Knowledge of bat migration routes and phenology is still incomplete, especially for small-bodied species. Here we report on autumn migration over a mountain barrier (1200 - 1400 m a.s.l.) and analyse differences between short- and long-distance migrants based on acoustic monitoring of the number and direction of bat flights. The number of flights over the mountain passes peaked in September and then slowly declined. This pattern occurred for both long-distance and shortdistance migrants, but long-distance migrants had a longer migration season. All bats migrated preferentially during milder weather (relatively dry, high temperature and low wind). As the migration season progressed, the proportion of southerly flights increased, and this tendency was stronger for long-distance migrants than for short-distance migrants. It appears that a proportion of the movements of short-distance migrants were associated with individuals commuting across the ridge to swarming and wintering sites on either side of the ridge. We conclude that long-distance migrants differ from other species only quantitatively: they have a longer migratory season and their migratory direction to the south is more defined. We hypothesise that the migration strategy of long-distance migrants depends on maximising the use of good weather windows rather than on persistent migration regardless of conditions.
Predators can indirectly stimulate the development of anti-predator strategies in prey species. Within populations, these behavioral responses may vary according to sex and age classes of individuals, although the existing literature presents conflicting results. Using camera trapping, spatiotemporal responses to the wolf Canis lupus were assessed in relation to sex and age classes in two prey species, the fallow deer Dama dama and the roe deer Capreolus capreolus, within a Mediterranean area recently recolonized by this canid. In fallow deer, results suggest stronger temporal avoidance in females than in adult males, increasing their diurnal activity as the wolf detection rate increased and reducing their temporal overlap with the predator. In roe deer, the avoidance responses were less marked, but females, particularly during the warm period, exhibited different activity patterns compared to males. Smaller body size (fallow deer) and presence of offspring are expected to make females more vulnerable to predation, which would emphasize the perceived predation risk in these individuals, in turn promoting a stronger response to predators compared to males. Females of both species may adopt different activity patterns from males to minimize temporal overlap with the wolf and reduce the risk of direct predator encounters. By providing support to sexual differences in antipredator responses, our results provide a novel contribution to increasing knowledge on the indirect effects of recolonizing predators in human-dominated landscapes of Europe.
Suncus murinus, a widespread Soricidae, has been introduced to several islands, strongly impacting endemic species. Its dietary habits, especially at its introduction sites, are poorly understood and the level of impact on native taxa remains unknown. Obtaining dietary samples from shrews is challenging because of their high metabolic rates and rapid digestion. We tested the effectiveness of stomach swabs in analysing the diet of S. murinus using DNA metabarcoding on 300 individuals from R & eacute;union Island (Western Indian Ocean). Non-target DNA amplification was substantial. We identified five preys belonging to three classes of Arthropoda (Arachnida, Insecta and Malacostraca) and one class of Annelida (Clitellata), with two of them assigned to species level, Amynthas rodericensis and Pycnoscelus surinamensis. Lycosidae and Malacostraca were the most frequent groups, each with a 50% frequency of occurrence. Stomach swabs provide insights into the dietary composition of S. murinus, but low DNA yield and purity limited detailed resolution. We highlight the importance of reducing the time lag between trapping and sample extraction and the use of blocking primers to prevent non-target amplification to enhance resolution of S. murinus' diet composition.
Understanding how genetic variations and environmental constraints influence morphological differences is crucial to interpreting phenotypic diversity. The mandible is a key structure widely used to make inferences about feeding ecology and habitat conditions in early ungulate growth. However, most studies focus on interspecific comparisons, and few address mandibular plasticity and variations at inter- and intrapopulation scales. In this study, we used a 2D geometric-morphometric approach to analyse how these factors shape the mandibles of two Cervini species characterised by different contexts, populations and belonging to distinct lineages: the red deer (Cervus elaphus) and the rusa deer (Rusa timorensis).For the European red deer, we found clear variations in mandibular morphology along a north-south transect from Norway to southern Spain. These variations are related to the need for different biomechanical forces to masticate vegetal resources with distinct physical properties, under contrasting climates. The mandibles of red deer in southern Europe are more robust, probably due to the higher proportion of highly fibrous, tough herbaceous monocotyledons in their diet. In contrast, northern populations have slender mandibles, reflecting the consumption of a softer diet. The American population of red deer from Argentina shows a different trend, both in size and shape. A recent study showed that New Caledonian rusa deer constituted a single genetic population. Here, we identified significant intrapopulation differences between contrasting local habitats. Gouaro-D & eacute;va rusa deer are significantly smaller, which we interpret as the consequence of greater stress, impacting the growth and ontogenic development of these animals. Deer from tropical forests have a more robust mandible than in grassy areas, aligning with the biomechanical needs of their respective diets. Morphological variations in deer jaws at intraspecific and interspecific scales provide insights into the ecology and environment of these animals, and offer potential for future (paleo)ecological research using geometric morphometric approaches.
Mitochondrial DNA sequences can be used to infer haplotype diversity in range-expanding species. The Eurasian beaver Castor fiber is experiencing a remarkable recovery in Europe following centuries of exploitation and local extinctions. The species has recently recolonized also Central Italy, likely due to unauthorized releases, whereas the first individuals occurring in North-Eastern Italy may be the results of natural range expansion from neighboring countries. Since the last months of 2023, presence signs were also observed in North-Western Italy, near the border with Switzerland. To assess the genetic diversity and origin of Italian beaver populations, we conducted mitochondrial DNA analysis on samples from this newly colonized area, revealing the occurrence of two mtDNA haplotypes belonging to the western mitochondrial lineage of the Eurasian beaver. Molecular sexing also confirmed the occurrence of both males and females. Therefore, monitoring this population should be urgently established following European laws. Future genetic investigations using nuclear DNA markers will be crucial for understanding the origin of these new populations and informing effective conservation strategies.
