Have you ever found some plants in the park with cut marks on their leaves, round or oval shapes, and are especially common on plants such as moons and roses. A closer look at the front and back of the leaves is hard to find, but when you look at the leaves a few days later, you will find more gaps. So, how exactly did these cut marks form?
In fact, this is the masterpiece of the leaf-cutting bee. Leafcutter bees are pale grey bees that are generally active during the summer months, especially between 1 and 2 p.m. on sunny days. Because of their short active time, it is difficult to find them on the leaves of plants. Leaf-cutting bees have large scissor-like jaws, and when they land on the leaves, they use their bodies as compasses to rotate their bodies while cutting a circular leaf on the leaves with two large jaws. The entire cutting process is fast, it only takes 2 to 3 seconds to complete, and then they quickly fly away with the cut blades.
All the blades cut are roughly the same shape and size, and this cutting technique of the leaf cutter was as good as using a mold. However, after careful observation, it will be found that the size of these blades can be divided into many types, and the role of each size of blades is different. What exactly are they going to do with these cut round blades?
Originally, leaf-cutting bees generally built their nests in dirt, tree holes, wall crevices, wood crevices, etc., to reproduce. The shape of the nest resembles a tunnel, and the bottom and entrance of the nest are basically circular, so they need to be covered by relatively small circular leaves. However, the placement direction of the leaves covering the side wall of the nest varies, and sometimes there are slight differences in size between the bottom leaf and the leaf inlet, so the size and shape of the cut leaf are different. For example, there is a leaf-cutting bee that has a leaf diameter of 11 mm at the bottom of its nest, 9 mm in diameter at the entrance, and a leaf diameter between 18 mm and 19 mm as feed.
Leaf cutters cannot always ensure the accuracy of the blade cut, and the size of the cut marks, the mastery of the cutting direction, and the deviation of the body rotation may cause the starting point of the final cut to fail to dock. Amazingly, leaf cutters are memorable and have their own unique workflow that adjusts to the cutting of the previous blade to produce the ideal next blade. In addition, leafcutters further process the cut round leaves and sew dice-like bags to store pollen, nectar and their eggs.
The nest built by the leafcutter bee contains a series of independent hives, each with several layers of leaves or petals and similar sizes. Usually, after laying eggs in the first hive, leafcutter bees will move to the top of this hive, create another hive in the same material and way, and so on, and so on, and then arrange them in turn.
Leaf-cutting bees and bees are close relatives and have the same life habits such as honey harvesting and pollination, but bees are social insects, leaf-cutting bees are not, female leaf-cutting bees like to live alone, and after mating with male bees, they begin to build nests and lay eggs.
Seemingly small nests, but with strict structural characteristics, coupled with leaf cutting bees are particularly particular about leaf size and shape, can provide a very comfortable home for the next generation, it can be seen that leaf cutting bees can also be regarded as the master tailors and architects in the animal kingdom.
This article is scientifically checked by Li Yanzhi, a senior teacher at Beijing No. 65 Middle School.
This work is the original of "Popular Science China - Scientific Principles One-Point Pass", please indicate the source when reprinting.