Network analysis of phenological units to detect important species in plant-pollinator communities: can it inform conservation strategies?

Conservation of species is often focused either only on those that are endangered, or on maximising the number recorded on species lists. However, species share space and time with others, thus interacting and building frameworks of relationships that can be unravelled by community-level network analysis. It is these relationships that ultimately drive ecosystem function via the transfer of energy and nutrients. However interactions are rarely considered in conservation planning. Network analysis can be used to detect key species ("hubs") that play an important role in cohesiveness of networks. We applied this approach to plant-pollinator communities on two montane Northern Apennine grasslands, paying special attention to the modules and the identity of hubs. We performed season-wide sampling and then focused the network analyses on time units consistent with plant phenology. After testing for significance of modules, only some modules were found to be significantly segregated from others. Thus, networks were organized around a structured core of modules with a set of companion species that were not organized into compartments. Using a network approach we obtained a list of important plant and pollinator species, including three Network Hubs of utmost importance, and other hubs of particular biogeographical interest. By having a lot of links and high partner diversity, hubs should convey stability to networks. Due to their role in the networks, taking into account such key species when considering the management of sites could help to preserve the greatest number of interactions and thus support many other species

Experimental loss of generalist plants reveals alterations in plant-pollinator interactions and a constrained flexibility of foraging

Species extinctions undermine ecosystem functioning, with the loss of a small subset of functionally important species having a disproportionate impact. However, little is known about the effects of species loss on plant-pollinator interactions. We addressed this issue in a field experiment by removing the plant species with the highest visitation frequency, then measuring the impact of plant removal on flower visitation, pollinator effectiveness and insect foraging in several sites. Our results show that total visitation decreased exponentially after removing 1–4 most visited plants, suggesting that these plants could benefit co-occurring ones by maintaining high flower visitor abundances. Although we found large variation among plant species, the redistribution of the pollinator guild affected mostly the other plants with high visitor richness. Also, the plant traits mediated the effect of removal on flower visitation; while visitation of plants which had smaller inflorescences and more sugar per flower increased after removal, flower visitors did not switch between flower shapes and visitation decreased mostly in plants visited by many morpho-species of flower visitors. Together, these results suggest that the potential adaptive foraging was constrained by flower traits. Moreover, pollinator effectiveness fluctuated but was not directly linked to changes of flower visitation. In conclusion, it seems that the loss of generalist plants alters plant-pollinator interactions by decreasing pollinator abundance with implications for pollination and insect foraging. Therefore, generalist plants have high conservation value because they sustain the complex pattern of plant-pollinator interactions

Flower visitation by hoverflies (Diptera: Syrphidae) in a temperate plant-pollinator network

Hoverflies (Diptera: Syrphidae) are among the most important pollinators, although they attract less attention than bees. They are usually thought to be rather opportunistic flower visitors, although previous studied demonstrated that they show colour preferences and their nectar feeding is affected by morphological constraints related to flower morphology. Despite the growing appreciation of hoverflies and other non-bee insects as pollinators, there is a lack of community-wide studies of flower visitation by syrphids. The aim of this paper is to provide a detailed analysis of flower visitation patterns in a species rich community of syrphids in a Central European grassland and to evaluate how species traits shape the structure of the plant-hoverfly flower visitation network. We found that different species varied in the level of specialisation, and while some species visited a similar spectre of flowers, others partitioned resources more strongly. There was a consistent difference in both specialisation and flower preferences between three syrphid subfamilies. Eristalinae and Pipizinae were more specialised than Syrphinae. Trait-based analyses showed that relative flower visitation (i) increased with plant height, but most strongly in Eristalinae; (ii) increased with inflorescence size in small species from all three subfamilies, but was independent of inflorescence size in large species of Eristalinae and Syrphinae; and (iii) depended on flower colour, but in a subfamily-specific way. Eristalinae showed the strongest flower colour preferences for white flowers, Pipizinae visited mostly white and yellow flowers, while Syrphinae were less affected by flower colour. Exploration of the structure of the plant-hoverfly flower visitation network showed that the network was both modular and nested. We also found that there were almost no differences in specialisation and relative visitation frequency between males and females. Overall, we showed that flower visitation in syrphids was affected by phylogenetic relatedness, body size of syrphids and several plant traits

Oxytocin Increases Phasic and Tonic GABAergic Transmission in CA1 Region of Mouse Hippocampus

Oxytocin is a neuropeptide that plays important peripheral and central neuromodulatory functions. Our data show that, following activation of oxytocin receptors (OtRs) with the selective agonist TGOT (Thr4,Gly7-oxytocin), a significant increase in frequency and amplitude of spontaneous inhibitory postsynaptic currents (sIPSC) occurred in hippocampal CA1 pyramidal neurons (PYR) in mice. TGOT affected also sIPSC deactivation kinetics, suggesting the involvement of perisynaptic GABAA receptors (GABAARs) as well. By contrast, TGOT did not cause significant changes in frequency, amplitude or deactivation kinetics of miniature IPSC, suggesting that the effects elicited by the agonist are strictly dependent on the firing activity of presynaptic neurons. Moreover, TGOT was able to modulate tonic GABAergic current mediated by extrasynaptic GABAARs expressed by PYRs. Consistently, at spike threshold TGOT induced in most PYRs a significant membrane hyperpolarization and a decrease in firing rate. The source of increased inhibition onto PYRs was represented by stuttering fast-spiking GABAergic interneurons (INs) that directly respond to TGOT with a depolarization and an increase in their firing rate. One putative ionic mechanism underlying this effect could be represented by OtR activation-induced up-modulation of L-type Ca2+ channels. In conclusion, our results indicate that oxytocin can influence the activity of a subclass of hippocampal GABAergic INs and therefore regulate the operational modes of the downstream PYRs by increasing phasic and tonic GABAergic transmission in CA1 region of mouse hippocampus

Coi nostri strumenti: la tradizione delle Quattro Province dall'artigianato alla festa

Based on both original accounts and published documents, this work describes the musical tradition still flourishing in the Four Provinces Apennines, the mountain region between Genua and Oltrepò. Among its peculiar features are the piffero, a folk oboe constructed and played on the ground, the musa, a bagpipe that accompanied it in the past, and the accordion, that replaced the musa in the first half of the 20th Century. The origins of instruments and customs have to be related to materials used by rural culture and to commercial contacts conveyed by mule caravans, which traversed these mountains and connected them, especially since the Late Middle Ages, to Genua harbour and the Orient on one side and to French and Flemish fairs on the other side. For the last centuries we know about a school of piffero masters who have trasmitted their art orally until contemporary players. They still lead the village feasts in the high valleys, which express a sound sociality as well as the traditional practice of old songs - bujascas, stranots... - and dances - piana, alessandrina, monferrina, giga a due, giga a quattro, povera donna, perigordino, skipping polka, mazurka, waltz... The unexpected richness of such cultural and human heritage leads both to carry it out and to wonder about its roles in our globalized world looking for new identities.Basandosi sia su testimonianze originali sia sui documenti già pubblicati, questo testo illustra la tradizione musicale tuttora viva nell'Appennino delle Quattro Province, il territorio montano compreso fra Genova e l'Oltrepò. Suoi elementi peculiari sono il piffero, un oboe popolare costruito e praticato sul posto, la musa, cornamusa che in passato lo accompagnava, e la fisarmonica, che ha sostituito la musa dalla prima metà del Novecento. Le origini di strumenti e usi sono da riconnettere ai materiali impiegati dalla cultura contadina e ai contatti commerciali veicolati dalle carovane di muli che percorrevano questi monti collegandoli, in particolare dal Basso Medioevo, da un lato al porto di Genova e all'Oriente e dall'altro alle fiere francesi e fiamminghe. Per gli ultimi secoli abbiamo notizia di una scuola di maestri pifferai che hanno trasmesso oralmente la loro arte fino ai suonatori contemporanei. Costoro guidano tuttora le feste dei paesi delle alte valli, nelle quali si esprimono una sana socialità e la pratica tradizionale degli antichi canti - bujasche, stranot... - e danze - piana, alessandrina, monferrina, giga a due, giga a quattro, povera donna, perigordino, polca a saltini, mazurca, valzer... L'insospettata ricchezza di questo patrimonio culturale e umano induce tanto a praticarlo quanto a interrogarsi sui suoi ruoli nel mondo globalizzato in cerca di nuove identità.Basée à la fois sur des témoignages originaux et sur des documents édités, cette oeuvre traite de la tradition musicale toujours vivante dans l'Apennin des Quatre Provinces, pays montagneux situé entre Gênes et l'Oltrepò. Parmi ses composantes spécifiques se trouvent: le piffero, un hautbois populaire confectionné sur place ; la musa, cornemuse qui autrefois accompagnait le piffero et l'accordéon qui remplaça cette dernière dans la première moitié du 20ème siècle. Les origines et usages de ces instruments sont à mettre en relation d'une part avec les matériaux employés par la culture paysanne et d'autre part avec les contacts commerciaux permis par les caravanes de mulets qui parcouraient ces montagnes (particulièrement dès le Moyen-Age central) en les reliant au port de Gênes et à l'Orient d'un côté et aux foires françaises et flamandes de l'autre. En ce qui concerne les derniers siècles nous avons connaissance d'une école de maîtres pifferistes qui ont transmis oralement leur art jusqu'aux musiciens contemporains. Ceux-ci guident toujours les fêtes de village dans les parties les plus hautes des vallées où s'exprime une socialisation équilibrée et se pratiquent, traditionnellement, des anciens chants - bujascas, stranots... et des danses - piana, alessandrina, monferrina, giga à deux, giga à quatre, povera donna, perigordino, polka sautillée, mazurka, valse... La richesse insoupçonnée de ce patrimoine culturel et humain conduit tant à le pratiquer qu'à s'interroger sur ses rôles dans un monde globalisé en quête d'identités nouvelles

A role for locus coeruleus in Parkinson tremor

We analyzed rest tremor, one of the etiologically most elusive hallmarks of Parkinson disease (PD), in 12 consecutive PD patients during a specific task activating the locus coeruleus (LC) to investigate a putative role of noradrenaline (NA) in tremor generation and suppression. Clinical diagnosis was confirmed in all subjects by reduced dopamine reuptake transporter (DAT) binding values investigated by single photon computed tomography imaging (SPECT) with [123I] N-ω-fluoropropyl-2β-carbomethoxy-3β-(4-iodophenyl) tropane (FP-CIT). The intensity of tremor (i.e., the power of Electromyography [EMG] signals), but not its frequency, significantly increased during the task. In six subjects, tremor appeared selectively during the task. In a second part of the study, we retrospectively reviewed SPECT with FP-CIT data and confirmed the lack of correlation between dopaminergic loss and tremor by comparing DAT binding values of 82 PD subjects with bilateral tremor (n = 27), unilateral tremor (n = 22), and no tremor (n = 33). This study suggests a role of the LC in Parkinson tremor

Revising the species statuses of overlooked West-Palaearctic bumblebees

peer reviewe

Exploring the hidden riches: Recent remarkable faunistic records and range extensions in the bee fauna of Italy (Hymenoptera, Apoidea, Anthophila)

The area sourrounding the Mediterranean basin is recognised as a major biodiversity hotspot for bees, and Italy is amongst the European countries with the highest bee species richness. Detailed knowledge of bee distribution is crucial for understanding bee biology and designing tailored conservation strategies, but is still insufficient in southern European countries, especially in Italy.We report recent finds of 48 bee species that yield significant novelties for the Italian bee fauna. Eight species, namely Andrena confinis Stöckhert, Anthidiellum breviusculum Pérez, Coelioxys alatus Foerster, Lasioglossum algericolellum Strand, Megachile lapponica Thomson, Megachile opacifrons Pérez, Megachile semicircularis auct. nec Zanden and Trachusa integra Eversmann are reported as new for Italy. In addition, Andrena binominata Smith, Andrena compta Lepeletier, Colletes acutus Pérez, Lasioglossum strictifrons Vachal, Rhodanthidium siculum Spinola and Rhodanthidium sticticum Fabricius are newly recorded from mainland Italy, Osmia heteracantha Pérez from Sardegna and Nomada flavopicta Kirby from Sicilia. We also report significant range extensions for other bee species and recent records of species that had long gone unrecorded in Italy. The combination of morphology and DNA barcoding provided reliable identifications even for the most challenging specimens. As several of our records come from areas neglected by bee experts in the past, this study stands out as a key indicator of a bee faunistic richness still awaiting discovery and hopefully it will stimulate the interest of taxonomists and stakeholders in pursuing bee research in Italy in the near future