Nomada | |
---|---|
Nomada succincta | |
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Arthropoda |
Class: | Insecta |
Order: | Hymenoptera |
Family: | Apidae |
Subfamily: | Nomadinae |
Tribe: | Nomadini Latreille, 1802 |
Genus: | Nomada Scopoli, 1770 |
Species | |
>850 species |
With over 850 species, the genus Nomada is one of the largest genera in the family Apidae, and the largest genus of cuckoo bees. Cuckoo bees are so named because they enter the nests of a host and lay eggs there, stealing resources that the host has already collected. [1] The name "Nomada" is derived from the Greek word nomas (νομάς ), meaning "roaming" or "wandering." [2]
Nomada are kleptoparasites of many different types of bees as hosts, primarily the genus Andrena, but also Agapostemon, Melitta, Eucera and Exomalopsis . [3] As parasites, they lack a pollen-carrying scopa, and are mostly hairless, as they do not collect pollen to feed their offspring. [4] Like non-parasitic bees, adults are known to visit flowers and feed on nectar. [5] Given the lack of scopa and general behavior, they are considered poor pollinators. [6]
They are often extraordinarily wasp-like in appearance, with red, black, and yellow colors prevailing, and with smoky (infuscated) wings or wing tips. They vary greatly in appearance between species, and can be stripeless, or have yellow or white integumental markings on their abdomen. There are specialized patches of hair on the tip of the abdomen of female Nomada. Males have an obvious, often notched pygidial plate. [3] In general, females are easily identifiable by the lack of scopa, reduced body hair, thick exoskeleton, and mandibles. [7]
Separation of this genus from other Nomadinae can be difficult; details of the wing venation, and the nature of the patch of silvery setae at the tip of the female metasoma are the best distinguishing features.
Species of Nomada exhibit an unusual behavior where adult bees are observed to be sleeping by using only their mandibles to hold onto plants. [7]
Nomada occur worldwide. [8] All known species parasitize ground-nesting bees, and their habitats and seasonality correlate with their hosts. [9] Ground nesting bees nest in soil, either in open habitats or in ones covered with vegetation, with a good floral source nearby. [10]
Bees of the genus Nomada most often parasitize bees of the genus Andrena , but have also been observed parasitizing other ground-nesting bees in the families Andrenidae, Melittidae, Halictidae, and Apidae. [11] As is the case for other nomadines, this behavior violates “Emery’s rule” which states that social parasites tend to be either closely related to or sister species of their host. [12]
Nomada are guided by visual cues to locate host nest entrances. [5] In early spring, they can be spotted flying low to the ground, searching for nests to parasitize. [4] Once a nest is found, studies show that Nomada females assess their hosts nests based on three guiding principles: 1) vulnerability and quality of the host cell, 2) threat of a maternal host's presence, 3) competition with other Nomada bees. These three factors are assessed by the bees' olfactory senses to determine if the nest is provisioned with pollen, if a host bee is nearby or in the nest, if the nest has been parasitized before, and if there are other parasitic bees nearby. [5]
The role of male and female cuckoos bees in the parasitism process differs. Before mating, male Nomada will fly locally secreting a scent which mimics the host female. Male cuckoo bees will secrete this scent near host nests to help female Nomada find a nest to deposit eggs. Furthermore, when male and female bees mate, there is evidence that part of the male's secreted scent rubs off onto female bees, which will actually provide an advantage to her finding and entering a host nest. [13]
Nomada parasitizes their host cells by laying eggs in host nests while the female host bee is foraging for pollen, or nectar. The female Nomada oviposits in the host's cells before host oviposition and nest cell closure. [5] The female cuckoo bee will lay her eggs in the host's nest and leave. Some species are known to bury the egg at right angles into the cell wall, while some only partially insert the egg. [1] Additionally, Nomada may sometimes leave multiple eggs into one host cell, a frequent trait of kleptoparasitic bees. Using their mandibles, the parasite larvae kill the host offspring and any conspecific larvae until only one is alive. This larva then consumes the host's provisions. [5] This type of parasitism is also known as brood parasitism, where the parasite's offspring develop on the nutrients gathered by the host for its own offspring. [11]
Observations of Nomada mating are relatively rare, however there are reports of mating behavior as described below.
In five species of Nomada, the main component of male odor secretions was identical to the Dufour's gland secretions of the female host species. The female Nomada interact with the male's secretion during the matting process. There is evidence these secretions help the female Nomada bees recognize the host nests. Furthermore, reports of non-lethal and non-threatening interactions between Nomada and the host Andrena suggest this chemical odor may provide camouflage to protect her from the host females because physically, these genera do not resemblance each other. [9]
There is evidence of “antennal grabbing” during copulation, in which the male Nomada strokes the female antenna. This process transfers pheromones from the male to the female and may make the female unattractive to other males, as well as provide chemical cues to the location of a host nest. The pheromone transfer may also disguise the scent of the female Nomada, allowing her to enter the host nest undetected. The pheromones are transferred when the males hold the female bees down with their feet, while they use their antennae to grab the females’ antennae. [14]
Other reports of Nomada mating includes males “swarming” willow and gooseberry plants. [14]
Nomada bees are holometabolous and they follow the general process of: (1) egg (2) larvae (3) pupa (4) adult. In one egg cell, the female Nomada will deposit 1-2 eggs. These eggs hatch and the larvae use their mandibles to kill other eggs and larvae. These larvae feed on the stored provisions. The offspring pupate in the host cell and finally emerge as adults the following season along with the hosts. [7]
Species of the genus Nomada are highly variable in behavior and habitat specialization. Occurring worldwide, their active periods vary based on their hosts. [15]
There is evidence that most species of Nomada are species-specific to their hosts, and that males mimic the specific scents of the species they parasitize. However, not much research has been done to understand the specialization of Nomada, and it is known that some species are more generalist than others. [16]
See list of Nomada species for a complete list.
Megachile rotundata, the alfalfa leafcutting bee, 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. Each female constructs and provisions her own nest, which is built in old trees or log tunnels. Being a leafcutter bee, these nests are lined with cut leaves. 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.
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.
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.
The term cuckoo bee is used for a variety of different bee lineages which have evolved the kleptoparasitic behaviour of laying their eggs in the nests of other bees, reminiscent of the behavior of cuckoo birds. The name is perhaps best applied to the apid subfamily Nomadinae, but is commonly used in Europe to mean bumblebees Bombus subgenus Psithyrus. Females of cuckoo bees are easy to recognize in almost all cases, as they lack pollen-collecting structures and do not construct their own nests. They often have reduced body hair, abnormally thick and/or heavily sculptured exoskeleton, and saber-like mandibles, although this is not universally true; other less visible changes are also common.
Nomadinae is a subfamily of bees in the family Apidae. They are known commonly as cuckoo bees.
Lasioglossum malachurum, the sharp-collared furrow bee, is a small European halictid bee. This species is obligately eusocial, with queens and workers, though the differences between the castes are not nearly as extreme as in honey bees. Early taxonomists mistakenly assigned the worker females to a different species from the queens. They are small, shiny, mostly black bees with off-white hair bands at the bases of the abdominal segments. L. malachurum is one of the more extensively studied species in the genus Lasioglossum, also known as sweat bees. Researchers have discovered that the eusocial behavior in colonies of L. malachurum varies significantly dependent upon the region of Europe in which each colony is located.
Andrena is a genus of bees in the family Andrenidae. With over 1,500 species, it is one of the largest genera of animals. It is a strongly monophyletic group that is difficult to split into more manageable divisions; currently, Andrena is organized into 104 subgenera. It is nearly worldwide in distribution, with the notable exceptions of Oceania and South America. Bees in this genus are commonly known as mining bees due to their ground-nesting lifestyle.
Bombus bohemicus, also known as the gypsy's cuckoo bumblebee, is a species of socially parasitic cuckoo bumblebee found in most of Europe with the exception of the southern Iberian Peninsula and Iceland. B. bohemicus practices inquilinism, or brood parasitism, of other bumblebee species. B. bohemicus is a generalist parasite, successfully invading several species from genus Bombus. The invading queen mimics the host nest's chemical signals, allowing her to assume a reproductively dominant role as well as manipulation of host worker fertility and behavior.
Andrena agilissima is a species of mining bee. They are present in most of Europe, the Near East and North Africa and can be found from April through July. Andrena agilissima is an oligolectic species, feeding only on the pollen of a few genera of Cruciferous vegetables.
Eucera is a genus of bees in the family Apidae, which comprises more than 100 species. These bees are commonly known as long-horned bees due to their characteristically long antennae, especially in males. Eucera species can be found in diverse habitats, including meadows, fields, and urban gardens, primarily in the Palearctic and Nearctic regions, covering parts of Europe, Asia, North Africa, and North America.
Exomalopsis is a genus of bees in the family Apidae. They occur in the Western Hemisphere.
Euglossa cordata is a primitively eusocial orchid bee of the American tropics. The species is known for its green body color and ability to fly distances of over 50 km. Males mostly disperse and leave their home nests, while females have been observed to possess philopatric behavior. Because of this, sightings are rare and little is known about the species. However, it has been observed that adults who pollinate certain species of orchids will become intoxicated during the pollination.
Xylocopa sulcatipes is a large Arabian carpenter bee. These multivoltine bees take part in social nesting and cooperative nesting. They are metasocial carpenter bees that nest in thin dead branches. One or more cooperating females build many brood cells. They have been extensively studied in Saudi Arabia and Israel.
Lasioglossum figueresi, formerly known as Dialictus figueresi, is a solitary sweat bee that is part of the family Halictidae of the order Hymenoptera. Found in Central America, it nests in vertical earthen banks which are normally inhabited by one, though sometimes two or even three, females. Females die before their larvae hatch. It was named after José Figueres Ferrer, a famous Costa Rican patriot, and studies of its behavior are now general models for social behavior studies.
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.
Macropis nuda is a ground nesting, univoltine bee native to northern parts of North America. Thus, this species cocoons as pupae and hibernates over the winter. The species is unusual as it is an oligolectic bee, foraging exclusively for floral oils and pollen from Primulaceae of the species Lysimachia ciliata.
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.
Andrena scotica, the chocolate mining bee or hawthorn bee, is a species of mining bee from the family Andrenidae. It occurs in western Europe and is one of the most frequently encountered mining bees found in Great Britain, where it had been previously misidentified as Andrena carantonica.
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.
Andrena prunorum, otherwise known as the purple miner bee, is a species of solitary bees in the family Andrenidae. It is commonly found in the continental United States as well as much of North and Central America. Andrena prunorum is a spring-flying, ground-nesting bee that serves as a ubiquitous generalist in ecological settings. Both males and females live as prepupae in the winter in which they mate, and the females seek new sites for ground burrows. From there, they construct small cells surrounding a ball of pollen combined with nectar to nourish a laid egg before each cell is sealed, and the cycle begins anew. A. prunorum generally prefer the pollen derived from Rosaceae plants but will pollinate fruit trees if given the opportunity.