This is the family of cuckoo bees, digger bees, and carpenter bees. Itis a diverse group of species with a greatrange ofhabits and habitats. Cuckoo bees are considered cleptoparasites in the nests of many families of bees. They lack the hairlike setae and pollen baskets ofother bees, and they resemble small wasps. Digger bees store a mixture of honey and pollen for larval food in burrows in the ground; a few are cleptoparasites on other members of the Anthophoridae. There are two primary genera of carpenter bees, Ceratina and Xylocopa. Most species collect pollen and make their nests in wood; some nest in the stems and branches of plants, and some in stumps, live trees, and structural wood in use. Beneficial aspects of the anthophorids include the pollination of a variety of trees and plants visited for pollen and nectar.

Carpenter bees

Xylocopa (Fig. 9.1a) is a very large genus consisting of several hundred species and distributed throughout much of the world. Most species are in Africa and Neotropical regions, where this genus probably originates. Some Proxylocopa excavate nests in the ground, in bricks, or in similar substrates. The majority of carpenter bees gnaw nesting tunnels in dead wood, including seasoned hardwoods, softwoods, decaying wood in various locations, and sometimes in bamboo and other hollow-stem plants. Several species excavate nesting tunnels in structural wood used in building, bridges, water storage tanks, fences, and house siding materials. Some Xylocopa have been able to extend their geographic range to suburban and urban sites by using structural wood for nests. Some have been transported to areas where natural nesting sites are limited, but urban sites are readily available. In Europe, the range of X. violacea extends as far north as Paris, perhaps carried there in infested wood and sustained by available nest sites. In Asia, X.phalothoraxandX.latipes are common species, and sometimes pests ofstructural timbers.

Pest status of carpenter bees is based on the threat of being stung - these are large bees - and the cosmetic and sometimes structural damage that results from their nests in structural wood. Males utilize aggressive and threatening behavior as they guard nest sites, but they are not able to sting. Females come

Figure9.1 Hymenoptera: Anthophoridae, Siricidae, Xiphydriidae. (a) Xylocopa sp. (Anthophoridae); (b) Urocerus gigas (Siricidae); (c) Tremex columba larva (Siricidae); (d) Xiphydria maculata larva (Xiphydriidae).

and go from the nest site during the day, but remain there at night; they are not usually aggressive, but are capable of stinging. In general, yearly nesting of carpenter bees causes annoyance from the sound of their gnawing and nest building in house siding. Unless there is an ongoing nest for several years, there is only minimal damage to infested wood. In southern Asia, X. rufescens is nocturnal and, where it is nesting, the loud buzzing and nest-building activity of the females can be heard throughout the night. Structural timbers in old or uninhabited buildings can be continuously infested by Xylocopa,and in some cases the wood becomes structurally unsound. Many species prefer natural sites, such as the wood of dead trees, stumps, and fallen logs. As natural or undisturbed areas for nesting become scarce, the abundance of some Xylocopa species may decrease, and those capable ofnesting in structural wood may increase.

Frass or the pieces of wood shavings resulting from carpenter bee tunneling in wood are usually scattered below the opening to the nest site. These irregular pieces of wood removed by the queens are 1-3 mm long, fibrous, and irregularly shaped. The composition is only wood shavings, unlike the frass of the pavement ant (Tetramorium caespitum) and carpenter ants (Camponotus spp.), in which there may be fragments of dead ants, soil, and other nest refuse.

Natural food includes nectar and pollen from flowering plants. A few species in the western hemisphere are considered necessary pollinators of some agricultural and horticultural crops. In tropical regions, Xylocopa species greatly increase fruit setting in passionfruit (Passiflora edulis). There are several Xylocopa species in Central America, including X.fimbrata and X. gualanensis. On the Galapagos Islands, X. darwini is the only bee species, and it may play a role in establishing immigrantplant species. Amongflowers visited and often pollinated by carpenter bees are many indigenous and introduced plants in the urban and rural landscape. Their nesting tunnels and pollen residues in unused nests can provide harborage and food for other arthropods, including spiders, mites, cockroaches, moths, and some stored-food beetles, such as dermestids, and tenebrionids.

Carpenter bees have relatively few predators and parasites. As regards Coleoptera, the eastern hemisphere (Old World) genus Hornia and the western hemisphere (New World) genus Cissites (Meloidae) are nest parasites of Xylocopa. They can destroy the contents of a few cells or an entire nesting tunnel. Referring to Diptera, Anthrax (Bombyliidae) and Hyperechia (Asilidae) contain species whose larvae are parasites of the larvae of Xylocopa. Various species of Ichneumonidae, Chal-cididae, Leucospididae, Encyrtidae, and Evaniidae have been reared from carpenter bee larvae. Woodpeckers, Baltimore oriole, and house wren attack the nest sites or otherwise feed on these bees. Humans are major predators of carpenter bees in certain places of the world, particularly in Asia. Adults are sometimes collected for food, or used to prepare a medication for the treatment ofsore throats in children.

Little carpenter bee, Ceratina dupla Adults are 6-8 mm long, and the body and legs are bluish green. Antennae are brown at the base and dark blue apically. Adults are often found at flowers. Nests are in the stems of pithy reeds and stems, such as sumac and brambles. However, they may use the exposed emergence hole to access the tunnels ofwood-infesting beetles as a nest site, and they nest in decaying wood. This species usually does not nest in structural wood. There are about 20 species in the USA, and they are generally distributed.

African carpenter bee, Xylocopa caffra Adults are about 20 mm long and the body is black. The female has a yellow to yellowish white band posteriorly on the thorax, and another band anteriorly on the abdomen; the wings are brown. The male is nearly covered with a dense coat of yellowish-white setae; the wings are light brown. In the interior regions ofSouth Africa, the markings are white instead of yellow or yellowish white. Nesting occurs in spring (October and November), and nest sites include tree branches or dry structural timber. The entrance hole to the nest is about 10 mm diameter and about 15 cm deep. Females provision the nest with pollen collected from pea, bean, and sage flowers. Nest construction is completed inabout30 days and developmentofthe immature stages is complete in 3-4 weeks. Adults emerge in January and February, but they remain in the nest until the following spring. In eastern and coastal areas of southern Africa there are two or three generations ofX. caffra per year. In the winter rainfall area at the southern tip of Africa there is one generation per year. Large mites in the genus Dinogamasus are found on the adults and in the nests ofX. caffra and allied species. The ensign wasp (Evaniidae), Gasteruption robustrum, is a parasite ofX. caffra, and is commonly found near the nests.

Xylocopa californica Adults are 20-24 mm long, and the body of both sexes is metallic blue or metallic green. The prono-tum of the male has white, yellow, or orange setae, and the entire first abdominal segment is covered with white setae. This species is known to nest in redwood and incense cedar in California and Oregon.

Xylocopa iridipennis Adults are about 26 mm long, the body of both sexes is metallic blue, and the wings are blackish blue. The pronotum is blackish blue and without yellow marking. This species occurs in southern Asia, where it commonly nests in bamboo stems, and locally is known as the bamboo carpenter bee.

Tropical carpenter bee, Xylocopa latipes Adults are 23-26 mm long; the body is metallic, bluish black, and with green and purple reflections. Wings are bluish black at the base and dark brown at the apical third. The head, antennae, and legs are bluish black. This species occurs in tropical regions of southern Asia. In Malaysia, the structural wood susceptible to attack includes Dyera costulata (jelutong), Agathisalba (damarminyak), Alstonia spp. (pulai), and Shorea spp. (light red meranti). Tropical woods that are relatively safe from attack by this species include nyatoh, kapur, kempas, and mengkulang.

Southern carpenter bee, Xylocopa micans Adults are 14-27 mm long, and the head and thorax are black and shiny; there is a band of pale white setae at the base of the abdominal segments. Males and females overwinter in nests constructed in fence posts, wood rails, and the eaves of buildings. This species occurs in southeastern USA.

Xylocopa tabaniformis orpifex Adults are 19-23 mm long, and the body is somewhat metallic, and the fine setae (pubescence) on the thorax are blackin females and yellowin males; the males have yellow spots on the face. This species occur throughout eastern USA and west to Texas, Oklahoma, Kansas, and Missouri.

Common carpenter bee, Xylocopa virginica virginica Adults are 19-23 mm long. The body is somewhat metallic, fine setae (pubescence) on the thorax are black in females and yellow in males; the males have yellow spots on the face. This species occurs throughout eastern USA and west to Texas, Oklahoma, Kansas, and Missouri.

Adult males and females overwinter in a nonreproductive phase in nest tunnels or in protected locations outdoors. In the northern hemisphere, overwintering quiescence usually lasts from October through March. Most quiescent females are unmated. In early spring, mating occurs following territorial flights by the males; this is followed by nest construction. Although males mate mainly during spring, they may also defend territories and mate in fall. For nesting, females may use an old gallery without further burrowing, or create an entirely new gallery, or make a new one from an entrance used by several females. Adults that have overwintered die during the summer of the second year, but usually after they have mated and produced male and queen galleries and eggs for the next generation. In temperate regions, there is usually one generation per year.

Selection of the nest site may be elaborate, and usually includes dry softwoods in exposed locations, but may also include hardwoods, even hardwood tool handles; white-painted wood may be avoided. In construction ofnew nest sites, female bees gnaw into the wood surface to make a hole about 15 mm diameter, and in most kinds of wood females can tunnel 10-15 mm per day. Boring proceeds slowly when galleries extend across the wood grain, and is much faster with the grain. Direction of the gallery depends on the orientation of the wood; if the grain is oriented vertically, the galleries are vertical, and if the grain is oriented horizontally, the galleries are horizontal with respect to the ground. Galleries extend 30-45 cm in newly completed nests. New galleries are smooth and uniform throughout, but old ones are irregular and often have depressions or excavations along their sides. Galleries may be used by several generations of bees, and the system of tunnels in one piece of wood may become very elaborate. Sawdust is pushed out of the nest by the head, abdomen, or legs of the female, and it may pile up at the nest entrance. A distinctive flight behavior, called the bobbing dance, has been reported for X. virginica.The bees hover in flight in front of the opening to the nest, and they position their head to strike the wood around the nest opening. This flightand behavior may persistfor several minutes. It is demonstrated primarily by males, and is probably linked to mating.

After excavating the nest site, provisioning individual cells in the gallery is begun. A mass of pollen and regurgitated nectar is placed at the end of the gallery, and the female deposits an egg on it. She then seals this portion of the gallery with a partition of chewed wood pulp. This procedure of provisioning, oviposition, and sealing is repeated until a series ofabout six cells is formed in the gallery. Eggs hatch in 2-3 days, and larval development is complete in about 15 days. The prepu-pal period is about 4 days and the pupal period about 15 days. Total development time is about 36 days and it is all spent within the cell. Following emergence from its cocoon, the adult bee spends 1-2 days in the cell grooming and feeding on the remaining food. The first bee to become an adult is usually in the first cell to be provisioned, which is at the end of the gallery. The adult cuts through the cell partitions of all the cells to emerge at the exterior of the nest. For the remainder of the season the adult bees gather pollen and nectar and store caches of food in the galleries for use during inclement weather. During this period, there is no mating and no nest construction.

Digger bees

These small bees store a mixture of honey and pollen for larval food in burrows in the ground. Their long burrows are lined with a waxlike substance produced by the female during construction. Nests of North American Anthophora are usually built in steeply inclined or perpendicular soil banks exposed to the sun, but they are also excavated in other locations, including in outside walls of adobe houses in western USA.

Mortar bees, Amegilla spp. These bees normally make their nests in banks ofhard soil or sand. In coastal areas they may nestinrockfissures.However, brick houses and buildings with brick foundation walls often serve as nests sites. Females take advantage of old or poor-quality mortar to construct burrows and brood cells. Amegilla females make their burrow deep into the mortar; other females dig lateral tunnels from the main burrow. Large numbers of females may use the same site. Damage to brick and mortar walls can be extensive, because they may return to the same site for several years. These species occur in Australia.

Digger bees, Centris spp., Ancyloscelis spp. Adults are 14-18 mm long. They are usually black with the abdomen (metasoma) red, yellow, or metallic green and covered with dense, yellow setae (Centris), or black with narrow white bands of setae on abdominal tergites (Ancyloscelis). Adults of Centris spp. either dig a burrow in the soil or use pre-existing holes in wood. Nests usually contain several brood cells that are provisioned with pollen and plant oil, which is collected from oil-bearing plants. Species that nest in holes in wood often line their cells with wood chips scraped from the existing gallery. This genus occurs in the deserts of North America, south to neotropical regions of Central America. Ancyloscelis spp. often nest in large aggregations. Adults usually dig nests in sloping ground or vertical embankments exposed to the sun; some species tunnel in the bricks ofadobe buildings in southwestern USA.

Eastern digger bee, Ptilothrix bombiformis Adults are 12-18 mm long. The body is black and without markings, except for thick, pale setae on the head, thorax, and apex of each abdominal segment. They resemble small bumble bees (thus the species name), and build nests in bare soil. This species is common is suburban habitats and distributed in eastern and southeastern USA.

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