Phenotypic plasticity and local adaptation in freeze tolerance and its implications for parasite dynamics in a changing world: the case of Marshallagia marshalli.

Phenotypic plasticity and local adaptation in freeze tolerance and its implications for parasite dynamics in a changing world: the case of Marshallagia marshalli. Int J Parasitol. 2020 Jan 28;: Authors: Alejandro Aleuy O, Peacock S, Hoberg EP, Ruckstuhl KE, Brooks T, Aranas M, Kutz S Abstract Marshallagia marshalli is a multi-host gastrointestinal nematode that infects a variety of artiodactyl species from temperate to Arctic latitudes. Eggs of Marshallagia are passed in host feces and develop through three larval stages (L1, L2, and L3) in the environment. Although eggs normally hatch as L1s, they can also hatch as L3s. We hypothesized that this phenotypic plasticity in hatching behaviour may improve fitness in subzero and highly variable environments, and this may constitute an evolutionary advantage under current climate change scenarios. To test this, we first determined if the freeze tolerance of different free-living stages varied at different temperatures (-9°C, -20°C and -35°C). We then investigated if there were differences in freeze tolerance of M. marshalli eggs sourced from three discrete, semi-isolated, populations of wild bighorn and thinhorn sheep living in western North America (latitudes: 40°N, 50°N, 64°N). The survival rates of eggs and L3s were significantly higher than L1s at -9°C and -20°C, and survival of all three stages decreased significantly with increasing freeze duration and decreasing temperature....
Source: International Journal for Parasitology - Category: Parasitology Authors: Tags: Int J Parasitol Source Type: research