cavity big enough for her needs; perhaps she had tunneled it herself in the dead wood of some post or stump, using her jaws to cut away the chips; maybe she had found a crevice beneath the shingles of a roof or beneath a stone in the field, or she may have rolled a leaf; anyway, her little cave was several inches long, circular in outline and large enough to admit her body. She first cut a long piece from the rose leaf and folded it at the end of the tunnel; and then she brought another and another long piece and bent and shaped them into a little thimble-like cup, fastening them together with some saliva glue, from her mouth. After the cup was made to her liking, she went in search of food, which was found in the pollen of some flowers. This pollen was carried not as the honey-bees do, because she has no pollen baskets on her legs; but it was dusted into the fur on the lower side of her body; as she scraped the pollen off, she mixed it with some nectar which she had also found in the flowers, and made it into a pasty mass and heaped it at the bottom of the cup; she probably made many visits to flowers before she had a sufficient amount of this bee pastry, and then she laid an egg upon it; after this, she immediately flew back to the rose bush to cut a lid for her cup. She is a nice mathematician and she cuts the lid just a little larger than the rim of the cup, so that it may be pushed down in, making it fit very closely around the edges; she then cuts another and perhaps another of the same size and puts them over and fastened to the first cover. When finished, it is surely the prettiest baby basket ever made by a mother, all safely enclosed to keep out enemies. But her work is then only begun. She has other baby baskets to make and she perhaps makes ten or more, placing one cup just ahead of another in the little tunnel.
But what is happening meanwhile to the bee babies in the baskets? The egg hatches into a little white bee grub which falls to and eats the pollen and nectar paste with great eagerness. As it eats, it grows and sheds its skeleton skin as often as it becomes too tight, and then eats and grows some more. How many mothers would know just how much food it would require to develop a child from infancy until it grows up! This bee mother knows well this amount and when the food is all gone, the little bee grub is old enough to change to a pupa; it looks very different now, and although mummy-shaped we can see its folded wings and antennæ. After remaining a motionless pupa for a few days, it sheds its pupa skin and now it is a bee just like its mother; but as the oldest bee is at the bottom of the tunnel, even after it gets its wings and gnaws its way out of its basket, it very likely cannot escape and find its way out into the sunshiny world, until its younger brothers and sisters have gone out before it.
There are many species of these leaf-cutter bees and each species makes its own kind of a nest, always cutting the same size of circlets and usually choosing its own special kind of leaf to make this cradle. Some are daintier in their tastes and use rolled petals instead of leaves; and we have found some tiny cups made of gorgeous peony petals, and some of pansy petals, a most exquisite material.
At Chautauqua we found a species which rolled maple leaves into a tube which held three or four cups, and we also found there a bee stowing her cups in the open end of a tubular rod, used to hold up an awning. There are other species which make short tunnels in the ground for their nests, but perhaps the most common of all wedge their cups between or beneath the shingles on the roofs of summer cottages. But, however or wherever the leaf-cutter works, she is a master mechanic and does her work with niceness and daintiness.
The Leaf-Cutter Bee
Leading thought—When we see the edges of rose leaves with holes of regular pattern in them, some of the holes being oblong and some circular, we know the leaf-cutter bee has cut them to make her cradle cups.
Method—It is very easy to find in June or autumn the leaves from which the leaf-cutter bee has cut the bedding for her young. Encourage the pupils to look for the nest during the summer and to bring some of the cups to school when they return, where they may be studied in detail; meanwhile the teacher may tell the story of the nest. This is rather difficult for the pupils to work out.
1. Do you find rose leaves with round holes cut in their edges? Do you find on the same bush some leaflets with oblong holes in them? Sketch or describe the rose leaf thus cut, noting exactly the shape of the holes. Are the circular holes of the same size? Are the long holes about equal in size and shape? Do you find any other plants with holes like these cut in them? Do you find any petals of flowers thus cut?
2. What do you think made these holes? If an insect was taking a leaf for food would the holes be as regular? Watch the rose bush carefully and see if you can discover the insect which cuts the leaf.
3. Have you ever seen the little black bee carrying pieces of rose leaves between her front feet? With what instrument do you suppose she cut the leaves? Where do you think she was going?
4. Have you ever found the nest of the leaf-cutter bee? Was it in a tunnel made in dead wood or in some crack or cranny? How many of the little rose leaf cups are there in it? How are the cups placed? Are the little bees still in the cups or can you see the holes through which they crawled out?
5. Take one cup and study it carefully. How are the pieces of leaves folded to make the cups? How is the lid put on? Soak the cup in water until it comes apart easily. Describe how many of the long pieces were used and how they were bent to make a cup. Of how many thicknesses is the cover made? Are the covers just the same size or a little larger than the top of the cup? How does the cover fit so tightly?
6. If you find the nest in July or early August, examine one of the cups carefully and see what there is in it. Take off the cover without injuring it. What is at the bottom of the nest? Is there an insect within it? How does it look? What is it doing? Of what do you think its food was made? How and by whom was the food placed in the cup? Place the nest in a box or jar with mosquito netting over the top, and put it out of doors in a safe and shaded place. Look at it often and see what this insect changes into.
7. If the mother bee made each little nest cup and put in the bee-bread, and honey for her young, which cup contains the oldest of the family? Which the youngest? How do you think the full-grown bees get out of the cup?
8. Do you think that the same species of bee always cuts the same sized holes in a leaf? Is it the same species which cuts the rose leaves and the pansy petals?