The diel activity pattern of mountain hare (Lepus timidus) on managed heather moorland in Scotland

The research presented in this paper provides an insight into the behavioral ecology of mountain hares on heather moorland in the Lammermuir Hills of southeast Scotland. We examine the seasonal and diel activity patterns using camera traps over a period of 12 months. The rate of camera detections was calculated for the different divisions of the 24-hr cycle (daylight, dusk, night, and dawn). During autumn and winter (October-February), the activity pattern was crepuscular with greater activity at dusk than at dawn. Daylight activity was relatively low, and there was a regular pattern of small peaks of activity during the night. In spring and summer (March-September), peaks of crepuscular activity remained evident but daylight activity was much more prevalent than during autumn and winter, and night activity was lower. We discuss the problematic definition of twilight and present an explanation for seasonal changes in the pattern of diel activity that is linked to the reproductive cycle of the mountain hare.

Introgression drives repeated evolution of winter coat color polymorphism in hares

Changing from summer-brown to winter-white pelage or plumage is a crucial adaptation to seasonal snow in more than 20 mammal and bird species. Many of these species maintain nonwhite winter morphs, locally adapted to less snowy conditions, which may have evolved independently. Mountain hares (Lepus timidus) from Fennoscandia were introduced into the Faroe Islands in 1855. While they were initially winter-white, within ∼65 y all Faroese hares became winter-gray, a morph that occurs in the source population at low frequency. The documented population history makes this a valuable model for understanding the genetic basis and evolution of the seasonal trait polymorphism. Through whole-genome scans of differentiation and single-nucleotide polymorphism (SNP) genotyping, we associated winter coat color polymorphism to the genomic region of the pigmentation gene Agouti, previously linked to introgression-driven winter coat color variation in the snowshoe hare (Lepus americanus). Lower Agouti expression in the skin of winter-gray individuals during the autumn molt suggests that regulatory changes may underlie the color polymorphism. Variation in the associated genomic region shows signatures of a selective sweep in the Faroese population, suggesting that positive selection drove the fixation of the variant after the introduction. Whole-genome analyses of several hare species revealed that the winter-gray variant originated through introgression from a noncolor changing species, in keeping with the history of ancient hybridization between the species. Our findings show the recurrent role of introgression in generating winter coat color variation by repeatedly recruiting the regulatory region of Agouti to modulate seasonal coat color change.

First report of hare treponematosis seroprevalence of European brown hares (Lepus europaeus) in the Czech Republic: seroprevalence negatively correlates with altitude of sampling areas

BACKGROUND

The aim of this study was to quantify the seroprevalence of hare treponematosis in European brown hare (Lepus europaeus) populations in the Czech Republic and to test for an association between treponematosis prevalence and the altitude of the areas in which hares were sampled. We tested 289 serum samples of brown hares collected between 2015 and 2017. The sampling areas included 12 districts (73 villages) distributed throughout the Czech Republic. Serum samples were tested for the presence of antibodies against the causative agent of hare treponematosis (Treponema paraluisleporidarum ecovar Lepus, TPeL) using two serological tests for human syphilis that cross-react with TPeL: the Treponema pallidum hemagglutination assay (TPHA) and the fluorescent treponemal antibody absorption (FTA-ABS) test. To account for the imperfect diagnostic sensitivity and specificity of each test, apparent prevalence estimates of TPeL were converted to true prevalence estimates using the Rogan Gladen estimator. The correlation between TPeL true seroprevalence and altitude of sampling areas was analyzed using Pearson's correlation coefficient at three levels of spatial resolution: (1) four groups, each composed of two merged districts, with ≥20 samples collected, differing in their altitude median (206, 348, 495, and 522 m above sea level); (2) separately tested eight districts, where ≥20 samples were collected per district; and (3) 27 groups composed of villages of the same altitude level distributed across the whole dataset.

RESULTS

One hundred and seven of the 289 samples were seropositive to both tests, the FTA-ABS test was positive for an additional 47 samples. Seropositive samples were found in all 12 districts. True seroprevalence of TPeL in the sampled hares was 52% (95% confidence interval 46 to 58%). A statistically significant negative correlation between TPeL seroprevalence and altitude was identified at the district level (Pearson's r = - 0.722, p = 0.043).

CONCLUSIONS

Between 2015 and 2017 hare treponematosis was present at a relatively high prevalence in brown hares in all 12 districts in the Czech Republic where sampling was carried out. The seroprevalence of TPeL in brown hares was negatively correlated with the altitude of the areas in which hares were sampled.

Overcoming species barriers: an outbreak of Lagovirus europaeus GI.2/RHDV2 in an isolated population of mountain hares (Lepus timidus)

Background

Prior to 2010, the lagoviruses that cause rabbit hemorrhagic disease (RHD) in European rabbits (Oryctolagus cuniculus) and European brown hare syndrome (EBHS) in hares (Lepus spp.) were generally genus-specific. However, in 2010, rabbit hemorrhagic disease virus 2 (RHDV2), also known as Lagovirus europaeus GI.2, emerged and had the distinguishing ability to cause disease in both rabbits and certain hare species. The mountain hare (Lepus timidus) is native to Sweden and is susceptible to European brown hare syndrome virus (EBHSV), also called Lagovirus europaeus GII.1. While most mountain hare populations are found on the mainland, isolated populations also exist on islands. Here we investigate a mortality event in mountain hares on the small island of Hallands Väderö where other leporid species, including rabbits, are absent.

Results

Post-mortem and microscopic examination of three mountain hare carcasses collected from early November 2016 to mid-March 2017 revealed acute hepatic necrosis consistent with pathogenic lagovirus infection. Using immunohistochemistry, lagoviral capsid antigen was visualized within lesions, both in hepatocytes and macrophages. Genotyping and immunotyping of the virus independently confirmed infection with L. europaeus GI.2, not GII.1. Phylogenetic analyses of the vp60 gene grouped mountain hare strains together with a rabbit strain from an outbreak of GI.2 in July 2016, collected approximately 50 km away on the mainland.

Conclusions

This is the first documented infection of GI.2 in mountain hares and further expands the host range of GI.2. Lesions and tissue distribution mimic those of GII.1 in mountain hares. The virus was most likely initially introduced from a concurrent, large-scale GI.2 outbreak in rabbits on the adjacent mainland, providing another example of how readily this virus can spread. The mortality event in mountain hares lasted for at least 4.5 months in the absence of rabbits, which would have required virus circulation among mountain hares, environmental persistence and/or multiple introductions. This marks the fourth Lepus species that can succumb to GI.2 infection, suggesting that susceptibility to GI.2 may be common in Lepus species. Measures to minimize the spread of GI.2 to vulnerable Lepus populations therefore are prudent.

Electronic supplementary material

The online version of this article (10.1186/s12917-018-1694-7) contains supplementary material, which is available to authorized users.