Birds are plagued by an impressive diversity of ectoparasites, ranging from feather-feeding lice, to featherdegrading bacteria. Many of these ectoparasites have severe negative effects on host fitness. It is therefore not surprising that selection on birds has favored a variety of possible adaptations for dealing with ectoparasites. The functional significance of some of these defenses has been well documented. Others have barely been studied, much less tested rigorously. In this article we review the evidence -or lack thereof -for many of the purported mechanisms birds have for dealing with ectoparasites. We concentrate on features of the plumage and its components, as well as anti-parasite behaviors. In some cases, we present original data from our own recent work. We make recommendations for future studies that could improve our understanding of this poorly known aspect of avian biology.

No abstract

The genus Brueelia Kéler, 1936a forms the core of the so-called “Brueelia-complex”, one of the largest and most heterogeneous groups of lice (Phthiraptera). Here we introduce the taxonomic history and present a revision of this group. The limits of the Brueelia-complex are discussed. We resurrect the genera Acronirmus Eichler, 1953, Corvonirmus Eichler, 1944, Guimaraesiella Eichler, 1949, Maculinirmus Złotorzycka, 1964a, Meropsiella Conci, 1941a, Olivinirmus Złotorzycka, 1964a, Osculonirmus Mey, 1982a, Rostrinirmus Złotorzycka, 1964a, Traihoriella Ansari, 1947, and Turdinirmus Eichler, 1951. We describe the following new genera: Anarchonirmus n. gen., Aporisticeras n. gen., Aratricerca n. gen., Buphagoecus n. gen., Ceratocista n. gen., Sychraella n. gen., Couala n. gen., Harpactrox n. gen., Hecatrishula n. gen., Indoceoplanetes n. gen., Manucodicola n. gen., Mirandofures n. gen., Nemuus n. gen., Priceiella n. gen., Psammonirmus n. gen., Resartor n. gen., Saepocephalum n. gen., Schizosairhynchus n. gen., Teinomordeus n. gen., Titanomessor n. gen., and Turdinirmoides n. gen.; and the following new subgenera: Camurnirmus n. subgen., Thescelovora n. subgen., Torosinirmus n. subgen., and Capnodella n. subgen.        The following 37 new species are described: Anarchonirmus albovittatus n. sp. ex Pomatostomus temporalis strepitans (Mayr & Rand, 1935); Brueelia aguilarae n. sp. ex Euplectes franciscanus pusillus (Hartert, 1901); Brueelia phasmasoma n. sp. ex Coereba flaveola luteola (Cabanis, 1850); Brueelia pseudognatha n. sp. ex Pycnonotus nigricans superior Clancey, 1959; Sychraella sinsutura n. sp. ex Pomatostomus isidorei isidorei Lesson, 1827; Couala dodekopter n. sp. ex Coua cristata pyropyga Grandidier, 1867; Guimaraesiella pandolura n. sp. ex Pericrocotus flammeus semiruber Whistler & Kinnear, 1933; Harpactrox geminodus n. sp. ex Harpactes erythorcephalus erythrocephalus (Gould, 1834); Harpactrox loeiensis n. sp. ex Harpactes erythrorhynchus annamensis (Robinson & Kloss, 1919); Harpactrox pontifrons n. sp. ex Harpactes ardens ardens (Temminck, 1824); Indoceoplanetes (Capnodella) loboccupatrix n. sp. ex Lobotos oriolinus Bates, 1909; Indoceoplanetes (Capnodella) laurocorythes n. sp. ex Edolisoma holopolium holopolium (Sharpe, 1888); Maculinirmus ljosalfar n. sp. ex Oriolus chinensis diffusus Sharpe, 1877; Manucodicola acantharx n. sp. ex Manucodia ater ater (Lesson, 1830); Manucodicola semiramisae n. sp. ex Phonygammus keraudrenii purpureoviolaceus (Meyer, 1885); Meropoecus balisong n. sp. ex Merops americanus Muller, 1776; Meropoecus bartlowi n. sp. ex Merops ornatus Latham, 1802; Mirandofures altoguineae n. sp. ex Oreostruthus fuliginosus De Vis, 1898; Mirandofures kamena n. sp. ex Erythrura trichroa sigillifer (De Vis, 1897); Nemuus hoedhri n. sp. ex Artamus fuscus Vieillot, 1817; Nemuus imperator n. sp. ex Artamus maximus Meyer, 1874; Priceiella (Camurnirmus) hwameicola n. sp. ex Garrulax taewanus Swinhoe, 1859; Priceiella (Camurnirmus) paulbrowni n. sp. ex Garrulax leucolophus diardi (Lesson, 1831); Priceiella (Thescelovora) alliocephala n. sp. ex Platylophus galericulatus ardesiacus (Bonaparte, 1850); Priceiella (Torosinirmus) koka n. sp. ex Turdoides tenebrosa (Hartlaub, 1883); Psammonirmus lunatipectus n. sp. ex Serilophus lunatus lunatus (Gould, 1834); Aratricerca cirithra n. sp. ex Ptiloprora guisei guisei (De Vis, 1894); Saepocephalum stephenfryi n. sp. ex Corcorax melanoramphos (Vieillot, 1817); Schizosairhynchus erysichthoni n. sp. ex Aplonis metallica metallica (Temminck, 1824) and Aplonis metallica nitida (Grey, 1858); Schizosairhynchus minovenator n. sp. ex Mino dumontii Lesson, 1827; Sturnidoecus australafricanus n. sp. ex Corvinella melanoleuca expressa Clancey, 1961; Sturnidoecus mon n. sp. ex Euplectes hordeaceus (Linnaeus, 1758); Sturnidoecus porphyrogenitus n. sp. ex Cinnyricinclus leucogaster verreauxi (Bocage, 1870); Sturnidoecus somnodraco n. sp. ex Quelea quelea quelea (Linnaeus, 1758) and Qualea quelea lathami (Smith, 1836); Teinomordeus entelosetus n. sp. ex Eurocephalus rueppelli Bonaparte, 1853; Titanomessor sexloba n. sp. ex Laniarius erythrogaster (Cretzschmar, 1829); and Turdinirmus australissimus n. sp. ex Zoothera lunulata lunulata (Latham, 1802). The name Olivinirmus paraffinis nom. nov. is proposed as a replacement for the preoccupied Brueelia affinis Carriker, 1963. We place 23 names in synonymy, and we consider 6 species as incertae sedis, 2 names as nomina nuda, and transfer 14 species names to genera not belonging to the Brueelia-complex.        We redescribe and illustrate most of the type species of the genera or subgenera included in this revision. Keys to genera, subgenera, and species groups are given, together with updated louse-host and host-louse checklists for 426 species of lice currently placed in the Brueelia-complex, including 183 new host-louse records.

Large-bodied species of hosts often harbor large-bodied parasites, a pattern known as Harrison's rule. Harrison's rule has been documented for a variety of animal parasites and herbivorous insects, yet the adaptive basis of the body-size correlation is poorly understood. We used phylogenetically independent methods to test for Harrison's rule across a large assemblage of bird lice (Insecta: Phthiraptera). The analysis revealed a significant relationship between louse and host size, despite considerable variation among taxa. We explored factors underlying this variation by testing Harrison's rule within two groups of feather-specialist lice that share hosts (pigeons and doves). The two groups, wing lice (Columbicola spp.) and body lice (Physconelloidinae spp.), have similar life histories, despite spending much of their time on different feather tracts. Wing lice showed strong support for Harrison's rule, whereas body lice showed no significant correlation with host size. Wing louse size was correlated with wing feather size, which was in turn correlated with overall host size. In contrast, body louse size showed no correlation with body feather size, which also was not correlated with overall host size. The reason why body lice did not fit Harrison's rule may be related to the fact that different species of body lice use different microhabitats within body feathers. More detailed measurements of body feathers may be needed to explore the precise relationship of body louse size to relevant components of feather size. Whatever the reason, Harrison's rule does not hold in body lice, possibly because selection on body size is mediated by community-level interactions between body lice.

Phylogenetic congruence is governed by various macroevolutionary events, including cospeciation, host switching, sorting, duplication, and failure to speciate. The relative frequency of these events may be influenced by factors that govern the distribution and abundance of the interacting groups; i.e., ecological factors. If so, it may be possible to predict the degree of phylogenetic congruence between two groups from information about their ecology. Unfortunately, adequate comparative ecological data are not available for many of the systems that have been subjected to cophylogenetic analysis. An exception is provided by chewing lice (Insecta: Phthiraptera), which parasitize birds and mammals. For a few genera of these lice, enough data have now been published to begin exploring the relationship between ecology and congruence. In general, there is a correspondence between important ecological factors and the degree of phylogenetic congruence. Careful comparison of these genera suggests that dispersal is a more fundamental barrier to host switching among related hosts than is establishment. Transfer experiments show that host-specific lice can survive and reproduce on novel hosts that are similar in size to the native host as long as the lice can disperse to these hosts. To date, studies of parasite dispersal have been mainly inferential. A better understanding of the role of dispersal will require more direct data on dispersal frequency and distances.