Marta Galloni

Pollinators play a vital role in most terrestrial ecosystems, supporting wild plant communities and enhancing agricultural yields. However, despite their ecological and economic importance, they have been experiencing an alarming decline over the past decades. The Mediterranean region, known for harboring highly diverse communities of plants and pollinators, is particularly vulnerable due to intense anthropogenic pressures. Furthermore, the ecological roles of many floral visitors remain poorly understood, hindering conservation efforts. In response, in recent years, growing attention has been directed toward the contribution that citizens can give in support of pollinator research. An increasing number of projects have adopted a Citizen Science approach to enable large-scale data collection. The LIFE 4 Pollinators project (LIFE18/GIE/IT/000755) “Involving people to protect wild bees and other pollinators in the Mediterranean” aims to promote the conservation of pollinating insects and entomophilous plants across the Mediterranean region by fostering progressive changes in human practices that threaten wild pollinators. In addition to the implementation of several actions to raise awareness, the project launched a web platform to collect photographic records of flower–insect interaction from the public. The platform is expected to remain active for at least ten years, during which we encourage continuing record submissions by interested bodies. With this data paper we are making the current dataset freely accessible to anyone, committing to periodic online updates.

While foraging, pollinators encounter a wide array of molecules, some of which may influence their internal states and behaviors. Among these, biogenic amines – nitrogenous compounds that serve as essential neuromodulators in animals – have only recently been detected in floral nectar. As a result, little is known about the effects of nectar concentrations of these compounds on pollinators. In this study, we tested how two key biogenic amines, octopamine and its precursor tyramine, affect bumble bee behavior by examining: 1) consumption and survival, 2) locomotion, and 3) feeding behavior. Our findings show a preference for low concentration of octopamine (0.1 mM) and a dose‐dependent effect on flight behavior. Specifically, a concentration equal to 0.1 mM of octopamine reduces the bee's motivation to fly, whereas a concentration of 1 mM increases flight duration. Tyramine has no significant effect on any of the behaviors tested. Our results demonstrate that nectar‐borne biogenic amines have the potential to influence various bumble bee behaviors critical to flower visitation.

Plant diversity is critical to ensure the future of humanity, as it provides essential ecosystem services and functioning. As recent estimates showed that animal-mediated pollination is crucial for the reproduction of approximately 90% of flowering plants, playing an essential role in maintaining biodiversity and agricultural productivity, effort to preserve plants cannot be disjoined from pollinator conservation initiatives. Despite their importance, pollinators have experienced alarming declines. The LIFE 4 Pollinators project was launched to involve people protecting wild bees and other pollinators in the Mediterranean. This study presents data collected through the project’s web-platform, where users uploaded over 2,000 photographs of plant-pollinator interactions between 2021 and 2024. The dataset focuses on the identification of flower-visiting insects and plants, and the current study gives emphasis to citizen scientists’ ability to identify plants and pollinators. 1,407 photo-records were analysed, revealing that bees and beetles were the most frequent pollinators, with plants of the Asteraceae and Cistaceae families being the most recorded. Users correctly identified 93.7% of insect taxonomic aggregations and 74.2% of plant species. The study also highlights the recording of threatened, alien, and invasive species, including the vulnerable Callicera spinolae and the invasive Vespa velutina. The plant-pollinator network analysis supports the floral syndrome concept, with floral morphologies like ‘Head’ and ‘Disk’ attracting a wide range of pollinators. The results indicate that citizen science contributes to the identification and monitoring of pollinators, generating knowledge that may be key to the conservation of these organisms and to better understand plant-pollinator interactions. Data collection through citizen-generated photographs allows to significantly expand the geographic area and the magnitude of studies, facilitating large-scale analyses that would be difficult to achieve with traditional monitoring methods. These findings provide a useful basis for future conservation initiatives and the development of policies aimed at mitigating pollinator decline.

Amino acids (AAs) are an abundant class of nectar solutes, and they are involved in the nectar attractiveness to flower visitors. Among the various AAs, proline is the most abundant proteogenic AA, and γ‐amino butyric acid (GABA) and β‐alanine are the two most abundant non‐proteogenic AAs. These three AAs are known to affect insect physiology, being involved in flight metabolism and neurotransmission. The aim of this study was to investigate the effects of artificial diets enriched with either β‐alanine, GABA, or proline on consumption, survival, and hemolymph composition in honey bees belonging to two different ages and with different metabolism (i.e., newly emerged and foragers). Differences in feed intake among diets were not observed, while a diet enriched with β‐alanine improved the survival rate of newly emerged honey bees compared to the control group. Variations in the hemolymph AA concentrations occurred only in newly emerged honey bees, according to the diet and the time of hemolymph sampling. A greater susceptibility of young honey bees to enriched diets than older honey bees was observed. The variations in the concentrations of hemolymph AAs reflect either the accumulation of dietary AAs or the existence of metabolic pathways that may lead to the conversion of dietary AAs into different ones. This investigation could be an initial contribution to studying the complex dynamics that regulate hemolymph AA composition and its effect on honey bee physiology.

In recent years, our understanding of the complex chemistry of floral nectar and its ecological implications for plant-pollinator relationships has certainly increased. Nectar is no longer considered merely a reward for pollinators but rather a plant interface for complex interactions with insects and other organisms. A particular class of compounds, i.e., nectar secondary compounds (NSCs), has contributed to this new perspective, framing nectar in a more comprehensive ecological context. The aim of this review is to draft an overview of our current knowledge of NSCs, including emerging aspects such as non-protein amino acids and biogenic amines, whose presence in nectar was highlighted quite recently. After considering the implications of the different classes of NSCs in the pollination scenario, we discuss hypotheses regarding the evolution of such complex nectar profiles and provide cues for future research on plant-pollinator relationships.