Morphometric characterization of Mesola red deerCervus elaphus italicus(Mammalia: Cervidae)

Variation of antlers in individual red deer (Cervus elaphus) stags: repeatability, age and side effects

Antlers are formed anew each year to realise an optimal relationship between their size and weight and the physical body condition in Cervidae. This results in the objective to match fighting abilities with size and mechanical performance of the antlers, as well as to advertise these correlated abilities to other males and females. The resulting variation in individual antler characteristics from year to year can show considerable differences. To characterise and understand these differences is important in hunting, game management and deer breeding, as well as potentially to assess the habitat quality. However, relatively few traits of the antler have been scientifically tested for this purpose, and only a few studies were conducted on the same individual in free-ranging red deer over the years. The objective of the present study was to quantify the influence of the individual (repeatability), the age and the site on the expression of 125 antler characteristics. For this purpose, we collected 35 stags with an average of about 10 consecutive antlers per individual (confirmed by genetic analysis), a total of 355 antlers. The antlers were scanned 3-dimensionally and measured semi-automatically. Numbers, lengths, distances, circumferences, bending, curvatures, angles, forms and CIC (International Council for Game and Wildlife Conservation) characteristics were compiled and evaluated in a generalised linear mixed model adapted to the distribution of the characteristics. The complete model explained 1.6 to 83% of character variation. Mean repeatability of the characteristics varied between 2.7 and 74.4%. The stags’ age explained 0 to 36.4%, and the side explained 0 to 2.5% of the variability. Some characteristics of burr, signet, beam and the lower tines reached the highest repeatability; the highest variability was found in characteristics of the crown. Values of 11 features that are frequently used in other studies corresponded very well with the present study. However, some features reached higher repeatability every year, whereas others varied more closely with age. Such characteristics might be selectively included into further research or practical applications to increase informative value.

The Application of 3D Imaging as an Appropriate Method of Wildlife Craniometry: Evaluation of Accuracy and Measurement Efficiency

The suitability of CT and 3D scanners for craniometric proposes was tested using digital calipers when determining linear measurements, and a measuring cylinder was used for the accuracy of 3D printing of deer antlers obtained by the CT and 3D scanners. The resolution of digitized objects from a 3D scanner ranged from 0.008 mm to 0.122 mm. For mandibular dimensions, a positive deviation (p < 0.01) from the primary control measurement was recorded. The average antler volume measured with the cylinder was 60.47 cm3 at the first measurement, in the case of the CT scanner 61.62 cm3 and for the 3D scanner 64.76 cm3—both technologies exhibit a positive deviation from the primary measurement. Precise sensing and measurements can be used to evaluate the quality and evolution of wildlife populations, create digital museum collections, or to examine in detail certain traits such as antler and horn development or dentition.

Spatial variation in antler investment of Apennine red deer

Heterogeneity in resource availability and quality can trigger spatial patterns in the expression of sexually selected traits such as body mass and weaponry. While relationships between habitat features and phenotypic quality are well established at broad geographical scales, information is poor on spatial patterns at finer, intrapopulation scales. We analyzed biometric data collected on 1965 red deer Cervus elaphus males over 20 years from a nonmigratory population living on two sides of a mountainous ridge, with substantial differences in land cover and habitat quality but similar climate and population density. We investigate spatial patterns in (i) body mass, (ii) antler mass, and (iii) antler investment. We also tested for site- and age-specific patterns in allometric relationship between body mass and antler mass. Statistically significant fine-scale spatial variations in body mass, antler mass, and, to a lesser extent, antler allocation matched spatial differences in land cover. All three traits were greater in the northern slope, characterized by higher habitat heterogeneity and greater availability of open habitats, than in the southern slope. Moreover, the allometric relationship between body mass and antler mass differed among age-classes, in a pattern that was consistent between the two mountain slopes. Our results support the occurrence of spatial patterns in the expression of individual attributes also at a fine, intrapopulation scale. Our findings emphasize the role of environmental heterogeneity in shaping spatial variations of key life-history traits, with potential consequences for reproductive success.