Acronirmus gracilis Bush 2017
Creators: name: Bush, Sarah E.
Publisher: name: Zenodo
Year: 2017
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Phthiraptera
Philopteridae
Acronirmus
Acronirmus gracilis

description: Acronirmus gracilis (Burmeister, 1838)
(Figs 83–89)
Philopterus (Nirmus) gracilis Nitzsch, 1818: 291 nomen nudum. Nirmus gracilis Burmeister, 1838: 429.
Nirmus elongatus Denny, 1842: 53 nec Nirmus elongatus Olfers, 1816: 88. Nirmus brevipes Piaget, 1880: 179 new synonymy.
Nirmus longus var. domesticus Kellogg & Chapman, 1899: 93 new synonymy. Degeeriella brevipes Piaget; Harrison, 1916: 109.
Degeeriella domestica Kellogg & Chapman, 1899; Harrison, 1916: 112. Degeeriella elongata Denny; Harrison, 1916: 112.
Degeeriella gracilis Nitzsch in Burmeister; Harrison, 1916: 114. Degeeiella gracilis (Nitzsch, 1818); Séguy, 1944: 312.
Brueelia brevipes (Piaget), 1880; Hopkins & Clay, 1952: 54.
Brueelia domestica (Kellogg & Chapman), 1899; Hopkins & Clay, 1952: 55. Brueelia elongata (Denny), 1842; Hopkins & Clay, 1952: 55 (as junior synonym of Br. gracilis). Brueelia gracilis (Burmeister), 1838; Hopkins & Clay, 1952: 56. Acronirmus buettikeri Eichler, 1953: 338 new synonymy.
Hirundiniella gracilis (Burmeister, 1838); Złotorzycka, 1997: 178. Hirundiniella domestica (Kellogg & Chapman, 1899); Złotorzycka, 1997: 178. Brueelia buettikeri (Eichler, 1953); Price et al. 2003: 153.
Type host. Delichon urbicum urbicum (Linnaeus, 1758).
Type locality. None given, likely Germany.
Other hosts. Cecropis abyssinica puella (Temminck & Schlegel, 1845) – lesser striped-swallow new host record. Cecropis abyssinica unitatis (Sclater & Mackworth-Praed, 1942) —lesser striped-swallow new host record. Cecropis badia Cassin, 1853 —rufous-bellied swallow new host record. Cecropis daurica erythropygia (Sykes, 1832) — red-rumped swallow new host record. Cecropis daurica japonica (Temminck & Schlegel, 1845) — red-rumped swallow new host record. Cecropis daurica rufula (Temminck, 1835) — red-rumped swallow new host record. Cecropsis senegalensis saturatior (Bannermann, 1923) — mosque swallow new host record. Delichon dasypus cashmirensis (Gould, 1858) —Asian housemartin new host record. Delichon dasypus dasypus (Bonaparte, 1850) —Asian house-martin new host record. Hirundo aethiopica amadoni White, 1956 — Ethiopian swallow new host record. Hirundo angolensis Bocage, 1868 — Angola swallow new host record. Hirundo rustica erythrogaster Boddaert, 1783 — barn swallow new host record. Hirundo rustica rustica Linnaeus, 1758 — barn swallow [Ref.: Złotorzycka,1997: 179]. Hirundo rustica savignii Stephens, 1817 — barn swallow new host record. Hirundo rustica tytleri Jerdon, 1864 — barn swallow new host record. Hirundo tahitica javanica Sparrman, 1789 — Pacific swallow new host record. Ptyonoprogne rupestris (Scopoli, 1769) —Eurasian cragmartin [Ref.: Blagoveshchensky 1951]. Riparia chinensis chinensis (Gray, 1830) —grey-throated martin new host record. Riparia diluta indica Ticehurst, 1916 —pale sand martin new host record.
Description. Both sexes. Head shape, structure, and chaetotaxy as in Fig. 85. Marginal carina widely interrupted laterally; the interruption of the carina is wider than the dorsal preantennal suture where it meets the lateral margin of the head. Dorsal anterior plate short, broadly pentagonal. Ventral anterior plate rounded. Dorsal preantennal suture completely separates dorsal anterior plate from main head plate. Ventral carinae very slender. Preantennal nodi not distinct. Coni very short. Preocular nodi small, rectangular. Postocular nodi small, not much wider than marginal temporal carina. Gular plate roundedly-triangular. Thoracic and abdominal segments as in genus description and Figs 83–84. 6 mms setae on each side, alternating between long and short setae.
Male. Abdominal chaetotaxy as in Table 2 and Fig. 83. Subgenital plate roughly triangular, narrowing only in distal third. Male genitalia (Fig. 86) dissimilar to those depicted by Fresca (1925: 287), apart from the general outline. Proximal mesosome broadly rounded, narrowed slightly at proximal third. Mesosomal lobes (Fig. 87) short and broad, rugose or fringed distally, with two pmes on each side. Parameral heads (Fig. 88) bifid anteriorly, but fingers very short. Parameral blades curved medianly, not much elongated distally; pst2 setae, lateral near distal tip. Measurements ex Cecropsis abyssinica puella (n = 1): TL = 1.49; HL = 0.33; HW = 0.25; PRW = 0.18; PTW = 0.22; AW = 0.24. Ex C. badia (n = 2): TL = 1.43–1.46; HL = 0.32–0.34; HW = 0.24–0.25; PRW = 0.16–0.17; PTW = 0.20–0.23; AW = 0.22–0.32. Ex C. daurica erythropygia (n = 1): TL = 1.40; HL = 0.33; HW = 0.23; PRW = 0.16; PTW = 0.20; AW = 0.25. Ex C. daurica rufula (n = 1): TL = 1.69; HL = 0.36; HW = 0.26; PRW = 0.18; PTW = 0.23; AW = 0.29. Ex C. senegalensis saturiator (n = 3): TL = 1.40–1.43; HL = 0.34–0.36; HW = 0.25; PRW = 0.17; PTW = 0.22–0.23; AW = 0.26–0.28. Ex Delichon dasypus dasypus (n = 2): TL = 1.43–1.50; HL = 0.33–0.34; HW = 0.24; PRW = 0.16; PTW = 0.21–0.23; AW = 0.27–0.28. Ex D. urbicum (n = 15): TL = 1.58–1.75 (1.63); HL = 0.34–0.37 (0.36); HW = 0.23–0.27 (0.25); PRW = 0.16–0.19 (0.17); PTW = 0.22–0.26 (0.24); AW = 0.26–0.34 (0.30). Ex Hirundo aethiopica (n = 2): TL = 1.46–1.61; HL = 0.31–0.35; HW = 0.23–0.26; PRW = 0.16–0.17; PTW = 0.21–0.23; AW = 0.25–0.29. Ex H. angolensis (n = 2): TL = 1.59–1.60; HL = 0.34; HW = 0.25; PRW = 0.16–0.17; PTW = 0.23; AW = 0.29–0.32. Ex H. rustica rustica (n = 15): TL = 1.50–1.72 (1.60); HL = 0.34–0.37 (0.35); HW = 0.25–0.27 (0.26); PRW = 0.17–0.19 (0.17); PTW = 0.22–0.26 (0.24); AW = 0.25–0.34 (0.30). Ex H. r. savignii (n = 1): TL = 1.58; HL = 0.35; HW = 0.26; PRW = 0.18; PTW = 0.23; AW = 0.27. Ex H. r. tytleri (n = 1): TL = 1.52; HL = 0.33; HW = 0.24; PRW = 0.17; PTW = 0.23; AW = 0.27. Ex H. tahitica javancia (n = 2): TL = 1.46–1.50; HL = 0.31–0.32; HW = 0.24; PRW = 0.17; PTW = 0.22; AW = 0.26–0.27. Ex Riparia chinensis (n = 1): TL = 1.52; HL = 0.34; HW = 0.26; PRW = 0.17; PTW = 0.23; AW = 0.25.
Female. Abdominal chaetotaxy as in Table 2 and Fig. 84. Female subgenital plate roughly pentagonal, with concave lateral margins (Fig. 89). Vulval margin (Fig. 89) with 3–4 short, slender vms on each side, and 5–7 short, thorn-like vss on each side; median vss progressively longer; 3–4 slender vos on each side. Measurements ex Cecropsis abyssinica puella (n = 1): TL = 1.88; HL = 0.37; HW = 0.29; PRW = 0.21; PTW = 0.28; AW = 0.36. Ex C. a. unitatis (n = 1): TL = 1.85; HL = 0.38; HW = 0.29; PRW = 0.19; PTW = 0.24; AW = 0.38. Ex C. badia (n = 1): TL = 1.80; HL = 0.37; HW = 0.27; PRW = 0.18; PTW = 0.24; AW = 0.39. Ex C. daurica japonica (n = 1): TL = 1.82; HL = 0.36; HW = 0.27; PRW = 0.17; PTW = 0.23; AW = 0.33. Ex C. d. rufula (n = 1): TL = 2.06; HL = 0.38; HW = 0.28; PRW = 0.19; PTW = 0.27; AW = 0.40. Ex C. senegalensis saturiator (n = 1): TL = 1.79; HL = 0.38; HW = 0.27; PRW = 0.18; PTW = 0.26; AW = 0.35. Ex Delichon dasypus cashmirensis (n = 1): TL = 1.82; HL = 0.36; HW = 0.27; PRW = 0.18; PTW = 0.25; AW = 0.31. Ex D. d. dasypus (n = 1): TL = 1.80; HL = 0.36; HW = 0.26; PRW = 0.17; PTW = 0.25; AW = 0.28. Ex D. urbicum (n = 15): TL = 1.84–2.11 (1.95); HL = 0.37–0.41 (0.38); HW = 0.26–0.30 (0.28); PRW = 0.18–0.21 (0.19); PTW = 0.25–0.30 (0.27); AW = 0.29–0.38 (0.33). Ex Hirundo aethiopica (n = 1): TL = 1.92; HL = 0.38; HW = 0.28; PRW = 0.19; PTW = 0.25; AW = 0.34. Ex H. angolensis (n = 2): TL = 1.97–2.08; HL = 0.37–0.39; HW = 0.29; PRW = 0.19; PTW = 0.26–0.28; AW = 0.39– 0.41. Ex H. rustica erythrogaster (n = 1): TL = 1.88; HL = 0.35; HW = 0.27; PRW = 0.18; PTW = 0.25; AW = 0.33. Ex H. r. rustica (n = 15): TL = 1.84–2.07 (1.94); HL = 0.37–0.41 (0.39); HW = 0.27–0.31 (0.29); PRW = 0.19–0.22 (0.20); PTW = 0.25–0.29 (0.27); AW = 0.32–0.38 (0.34). Ex H. r. savignii (n = 5): TL = 1.91–2.04; HL = 0.36–0.38; HW = 0.28–0.29; PRW = 0.18–0.20; PTW = 0.25–0.27; AW = 0.29–0.35. Ex H. r. tytleri (n = 2): TL = 1.91–1.99; HL = 0.36–0.38; HW = 0.28; PRW = 0.19; PTW = 0.26–0.27; AW = 0.35–0.38. Ex H. tahitica javanica (n = 3): TL = 1.79–1.92; HL = 0.36–0.38; HW = 0.28–0.29; PRW = 0.19–0.20; PTW = 0.25–0.26; AW = 0.32–0.37. Ex Ptyonoprogne rupestris (n = 2): TL = 2.03–2.05; HL = 0.39–0.40; HW = 0.29–0.30; PRW = 0.19; PTW = 0.27–0.28; AW = 0.39–0.40. Ex Riparia diluta diluta (n = 2): TL = 1.98–2.07; HL = 0.37–0.38; HW = 0.28–0.29; PRW = 0.19–0.20; PTW = 0.26–0.27; AW = 0.30–0.34.
Type material. Ex Delichon urbicum urbicum: Holotype ♀, Ilkley, Yorkshire, England, United Kingdom, Denny Collection, [BM] 1852-98 (NHML). Paratypes: 2♀, same data as holotype (NHML).
Ex Hirundo rupestris: Holotype ♀ of Acronirmus buettikeri: Capri, Italy, Dec. 1885, A. König, 302b (MFNB).
Ex Calidris ferruginea: Syntypes of Brueelia brevipes: 2♀, unknown locality, Piaget Collection, 767 (NHML).
Additional material examined (non-types)
Ex Cecropsis abyssinica puella: 1♂, 1♀, Kumasi, [Ashanti Region], Ghana, 30 Apr. 1966, F.R. Allison, BM 1966-291 (NHML).
Ex Cecropsis abyssinica unitatis: 1♀, Kenya, Feb. 1930, R. Meinertzhagen, 6791 (NHML).
Ex Cecropsis badia: 1♂, Wang Blachun, Satun Province, Thailand, 8 Aug. 1967, 7E-1544, 24616 on reverse (NHML); 1♂, “on road”, Krabi Province, Thailand, 28 Jun. 1962, W. Songprakob, RE-6317 (PIPeR); 1♀, Thap Put District, Phang Nga Province, Thailand, 20 Aug. 1962, W. Songprakob, RE-6396 (PIPeR).
Ex Cecropsis daurica erythropygia: 1♂, Yercaud, Salem District, Tamil Nadu, India, 11 May 1970, XIE-951, 24613 on reverse (NHML).
Ex Cecropsis daurica japonica: 1♂, Mount Cagua, Philippines, 11 Jul. 2011, P4494 RMT121 (PIPeR); 1♀, Philippines, voucher for sequence Brsp.Hidau.10.25.2011.9 (PIPeR).
Ex Cecropsis daurica rufula: 1♂, 1♀, “ M.M. ”, Israel, 4 Aug. 1959, 80b/4, BM 1959-541 (NHML).
Ex Cecropsis senegalensis saturatior: 1♂, Kenya, Jan. 1936, R, Meinertzhagen, 6214 (NHML); 2♂, 1♀, Kenya, Mar. 1936, R. Meinertzhagen, 7002 (NHML).
Ex Delichon dasypus cashmirensis: 1♀, Sankhuwasabha District, Kosi Zone, Eastern Region, Nepal, 29 Jul. 1973, HE-0654 (NMNH).
Ex Delichon dasypus dasypus: 1♂, 1♀, Tachikawa Air Force Base, Tokyo, Japan, 31 May 1965, H.E. McClure, SE-1537–8, 16461 and 16464 on reverse (OSUS); 1♂, Chino, Nagano Prefecture, Japan, 7 Jul. 1964, H.E. McClure, SE-1633, 16463 on reverse (OSUS); 1♀, Fort Brooks, Malaysia, 26 Jan. 1963, M-02325, 16465 on reverse (OSUS).
Ex Delichon urbicum urbicum: 1♂, Khuta Maji, Vwaza Marsh, Vwaza Wildlife Preserve, Malawi, 17 Oct. 2009, Swati Patel, FMNH-INS 0 0 0 0 0 29 0 59, voucher for sequence Brgr.2.9.2011.37 (FMNH); 1♂, 1♀, Borovnica, Slovenia, 25 Feb. 1953, S. Brelih, 2515, 2517 (NMNH); 3♂, 3♀, unknown locality and date, 50356, 50357, and 50406 (MFNB); 1♂, 1♀, Netherlands? [host name in Dutch], 24 Jul. 1937, Geihskers, 418 (MFNB); 1♀, Tolmin, Slovenia, 18 Jun. 1958, S. Brelih, 2520 (PMSL); 1♀, Borovnica, Slovenia, 25 Aug. 1953, F. Leben, 29 (PMSL); 5♂, 4♀, Borovnica, Slovenia, 25 Aug. 1953, S. Brelih, 216–8, 1987–8, 2029–30, 2513–4, 25–6, 2518–9 (PMSL); 1♂, 1♀, Stozice, Ljubljana, Slovenia, 25 Jul. 1978, D. Sere, 13589–90 (PMSL); 1♀, Tolmin, Slovenia, 18 Jun. 1958, S. Brelih, 16466 on reverse (OSUS); 1♂, 4♀, Bolton, United Kingdom, 2 Sep. 1953 (NHML); 10♂, 4♀, Wiltshire, United Kingdom, Aug. 1946, R. Meinertzhagen, 15882 (NHML); 1♂, 1♀, Midlothian, Scotland, United Kingdom, 26 Jul. 1965, Eskgrove Lab, BM 1965-641 (NHML); 1♀, Ross-Shire, Scotland, United Kingdom, Jul. 1934, R. Meinertzhagen, 1230 (NHML); 5♂, 5♀, Barns Elm Reservoir, Surrey, England, United Kingdom, 27 Jul, 1965, C. A. Walker, BM 1965-307 (NHML); 1♀, Budds Farm Sweage Works, Bedhampton, Hampshire, United Kingdom, 20 May 1979, W. Sanders, BM 19789-308 (NHML); 1♂, 1♀, Bolton, Lancashire, United Kingdom, 28 Sep. 1958, A. Hazelwood, BM 1958-561 (NHML); 3♂, 4♀, Suffolk, United Kingdom, Jun. 1934, R. Meinertzhagen, 1284 (NHML); 1♂, 1♀, Austey Hall, Cambridgeshire, United Kingdom, Sep. 1949, G.B. Thompson, BM 1980-40 (NHML); 1♂, 6♀, Morocco, Nov. 1938, R. Meinertzhagen, 12129 (NHML).
Ex Hirundo aethiopica amadoni: 2♂, 1♀, Somalia, Jan, 1949, R. Meinertzhagen, 18188 (NHML).
Ex Hirundo angolensis: 2♂, 2♀, “ Baluba Stream ”, Zambia, 16 Nov. 1953, BM 1954-137, ML/110 (NHML).
Ex Hirundo rustica erythrogaster: 1♀, Orr’s Farm, Dugway, Tooele County, Utah, USA, 14 Jan. 1954, N.V. Chamberlain, 382 B-1601, 16450 on reverse (OSUS).
Ex Hirundo rustica rustica: 1♀, Ljubljane Okolica, Slovenia, 21 Apr. 1956, S. Brelih, 213 (NMNH); 1♀, Miez. Wisl., Skowronki, Poland, 12 Sep. 1962, [J.] Złotorzycka, 18/a/7 (MFNB); 2♂, unknown locality, Eichler Collection, 7005 (MFNB); 3♂, 1♀, Berlin, Germany, 26 Jun. 1952, Sanft, IN 1388/1 (MFNB); 2♂, 2♀, Sliven, Bulgaria, 26 May 1957, F. Balát (PMSL); 2♀, Idrija, Slovenia, 22 Aug. 1974, S. Brelih, 13000 (PMSL); 1♂, 3♀, Stozice, Ljubljana, Slovenia, 12 Jul. 1977, D. Sere, 13015–13018 (PMSL); 4♂, 1♀, Idrija, Slovenia, 18 Sep. 1977, D. Sere, 13121–13125 (PMSL); 1♀, Jarse ob Savi, Ljubljana, Slovenia, 1 Oct. 1980, D. Sere, 14040 (PMSL); 1♂, 2♀, Cleveland, Yorkshire, United Kingdom, 21 May 1954, BM 1954-473 (NHML); 1♀, Norfolk, United Kingdom, 29 Jun. 1969, M. Payne, BM 1970-259 (NHML); 1♂, North Stoke, Sussex, United Kingdom, 20 May 1937, G.B. Thompson, BM 1980-40 (NHML); 1♀, Hursley Road, Chandler’s Ford, Hampfordshire, United Kingdom, 10 Aug. 1978, W.P. Sanders BM 1979-251 (NHML); 4♂, 4♀, Ushant, Brittany, France, Apr. 1935, R. Meinertzhagen, 3409, 3350 (NHML); 2♂, Dollymount, Leinster County, Ireland, 7 Sep. 1938, O. Mahoney, BM 1980-40 (NHML); 1♀, Tel Fara, Israel, 29 Sep. 1960, 1220/1 and BM 1961-403 (NHML); 2♂, near Figuig, Morocco, 12 Apr. 1965, C. A. Walker, BM 1965-307 (NHML); 6♂, 16♀, Morocco, Oct. 1938, R. Meinertzhagen, 12131 (NHML); 1♂, 1♀, Slivem, Bulgaria, 26 May 1957, F. Balát, BM 1972-342 (NHML).
Ex Hirundo rustica savignii: 1♂, 5♀, Egypt, Apr. 1936, R. Meinertzhagen, 4828 (NHML).
Ex Hirundo rustica tytleri: 1♂, 2♀, Imphal, Manipur, India, 13 Jan. 1952, R. Meinertzhagen, 19715 (NHML).
Ex Hirundo rustica ssp. [Material from Thailand and Malaysia is likely from either H. r. gutturalis Scopoli, 1786, or H. r. tytleri Jerdon, 1864]: 2♀, Phayuha Khiri District, Nakhon Sawan Province, Thailand, 8 Mar. 1953, R.E. Elbel, RE-1659, RT-B-17592 (PIPeR); 2♂, 2♀, Bangkok, Thailand, 18 Jan. 1 966, MAPS-3870 (OSUS); 1♂, 1♀, same data as previous (NHML); 2♂, 3♀, Bangkok, Thailand, 10 Mar. 1965, H.E. McClure, SE-1696, one slide marked 16455 on reverse (OSUS); 1♂, 1♀, Phayuha Khiri District, Nakhon Sawan Province, Thailand, 8 Mar. 1953, R.E. Elbel, RE-1659, RT-B-17597 (OSUS); 1♂, 1♀, Mount Brinchang, Pahang State, Malaysia, 14 Dec. 1961, M-00723 (OSUS); 3♂, no collection data, (NHML); 1♂, 1♀, Phayuha Khiri District, Nakhon Sawan Province, Thailand, 8 Mar. 1953, R.E. Elbel, RE-1659, RT-B-17597, PIPeR#116 (PIPeR)
Ex Hirundo tahitica javanica: 2♂, 2♀, Calatagan, Batangas Province, Philippines, 8 Sep. 1965, MAPS 6 E- 1263, 24614 and 24611 on reverse (NHML); 1♀, Banjarmasin, South Kalimantan Province, Borneo, Indonesia, 7 Jan. 1971, XIE-122, 015-71800, 24612 on reverse (NHML).
Ex Ptyonoprogne rupestris: 1♀, Dubrovnik, Croatia, 10 Jan. 1977, A Lesinger, 13560 (PMSL); 1♀, Afghanistan, May 1937, R. Meinertzhagen, 10244 (NHML).
Ex Riparia chinensis chinensis: 1♂, Sind, India, Jan. 1937, R. Meinertzhagen, 10374 (NHML).
Ex Riparia diluta indica: 3♀, Peshawar, India, Mar. 1937, R. Meinertzhagen, 9234-35 (NHML).
Ex “Mehlschwalbe”: 3♀, unknown locality and date, IN 1335/44 (MFNB).
Remarks. First mentioned as Philopterus (Nirmus) gracilis by Nitzsch (1818: 291), but this is a nomen nudum. When Burmeister (1838: 421) gave the first formal description of the species, he changed the type host from Hirundo rustica to Delichon urbicum, which is therefore the correct type host and author.
We were unable to find any morphological differences among Acronirmus gracilis, Ac. buettikeri, and Ac. longus domesticus from their type hosts, or among these and most specimens of Acronirmus from other Old World hosts (see host list). Genetically, material from Eurasian D. urbicum, H. rustica, and Cecropsis daurica is virtually identical (Bush et al. 2016 and unpublished data). We therefore consider Brueelia longus domesticus and Ac. buettikeri to be junior synonyms of Br. gracilis. The original descriptions of all three species are poor, and modern redescriptions (Złotorzycka 1997) of Ac. gracilis and Ac. domesticus are uninformative.
We here report many new host records. Material examined from these hosts is morphologically inseparable from that of D. urbicum. This suggests that virtually all Old World hosts from which Acronirmus are known are parasitised by the same species, Ac. gracilis. We have not seen any material of Ac. tenuis (Burmeister, 1838), with type host Riparia riparia, but this louse species is very likely conspecific with Ac. gracilis.
Some material examined, ostensibly from D. urbicum, is from outside the range of this host (see Turner & Rose 1994), and most likely collected from its close relative D. dasypus, now often considered a separate species (see e.g. Sheldon et al. 2005). Other reports from East Asia (e.g. McClure & Ratanaworabhan 1973) may also refer to this host species, but the wintering ranges overlap (see Turner & Rose 1994).
We have examined two females of Bruelia brevipes from the Piaget Collection at the NHML, and both are Ac. gracilis. The type host of this species is Tringa subarquata (= Calidris ferruginea Pontoppidan, 1763), but extensive surveys of this host (DG, unpublished data) have revealed no specimens of Acronirmus. We therefore assume this is a straggler or a misattribution of the host, and do not list this host species in the checklist.
In general, heads of both sexes are smaller towards southern localities (see measurements), with Southeast Asian and Australasian specimens having smaller heads than European and Mediterranean specimens. This distinction does not hold for material from migratory species (D. urbicum, H. rustica, and C. daurica), which contain both small-headed and large-headed specimens collected from the same general areas. We therefore do not presently attach any significance to these differences. Potentially, this could be evidence of a difference between small-headed lice on host wintering grounds in Africa or South-East Asia, and large-headed lice on host breeding grounds in temperate Eurasia. The material available to us from wintering grounds of the hosts is not sufficient to test this hypothesis.
This louse species has an unusually wide host range, and we can only speculate about why it infests so many host species across Eurasia, Africa, and North America. Hippoboscid flies are common on swallows (DG, pers. obs.) and may provide means of transmission by phoresy. Keirans (1975) listed a single record of phoresy on a hippoboscid fly taken from a swallow. There may also be opportunities for direct contact among those host species that have overlapping wintering or breeding grounds.
description: Published as part of Bush, Sarah E., 2017, Morphological revision of the hyperdiverse Brueelia - complex (Insecta: Phthiraptera: Ischnocera: Philopteridae) with new taxa, checklists and generic key, pp. 1-443 in Zootaxa 4313 (1) on pages 60-66, DOI: 10.11646/zootaxa.4313.1.1, http://zenodo.org/record/883161