Are warbles and bots related to reproductive status in West Greenland caribou?

Abstract

Abstract:In March-April 2008-09, using CARMA protocols, 81 cows and 16 calves were collected in West Greenland from two caribou populations; Akia-Maniitsoq (AM) and Kangerlussuaq-Sisimiut (KS). In both populations, warble larvae numbers were highest in calves and higher in non-pregnant than pregnant cows. Nose bots showed no relationship with pregnancy or lactation; KS calves had higher nose bot loads than cows, a pattern not observed in AM. Pregnant cows had more rump fat than non-pregnant cows. KS cows lacking rump fat entirely had the highest warble burdens. We observed lactating pregnant cows with moderate larval burdens. Projected energy cost of the heaviest observed combined larvae burdens was equivalent to 2-5 days basal metabolic rate (BMR) for a cow, and 7-12 days BMR for a calf. Foregone fattening in adult cows with average burdens was 0.2 to 0.5 kg, but almost doubled with the heaviest infestations to 0.4 and 0.8 kg. Average burdens in calves resulted in forgone fattening of about 0.5 kg, with peak costs equivalent to 0.7 and 1.1 kg fat for AM and KS calves respectively. Although modest, these projected energy costs of hosting larvae for cows support the negative relationship between rump fat and larvae burden. For calves, hosting high burdens of warble larvae could affect winter survival, specifically those weaned normally in October or in early winter. Harmful effects of oestrid larvae burdens may remain subtle but clearly cumulative in relation to seasonal forage availability and incidence of other parasites.

Simulation of maintenance, growth and reproduction of caribou and reindeer as influenced by ecological aspects of nutrition, climate change and industrial development using an energy-protein model

“…Caribou and wild reindeer are adapted to characteristically high seasonal and annual variability that is typical of the higher latitudes. Variability includes accumulation and structure of winter snow, spring snow melt and linked plant phenological dynamics (Klein, 1990;Albon & Langvatn, 1992), quality and accessibility of summer forage and disruptive impacts of biting and parasitic insects in the summer (Klein, 1990;Russell et al, 1993;Witter et al, 2011;Cuyler et al, 2012). Thus habitat characteristics and variability in risk (Kie, 1999) influence reproductive allocation patterns (Munns, 2006;Bårdsen et al, 2008;Monteith et al, 2013).…”

Observed and predicted effects of climate change on Arctic caribou and reindeer

“…The deleterious effects of parasitic insects are twofold. There are, of course, the direct effects of the parasitic burden that results from successful parasite attacks, with increasing parasite load in an individual associated with decreasing body condition and reproduction (Thomas and Kiliaan 1990;Albon et al 2002;Hughes et al 2009;Ballesteros et al 2012;Cuyler et al 2012;Pachkowski et al 2013). Second, the behavioural response of Rangifer to insect harassment is detrimental to individuals through a reduction in time spent foraging and increased energy expenditure (Downes et al 1986;Ion and Kershaw 1989;Mörschel and Klein 1997;Hagemoen and Reimers 2002;Skarin et al 2010;Witter et al 2012b).…”

Variation in the intensity and prevalence of macroparasites in migratory caribou: a quasi-circumpolar study

“…Caribou from Greenland had a much greater abundance of H. tarandi and C. trompe. The short migration (<200 km) of Greenland herds may be the principal factor explaining these high values (Cuyler et al 2012), however, a relatively short host-parasite association caused by the recent introduction of these parasites to these historically isolated herds is also postulated as a reason for the high abundance. Longer migrations in North America could minimize reinfestation of H. tarandi and C. trompe by separating hosts from the areas where the larvae were dropped and adult flies eventually emerge (Thomas and Kiliaan 1990;Folstad et al 1991).…”