06 Oct Leaf cutter bees
Mention of the word ‘Bees’, brings to mind, those huge swarms of buzzing insects living in a very well established social setup. Building huge colonies, consisting of thousands of individuals.
However, very recently did I learn that, not all bees live in colonies, meaning, live in a social group of many individuals. There are bees that live a very solitary life. One such, are the bees, belonging to the Megachilidae family, more commonly known as the leaf cutter bees. They are called so, based on the kind of material they use to prepare their nest cells, namely, small pieces of leaves. There are others in this family,like the mason bees, which collect soil as the material for their nest cells.
Leaf cutter bees are very important as pollinators.They are not aggressive and have a mild sting that is used only when they are handled.They cut the leaves of plants and use the cut leaf fragments to form nest cells. They nest in soft, rotted wood or in the stems of large, pithy plants, such as roses.
One leaf cutter bee individual had made its home inside a small crevice, in an old rusted gate of an empty site near my house. It was constantly flying to and from its new found home, each time returning with a small piece of something that looked like a fragment of a leaf. Curious about what it was up to, sat there observing it for a while, over one of the weekends. Did a bit of reading on them as well.
The crevice was more like an entrance to, what I felt, was a long tunnel inside the frame of the gate. Before flying out to fetch a leaf, the bee, very diligently, would clear the place of small stones, sand and other debris. Then, it would fly out, returning after a while, with a small piece of a leaf.
Arrives home with a leaf fragment….
It would enter its home with the leaf and get into the tunnel that it had cleared just before leaving. Since it was holding on to the leaf with its mandibles, it seemed that it wasn’t very easy for the bee to turn the leaf around to align it properly with the entrance to its tunnel home. So, for the initial few times, it used to fly out of the crevice and fly back in at the right angle to be able enter properly.
Flies out, to come back in, at an appropriate angle….
Slowly, it seemed to have learned and thereafter was getting inside very smoothly, with one flight, straight in.
Enters now with one straight flight in…..
This bee wasn’t really going too far to look for its leaf requirements. It had picked a tree close by, to cut out the pieces of leaf from. Was very skilfully cutting out the leaf using its mandibles. It seemed to be flying around the tree looking for the right leaf ( don’t know what the criteria for selection was ) and upon finding one, was making a very precise cut each time.
Cutting out a leaf with its mandibles….
An interesting fact about the bee’s leaf cutting exercise …… ( Src: Our Native Bees )
They cut the leaves with their scissor-like mandibles, making smooth, circular or oval cuts from the edges of leaves that are about 1/2″ in diameter. According to The Xerces Society, it only takes two or three seconds for the female to cut a piece of leaf. Just before she finishes cutting it, the female starts to beat her wings, so she is already flying by the time the leaf fragment is severed
The cut out designer leaves, thus remain, on the tree…., but don’t in any way harm it.
Cut out leaf sections…
Also, read that these pieces of the leaf that are carried into the bee’s home are used to embellish its nest cells and also to separate the individual cells. These cells would then contain one egg each, along with a little bit of nectar and pollen to provide for the larvae that would hatch out of the egg. The females of these bees are the ones that do all the work.
It takes an average of 15 leaf pieces or flower petals to line one brood cell, and a total of 20 to 30 trips may be required to gather the necessary pollen and nectar to provision just one cell. Under favorable conditions a female bee may finish an average of 30 cells in her lifetime. ( Src: Our Native Bees )
Really hard working mothers, these leaf cutter bees, are indeed………….