Roberto Cozzolino

Wild boar rooting behaviour can be shaped by several environmental variables (e.g., food availability and habitat features) and can directly or indirectly influence various habitats, ecological processes and taxa. One of these, ground-dwelling rodents, are known to be affected by wild boar foraging activity due to food competition and direct disturbance. In the current study, the following questions were investigated: do vegetation composition, structural components of forest habitats (at ground, shrub, and tree levels) and acorn availability influence rooting activity of wild boars and consequently, also the abundance of Apodemus flavicollis and A. sylvaticus in the same area. This research was carried out in a Mediterranean deciduous oak forest across 12 sampling sites. The results showed that, among the habitat variables considered, only shrub cover at 1 m height had a significant association with the extent of wild boar rooting. Contrary to expectations, acorn availability did not significantly influence rooting activity, suggesting either a more complex relationship between food availability and rooting behaviour or the influence of other local factors. Likewise, the number of Apodemus spp. individuals captured was not significantly related to rooting activity, indicating no detectable effects of wild boar rooting on rodents in the study area. This study contributes to our understanding of the factors driving this foraging behaviour and its ecological and socioeconomic implications.

Rodent–seed foraging behavior plays a key role in seed fate and plant regeneration. Seed mass is a central trait influencing seed predation, removal and caching by hoarding rodents. In ecosystems with multiple sympatric rodent species, differential seed use can exert varying selective pressures on seeds. In a semi-natural experiment, we observed how Quercus cerris acorn mass affected seed predation, removal, and dispersal by 2 sympatric rodents of different body sizes, Apodemus flavicollis and A. sylvaticus. For both species, seed mass had a consistent effect in predicting seed fate. We detected a species-specific response in seed predation: A. flavicollis more likely predated heavier acorns, while seed mass was not found to affect acorn use in A. sylvaticus. Seed removal probability was affected by seed mass but it did not differ between the 2 species, which both showed similar removal patterns with respect to seed mass. Although the mass of removed acorns did not differ between the 2 species, the acorn mass to rodent body mass ratio of removed seeds was higher in A. sylvaticus compared with A. flavicollis. The likelihood of predation versus that of dispersal after removal was found to be species-specific: seed dispersal did not vary with seed mass for A. flavicollis, while A. sylvaticus dispersed heavier acorns. These results suggest that the 2 species might play distinct roles in determining seed fate. Our findings highlight the importance of considering species-specific foraging strategies when assessing the role of sympatric hoarding rodents in seed dispersal and forest regeneration.

Glucocorticoids regulate many physiological functions and play an important role in coping with challenging stimuli. The non‐invasive assessment of glucocorticoids is increasingly used as a tool to evaluate individual and population health status in wild animals. Given the crucial role of rodents in forest ecosystems, it may be useful to study the glucocorticoid profile of these species to find possible links with the characteristics of the environment in which they live and facilitate the development of biodiversity management plans. We studied two closely related species that are the main representatives of the ground‐dwelling rodent communities in sub‐Mediterranean forested areas: Apodemus sylvaticus and A. flavicollis . The fecal corticosterone metabolite (FCM) levels of animals captured in a Mediterranean agroforestry system were measured, taking into account the evidence of methodological assessments to evaluate hormone metabolite differences between feces excreted at different times under captive conditions and the stability of these metabolites. We found that A. sylvaticus males excreted lower FCM levels than females, while A. flavicollis males showed higher FCM levels than females. Males of the two species excreted similar FCM levels, while higher FCM levels were recorded in A. sylvaticus females than in their A. flavicollis counterparts. The FCM levels in both species were similar between breeding conditions, seasons and habitat types. The results of our exploratory investigation suggest that traditional silviculture may not trigger the activity of the hypothalamus‐pituitary‐adrenal axis. Further studies are required for a more detailed examination of how environmental factors affect FCM levels. Long‐term studies may disclose possible effects of interannual environmental factor variability in ground‐dwelling rodents.

The wood mouse Apodemus sylvaticus is common in woodlands and open areas of the Western Palearctic. Despite extensive research, little is known about its population ecology in fields in the Mediterranean area, where the climate involves great seasonal changes in environmental features. Here, we investigated wood mice seasonal fluctuations in the number of captures and population structure by sampling long-fallow fields and woodlands, i.e., oak forest and conifer plantation, in a heterogeneous landscape of central Italy. Mice were live-trapped every two months for three years (23.814 trap-days). The number of captures, mice body weight, and proportion of adult, residents and breeding individuals were analyzed. Mice dynamics changed across seasons and habitats. In fields, we recorded more captures, more reproductive individuals, and fewer non-adults and resident individuals in the warmer months compared to the colder months; mice were heavier in warmer months. During the cold season, the captures and adult proportion in fields were lower than in resource-rich woodlands. Breeding and non-resident mice were more abundant in fields than in woodlands in warmer months. Overall, the seasonal demographic variations we recorded provide evidence that fields can represent a suboptimal habitat in Mediterranean heterogeneous landscapes, acting nonetheless as a source of food resources, cover, and mates for mice in spring–summer.

It was long assumed that only humans can distinguish the living from the dead. Renewed interest in this question over the last decade has led several authors to assert that non-human primates are also aware of death. We investigate this issue by comparing the behaviours of monkeys and great apes toward helpless conspecifics, basing our analysis on published reports. We first examine the behaviours of mothers towards the body of their dead offspring. They may carry the corpse for days or more before abandoning it. They groom, inspect and protect it, sometimes allowing group members to explore it, and rare cases of cannibalism have been reported. No significant difference is observed in the way that monkeys and great apes treat the bodies of infants. We then examine responses to collapsed (still able to move and react) and inanimate (unresponsive or dead) conspecifics. Monkeys and great apes guard, care for and inspect their helpless partners, and also manipulate and mobilise them. Through these actions, individuals may inform themselves about the state of their partners, test their responsiveness and/or attempt to rouse them. It appears that only chimpanzees and gorillas show violent action such as display behaviours and the rough treatment of bodies. They can also make distress calls, and periods of “stunned silence” sometimes occur in chimpanzees, indicating that they are experiencing intense emotion. Finally, we argue that while both monkeys and great apes detect body dysfunction through the victims’ inability to wake up and move, only great apes can understand that something serious has happened. The signs of emotional disturbance reported in them indicate that they may believe that inanimate conspecifics have entered a state of “dormancy”, meaning that they are unlikely to regain wakefulness. However, there is no evidence that any non-human primates are aware of mortality.

While there is no consensus about the definition of complexity, it is widely accepted that the ability to produce uncertainty is the most prominent characteristic of complex systems. We introduce new metrics that purport to quantify the complexity of living organisms and social organizations based on their levels of uncertainty. We consider three major dimensions regarding complexity: diversity based on the number of system elements and the number of categories of these elements; flexibility which bears upon variations in the elements; and combinability which refers to the patterns of connection between elements. These three dimensions are quantified using Shannon's uncertainty formula, and they can be integrated to provide a tripartite complexity index. We provide a calculation example that illustrates the use of these indices for comparing the complexity of different social systems. These indices distinguish themselves by a theoretical basis grounded on the amount of uncertainty, and the requirement that several aspects of the systems be accounted for to compare their degree of complexity. We expect that these new complexity indices will encourage research programmes aiming to compare the complexity levels of systems belonging to different realms.

The theory of sexual selection predicts that females should be discriminatory in the choice of sexual partners. Females can express their choice in two ways. In direct mate choice, they show preferences for certain partners. In indirect mate choice, they select partners by displaying sexually attractive traits, thus eliciting contest competition between males. We focused on a primate species in which females advertise the timing of their ovulation and studied the balance between these two choice strategies. We tested predictions related to three hypotheses about direct and indirect female choice, namely the best‐male, graded‐signal and weak‐selectivity hypotheses. We investigated the sexual and agonistic interactions occurring during oestrous periods in five captive groups of Tonkean macaques (Macaca tonkeana). The results showed that dominant males used mate guarding to monopolise sexual access to parous females that were in the fertile stage of their reproductive cycle, while lower‐ranking males monitored only nulliparous females. The distribution of sexual presentations indicated that females accepted different types of partners, supporting the weak‐selectivity hypothesis regarding direct mate choice. The analysis of behavioural sequences revealed that mate‐guarding males used mild coercive behaviours to prevent females from mating with other males at conception time. The distribution of mounts showed that females mainly mated with dominant males, which leads us to argue that the best‐male hypothesis provides the most parsimonious explanation regarding indirect mate choice in Tonkean macaques. At the individual level, it may be concluded that male competitive strategies prevented females from exercising direct mate choice. At the evolutionary level, however, female sexual advertising and thus indirect choice promoted competition between males. The outcome is that indirect mate choice appears more important than direct mate choice in female Tonkean macaques.