Coevolution and Biogeography Among Nematodirinae (Nematoda: Trichostrongylina) Lagomorpha and Artiodactyla (Mammalia): Exploring Determinants of History and Structure for the Northern Fauna Across the Holarctic

Discovery of New Ohbayashinema spp. (Nematoda: Heligmosomoidea) in Ochotona princeps and Ochotona cansus (Lagomorpha: Ochotonidae) From Western North America and Central Asia, with considerations of Historical Biogeography

“…Origins of Ohbayashinema appear related to an early event of host colonization of Ochotona (after divergence of Ochotonidae + Leporidae) by heligmosomoids from sciurid or arvicoline rodents in Eurasia as indicated by affinities to Citellinema and Heligmosoma-Heligmosomoides (Durette-Desset, 1974a); no particular affinities with parasites of Leporidae are evident. These observations are consistent with the concept of ''host capture'' (Chabaud, 1965) as a primary driver for diversification among many taxa of the Trichostrongylina (Durette-Desset, 1985), and processes of colonization as more general phenomena in the radiation of complex assemblages of hosts and parasites (Hoberg and Brooks, 2008). This contrasts with the deeper coevolutionary history postulated for some molineoids in Lagomorpha, and the respective origins and diversification for Murielus in Ochotonidae and Rauschia + Nematodiroides in Leporidae coinciding with divergence of these mammalian families in the Oligocene.…”

Post-Miocene expansion, colonization, and host switching drove speciation among extant nematodes of the archaic genus Trichinella

“…Increasingly cold and insular conditions in the Arctic during the late Miocene and Pliocene favored the development of cold-adapted forms at a time when Beringia may have represented a filter bridge for host-parasite assemblages limited by arctic and subarctic conditions. Like other taxa (26,27), Trichinella expanded through Beringia during the Pliocene and Quaternary and subsequently experienced isolation events that promoted speciation during stadial-interstadial cycles. Isolation during the Quaternary across the Bering Land Bridge, and north and south of the Laurentide and Cordilleran ice, likely drove the divergence of T. murrelli and crown taxa including Trichinella T9, T. nativa, and Trichinella T6 (Fig.…”

“…Indeed, secondary contact zones in western North America have developed for some hosts tracking the retreat of glaciers (29). Populations of T. nativa may have expanded into high arctic habitats of Canada and Greenland during the Holocene, as has been postulated for other Holarctic parasitic nematodes and their mammalian hosts (26,30,31). Alternatively, assuming that peripheral isolation played a role in diversifying these crown species, T. nativa may instead represent an ancestral and persistent high-latitude population in the Holarctic.…”

Climate change and infectious disease: helminthological challenges to farmed ruminants in temperate regions

“…(3) At above-development threshold temperatures, the change in the proportion of egg populations being able to develop as a result of temperature increases varies between species. For arctic-adapted species like N. battus and T. circumcincta (Hoberg et al, 1999;Hoberg, 2005), a large proportion of the population is able to develop at the lower threshold for development (Pandey et al, 1989;Rossanigo and Gruner, 1995;Morgan, 2008 and. Although the larval development rates of these parasites increase with increasing temperatures, the increase in the proportion of the egg population being able to benefit from these increases is relatively small.…”