Chiara Benedetta Boni

Insect pollination supports biodiversity in natural and agricultural systems. However, increasing beekeeping activity raises concerns about the impacts of managed Apis mellifera on wild bees, already threatened by land-use change, agricultural intensification, pesticides, climate change, and invasive species. Understanding interspecific interactions is therefore essential to inform wild bee conservation and management strategies. This study investigated pollen resource use and trophic niche overlap between managed honey bees and wild bee communities on Capraia, Elba, and Giglio islands, within the Tuscan Archipelago National Park, through morphological and molecular pollen analyses. Pollen-use overlap with managed honey bees was recorded in 58.7% of the interactions with wild bee species, with an overall medium–low niche overlap (α ≤ 0.59), while only 16.7% of interactions showed high overlap. Significant differences in pollen composition were detected between honey bees and the genera Andrena, Bombus, Ceratina, Colletes, Heriades, Megachile and Seladonia. These patterns may suggest limited trophic competition between honey bees and wild bees, but low niche overlap does not necessarily imply its absence. The negative relationship observed between honey bee density and pollen overlap suggests that wild bees may increasingly rely on alternative pollen sources under higher honey bee densities, indicating trophic repartition as a potential response to competitive pressure. Since National Parks play a key role in conserving pollinators, precautionary approaches towards a low-intensity beekeeping management and further research on the mechanisms underlying these interactions that may potentially threat the survival of wild bee communities are essential for their conservation.

Saliva is an important biological matrix that allows the investigation of various welfare parameters; in ruminants, it is abundant and can be easily collected without requiring professional veterinary intervention. The aim of the investigation was to provide additional information on both digestive and antioxidant enzymes of sheep farmed in good welfare conditions, assessed with the Animal welfare indicators (AWIN) protocol. Small surgical forceps holding a Salivette^® device (Sarstedt, Nümbrecht, Germany) were gently inserted into the sheep’s mouths without any force. The sheep chewed the swabs independently for a few seconds, allowing saliva collection. Seventeen enzymes from the saliva of 15 sheep were analyzed: antioxidant enzymes (catalase, glutathione S transferase), proteolytic enzymes (trypsin, chymotrypsin, N-aminopeptidases, carboxypeptidase A and B), carbohydrases (glucose oxidase, amylase, cellulase, lignin peroxidase, chitinase and α-glycosidase), and esterases (alkaline and acidic phosphatases, lipase and esterase). Esterase activity showed the highest value (12.95 ± 1.25 U/mg of proteins), whereas lignin peroxidase activity showed the lowest (2.23 ± 0.37 µU/mg of proteins). The activity of all enzymes was observed except for glutathione S transferase and α-glycosidase. Among the enzymes, lipase activity has already been identified as a biomarker of stress in sheep saliva. This investigation may represent a basis for further investigations into the diet and adaptive responses of sheep to different environmental conditions. Furthermore, samples collected using the Salivette^® device can be easily obtained without requiring specialized staff and without causing any stress to the animals. Further investigations into the origin of individual enzymes using a proteomic approach are desirable.

Despite its global importance for the maintenance of healthy ecosystems and its contribution in providing economic benefits to human society, the clade Anthophila is in severe decline worldwide. In this context, counteracting the decline in Apoidea is of fundamental importance. Honey bee density and beekeeping are believed to negatively impact wild bee populations, mostly through competition for food sources. In this study, interspecific trophic competition was investigated using the still seldom exploited approach of a palynological analysis combined with a metabarcoding analysis of the pollen gathered by both managed honey bees and wild bees in three Italian national parks. The entire trophic network was identified as highly specialized (H2′ = 0.933). The results obtained suggest that, overall, wild bee species are sustained by different pollen sources than honey bees. This low sharing of resources could be due to the natural trend occurring in natural populations, where species tend to minimize the competitive overlap through niche differentiation or niche complementarity as a result of coevolution. National parks play a fundamental role in animal and plant species protection and conservation. Therefore, plans should focus on evaluating honey bee densities in the interests of achieving less intensive, more traditional, and sustainable beekeeping, as well as habitat restoration, to promote the survival and reproduction of wild bee populations.

Senotainia tricuspis (Meigen, 1838) is a Sarcophagid dipteran endoparasitoid of Apis mellifera L., and myiasis, caused by this fly, is reported in several European, North African and Middle Eastern countries. Nevertheless, very little knowledge concerning the aggression and parasitisation behavior of S. tricuspis toward A. mellifera is available in the scientific literature, and the temporal pattern of aggression remains unclear. The aim of this investigation was to describe the aggressive behavior of S. tricuspis and to provide data on pupation and adult emergence in order to identify further tools for the control of senotainiosis in beekeeping. Data were collected in an apiary in Pisa province (Tuscany, Italy), where observations of aggressive behavior were conducted indirectly by using a VHS camera and also directly by an observer. Four behavioral categories of the attack were described. A total of 55 aggressions, 21 beecatchers, 104 chases and 6 parasitization events were recorded with the camera. Slow-motion recording analyses of the parasitization episodes resulted in contact of at least 1/6 s between the parasitoid and the host. Through four days of direct observations, a total of 1633 aggression events were recorded. The daily temporal pattern of the number of aggressions showed two main peaks: one during the morning hours (i.e., from 10:00 to 11:00) and one in the afternoon (i.e., from 15:00 to 17:00). The morphometric data on the first-instars of S. tricuspis allowed us to hypothesize a penetration in the bee through its prothoracic spiracle as a modality of entrance in the host body. Third-instars successfully pupate when sinking in topsoil or clay soil, and adults emerge when left to a 4 °C overwintering period of six months. Furthermore, the high mortality rate of those larvae that did not sink and did not pupate successfully suggests that reaching a certain depth in the soil is a determining factor for larvae survival and that mulch and/or minimum soil tillage could prevent severe senotainiosis in apiaries.

Osmia cornuta Latr. is largely managed worldwide for the pollination of orchard crops, playing a key role in the maintenance of healthy ecosystems and ensuring economic and social benefits for human society. The management techniques of this pollinator include the possibility of delaying emergence from cocoons after diapause, allowing for the pollination of later-blooming fruit crops. In this study, the mating behaviour of bees emerging at the natural time (Right Emergence Insects) and of late-emerged bees (Aged Emergence Insects) was described in order to test if a delay in emergence could affect the mating sequence of O. cornuta. Markov analysis of the mating behaviour revealed the occurrence of antenna motion episodes that were repeated in a stereotyped manner at regular intervals during the mating sequence of both Right Emergence Insects and in Aged Emergence Insects. Pouncing, rhythmic and continuous emission of sound, motion of antennae, stretching of the abdomen, short and long copulations, scratching, inactivity, and self-grooming were identified as the stereotyped behavioural units of a behavioural sequence. The occurrence of short copulations, the frequency of which increased with the age of bees, could lead to a failure in the reproduction of the mason bee.