No preference in female sika deer for conspecific over heterospecific male sexual calls in a mate choice context

Mating signals can be used both in contexts of species recognition and mate quality assessment. This study examines species recognition abilities in oestrous females presented with male mating calls from both conspecifics and closely related allopatric heterospecifics. Red deer and sika deer are naturally allopatric polygynous species capable of hybridization during sympatry. Male mating calls are sexually selected and differ greatly between species. Previous work indicated that most but not all oestrous red deer hinds prefer male mating calls from conspecifics over heterospecific sika deer. Using two-speaker playback experiments, we extend this examination by measuring the preference responses of oestrous sika deer hinds to these stimuli. We predicted that oestrous sika deer hinds will show little flexibility in behavioural responses and prefer conspecific calls over heterospecific calls, similar to those of red deer hinds. In contrast, sika deer hinds showed high levels of flexibility and no difference in overall preference behaviours, suggesting that vocal behaviour does not provide a solid barrier to hybridization in this species. The asymmetry in heterospecific preference responses between these species is discussed in relation to possible causation and hybridization patterns observed in free-ranging populations

The interaction of Sika deer (Cervus nippon Temminck 1838) with lowland heath mosaics.

Sika deer (Cervus nippon) has become an invasive species in many parts of the world. In the south of England large populations appear to be concentrated in landscapes comprising of mosaics of lowland heath, woodlands and grassland. Despite the association between the distribution of Sika deer and that of lowland heath, little is known regarding the extent to which Sika deer utilize lowland heath and their impacts on its plant and animal communities. The aim of this thesis was to investigate the ecological interaction of Sika deer with lowland heath set in a mosaic of other habitats. Specifically, the main three objectives of this thesis were: i) to investigate the different ecological factors affecting the distribution and habitat use by Sika deer; iii) to explore consistency in Sika deer habitat associations as a potential tool to predict the distribution and abundance ofSika deer; iii) to investigate the ecological impacts of the usage of areas of lowland heath by Sika deer upon plant and animal communities oflowland heath. Results showed that Sika deer distribution and habitat use are affected by the availability of habitats, landscape structure and human disturbance at both the landscape and home range scale (i.e. few hundred of hectares and few dozens of hectares respectively). At the landscape scale, Sika deer seemed to use the requirement for safe access to pastures as the main criteria for their habitat selection. At the home range scale, the criteria of choice in the use of resources by Sika deer seemed to be related to a requirement for an appropriate balance of food and cover as the selection of pastures and cover were inversely related to their availability. However, human disturbance, as a form of perceived risk, was also a limiting factor of habitat use at the home range scale. Consistencies in the habitat selection by Sika deer at the landscape scale between areas with similar landscape were detected, which could potentially be used to develop models to predict the distribution and abundance of Sika deer and their subsequent impacts in areas of lowland heath. This study has found a different response of plant and animal communities between dry and wet heath to levels in usage of areas of heath by Sika deer. The existence of a threshold in the local density of Sika deer on areas of heath above which dry lowland heath showed signs of decline in quality has also been identified

Intraspecific evolution within an ecologically diverse species can be used to examine evolutionary trends observed in ruminant morphology: a review of case studies of the Japanese sika deer

This review addresses the question “Are interspecific and macroevolutionary trends observed in ruminant morphology found among populations of a single species?” Several case studies of the Japanese sika deer, Cervus nippon, are discussed. The Japanese sika deer is a suitable species for this purpose because it inhabits various environments from the northern subarctic forests to the southern subtropical forests. It shows conspicuous variations in feeding habits, body size, and other morphological and behavioral traits. It can be concluded that selective pressures governing interspecific variations among ruminants, e.g., tooth wear due to grazing or mountainous habitat, promote morphological adaptation of local sika deer populations. However, in some cases, genetic differentiation among local populations is relatively small, resulting in a small degree of change compared to that observed between species. Intraspecific comparison of an ecologically diverse species like the Japanese sika deer is useful for elucidating the evolutionary patterns within ruminants and the possible causes for those patterns

Habitat Selection of Invasive Sika Deer Cervus nippon Living in a UK Lowland Heathland-Woodland-Grassland Mosaic: Implications for Habitat Conservation Management.

Understanding the factors determining the choice and use of habitats by invasive species is key to the conservation management of habitats and may also enable species to be harnessed as conservation tools. Here we explore the habitat use of an invasive population of sika deer, Cervus nippon on internationally important heathland in a landscape of heathland, grassland and woodland in southern UK. We used radio telemetry to test two hypotheses 1) grasses form a major part of the diet of non-native UK sika deer throughout the year 2) deer select grassland habitats above other habitats available. Results showed that although grasses form a major part of their diet, the strongest habitat selection was for heathland, the habitat that offered the least nutrient reward but which offered a source of roughage in the diet and some harbourage from human disturbance. This has implications for the conservation management of heathlands used by sika deer as it strongly indicates that heathland is a vulnerable habitat due to being favoured by sika deer but that its vulnerability can be reduced by coupling population control with targeted habitat management action such as increased disturbance or the removal of harbourage

Female sexual preferences toward conspecific and hybrid male mating calls in two species of polygynous deer, Cervus elaphus and C. nippon

The behavioral processes at the basis of hybridization and introgression are understudied in terrestrial mammals. We use a unique model to test the role of sexual signals as a reproductive barrier to introgression by investigating behavioral responses to male sexual calls in estrous females of two naturally allopatric but reproductively compatible deer species, red deer and sika deer. Previous studies demonstrated asymmetries in acoustic species discrimination between these species: most but not all female red deer prefer conspecific over sika deer male calls while female sika deer exhibit no preference differences. Here, we extend this examination of acoustic species discrimination to the role of male sexual calls in introgression between parent species and hybrids. Using two-speaker playback experiments, we compared the preference responses of estrous female red and sika deer to male sexual calls from conspecifics versus red × sika hybrids. These playbacks simulate early secondary contact between previously allopatric species after hybridization has occurred. Based on previous conspecific versus heterospecific playbacks, we predicted that most female red deer would prefer conspecific calls while female sika deer would show no difference in their preference behaviors toward conspecific and hybrid calls. However, results show that previous asymmetries did not persist as neither species exhibited more preferences for conspecific over hybrid calls. Thus, vocal behavior is not likely to deter introgression between these species during the early stages of sympatry. On a wider scale, weak discrimination against hybrid sexual signals could substantially contribute to this important evolutionary process in mammals and other taxa

The interaction of Sika deer (Cervus nippon Temminck 1838) with lowland heath mosaics

Sika deer (Cervus nippon) has become an invasive species in many parts of the world. In the south of England large populations appear to be concentrated in landscapes comprising of mosaics of lowland heath, woodlands and grassland. Despite the association between the distribution of Sika deer and that of lowland heath, little is known regarding the extent to which Sika deer utilize lowland heath and their impacts on its plant and animal communities. The aim of this thesis was to investigate the ecological interaction of Sika deer with lowland heath set in a mosaic of other habitats. Specifically, the main three objectives of this thesis were: i) to investigate the different ecological factors affecting the distribution and habitat use by Sika deer; iii) to explore consistency in Sika deer habitat associations as a potential tool to predict the distribution and abundance ofSika deer; iii) to investigate the ecological impacts of the usage of areas of lowland heath by Sika deer upon plant and animal communities oflowland heath. Results showed that Sika deer distribution and habitat use are affected by the availability of habitats, landscape structure and human disturbance at both the landscape and home range scale (i.e. few hundred of hectares and few dozens of hectares respectively). At the landscape scale, Sika deer seemed to use the requirement for safe access to pastures as the main criteria for their habitat selection. At the home range scale, the criteria of choice in the use of resources by Sika deer seemed to be related to a requirement for an appropriate balance of food and cover as the selection of pastures and cover were inversely related to their availability. However, human disturbance, as a form of perceived risk, was also a limiting factor of habitat use at the home range scale. Consistencies in the habitat selection by Sika deer at the landscape scale between areas with similar landscape were detected, which could potentially be used to develop models to predict the distribution and abundance of Sika deer and their subsequent impacts in areas of lowland heath. This study has found a different response of plant and animal communities between dry and wet heath to levels in usage of areas of heath by Sika deer. The existence of a threshold in the local density of Sika deer on areas of heath above which dry lowland heath showed signs of decline in quality has also been identified.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Fraying by Sika Deer (Cervus nippon) in an Evergreen Broadleaf Forest in Miyajima Island, Hiroshima, Japan

The fraying by sika deer (Cervus nippon) in an evergreen broadleaf forest in Miyajima Island, Hiroshima, Japan, was studied. The proportion of trees frayed by deer to the total trees sampled (N = 1209) was 8.1%. Our data suggest that sika deer performed fraying on trees irrespective of diameter at breast height. We found that of the 29 tree species examined, 16 were frayed. Cleyera japonica had a significantly higher proportion of trees frayed by sika deer than the average overall proportion, suggesting that the species attracts sika deer for fraying. By contrast, sika deer significantly avoided Pinus densiflora, Lyonia ovalifolia var. elliptica, and Eurya japonica for fraying. Trees frayed were significantly spatially distributed aggregately. The fraying by deer occurred randomly, regardless of slope angles; sika deer can perform fraying even on very steep slopes. Trees on ridges avoided being frayed by deer, however. This may be explained by the presence of the trees that were less favored for sika-fraying performance (Pinus densiflora, Lyonia ovalifolia var. elliptica, and Eurya japonica), which were mainly distributed on ridge sites

Effects of dietary forage-to-concentrate ratio on nutrient digestibility and enteric methane production in growing goats () and Sika deer ()

Objective Two experiments were conducted to determine the effects of forage-to-concentrate (F:C) ratio on the nutrient digestibility and enteric methane (CH4) emission in growing goats and Sika deer. Methods Three male growing goats (body weight [BW] = 19.0±0.7 kg) and three male growing deer (BW = 19.3±1.2 kg) were respectively allotted to a 3×3 Latin square design with an adaptation period of 7 d and a data collection period of 3 d. Respiration-metabolism chambers were used for measuring the enteric CH4 emission. Treatments of low (25:75), moderate (50:50), and high (73:27) F:C ratios were given to both goats and Sika deer. Results Dry matter (DM) and organic matter (OM) digestibility decreased linearly with increasing F:C ratio in both goats and Sika deer. In both goats and Sika deer, the CH4 emissions expressed as g/d, g/kg BW0.75, % of gross energy intake, g/kg DM intake (DMI), and g/kg OM intake (OMI) decreased linearly as the F:C ratio increased, however, the CH4 emissions expressed as g/kg digested DMI and OMI were not affected by the F:C ratio. Eight equations were derived for predicting the enteric CH4 emission from goats and Sika deer. For goat, equation 1 was found to be of the highest accuracy: CH4 (g/d) = 3.36+4.71×DMI (kg/d)−0.0036×neutral detergent fiber concentrate (NDFC, g/kg)+0.01563×dry matter digestibility (DMD, g/kg)−0.0108×neutral detergent fiber digestibility (NDFD, g/kg). For Sika deer, equation 5 was found to be of the highest accuracy: CH4 (g/d) = 66.3+27.7×DMI (kg/d)−5.91×NDFC (g/kg)−7.11× DMD (g/kg)+0.0809×NDFD (g/kg). Conclusion Digested nutrient intake could be considered when determining the CH4 generation factor in goats and Sika deer. Finally, the enteric CH4 prediction model for goats and Sika deer were estimated

Identification of single-nucleotide polymorphisms of the prion protein gene in sika deer (Cervus nippon laiouanus)

Polymorphisms of the prion protein gene (PRNP) have been detected in several cervid species. In order to confirm the genetic variations, this study examined the DNA sequences of the PRNP obtained from 33 captive sika deer (Cervus nippon laiouanus) in Korea. A total of three single-nucleotide polymorphisms (SNPs) at codons 100, 136 and 226 in the PRNP of the sika deer were identified. The polymorphic site located at codon 100 has not been reported. The SNPs detected at codons 100 and 226 induced amino acid substitutions. The SNP at codon 136 was a silent mutation that does not induce any amino acid change. The genotype and allele frequencies were determined for each of the SNPs