44 research outputs found

    Bedbugs evolved before their bat hosts and did not co-speciate with ancient humans

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    All 100+ bedbug species (Cimicidae) are obligate blood-sucking parasites [1, 2]. In general, blood sucking (hematophagy) is thought to have evolved in generalist feeders adventitiously taking blood meals [3, 4], but those cimicid taxa currently considered ancestral are putative host specialists [1, 5]. Bats are believed to be the ancestral hosts of cimicids [1], but a cimicid fossil [6] predates the oldest known bat fossil [7] by >30 million years (Ma). The bedbugs that parasitize humans [1, 8] are host generalists, so their evolution from specialist ancestors is incompatible with the "resource efficiency" hypothesis and only partially consistent with the "oscillation" hypothesis [9-16]. Because quantifying host shift frequencies of hematophagous specialists and generalists may help to predict host associations when vertebrate ranges expand by climate change [17], livestock, and pet trade in general and because of the previously proposed role of human pre-history in parasite speciation [18-20], we constructed a fossil-dated, molecular phylogeny of the Cimicidae. This phylogeny places ancestral Cimicidae to 115 mya as hematophagous specialists with lineages that later frequently populated bat and bird lineages. We also found that the clades, including the two major current urban pests, Cimex lectularius and C. hemipterus, separated 47 mya, rejecting the notion that the evolutionary trajectories of Homo caused their divergence [18-21]

    The chironomid (Diptera) communities in two sediment cores from Store Hovvatn, S. Norway, an acidified lake

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    Two sediment cores from acid lake Store Hovvatn were analysed for chironomid head capsule remains over a sequence spanning from about 1730 A.D. to the late 1970s. Up to 30 taxa were identified from one (0.5 cm) level in the cores. Principal component analysis of taxon relative abundances showed a gradient corresponding more or less to the sediment sample chronology. Redundancy analysis with some chemostratigraphical variables, and with pH values inferred from diatoms, indicated that chironomid community change could be explained as a response to acidification. However, most of the taxa that declined or disappeared up-core are known to occur in acid lakes and pH sensitivity per se does not seem to explain the response of individual species. The relative abundance of Orthocladiinae increased up-core and the long term change may be conceived in terms of a retarded productivity or oligotrophication. The most conspicuous change in the chironomid community appears to coincide with decreasing aluminium concentrations in the sediments and may indicate toxic effects from labile aluminium in the water column

    Marine Biodiversity of West Africa

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    JRS Biodiversity Foundation. NORAD (Norwegian Environment Agency

    Diversity and systematics of philinid snails (Gastropoda: Cephalaspidea) in West Africa with remarks on the biogeography of the region

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    West Africa is often considered one of the least studied regions of the world concerning marine biodiversity. Knowledge about the philinid snails of the region has largely been based on shells, but shells can be insufficient to discriminate between species. In this paper, we review the diversity and revise the systematics of the West African species of Philinidae sensu lato based on a comprehensive literature review and the study of shells, anatomy and DNA sequence data of novel specimens obtained by the R/V Dr Fridtjof Nansen (2005–2012) between Morocco and Angola. We use scanning electron microscopy together with a cytochrome c oxidase subunit I molecular phylogeny and molecular species delimitation methods (ABGD and SDP Geneious Plug In) to define species. Twenty species (19 formally named) were found to occur in the region, including four new species we describe here: Laona nanseni sp. nov., Philine cerebralis sp. nov., Philine schrammi sp. nov. and Spiniphiline caboverdensis sp. nov. We identified a complex of four cryptic species under the name P. quadripartita (P. guineensis, P. quadripartita, Philine schrammi sp. nov., Philine sp.). A biogeographical break is observed around Cape Verde and the Sahelian upwelling system coinciding with the West African Transition Province; eight species have their northern geographical limit or are restricted to this Province, while ten species have their southern limit here or just further north. Only one species seems to span across this biogeographical breaking point (P. scabra), but we speculate that this might result from taxonomic misidentifications

    Forensics of computers and handheld devices

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