Megachile latimanus (leafcutting bee) | INFORMATION

Scientific Classification

Rank	Scientific Name
Kingdom	Animalia animals
Class	Insecta insects
Order	Hymenoptera
Family	Megachilidae leafcutting bees
Genus	Megachile
Species	Megachile latimanus leafcutting bee

By Megan Bush

Geographic Range

Leaf cutting bees, Megachile latimanus , live in the western parts of Canada and the United States, New Zealand, South America, and Europe. This species was accidentally introduced into North America during World War II through the movement of nests in crated war material. Once in North America, they developed large populations under favorable conditions.

Habitat

This species prefers a dry, warm habitat with temperatures exceeding 69 degrees Farenheit. Although Megachile latmanus is most active under these conditions, this species needs a colder temperature in order to break diapause and complete metamorphosis.

Habitat Regions
temperate
terrestrial

Terrestrial Biomes
savanna or grassland

Other Habitat Features
agricultural

Physical Description

Most leafcutting bees are moderate-sized, stout-bodied and dark colored. They average about 10 to 20 millimeters in length. Leafcutting bees, like other bees, are covered in tiny, branched body hairs that assist in collecting pollen. This particular species carries pollen on a brush of hair on the ventral side of the abdomen. Males have 13 antennal segments and 7 abdominal tergites, whereas the females have 12 antennal segments and 6 abdominal tergites. Like most other bee species, leafcutting bees have an elongated tongue for reaching the nectar of flowers.

Other Physical Features
ectothermic
bilateral symmetry
polymorphic

Development

Leafcutting bees develop in the same way as other Hymenoptera, undergoing complete metamorphosis. First larvae hatch from an egg, then as the larvae grows it passes through several instars (stages of growth) each ending with a molt of the exoskeleton. Once the larvae has fully matured it enters the pupal stage where it does not eat or move, but transforms into its adult morphology.

Development - Life Cycle
metamorphosis

Reproduction

Leafcutting bees reproduce sexually. This species mates on or around the nest. Usually during the morning, a male will seek out a female and attempt to mate by pulling at the tip of the female's abdomen. If the female is receptive, she will evert her stinger, allowing mating to take place.

A female will produce about one egg per day and an average of about 28 in a lifetime. As with all hymenoptera, the fertilized eggs will be female and unfertilized eggs will be male.

The females of this species provisions the nest with enough food for the larvae to eat throughout its developement. Megachile latimanus females lay their eggs on the larval food supply so as to guarantee the larvae will be able to grow. After the female lays her egg she seals the nest in order to protect the developing insect. Once the nest is plugged, there is no further parental involvement.

Parental Investment
pre-hatching/birth
- provisioning
  - female

Lifespan/Longevity

Females of this species live for at least one year, although little more is known about the lifespan of this species.

Behavior

One of the most distinguishing characteristics of leafcutting bees is their nest building behavior. Once a suitable tunnel has been found, usually a hole bored in wood or crevices in between rocks, a bee will build a thimble-shaped tube using leaf cuttings. Equipped with large mandibles, the bee cuts circular discs from the leaves of rose bushes and shrubs to build its nest. Bees transport the leaves by rolling them between their legs. In the first cell of the tunnel, the bee uses small, round leaves and then larger oval pieces. Plant juices and bee secretions are used as a paste to hold the leaves together. The bee will then fill the tube with a pollen and nectar mix and lay an egg on top of the food supply. Using more circular leaf cuttings, the bee then builds a tight fitting plug for the nest, which makes the nest water proof. Leafcutter bees are solitary insects.

After comleting metamorphosis within their nests, most adults will remain withing the nest to overwinter, chewing their way out of the cell the following spring.

Key Behaviors
flies
diurnal
solitary

Communication and Perception

Since this bee is a solitary insect little is known of their communication habits.

Food Habits

Leafcutting bees and their larvae feed on the nectar and pollen of legume flowers such as alfalfa and sweet clover. Their diet consists of about 64% nectar and 34% pollen. In order to obtain the nectar and pollen, a bee pries open the keel of a flower while inserting the proboscis (tongue) to suck the nectar. While sucking the nectar, a bee will collect pollen by rubbing against the stamen. To feed its larvae, a bee regurgitates the nectar and brushes off the pollen.

Primary Diet
herbivore
- nectarivore

Plant Foods
nectar
pollen

Predation

There are many parasites of leafcutting bees. Many species of flies, wasps ( Mutillidae ) and beetles ( Rhipiphoridae , Meloidae , and Cleridae ) parasitize the bees and their larvae, including Coelioxys bees that lay their eggs in the nests of M. latimanus to steal the food of the M. latimanus larvae. Certain ant species in the Crematogaster genus have also been known to attack leafcutter bee nests.

Ecosystem Roles

Leafcutting bees are important pollinators in natural and agricultural ecosystems.

Ecosystem Impact
pollinates

Economic Importance for Humans: Positive

This species of bees is important to the alfalfa industry in Canada and the United States. Leafcutter bees have been domesticated in these areas for farming purposes because of their alfalfa pollinating efficiency, ease of management, and usually rapid increase in populations. These bees adapt to a wide variety of climatic, nesting, and foraging conditions and maintain populations through the presence of predators, parasites, and insecticide poisoning.

Positive Impacts
pollinates crops

Economic Importance for Humans: Negative

Leafcutter bees damage the leaves of plants in order to build nests, but the good they do by pollinating plants far outweighs the damage in cutting the leaves.

Negative Impacts
crop pest

Conservation Status

This species is not in any danger of becoming extinct.

Other Comments

The common name of this species, leafcutting bee, is derived from its nesting behavior.

Additional Links

Encyclopedia of Life

Contributors

Sara Diamond (editor), Animal Diversity Web.

Nancy Shefferly (editor), Animal Diversity Web.

Megan Bush (author), Southwestern University, Stephanie Fabritius (editor), Southwestern University.

Nearctic

living in the Nearctic biogeographic province, the northern part of the New World. This includes Greenland, the Canadian Arctic islands, and all of the North American as far south as the highlands of central Mexico.

World Map

introduced: referring to animal species that have been transported to and established populations in regions outside of their natural range, usually through human action.

Palearctic

living in the northern part of the Old World. In otherwords, Europe and Asia and northern Africa.

World Map

introduced: referring to animal species that have been transported to and established populations in regions outside of their natural range, usually through human action.

Neotropical

living in the southern part of the New World. In other words, Central and South America.

World Map

Australian

Living in Australia, New Zealand, Tasmania, New Guinea and associated islands.

World Map

temperate: that region of the Earth between 23.5 degrees North and 60 degrees North (between the Tropic of Cancer and the Arctic Circle) and between 23.5 degrees South and 60 degrees South (between the Tropic of Capricorn and the Antarctic Circle).

terrestrial: Living on the ground.

tropical savanna and grassland: A terrestrial biome. Savannas are grasslands with scattered individual trees that do not form a closed canopy. Extensive savannas are found in parts of subtropical and tropical Africa and South America, and in Australia.

savanna: A grassland with scattered trees or scattered clumps of trees, a type of community intermediate between grassland and forest. See also Tropical savanna and grassland biome.

temperate grassland: A terrestrial biome found in temperate latitudes (>23.5° N or S latitude). Vegetation is made up mostly of grasses, the height and species diversity of which depend largely on the amount of moisture available. Fire and grazing are important in the long-term maintenance of grasslands.

agricultural: living in landscapes dominated by human agriculture.

ectothermic: animals which must use heat acquired from the environment and behavioral adaptations to regulate body temperature

bilateral symmetry: having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.

polymorphic: "many forms." A species is polymorphic if its individuals can be divided into two or more easily recognized groups, based on structure, color, or other similar characteristics. The term only applies when the distinct groups can be found in the same area; graded or clinal variation throughout the range of a species (e.g. a north-to-south decrease in size) is not polymorphism. Polymorphic characteristics may be inherited because the differences have a genetic basis, or they may be the result of environmental influences. We do not consider sexual differences (i.e. sexual dimorphism), seasonal changes (e.g. change in fur color), or age-related changes to be polymorphic. Polymorphism in a local population can be an adaptation to prevent density-dependent predation, where predators preferentially prey on the most common morph.

metamorphosis: A large change in the shape or structure of an animal that happens as the animal grows. In insects, "incomplete metamorphosis" is when young animals are similar to adults and change gradually into the adult form, and "complete metamorphosis" is when there is a profound change between larval and adult forms. Butterflies have complete metamorphosis, grasshoppers have incomplete metamorphosis.

semelparous: offspring are all produced in a single group (litter, clutch, etc.), after which the parent usually dies. Semelparous organisms often only live through a single season/year (or other periodic change in conditions) but may live for many seasons. In both cases reproduction occurs as a single investment of energy in offspring, with no future chance for investment in reproduction.

seasonal breeding: breeding is confined to a particular season

sexual: reproduction that includes combining the genetic contribution of two individuals, a male and a female

fertilization: union of egg and spermatozoan

internal fertilization: fertilization takes place within the female's body

oviparous: reproduction in which eggs are released by the female; development of offspring occurs outside the mother's body.

sperm-storing: mature spermatozoa are stored by females following copulation. Male sperm storage also occurs, as sperm are retained in the male epididymes (in mammals) for a period that can, in some cases, extend over several weeks or more, but here we use the term to refer only to sperm storage by females.

delayed fertilization: a substantial delay (longer than the minimum time required for sperm to travel to the egg) takes place between copulation and fertilization, used to describe female sperm storage.

diurnal

active during the day, 2. lasting for one day.

solitary: lives alone

herbivore: An animal that eats mainly plants or parts of plants.

nectarivore: an animal that mainly eats nectar from flowers

References

Andrewes, C. 1969. The Lives of Wasps and Bees . New York: American Elsevier.

Borror, D., D. De Long, C. Triplehorn. 1981. An Introduction to the Study of Insects Fifth Editon . Philadelphia: Sauders.

Borror, D., R. White. 1970. Peterson Field Guides Insects . Boston: Houghton.

Comstock, J. 1947. An Introduction to Entomology . New York: Comstock.

Essig, E. 1926. Insects of Western North America . New York: Macmillan.

Manitoba Forage Seed Association, 2004. "Pollination and Leafcutting Bees" (On-line). Accessed January 25, 2005 at http://www.forageseed.mb.ca/ .

Serrano, D. 2005. "Leafcutting Bees" (On-line). Featured Creatures. Accessed (Date Unknown) at http://creatures.ifas.ufl.edu/misc/bees/leafcutting_bees.htm .