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| - Megachile (Eutricharaea) Thomson 1872: 228. Type species: Apis argentata Fabricius. Gnathocera Provancher 1882: 232 (not Kirby). Type species: Gnathocera cephalica Provancher. Synonymy of Mitchell 1934: 297. Megachile (Paramegachile) Friese 1898: 198. Type species: Apis argentata Fabricius. Synonymy of Mitchell 1934: 298. Megachile (Paramegalochila) Schulz 1906: 71. Emendation. Synonymy of Hurd 1979: 2057. Androgynella Cockerell 1911b: 313-314. Type species: Megachile detersa Cockerell. Monotypic and original designation. Synonymy of Hurd 1979: 2057. Megachile (Eutricharaea) Mitchell 1934: 304. Megachile (Neoeutricharaea) Rebmann 1967: 36. Type species: Megachile rotundata (F). Original designation. Synonymy of Hurd 1979: 2057. Eutricharaea is an Old World group at present numbering some 140 species. More than one third (54) are African, 36 are Australian, 15 range from the East Indies to Taiwan and 12 occur on Pacific islands. Two occur in Europe. Five species have been introduced into the New World; three to the West Indies and two to U.S.A. Parker (1978) provided a key to the identification of the three North American species.
* 1. Megachile (Eutricharaea) concinna Smith Megachile concinna Smith 1879: 79-80. Female. Type locality: St. Domingo [West Indies]. Type repository: NHML 17a2421. Examined. Megachile (Eutricharaea) concinna : Mitchell 1943b: 671. Megachile (Eutricharaea) argentata Hurd 1954: 94 (D, F) and Krombein 1958: 244. Misidentification, see Mitchell 1962: 121. ADDITIONAL REFERENCES. Cockerell 1905: 341 (K); Friese 1902: 199 (D); Gowdey 1926: 99 (D); Wolcott 1948: 869 (D, F); Mitchell 1962: 121-122 (D, F, R-FM); Butler & Ritchie 1963: 153-157 (F, L, P); Butler & Wargo 1963: 201-206 (D, F, L, N, P); Pasteels 1965: 239- 240 (D, R-F); Parker & Bohart 1966: 97 (D, N); Krombein 1967: 326-327 (L, N, P); Baker 1975: 657 (P); Parker 1978: 61- 64 (K); Hurd 1979: 2057 (D, F, N); Jayasingh & Freeman 1980: 215-216 (F, L, N, P); Raw 1984a: 500-502 (F, L, N, P); Raw 1985: 13 (D); Ayala et al 1997: 455 (D). DISTRIBUTION. Old World: CHAD. GHANA. SENEGAL. New World: JAMAICA: widespread, but more numerous in drier areas. MEXICO: JA; SO. PUERTO RICO: Main island, Mona. SANTO DOMINGO. U.S.A.: Most states from FL and AL north to PA, OH, KA and UT and west to CA and WA. Probably introduced from Africa to the West Indies during the slave trade. "Presumably introduced from West Indies [to U.S.A. and Mexico] after World War II" (Hurd 1979: 2057). FLOWERS. Polylectic. Visits 27 genera of plants in U.S.A. including Acacia, Asclepias, Aster, Baccharis, Bidens, Centromadia pungens, Citrus, Croton californicus, Euphorbia albomarginata, Heliotropium aculeatum, H. curassavicum, Hemizonia pungens, Ipomaea, Lepidium, Lippia, Lotus purshianus, Medicago sativa, Melilotus alba, M. indica, Onobrychis vicaefolia, Polygonum aubertii, Prosopis, Raphanus sativus, Senecio, Sicyos, Tamarix, Trifolium repens, Vernonia, Wislizenia refracta. In Jamaica both sexes visit Tribulus cistoides, Alternanthera ficoides, Bidens pilosa and species of Heliotropium, Tephrosia, Sida. In Puerto Rico the bees visited Moringa oleifera and Pisonia albida. On alfalfa bees tripped on average 10 flowers per minute. LIFE HISTORY. Developmental period is 3 to 6 weeks depending on temperatureat. The developmental stages can survive higher daily temperatures (>42oC) than thgose of M. rotundata and occur in hotter climates. Adults are active April to September in much of U.S.A., March to October in Florida throughout the year in Jamaica. Males fly quickly around flowers searching for females. NESTING. Adventive nester in disused beetle borings and nail holes in wood, mortar cracks of buildings, folds of cloth, old stems of Sambucus and trapnests. In Jamaica bees also used old nests of Sceliphron assimile, disused toredo worm borings in wood and wooden trap- nests and lined the nest with cuttings of Cassia leaves and flower bracts of Bougainvillea. In U.S.A. leaves cut from alfalfa. Nests averaged 4.4 cells (maximum 16). Cells averaged 5.6 mm wide. Foraging trips were 10 - 20 min. PREDATORS. In U.S.A. - Anthrax cintalapa, Coelioxys moesta, Nemognatha lurida, Tetrasticus megachilidis, Trogoderma. In Jamaica - Melittobia sp. nr. hawaiiensis, Suidasia mites and dermestid beetles. Developmental survival in Jamaica was 49% to 52% with the Melittobia species responsible for 62% of nest deaths. In cells built in old nests of Sceliphron assimile it was 42%.
* 2. Megachile (Eutricharaea) derelictula Cockerell Megachile derelictula Cockerell 1937a: 112-113. Male. Type locality: Barbados [West Indies] 15 April (J. Ogilvie). Type repository: AMNH. Examined. Megachile (Eutricharaea) derelictula : Mitchell 1943b: 671. ADDITIONAL REFERENCE. Pasteels 1965: 237-239 (D, R-F). DISTRIBUTION. Old World: MALI. NIGERIA. SENEGAL. New World: BARBADOS. ST. LUCIA.
* 3. Megachile (Eutricharaea) multidens Fox Megachile multidens Fox 1891: 345. Sex not indicated. Type locality: Jamaica. Type repository: ANSP 10402/ USNM 1863 ? Megachile (Eutricharaea) multidens : Mitchell 1943b: 671. Megachile tenuicornis Cockerell 1937b: 241-242. Male. Type locality: Elisabethville, Katanga, Belgian Congo, 11-17 September (L. Ogilvie). Synonymy of Pasteels 1965: 240. ADDITIONAL REFERENCES. Crawford 1914: 132 (D, R-F & M); Gowdey 1926: 100 (D); Cresson 1928: 69 (T); Pasteels 1965: 240-241 (D, R-M). DISTRIBUTION. Old World: WEST AFRICA. ZAIRE: Katanga. New World: DOMINICA. JAMAICA.
* 4. Megachile (Eutricharaea) rotundata (F) Apis pacifica Panzer 1798: 16. Female. Type locality: Unknown. Type repository: Unknown. Megachile pacifica Walkenaer 1802: 140. Anthophora pacifica Illiger 1806: 114. Male. Type locality: Unknown. Type repository: Unknown. Megachile argentata var. pacifica Spinola 1806: 142. Sex not indicated. Type locality: Unknown. Type repository: Unknown. Synonymy of Friese ? Megachile imbecilla Gerstaecker 1869: 359. Female. Type locality: Unknown. Type repository: Unknown. Synonymy of Friese ? and Mitchell 1962: 122. Megachile (Paramegachile) rotundata Friese 1911: 178 (D, F, P). Megachile (Eutricharaea) rotundata Stephen & Torchio 1961: 85-93 (D, L, N). Megachile (Eutricharaea) pacifica Hurd 1967: 5 (R-F). Not Apis rotundata Fabricius 1787: 303. Sex not indicated. Type locality: Unknown. Type repository: Unknown. [= M. (Megachile) centuncularis (L)]. (See Hurd 1967: 5.) Most studies on the species have been published under the name M. rotundata (F). Roberts (1974: 190-192) applied to the International Commission on Zoological Nomenclature to recognize a neotype and the name Apis rotundata Fabricius for the species. However, the latter is a synonym of M. (Megachile) centuncularis (Hurd 1967: 5 (L)). See resumé of Hurd 1979: 2058. ADDITIONAL REFERENCES. As a result of its economic importance and wide range it is the best known member of the genus. Hurd (1979: 2057-2059 (D, F, P) lists seven publications on taxonomy, 46 on biology and two on morphology. Selected references are:- Baker 1975: 657 (P); Daly 1952: 210-211 (D); Eves & Johansen 1974: 1-13 (L, P); Gerber & Akre 1969: 1-36; Hobbs 1968: 781-784 (P); 1973: 1-30 (D, N, L); Holm & Skou 1972: 169-180; Hurd 1954: 93-95 (D, F); 1967: 3-10 (T); Johansen et al 1963: 1-11 (F); Johansen & Eves 1973 (P); Klostermeyer et al 1973: 536-548 (N); Krombein 1948: 14 (D); Krunik & Hinks 1972: 889-893 (L); Mitchell 1962: 122- 124 (D, F, L, R-FM); Nelson et al 1972: 153-156 (L); Nielsen & Bohart 1967: 415-418 (M); Pankiw & Siemens 1974: 1003-1008 (D); Parker 1978: 61-64 (K); 1979: 90-94 (P); 1983: 62-68 (L, P); 1984: 113-117 (P); Parker & Bohart 1966: 97 (D, N, P); Parker & Tepedino 1982: 407-410 (L); Peterson et al 1992 (P); Rothschild 1979: 392-401 (L); Stephen 1981 (N, P); Stephen & Osgood 1965 (N); Stephen & Torchio 1961: 85-93; Stephen & Undurraga 1976: 81-87 (P); Szabo & Smith 1972: 157-165 (L); Torchio 1972a: 1- 22 (P); 1972b: 23-29 (P); 1978: 412-419 (P). Other references are cited in Wightman & Rogers 1978 (D, N); Hurd 1979: 2058-2059 (F, L, M, N, P). DISTRIBUTION. Originally palaearctic occurring in Turkey, Iran and south-eastern Europe. It was first recorded in North America from Rosemont, Virginia by Mitchell (1937: 417) and apparently spread quickly, and has reached Washington DC (1948), Missouri and Texas (1952) and California (1954). It has since been introduced into Chile (Stephen 1972), Australia (Winn 1988, Woodward 1994, 1996), New Zealand, (Donovan 1980) Sweden and Denmark. In Canada the range is largely limited to those parts with a minimum temperature of 20o C for > 350 daylight hours per year, but reaches 55oN in British Columbia and Alberta. CANADA: BC, AL, SA, MA. U.S.A.: MA, PA to VI and west and south to WA, OR, KA, MO, TX and CA. CHILE. ARGENTINA. AUSTRALIA. NEW ZEALAND. FLOWERS. The most important pollinator of alfalfa in most of the Americas. In western U.S.A about 25% of the cost of alfalfa production is spent on the management of M. pacifica for pollination. In North America it also visits 14 other genera. Asclepias, Centromadia pungens, Chicorium intybus, Cosmos, Euphorbia albomarginata, Heliotropium curassavicum, Lotus corniculatus, Medicago sativa, Melilotus alba, Phacelia ramosissima, Polygonum aubertii, Senecio douglasii, Solidago, Veronica. In the Palaearctic it visits Reseda odorata, Sedum reflexum and Centaurea species. It is more susceptible than honeybees to most pesticides used on alfalfa. Previously application of insecticides killed many bees, but integrated pest management has significantly reduced bee deaths. Use of the insecticide trichlorfon to alfalfa fields did not affect the numbers of bees present, but reduced the numbers of cells they provisioned. NESTING. Nests in hollow twigs, beetle tunnels in wood, Old nests of Sceliphron, etc. Bees do not excavate tunnels. Readily uses trap-nests with tunnels 5-7 mm diameter (usually trap-nests of 6.4 mm diameter are provided) and is now semi- domesticated. The trap-nests are placed in shelters designed for the exigencies of climate and predators. Nest shelters 3m tall X 6 m long containing 60,000-80,000 nest holes are recommended. Nests successfully in insectaries in cavities 4.0mm to 6.2 mm diameter. The nesting female carries leaf pieces representing 17% and food loads 23% of her body weight. Uses leaves of alfalfa, sunflower, etc. The cell is about 8 mm long and composed of 15 leaf pieces. In warm weather a female builds and provisions about one cell per day. The adult female lives up to one month and produces up to 30 cells and eggs in 4-7 nests with female offspring located towards the back of each nest. Sex ratio is about 1 female: 2 males, but depends on cell diameter with more or only males in narrower nests. LIFE HISTORY. Univoltine in the northern part of its range (where adults fly from June to August) and multivoltine elsewhere. The start and end of the females' flight activity is negatively correlated firstly with temperature and then with light intensity. The egg hatches in 2-3 days and development is completed in one month. Prepupae enter diapause, but emergence of adults is less synchronized after diapause temperatures below 5oC and above 15oC. Emergence is protandrous, with most males appearing about one week before females. Diapause is genetically influenced (on the maternal side). Sex ratio in an insectary was 1F: 2 M. Attempts have been made to rear them on artificial diets. PREDATORS. In North America many native predators of local bees now attack M. pacifica. These include:- Anthrax irroratus, Anthrenus verbasci, Ascosphaera, Attagenus picens, Coelioxys funeraria, C. gilensis, C. moesta, C. novomexicana, C. octodentata, C. sodalis, Cryptolestes ferrugineus, Dibrachys cavus, D. maculipennis, Leucospis affinis, Melittobia acasta, M. chalybii, M. hawaiiensis, Monodontomerus montivagus, M. obscurus, Nemognatha lurida, N. lutea, Plodia interpunctella, Pteromalus venustus, Ptinus californicus, Sapyga pumila, Stelis (Pavostelis) montana, Tenebrioides mauritanicus, Tetrasticus albipes, T. megachilidis, Trichodes ornatus, Trilobium audax, T. brevicornis, T. madens, Trogoderma glabrum, T. granarium, T. inclusum, T. simplex, T. sternale, T. variabile, Vitula edmandsae. In Europe:- Coelioxys rufocaudata, Melittobia acasta. The first instar larva of Sapyga pumila kills the egg or young larva of the bee. Up to 78% of the bees' offspring are killed. Management for alfalfa pollination includes opening nests and incubating cells in closed rooms to stimulate emergence of predators which are killed before the bees emerge. Management also includes treatment of cells containing bees with repellents to deter attacks by Monodontomerus and Tetrasticus and open cells with fungicide to reduce the incidence of chalkbrood. Several methods have been devised to control the populations of Sapyga pumila. X- radiography has been used to detect predators and diseases inside the nest. M. pacifica is rather less susceptible to some pesticides than honeybees. MORPHOLOGY. Detailed examination of external morphology of adult male and female. Sexual differentiation in second instar larva.
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