Data incongruence and the problem of avian louse phylogeny

Recent studies based on different types of data (i.e. morphological and molecular) have supported conflicting phylogenies for the genera of avian feather lice (Ischnocera: Phthiraptera). We analyse new and published data from morphology and from mitochondrial (12S rRNA and COI) and nuclear (EF1-) genes to explore the sources of this incongruence and explain these conflicts. Character convergence, multiple substitutions at high divergences, and ancient radiation over a short period of time have contributed to the problem of resolving louse phylogeny with the data currently available. We show that apparent incongruence between the molecular datasets is largely attributable to rate variation and nonstationarity of base composition. In contrast, highly significant character incongruence leads to topological incongruence between the molecular and morphological data. We consider ways in which biases in the sequence data could be misleading, using several maximum likelihood models and LogDet corrections. The hierarchical structure of the data is explored using likelihood mapping and SplitsTree methods. Ultimately, we concede there is strong discordance between the molecular and morphological data and apply the conditional combination approach in this case. We conclude that higher level phylogenetic relationships within avian Ischnocera remain extremely problematic. However, consensus between datasets is beginning to converge on a stable phylogeny for avian lice, at and below the familial rank

Louse (Insecta : Phthiraptera) mitochondrial 12S rRNA secondary structure is highly variable

Lice are ectoparasitic insects hosted by birds and mammals. Mitochondrial 12S rRNA sequences obtained from lice show considerable length variation and are very difficult to align. We show that the louse 12S rRNA domain III secondary structure displays considerable variation compared to other insects, in both the shape and number of stems and loops. Phylogenetic trees constructed from tree edit distances between louse 12S rRNA structures do not closely resemble trees constructed from sequence data, suggesting that at least some of this structural variation has arisen independently in different louse lineages. Taken together with previous work on mitochondrial gene order and elevated rates of substitution in louse mitochondrial sequences, the structural variation in louse 12S rRNA confirms the highly distinctive nature of molecular evolution in these insects

Preliminary archaeoentomological analyses of permafrost-preserved cultural layers from the pre-contact Yup’ik Eskimo site of Nunalleq, Alaska : implications, potential and methodological considerations

Acknowledgements Site excavation and samples collection were conducted by archaeologists from the University of Aberdeen, with the help of archaeologists and student excavators from the University of Aberdeen University of Alaska Fairbanks and Bryn Mawr College, Kuskokwim Campus, College of Rural Alaska and residents of Quinhagak and Mekoryuk. This study is funded through AHRC grant to the project ‘Understanding Cultural Resilience and Climate Change on the Bering Sea through Yup’ik Ecological Knowledge, Lifeways, Learning and Archaeology’ to Rick Knecht, Kate Britton and Charlotta Hillderal (University of Aberdeen; AH/K006029/1). Thanks are due to Qanirtuuq Inc. and Quinhagak, Alaska for sampling permissions and to entomologists working at the CNC in Ottawa for allowing access to reference collections of beetles, lice and fleas. Yves Bousquet, Ales Smetana and Anthony E. Davies are specially acknowledged for their help with the identification of coleopteran specimens. Finally, we would also like to thank Scott Elias for useful comments on the original manuscript.Peer reviewedPublisher PD

Countdown to 2010: Can we assess Ireland’s insect species diversity and loss?

peer-reviewedThe insects are the most diverse organisms on this planet and play an essential role in ecosystem functioning, yet we know very little about them. In light of the Convention on Biological Diversity, this paper summarises the known insect species numbers for Ireland and questions whether this is a true refl ection of our insect diversity. The total number of known species for Ireland is 11,422. Using species accumulation curves and a comparison with the British fauna, this study shows that the Irish list is incomplete and that the actual species number is much higher. However, even with a reasonable knowledge of the species in Ireland, insects are such speciose, small, and inconspicuous animals that it is diffi cult to assess species loss. It is impossible to know at one point in time the number of insect species in Ireland and, although it is useful to summarise the known number of species, it is essential that biodiversity indicators, such as the Red List Index, are developed

Herbivory increases diversification across insect clades.

Insects contain more than half of all living species, but the causes of their remarkable diversity remain poorly understood. Many authors have suggested that herbivory has accelerated diversification in many insect clades. However, others have questioned the role of herbivory in insect diversification. Here, we test the relationships between herbivory and insect diversification across multiple scales. We find a strong, positive relationship between herbivory and diversification among insect orders. However, herbivory explains less variation in diversification within some orders (Diptera, Hemiptera) or shows no significant relationship with diversification in others (Coleoptera, Hymenoptera, Orthoptera). Thus, we support the overall importance of herbivory for insect diversification, but also show that its impacts can vary across scales and clades. In summary, our results illuminate the causes of species richness patterns in a group containing most living species, and show the importance of ecological impacts on diversification in explaining the diversity of life

Population characteristics of Phthiraptera occurring on Red Whiskered Bulbul (Pycnonotus jocosus)

Two phthirapteran species, Menacanthus eurysternus (Amblycera) and Brueelia sp. (Ischnocera) were recovered from 100 Red Whiskered Bulbuls (Pycnonotus jocosus) during March to December 2006. The occurrence of both the phthirapteran species on the aforesaid host are new host records. The prevalence, intensity of infestation, range of infestation, variance to mean ratio, sex ratio, adult nymph ratio, index of discrepancy (D) and exponent of negative binomial (k) were computed. The frequency distribution pattern of M. eurysternus conforms to negative binomial model. The frequency distribution pattern of Brueelia sp. was skewed but not described by the negative binomial

The lice (Insecta : phthiraptera) of short-tailed shearwaters, ardenna tenuirostris, in Bass Strait, Tasmania

There is a paucity of research into the louse fauna of Shorttailed Shearwaters, Ardenna tenuirostris (Temminck, 1835), despite this species being one of the world's most studied seabirds (Bradley et al. 1991 and references therein). Research has been undertaken on these shearwaters at their breeding grounds in Bass Strait, Tasmania, since 1947 (Bradley et al. 1991). As Short-tailed Shearwaters are long-lived, with an estimated average longevity of 38 years (Skira et al. 1985), they may offer a long-term host potential to host-dependent ectoparasites (i.e., lice) (Crompton 1997). Also, with approximately 23 million shearwaters breeding in burrows in dense rookeries on the islands and headlands of southern Australia, from southern New South Wales to Tasmania and from Victoria to Western Australia (Marchant & Higgins 1990), there may be the potential for increased transmission of ectoparasites between individual birds. Increased infestation rates by lice have been shown in colonial living birds. For instance, Rozsa et al. (1996) found an increase in louse infestation on Colonial Rooks, Corvus frugilegus Linnaeus, 1758, as compared to the territorial Hooded Crow, Corvus corone cornix Linnaeus, 1758. Short-tailed Shearwaters undertake an annual transequatorial migration to the Bering Sea for the austral winter (Serventy 1967), and so may act as vectors for the transmission of parasites across hemispheres (Lopez et al. 2005, Price et al. 2003). There are three publications that list the lice of Shorttailed Shearwaters. Green & Munday (1971) were the first to document the ectoparasites of Tasmanian fauna, albeit from personal communications- no published literature was cited. Twenty years later, Green & Palma (1991) listed the lice of Tasmania's vertebrates. They essentially used Green & Munday's (1971) list of lice on shearwaters and added Austromenopon paululum, listed as Austromenopon sp. in Green & Munday (1971). Price et al. (2003), in their checklist of the chewing lice (Phthiraptera) of the world, also listed the lice of Short -tailed Shearwaters. Included in this list were two louse species, Naubates harrisoni (Bedford, 1930) and Ancistrona vagelli (Fabricus, 1787), not mentioned in Green & Munday (1971). As part of the long-term research into Bass Strait's Short-tailed Shearwaters, this study aimed to confirm their current louse fauna, detailing the specific location, and collection method, to fill a gap in the primary literature

Population characteristics of Brueelia sp. on certain Indian Finches

Five kinds of finches were examined during 2004-06. Two kinds of finches were found infested with ischnoceran lice, Brueelia sp. (Prevalence-20.5%, mean intensity of infestation-4.7 and range of infestation, 1-23). The frequency distribution pattern of Brueelia sp. on Indian finches conformed to the negative binomial model. Sex ratio was skewed in favour of females and adults outnumbered the nymphs in natural population

Biology, ecology, and evolution of chewing lice

Book ChapterChewing lice are small, dorsoventrally compressed insects and are parasites of virtually all birds (Fig. 1) and some mammals (Fig. 2). Many chewing lice are host specific, being found on only a single species of host. All chewing lice are permanent ectoparasites and complete their entire life cycle on the body of the host, where they feed mainly on feathers, dead skin, blood, or secretions. Chewing lice on mammals apparently do not ingest hair, rather they feed on skin and skin products (Waterhouse 1953). Some species of lice feed on the eggs and molting stages of mites and other lice, including members of their own species (Nelson and Murray 1971). Lice also ingest microbes, such as bacteria and fungi, which are of unknown nutritive value

Nature of crop contents of an amblyceran pigeon louse, Colpocephalum turbinatum (Phthiraptera: Insecta)

Selected haemetophagous phthirapterans have been convicted to act as reservoir and transmitter of pathogens among their hosts. Amblyceran Phthiraptera are generally believed to exhibit varying degree of haemetophagy. The microscopic examination of 100 adults (both sexes) and 47 nymphal instars of an amblyceran louse, Colpocephalum turbinatum revealed their non haemetophagous nature as any red content compatible with host blood was not detected in their crops. The crops of the lice were found packed with only feather barbules. On seven instances the pieces of egg chorion and in 20 cases the presence of epidermal tissue were also detected in crop contents. However, the presence of any triturating agent (any structure which can help in grinding the feather contents) was not noticed. SEM studies on the ventral side of the head of the louse do not indicate the presence of any pointed gear which can be used to pierce the skin blood vessels of host. Present study suggests that few amblyceran species of Phthiraptera are not in haemetophagous in nature