Megachile rotundata

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Megachile rotundata
ARS Megachile rotundata.jpg
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Megachilidae
Genus: Megachile
Subgenus: Eutricharaea
Species:
M. rotundata
Binomial name
Megachile rotundata
(Fabricius, 1787)

Megachile rotundata, the alfalfa leafcutting bee, [1] is a European bee that has been introduced to various regions around the world. As a solitary bee species, it does not build colonies or store honey, but is a very efficient pollinator of alfalfa, carrots, other vegetables, and some fruits. Because of this, farmers often use M. rotundata as a pollination aid by distributing M. rotundata prepupae around their crops. [2] Each female constructs and provisions her own nest, which is built in old trees or log tunnels. [3] Being a leafcutter bee, these nests are lined with cut leaves. [4] These bees feed on pollen and nectar and display sexual dimorphism. This species has been known to bite and sting, but it poses no overall danger unless it is threatened or harmed, and its sting has been described as half as painful as a honey bee's. [5]

Contents

Taxonomy and phylogeny

Megachile rotundata is a member of the subfamily Megachilinae, which includes more than 4,000 bee species; this currently makes this family the second-largest among all bee families. This subfamily is one of four other subfamilies of Megachilidae, the other three being the Fideliinae, Pararhophitinae, and Lithurginae. Phylogenetic studies suggest that this subfamily is monophyletic. [6] More specifically, it belongs to the genus Megachile , which contains 52 subgenera and 1,478 species. The genus Megachile consists of bees that cut leaf pieces to line their nests. [5]

Heads-on view of female Megachile rotundata, F, Face, MD, Cecil County 2013-07-08-18.34.45 ZS PMax (10825248485).jpg
Heads-on view of female

Description and identification

Backside of female, showing such features as the thorax, abdomen, wings, and color of the body hairs Megachile rotundata, F, Back, MD, Cecil County 2013-07-08-18.28.02 ZS PMax (10825526013).jpg
Backside of female, showing such features as the thorax, abdomen, wings, and color of the body hairs

Megachile rotundata is a European leaf-cutting bee placed in the subgenus Eutricharia, the "small leaf-cutting bees"; they are 6–9 mm (0.24–0.35 in) in length. [7] [8] They are partially bivoltine, meaning that under the right conditions they can produce two generations per year. [9] These bees present a sexual dimorphism, in which the males are smaller than the females and differently marked. [10] Megachile rotundata bees are a dark grey color. Females have white hairs all over their bodies, including on their scopae. In contrast, males have white and yellow spots on their abdomens. [5]

Distribution and habitat

Megachile rotundata is currently found on all continents except Antarctica. [6] In North America, the species was deliberately imported to assist in the pollination of food crops, but has now become feral and widespread. [11] M. rotundata was also introduced to New Zealand in 1971 [12] [13] and Australia in 1987 to assist in the pollination of alfalfa (known locally as lucerne). [14] [15]

Nest construction

Females construct tubular nests in a variety of sites, including rotting wood, flower stems, reeds, and soda straws. In the wild, females also create nests in small holes in the ground or in available cracks/crevices in trees or buildings. The nests are composed of a string of individual cells, as many as the space will allow. When managed for pollination, the females are induced to nest in paper cylinders similar to drinking straws or drilled blocks of wood.

Each cell is made from circular disks cut from plant leaves using the bee's mandibles, hence the name "leafcutter". [11] Females use about 15 leaves per cell, called a concave bottom, overlapping the leaves to produce the thimble-shaped cell. [3] While the bees do not store honey, females do collect pollen and nectar which they store in the cells of their nests. [11] Specifically, females first regurgitate the nectar they have provisioned into the cell and then transfer the pollen that is attached to their scopa on top of the nectar. [3] Each cell contains one pollen and nectar ball, and one egg [11] with each cell containing a 2:1 nectar-to-pollen ratio. [3] The completion of one cell in the nest requires between 15 and 20 provisioning trips. After the female lays her eggs, she seals the cell with circular leaf pieces. [3]

Nest dimensions and sex ratio

Studies reveal that positioning of male and female progeny in the nest is strategic and that cell size plays a major role in the size of progeny, independent of the mother's size. Females have been observed to lay female eggs in the inner cells and male eggs in the outer cells. With respect to sex ratios, larger cell provisions are correlated with a greater production of female offspring. Two explanations exist for these behaviors in terms of mother's foraging behaviors: 1) The mother brings more provisions to the inner cells because she expects that female progeny will be produced there and 2) the mother chooses to fertilize her egg, and therefore promotes the production of female progeny, because she has to bring larger provision proportions to a larger cell. [16] The sex ratio changes depending on nest size, length, and nesting material. This ratio is controlled by the female. These observations have been made for females that make their nests in tunnels. For example, a 5.5 mm tunnel diameter is associated with a 3:1 ratio and a 6.0 mm tunnel diameter is associated with a 2:1 ratio of males to females. Shorter tunnels, those that are below 5.0 cm long, are less favorable. [17]

Nest recognition

During nest construction, females transfer olfactory cues onto their nests to facilitate nest recognition. Specifically, they transfer these hormones by running their abdomens along the nest or excreting liquid from the tip of the abdomen. The olfactory cues are especially concentrated around the nest entrance. When these olfactory cues were experimentally removed, females of M. rotundata were unable to identify their own nests, revealing the importance of these chemicals. The chemical composition of these olfactory cues includes hydrocarbons, wax esters, fatty aldehydes, and fatty alcohol acetate esters. [18]

Life cycle

Pupae of (A) female M. rotundata and (B) subfossil male Megachile gentilis Leafcutter bee pupae.png
Pupae of (A) female M. rotundata and (B) subfossil male Megachile gentilis

As a member of the Hymenoptera order, the alfalfa leafcutter bee is haplodiploid. [19] Adults emerge by the end of the summer through one of two developmental pathways: larvae will develop by the end of one summer and proceed through the a prepupal diapause phase until the next summer; or larvae, known as "second-generation" bees, skip this phase and emerge as adults in the same summer. [9]

The larva transitions through four instar stages before emerging as an adult. During its development, which occurs rapidly, the larva consumes the pollen ball and enters diapause when the pollen is fully consumed. In its progression into the diapause phase, the larva defecates pellets in a ring formation and then spins its cocoon out of silk threads. The next spring, the mature larva pupates, a process that lasts 3–4 weeks, and completes its development. Once the bee is developed, it cuts its way out from the nest by chewing itself out of its cocoon. [3]

Upon emergence, females mate immediately and begin constructing their nests after a week. [4]

Progeny released via the two alternative pathways for emergence display different sex ratios and sizes. Among adults that emerge during the summer of the same year, the sex ratio is biased towards males. Among the "second-generation bees", however, the sex ratio is female biased. Further, spring-emergent adults weigh more than summer-emergent ("second-generation") adults. These differences have been proposed to be attributed to the chances of survival to mating of the two sexes and the metabolic costs involved in development. Bees that undergo diapause and emerge in the spring must endure the long winter, so require more food stores. As a result, they will be larger when they mature. Another explanation has been that smaller bees mature faster, thus are able to mate more quickly when they emerge in the summer to avoid the cold, harsh conditions of the winter. [20]

The sex ratio of the offspring also depends on the distance between nesting and foraging sites. Females have been observed and determined to bias their offspring sex ratio to males at larger flight distances from the nest. [10]

Kin recognition and fratricide

Research on second-generation bees illustrates that kin recognition of nest mates is not a genetically based behavior. Further, fratricide has been hypothesized to be a nondiscriminatory behavior; emerging individuals treat developing siblings and non-siblings similarly. When developing in cells behind diapausing bees, inner-nesting bees either bypass the nest in front of them, retreat back to their nests until diapausing individuals emerge, or chew through the nesting cells in front of them, killing the diapausing bees. These decisions are contingent on the extent of development of delay of nestmates. For example, emerging individuals would remain in their cells when they were delayed from emerging for a relatively short period of time. When delayed for longer periods of times, however, emerging individuals would use their mandibles to destroy the cells of their nest mates. With respect to sex differences, males have been observed to bypass nests more frequently than females due to the small size of males. [21]

Sexual behavior

Mating

Megachile rotundata has been found to be a monandrous bee species. [22] During the mating season, males attempt to obtain mates by positioning themselves at sites where female are likely to be, including foraging sites and nests. While females can mate several times, they resist male advances by restricting their mating to one sexual interaction and fleeing from these males. This behavior is attributed to female productivity during the construction of her nest and egg-laying. When harassed, females are unable to build their nests efficiently, making less foraging trips and spending a longer time overall in nest construction. Fleeing allows females to avoid being mounted. In the process of fleeing, however, females may lose their nesting materials, such as leaves and must then make an additional trip to make up for the lost materials. [19]

Sexual pheromones

Sexual pheromones in epicuticular waxes are released by females to assist in attracting males as mates. Studies of the emissions from these waxes reveal that alkenes are the primary compound detected by males. Further, females of different ages emit different pheromones, containing different alkene compositions. In young females, substances that classify as either 7-pentacosene or 9-pentacosene are present in the highest concentrations and, in older females, 5-monoene compounds predominate. During mating season, males are able to detect these pheromones and preferentially select young females to copulate with. [23]

Interaction with other species

Diet

Megachile rotundata can feed on nectar and pollen from a variety of plants [24] but prefer Medicago sativa . [5] Females will immediately begin feeding after emergence during the maturation period of their eggs. [4] During feeding, the bee will insert its proboscis into the keel of the plant. In the process, pollen is brushed onto its scopa. [5]

One predator of M. rotundata, Trichodes ornatus, on a yellow inflorescence Trichodes ornatus on a flower.jpg
One predator of M. rotundata, Trichodes ornatus, on a yellow inflorescence

Predators

Currently, 28 species are known to prey on M. rotundata, all of which have unique ways of invading and destroying their host nests. Some species include Trogoderma glabrum , Trogoderma variabile , Tribolium audax , Tribolium brevicornis , and Trichodes ornatus . T. ornatus is the most formidable predator, with females laying their eggs in cracks between leaf pieces. During development, T. ornatus larvae kill host bee larvae and consume pollen from nest provisions. When it reaches the third stage of development, it burrows into adjacent cells and consumes host larvae irrespective of host larval instar stage. In another case, female T. glabrum females lay eggs in cracks between cells at the back of the nest. As they develop, the larvae begin to consume host larvae, moving towards the front of the nest and eating females first. In a third case, T. variabile attacks M. rotundata when it is in its cocoon or the pupal stage. [25]

Parasites

Various families of wasps are the primary parasites of M. rotundata. Some species include Pteromalus venustus , Monodontomerus obscurus , Melittobia chalybii , Diachys confusus , [3] and Sapyga pumila . [4] The most formidable predator of this species is P. venustus, a parasitoid wasp in which the female uses her ovipositor to sting a developing M. rotundata larvae or pupae. [3] After stinging to paralyze its host, the female lays her eggs on the host's surface and the development of the parasite offspring takes place. After about 15–20 weeks, adults of P. venustus emerge. [3]

Other parasites include several species of Coelioxys and Nemognatha lutea . Coelioxys spp. take advantage of instances when females of M. rotundata are away from the nest, such as during foraging, to lay their egg in the host nest cells. Once a Coelioxys reaches the larval stage, it will kill the developing, host larva and consume all of the provisions that the host female placed in the nest. N. lutea, in contrast, initiate parasitism of hosts at foraging sites. Specifically, female N. lutea will lay their eggs on flowers and, when a bee arrives at this flower during provisioning, will secure itself, as a triungulin stage, to the bee. The triungulin will then, upon the host bee's arrival to its nest, remove itself from the bee, entering a cell and consuming all the provisions gathered by the host female. [3]

Slide illustrating Streptomyces culture Streptomyces sp 01.png
Slide illustrating Streptomyces culture

Mating

Males of the species may, presumably by mistake, attempt to mate with other bee species that are using the same foraging areas as female leaf cutters. They follow several inches behind their intended partner, whether a leaf cutter or bumble bee, which is moving around a plant seeking a flower; then when the target does alight, the male leaf cutter darts rapidly onto the target's back. This causes bumble bees and nonreceptive female leaf cutters to move to another flower and in the process shed the male leaf cutter. The male may then move right to the next prospect, or may first stop for a sip of nectar.[ citation needed ]

Disease

Chalkbrood disease in M. rotundata, specifically larvae, was discovered in 1974 in Nevada. This disease occurs from exposure of M. rotundata to Ascosphaera aggregata , which is introduced into the nest cells through nectar and pollen provisions that females bring back from foraging visits. [26] Signs of chalkbrood infection have been observed to occur in the fifth-instar larvae, leading to the milky appearance of the larval hemolymph and development of a pink, tan, or gray cast in their head or abdominal regions. These changes are accompanied by the spread of pink, tan, or gray color throughout the body of the larvae, and dark-colored, fungal cysts appear under the cuticle. [27]

A variety of microorganisms have been isolated from the alimentary canals and frass of M. rotundata. Bacteria include Bacillus firmus , B. licheniformis , B. megaterium , B. pumilus , and Streptomyces spp., and fungi include Trichosporonoides megachiliensis . [10] With respect to the development of chalkbrood, the bacteria and fungi may promote the inhabitation of A. aggregata. This is supported by observations in chalkbrood-diseased larvae, which contain higher levels of bacteria and fungi in their guts than in healthy larvae. [26]

In controlling chalkbrood, such methods as decontamination of nest cells and materials and shelters was initially achieved using household bleach. Current methods include paraformaldehyde fumigation. [3]

Defense

Female alfalfa leafcutter bees have stingers, but both sexes usually use their mandibles as a defensive mechanism, usually only defending themselves when squeezed or antagonized. So, bee suits, such as those required with honey bees, are not necessary when dealing with these bees. When these bees do sting, however, they do not lose their stingers or die after stinging. [5]

Human importance

Human assistance in pest control

In managing M. rotundata for pollination, such methods as dichlorvos pest strips and ultraviolet lamps placed above liquid traps are effective in killing parasitoids, but not harming M. rotundata. [4] Other methods of preventing parasitoid invasion include physical barriers. For example, the presence of thick artificial cavities separating the exterior from the nest and application of a felt cloth sealing to the back of the nesting board prevents parasitoid access to the nest. [3] Another way that pest are controlled is by opening up the nesting material and cleaning the cocoons. [28]

Pollination

M. rotundata pollinator on alfalfa flower Megachile 1084.JPG
M. rotundata pollinator on alfalfa flower

Megachile rotundata was accidentally introduced into the United States during the 1940s, and its management as a pollinator leads to increases in seed production of some crops in the U.S. It has been shown to pollinate these plant species: [4]

Such behaviors as gregarious nesting, use of leaves and nesting materials that have been mass-produced by humans, efficient pollination of M. sativa, and synchronous emergence of adult bees during alfalfa blooming period provide positive benefits for the use of these bees in agricultural development.

When these bees are supplied to farmers for pollinating crops, they are usually supplied in a dormant state called prepupal, and kept in such state by a constant temperature of about 7 °C (45 °F). At a time that is appropriate for the crop's flowers, the farmer puts the prepupal form in an incubating environment, a constant temperature around 27 °C (81 °F) The adult bees emerge from the pupal form after about 25 days at that temperature. Then, the farmer brings the bees to the field. [2] [29]

See also

Related Research Articles

<span class="mw-page-title-main">Megachilidae</span> Cosmopolitan family of bees

Megachilidae is a cosmopolitan family of mostly solitary bees. Characteristic traits of this family are the restriction of their pollen-carrying structure to the ventral surface of the abdomen, and their typically elongated labrum. Megachilid genera are most commonly known as mason bees and leafcutter bees, reflecting the materials from which they build their nest cells ; a few collect plant or animal hairs and fibers, and are called carder bees, while others use plant resins in nest construction and are correspondingly called resin bees. All species feed on nectar and pollen, but a few are kleptoparasites, feeding on pollen collected by other megachilid bees. Parasitic species do not possess scopae. The motion of Megachilidae in the reproductive structures of flowers is energetic and swimming-like; this agitation releases large amounts of pollen.

<span class="mw-page-title-main">Mason bee</span> Genus of insects

Mason bee is a name now commonly used for species of bees in the genus Osmia, of the family Megachilidae. Mason bees are named for their habit of using mud or other "masonry" products in constructing their nests, which are made in naturally occurring gaps such as between cracks in stones or other small dark cavities. When available, some species preferentially use hollow stems or holes in wood made by wood-boring insects.

<i>Osmia lignaria</i> Species of bee

Osmia lignaria, commonly known as the orchard mason bee or blue orchard bee, is a megachilid bee that makes nests in natural holes and reeds, creating individual cells for its brood that are separated by mud dividers. Unlike carpenter bees, it cannot drill holes in wood. O. lignaria is a common species used for early spring fruit bloom in the United States and Canada, though a number of other Osmia species are cultured for use in pollination.

<i>Osmia cornifrons</i> Species of bee

Osmia cornifrons, also known as the horned-face bee, is a species of solitary bee indigenous to Northern Asia. Physically, this species of bee is recognized for its horn-like extensions originating from its lower face. Populations of O. cornifrons have been recorded in multiple locations, including Japan, Korea, China, and Russia. O. cornifrons are more docile as compared to other species of bees and are less prone to sting when aggravated.

<i>Halictus rubicundus</i> Species of bee

Halictus rubicundus, the orange-legged furrow bee, is a species of sweat bee found throughout the Northern Hemisphere. H. rubicundus entered North America from the Old World during one of two main invasions of Halictus subgenera. These invasions likely occurred via the Bering land bridge at times of low sea level during the Pleistocene epoch.

<i>Megachile</i> Genus of bees

The genus Megachile is a cosmopolitan group of solitary bees, often called leafcutter bees or leafcutting bees; it also includes the called resin bees and mortar 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 more than 1500 species in over 50 subgenera. The alfalfa leafcutter bee is managed on a commercial scale for crop pollination, and has been introduced by humans to various regions around the world.

<i>Osmia bicornis</i> Species of bee

Osmia bicornis is a species of mason bee, and is known as the red mason bee due to its covering of dense gingery hair. It is a solitary bee that nests in holes or stems and is polylectic, meaning it forages pollen from various different flowering plants. These bees can be seen aggregating together and nests in preexisting hollows, choosing not to excavate their own. These bees are not aggressive; they will only sting if handled very roughly and are safe to be closely observed by children. Females only mate once, usually with closely related males. Further, females can determine the sex ratio of their offspring based on their body size, where larger females will invest more in diploid females eggs than small bees. These bees also have trichromatic colour vision and are important pollinators in agriculture.

<i>Anthidium florentinum</i> Species of bee

Anthidium florentinum, one of several European wool carder bees, is a territorial species of bee in the family Megachilidae, the leaf-cutter, carder, or mason bees.

<span class="mw-page-title-main">Alkali bee</span> Species of insect

The alkali bee, Nomia melanderi, is a ground-nesting bee native to deserts and semi-arid desert basins of the western United States. It was described by Theodore Dru Alison Cockerell in 1906. While solitary, these bees nest near each other and can form extremely dense aggregations in areas with favorable conditions.

<i>Anthidium manicatum</i> Species of bee

Anthidium manicatum, commonly called the European wool carder bee, is a species of bee in the family Megachilidae, the leaf-cutter bees or mason bees.

<i>Anthidium maculosum</i> Species of bee

Anthidium maculosum is a species of bee in the family Megachilidae, the leaf-cutter, carder, or mason bees. It is a solitary bee where the males are territorial and the females take part in polyandry. The males of A. maculosum differ from most other males of bee species because the males are significantly larger than females. In addition, subordinate males that act as satellites are smaller than territory-owning males. This species can be found predominately in Mexico and the United States.

<i>Halictus ligatus</i> Species of bee

Halictus ligatus is a species of sweat bee from the family Halictidae, among the species that mine or burrow into the ground to create their nests. H. ligatus, like Lasioglossum zephyrus, is a primitively eusocial bee species, in which aggression is one of the most influential behaviors for establishing hierarchy within the colony, and H. ligatus exhibits both reproductive division of labor and overlapping generations.

<i>Megachile campanulae</i> Species of bee

Megachile campanulae, known as the bellflower resin bee, is a species of bee in the family Megachilidae. Described in 1903, these solitary bees are native to eastern North America. Studies in 2013 placed them among the first insect species to use synthetic materials for making nests. They are considered mason bees, which is a common descriptor of bees in several families, including Megachilidae. Within the genus Megachile, frequently also referred to as leafcutter bees, M. campanulae is a member of the subgenus Chelostomoides, which do not construct nests from cut leaves, but rather from plant resins and other materials. Females lay eggs in nests constructed with individual cell compartments for each egg. Once hatched, the eggs progress through larval stages and subsequently will overwinter as pupae. The bees are susceptible to parasitism from several other bee species, which act as brood parasites. They are medium-sized bees and the female adults are typically larger than the males. They are important pollinators of numerous native plant species throughout their range.

<i>Megachile melanophaea</i> Species of bee

Megachile melanophaea is a species of leaf-cutter bee in the family Megachilidae. It was first described by the British zoologist Frederick Smith in 1853. It is native to North America.

<i>Megachile texana</i> Species of bee

Megachile texana, the Texas leafcutter bee, is a species of bee in the family Megachilidae. It was first described by the American entomologist Ezra Townsend Cresson in 1878. It is native to the United States and southern Canada.

<i>Lasioglossum cressonii</i> Species of insect

Lasioglossum cressonii is a species in the sweat bee genus Lasioglossum, family Halictidae. Halictidae exhibit eusocial hierarchy behavior which is interesting given that eusociality in this group is hard to evolve and easy to lose. L. cressonii is found throughout North America. L. cressonii have been shown to be important pollinators for apple trees and many other North American native plants.

<i>Xylocopa pubescens</i> Species of carpenter bee

Xylocopa pubescens is a species of large carpenter bee. Females form nests by excavation with their mandibles, often in dead or soft wood. X. pubescens is commonly found in areas extending from India to Northeast and West Africa. It must reside in these warm climates because it requires a minimum ambient temperature of 18 °C (64 °F) in order to forage.

<i>Macrotera portalis</i> Species of bee

Macrotera portalis is a species of communal, ground nesting, partially bivoltine bees found in arid grasslands and desert regions of North America. An oligolectic bee, M. portalis gathers pollen only from plants in the genus Sphaeralcea and has patterns of seasonal emergence to survive the harsh conditions of the desert, with emergence delayed until monsoon rains arrive.

<i>Colletes validus</i> Species of bee

Colletes validus, colloquially known as the blueberry cellophane bee, is a solitary, specialist bee in the family Colletidae. It is found primarily in eastern North America where it nests in sandy soils near ericaceous plants.

<i>Ascosphaera aggregata</i> Species of fungus

Ascosphaera aggregata is a species of fungus.

References

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  13. ↑ "Selection and importation of new pollinators to New Zealand" Archived 2008-10-15 at the Wayback Machine , B. J. Donovan, DSIR Plant Protection
  14. ↑ "There have been several importations of the alfalfa leafcutting bee, beginning in 1987...", Australian Honey Industry Monthly Review, January 2001
  15. ↑ "Introducing the Alfalfa Leafcutting Bee into Australia - A Case Study, R.M. Bitner and S.S. Peterson"
  16. ↑ Klostermeyer, E. C.; Mech, Stephen J.; Rasmussen, Wm. B. (1973). "Sex and Weight of Megachile rotundata (Hymenoptera: Megachilidae) Progeny Associated with Provision Weights". Journal of the Kansas Entomological Society. 46 (4): 536–548. JSTOR   25082604.
  17. ↑ Stephen, W. P.; Osgood, Charles E. (1965-10-01). "Influence of Tunnel Size and Nesting Medium on Sex Ratios in a Leaf-Cutter Bee, Megachile rotundata". Journal of Economic Entomology. 58 (5): 965–968. doi:10.1093/jee/58.5.965. ISSN   0022-0493.
  18. ↑ Guédot, Christelle; Buckner, James S.; Hagen, Marcia M.; Bosch, Jordi; Kemp, William P.; Pitts-Singer, Theresa L. (2013). "Nest Marking Behavior and Chemical Composition of Olfactory Cues Involved in Nest Recognition in Megachile rotundata". Environmental Entomology. 42 (4): 779–789. doi: 10.1603/en13015 . PMID   23905742.
  19. 1 2 Rossi, Benjamin H.; Nonacs, Peter; Pitts-Singer, Theresa L. (2010-01-01). "Sexual harassment by males reduces female fecundity in the alfalfa leafcutting bee, Megachile rotundata". Animal Behaviour. 79 (1): 165–171. doi:10.1016/j.anbehav.2009.10.023. S2CID   53192944.
  20. ↑ Tepedino, V. J.; Parker, F. D. (1988-05-01). "Alternation of Sex Ratio in a Partially Bivoltine Bee, Megachile rotundata (Hymenoptera: Megachilidae)". Annals of the Entomological Society of America. 81 (3): 467–476. doi:10.1093/aesa/81.3.467. ISSN   0013-8746.
  21. ↑ Tepedino, V. J.; Frohlich, D. R. (1984-01-01). "Fratricide in Megachile rotundata, a Non-Social Megachilid Bee: Impartial Treatment of Sibs and Non-Sibs". Behavioral Ecology and Sociobiology. 15 (1): 19–23. doi:10.1007/bf00310210. JSTOR   4599689. S2CID   26028688.
  22. ↑ Paxton, Robert John (2005). "Male mating behaviour and mating systems of bees: an overview" (PDF). Apidologie. 36 (2): 145–156. doi: 10.1051/apido:2005007 .
  23. ↑ Paulmier, Ivan; Bagnères, Anne-Geneviève; Afonso, Carlos M. M.; Dusticier, Georges; Rivière, Germaine; Clément, Jean-Luc (1999-03-01). "Alkenes as a Sexual Pheromone in the Alfalfa Leaf-Cutter Bee Megachile rotundata". Journal of Chemical Ecology. 25 (3): 471–490. doi:10.1023/A:1020993518226. ISSN   0098-0331. S2CID   38411367.
  24. ↑ O'Neill, Kevin M.; O'Neill, Ruth P.; Blodgett, Sue; Fultz, Jessica (2004). "Composition of Pollen Loads of Megachile rotundata in Relation to Flower Diversity (Hymenoptera: Megachilidae)". Journal of the Kansas Entomological Society. 77 (4): 619–625. doi:10.2317/E-24.1. JSTOR   25086246. S2CID   86689599.
  25. ↑ Eves, Jack D.; Mayer, Daniel F. (1980). Parasite, predators, and nest destroyers of the alfalfa leafcutting bee, Megachile rotundata. Western Regional Extension Publication.
  26. 1 2 Inglis, G. Douglas; Sigler, Lynne; Goette, Mark S. (1993-09-01). "Aerobic microorganisms associated with alfalfa leafcutter bees (Megachile rotundata)". Microbial Ecology. 26 (2): 125–143. doi:10.1007/BF00177048. ISSN   0095-3628. PMID   24190009. S2CID   2331321.
  27. ↑ Vandenberg, John D.; Stephen, W. P. (1982-03-01). "Etiology and symptomatology of chalkbrood in the alfalfa leafcutting bee, Megachile rotundata". Journal of Invertebrate Pathology. 39 (2): 133–137. doi:10.1016/0022-2011(82)90002-7.
  28. ↑ "Pests, Chemicals, & Drilled Wood". crownbees.com. Retrieved 2017-04-18.
  29. ↑ Alfalfa Leafcutter Bee (Megachile rotundata)
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