Parasites of an Arctic scavenger; the wolverine (Gulo gulo)

Abstract

Parasites are fundamental components within all ecosystems, shaping interaction webs, host population dynamics and behaviour. Despite this, baseline data is lacking to understand the parasite ecology of many Arctic species, including the wolverine (Gulo gulo), a top Arctic predator and scavenger. Here, we combined traditional count methods (i.e. adult helminth recovery, where taxonomy was confirmed by molecular identification) with 18S rRNA high-throughput sequencing to document the wolverine parasite community. Further, we investigated whether the abundance of parasites detected using traditional methods were associated with host metadata, latitude, and longitude (ranging from the northern limit of the boreal forest to the low Arctic and Arctic tundra in Nunavut, Canada). Adult parasites in intestinal contents were identified as Baylisascaris devosi in 72% (n = 39) of wolverines and Taenia spp. in 22% (n = 12), of which specimens from 2 wolverines were identified as T. twitchelli based on COX1 sequence. 18S rRNA high-throughput sequencing on DNA extracted from faeces detected additional parasites, including a pseudophyllid cestode (Diplogonoporus spp. or Diphyllobothrium spp.), two metastrongyloid lungworms (Angiostrongylus spp. or Aelurostrongylus spp., and Crenosoma spp.), an ascarid nematode (Ascaris spp. or Toxocara spp.), a Trichinella spp. nematode, and the protozoan Sarcocystis spp., though each at a prevalence less than 13% (n = 7). The abundance of B. devosi significantly decreased with latitude (slope = -0.68; R² = 0.17; P = 0.004), suggesting a northerly limit in distribution. We describe B. devosi and T. twitchelli in Canadian wolverines for the first time since 1978, and extend the recorded geographic distribution of these parasites ca 2000 km to the East and into the tundra ecosystem. Our findings illustrate the value of molecular methods in support of traditional methods, encouraging additional work to improve the advancement of molecular screening for parasites.

Keywords: 18S sequencing; Arctic; Helminths; Parasite community; Parasite surveillance; Wolverine.

Graphical abstract

Fig. 1

Map of individual wolverine hunting locations close by Inuit communities (circles = Arviat, triangles = Baker Lake, diamonds = Repulse Bay (Naujaat), squares = Cambridge Bay, inverse triangles = Kugluktuk) in Nunavut, Canada, 2010–2013. Inset shows sampling location (black outline) on a map of North America.

Fig. 2a

Records of Baylisascaris devosi in Nunavut, Canada detected within this paper (yellow), where each point is weighted by parasite abundance. Black squares represent wolverines in which B. devosi was not detected. Blue hashed line area indicates the previously known records of B. devosi reported by Addison and Bole (1978)b) Records of Taenia spp. in Nunavut, Canada detected within this paper (red). Previously known records of Taenia spp. (T. twitchelli and T. martis) reported by Addison and Bole (1978) are indicated by the blue hashed line area. Black squares represent wolverines in which Taenia spp. was not detected. (For interpretation of the references to colour in this figure legend, the reader is referred to the Web version of this article.)