alfalfa leafcutting bee

Published on Oct 6, 2016

Leafcutter Bee (Megachile)

The genus Megachile is a cosmopolitan group of solitary bees, often called leafcutter bees or leafcutting bees. While other genera within the family Megachilidae may chew leaves or petals into fragments to build their nests, certain species within Megachile neatly cut pieces of leaves or petals, hence their common name. This is one of the largest genera of bees, with almost 1500 species in over 50 subgenera. North America has many native Megachile species. The introduced alfalfa leafcutter bee (Megachile rotundata) is managed for crop pollination.

Nests are sometimes constructed within hollow twigs or other similarly constricted natural cavities, but often are in burrows in the ground. Nests are typically composed of single long columns of cells, the cells being sequentially constructed from the deepest portion of the tunnel outwards. The female places an egg in each cell with a supply of food, generally pollen, sometimes mixed with nectar. She builds a cap and walls off the cell. The larva hatches from the egg and consumes the food supply. After moulting a few times, it spins a cocoon and pupates, often after several months of hibernation as a prepupa. It emerges from the nest as an adult. Males, which are typically smaller and emerge in advance of females, die shortly after mating, but females survive for another few weeks, during which time they build new nests. Numerous families of wasps and bees parasitize Megachile nests, including Gasteruptiidae, Leucospidae, Sapygidae, and various kleptoparasitic megachilids, such as the closely related genus Coelioxys. Megachile rotundata and Megachile campanulae are among of the first insects documented in scientific literature to use synthetic materials for making nests.

Notable species:
Megachile albisecta (Klug, 1817)
Megachile campanulae, bellflower resin bee
Megachile fidelis, faithful leafcutting bee
Megachile perihirta, western leafcutting bee
Megachile pluto, the largest bee in the world
Megachile rotundata, alfalfa leafcutter bee
Megachile rubi
Megachile sculpturalis, giant resin bee
Megachile texana

Leafcutting bees are important native pollinators of North America. They use cut leaves to construct nests in cavities (mostly in rotting wood). They create multiple cells in the nest, each with a single larva and pollen for the larva to eat. Leafcutting bees are important pollinators of wildflowers, fruits, vegetables and other crops. Some leafcutting bees, Osmia spp. are even used as commercial pollinators (like honey bees) in crops such as alfalfa and blueberries.

How Do They Differ From Honey Bees?

On first sighting, many species of solitary bees can easily be mistaken for honey bees or even hoverflies. So how can you tell the difference between honey bees and leafcutters, if the leafcutter is not engaged in the activity of cutting leaves or building its nest, but instead, is foraging on flowers?

One give away lies in their methods for collecting pollen. Worker honey bees, like bumblebees, collect pollen in their pollen baskets or ‘corbicula’ on the hind legs, then transport it back to the hive or nest.

Leafcutter bees do not have pollen baskets on their hind legs. Instead, they collect pollen on hairs on the underside of their abdomens. When the bee is carrying pollen, it is quite visible as a pale yellow colour.

Published on Jul 7, 2016

ღ SLEEPING ON LAVENDER ღ
Alfalfa Leafcutter Bee - Megachile rotundata L. - female ~ By Dragana M. Redzic, Serbia
Recorded : July 7, 2016 in 8:04 PM in Arandjelovac city, Sumadia Region, Serbia;
Frame width: 1929
Frame height: 1080
Frame rate: 29 frames/second
Data rate: 15024 kbps
Total bitrate: 15151 kbps

Published on Jul 25, 2011

Photographed at Grand Forks, North Dakota (25 July 2011). Thank you to John Ascher (@Bugguide.net) for identifying this specimen!

Published on Jun 23, 2011