Leafcutter Bee (Megachile)

Description

Most of the bees belonging to the leaf-cutting genus are of a moderate size ranging between 5 mm and 24 mm, similar to the size of a honey bee. They have a dark or black body with whitish hairy bands passing through their abdomen. These bees have a reputation for being effective pollinators. When they carry pollen in the undersides of their abdomen, the coloration of that particular area changes, appearing light yellow or deep gold.

The females appear larger with triangular-shaped abdomen pointed towards the tip. The males are smaller, with long antennae and a blunt abdominal tip.

Other Common Names: Mortar bees, megachild bees, resin bees

Distribution: Throughout the United States

Habitat: In burrows, hollow twigs, crevices, flower stems, rotting wood

Do They Bite/Sting: Yes, only for defense, their sting being mild and less painful than the yellowjacket wasps or honeybees

Lifespan: Males: 10 – 14 days, dying soon after mating; Female: Around two months

Predators: Beetles, wasps, flies, ants, and other wasp species

Behavior and Characteristics

Nesting

Living up to their name, the leafcutter bees neatly cut the leaves in a circular or semicircular manner. It uses the leaves as a lining to their nests that they make in the soil, inside holes in the wood perhaps made by other insects, or within stems of plants by constructing tunnels. The nests or these bee’s dwelling places are made up of several cells or chambers arranged sequentially in a single column. Each cell comprises a single egg placed by the female, alongside pollen often mixed with nectar as a food source for the larva that would eventually hatch out. There are exceptions, too, as all species of the leaf cutter genus do not cut leaves. Some, like those belonging to the Chalicodoma subgenus, carry dry plant resin in their mandibles to make their nests.

Social

All bees of the leafcutting genus are solitary. Most live by themselves instead of in big colonies or groups, unlike other social insects such as the yellowjackets, ants, bumblebees, etc. Most of the work, which includes digging the areas for constructing the nest, creating the nest cells, and supplying food to the young, is done by the female. After selecting the nesting site, the females hover in a zigzag pattern over the place to memorize the location.

They also defend and protect their nests but display less aggressiveness than the bumble or honeybees.

Diet

Like most other bees, their primary food includes nectar and pollen that they gather from flowers. They don’t have pollen baskets on the hind legs, unlike honeybees. Instead, the leafcutter uses its abdomen’s undersides to collect the pollen.

Life Cycle

1. Egg Stage

The adult females lay between 35 and 40 eggs on average during their 2-month life span. The eggs are laid inside the cells of the nests, with each egg placed inside a single cell. Then, the cells are securely sealed using a leaf segment, resembling the butt of a cigarette. The eggs that hatch into males are in front of the nest. Those that would develop into females remain positioned behind.

2. Larva Stage

The larva hatches from the eggs inside the nest, nurturing the food the mother bees leave for them. The mature larva remains dormant throughout the winter, mainly when the temperature is around 50°F.

3. Pupa Stage

The pupation stage also takes place inside the nest. They finally come out of their cocoon to develop into adult bees when the temperature gets slightly warmer to around 70 °F.

4. Adult Stage

Males hatch earlier than their female counterparts, searching for their mate right after their emergence. During mating, the males use their middle legs to clasp the female’s wings, pressing them against her body. The male’s sole function is to fertilize the female leafcutter bees, after which he dies.