Carlo Polidori

University of Milan | UNIMI · Department of Environmental Science and Policy – ESP

One of the most prominent problems related to biological invasions is the variation of local species composition, which often leads to ex novo interspecific interactions. Here, we explored and analysed the native species composition of gall inducers and their associated parasitoids and inquilines in Spanish areas invaded by Dryocosmus kuriphilus Ya...

Urbanisation, leading to the reduction and fragmentation of green areas and an increase in temperature (urban heat island effect), is known to be a strong driver of intraspecific phenotypic variation in wild bees. However, the effects of urbanisation on many functionally relevant morphological traits are still unstudied or debated. Here, males of t...

The extraordinary adaptations that Hymenoptera (sawflies, wasps, ants, and bees) exhibit on their body surfaces has long intrigued biologists. These adaptations, which enabled the immense success of these insects in a wide range of environments and habitats, include an amazing array of specialized structures facilitating attachment, penetration of...

Glaciers are retreating worldwide at an ever‐increasing rate, exposing new ice‐free areas to ecological succession. This process leads to changes in biodiversity and potentially to novel species interactions. However, we still have a limited understanding of how glacier retreat influences species interaction networks, particularly the structure and...

One of the most variable traits associated with insect cuticle structure concerns the presence of both transition metals and alkaline earth metals, which are believed, and in few cases were proven, to increase hardness and resistance to wear. Velvet ants (Hymenoptera: Mutillidae) are peculiar aculeate parasitoids of mainly bees and wasps, and are k...

Spiders (Arachnida, Araneae) are a widespread group of generalist predators, principally feeding on insects. Among them, the crab spiders of the family Thomisidae Sundevall, 1833 are ambush predators, generally living on the ground or on plants, especially on their flowers. Previous studies have largely overlooked tri-trophic networks between spide...

Fig pollinating wasps (Hymenoptera: Chalcidoidea: Agaonidae) constitute a key ecological role since they are the only known pollinators to Ficus (Moraceae), founding complex food webs. Taxonomy of Agaonidae is relatively well known due to their ecological importance and their mutualistic closed relationship with Ficus. However, the spatial and temp...

The use of sewage sludge as a soil improver has been promoted in agroecosystems. However, sludges can contain toxic trace elements because of suboptimal wastewater treatment. Nonetheless, field studies investigating the negative effects of these practices on pollinators are lacking. We collected honeybees from an area where sewage sludge use is wid...

Urbanisation is associated with air and soil pollution, particularly from heavy metals. One of the tissues most exposed to such pollutants is the midgut epithelium as insects may ingest these pollutants with food. Bees are one of the most important urban insects, providing important ecosystem services such as pollination. However, to the best of ou...

Glaciers are retreating worldwide at an ever-increasing rate, exposing new ice-free areas to ecological succession. This process leads to changes in biodiversity and potentially to species interactions. However, we still have a limited understanding of how glacier retreat influences species interaction networks, particularly the structure and robus...

Microplastic pollution is a pervasive global issue affecting various ecosystems. Despite the escalating production and well-documented contamination in both aquatic and terrestrial environments, the research focused on airborne microplastics and their interaction with terrestrial birds remains limited. In this study, we collected fecal sacs from Co...

Climate change and/or land use change were repeatedly reported as important for both range expansion of alien bee species and range shrinking for native bee species. However, environmental changes may also positively affect native species that may expand across contiguous areas to their native ones. Here, we focused on Halictus scabiosae (Rossi, 17...

Ant mandibles perform different functions (e.g. feeding, hunting, and nest building), and previous studies on workers of some species revealed that they are enriched in transition metals (Zn and Mn), which improve cuticle hardness. Whether this trait is adaptive in all ant species is still unclear. One way to test for such adaptation is to compare...

Increased temperature and fragmentation of green spaces in urban areas could drive variations in functional traits of insects. Such morphological shifts may occur for sensory systems, which were previously reported to be prone to change with habitat characteristics in non-urban contexts. Here, we measured traits related to the visual and antennal s...

Due to global warming, the worldwide retreat of glaciers is causing changes in species diversity, community composition, and species interactions. However, the impact of glacier retreat on interaction diversity and ecological networks remains poorly understood. An integrative understanding of network dynamics may inform conservation actions that su...

In insects, different pigments, such as melanins and pterins, are involved in thermoregulation. The degree of melanisation often varies along geographical gradients, according to the so-called thermal melanism hypothesis, i.e. darker forms are found in colder places because they can warm up more quickly. Similarly, pterins work as heat sinks and th...

[This corrects the article DOI: 10.1371/journal.pone.0292043.].

Urbanisation is a main driver of land-use change, leading to rising in temperatures and fragmentation and reduction of green areas. Bees and wasps, which are important insect groups due to the ecosystem services they provide, may respond to this disturbance via changes in morphological traits which are functionally relevant. To date, studies focusi...

Urbanization leads to cities having higher temperatures than surrounding non-urban areas [this is known as the urban heat island (UHI) effect]. Very little is known about the impacts of the UHI effect on bees, despite the importance of temperature on many aspects of bees' life suggesting that these may be not negligible. In this study, we aimed to...

Photinus signaticollis Blanchard, 1846 (Coleoptera: Lampyridae) is a firefly native to South America and recently established in Europe. Since 2016, this firefly has colonized the northeastern part of the Iberian Peninsula and crossed the Pyrenees to reach southern France in 2019. The larvae of this firefly feed on earthworms, so a high density of...

Wild bees (Hymenoptera: Apoidea) play an important role as pollinators of many crops and managed populations of Osmia spp. (Megachilidae), through the installation of trap-nests, proved to be efficient in several fruit orchards. In order to optimize the trap-nest protocols, it is necessary to understand which environmental factors play a major role...

The “Sterile Insect Technique” (SIT), a promising method to control Aedes albopictus, the Asian tiger mosquito, is gaining increasing interest. Recently, the role of microbiota in mosquito fitness received attention, but the link between microbiota and larval diet in mass rearing programs for SIT remains largely unexplored. We characterized the mic...

The genus Leptoconops Skuse (Diptera: Ceratopogonidae) are blood-sucking midges known to pester humans and domestic animals. In certain Mediterranean areas, midges occur in large numbers during summer and limit the use of recreational areas, also raising serious health and social concerns. Despite such impact, the diversity and distribution of Lept...

The retreat of glaciers worldwide is causing changes in species diversity, community composition and species interactions. However, the impact of glacier retreat on interaction diversity and ecological networks remains poorly understood. An integrative understanding of network dynamics is of major importance to supporting biodiversity and ecosystem...

Although recognition using cuticular chemistry is important for host–parasite interactions within aculeate Hymenoptera, cuticular hydrocarbon (CHC) profles of only a few host–parasite pairs were characterized and compared. One largely neglected family in this context is the Mutillidae (velvet ants), whose species are ectoparasitoids of bees and w...

Highlights •Torymus sinensis can attack native species under laboratory and field conditions. •Molecular and mating data show that there is no hybridization with the native species. •We detected the presence of the alien species Torymus beneficus in Spain. •Decisions on biological control of D. kuriphilus by T. sinensis are discussed. BACKGROU...

The effects of the maternally-inherited intracellular bacteria of the genus Wolbachia on insect physiology remain obscure for many hosts. Here, we report a link between the infection of Wolbachia of supergroup A and the cuticular hydrocarbon (CHC) profile in the parasitoid wasp Myrmilla capitata (Lucas) (Hymenoptera: Mutillidae), providing the seco...

Background Brood parasites can exert strong selection pressure on their hosts. Many brood parasites escape their detection by mimicking sensory cues of their hosts. However, there is little evidence whether or not the hosts are able to escape the parasites’ mimicry by changing these cues. We addressed this question by analyzing cuticular hydrocarbo...

Bees provide important ecosystem services and are subjects of extensive studies on their α‐diversity, which is generally calculated with indices that integrate the number of species with their abundances. Variation in social behaviour, though expected to impact genetic diversity, is still largely neglected in such studies. We propose a simple metho...

Despite growing interest in gut microbiomes of aculeate Hymenoptera, research so far focused on social bees, wasps and ants, whereas non-social taxa and their brood parasites have not received much attention. Brood parasitism however allows to distinguish between microbiome components horizontally transmitted by spill-over from the host with such i...

Urbanization is one of the main causes of natural habitats alteration. Particularly, urbanization is associated with a reduction and fragmentation of green areas and an increase in temperatures, in a phenomenon called “Urban Heat Island Effect” (UHI). Wild bees and wasps (Hymenoptera) can be affected by – or adapt to - these changes by shifting som...

Land-use change, including urbanization, is known to affect wild bee (Hymenoptera: Apoidea) diversity. However, while previous studies have focused on differences across local urbanization gradients, to the best of our knowledge, none focused on differences among cities at a wide geographical scale. We here used published data for wild bee communit...

List of wild bee species recorded in the analysed studies, togheter with their functional traits

Microplastics (MP) are ubiquitous contaminants of great concern due to their high persistence and potential hazardous impact on the environment. Depending on their size and shape, as well as the chemical additives they can have in their polymeric structure, MP can be taken up by organisms, ultimately leading to direct and indirect toxic effects. In...

Insect sensory systems are the subjects of different selective pressures that shape their morphology. In many species of the flesh fly subfamily Miltogramminae (Diptera: Sarcophagidae) that are kleptoparasitic on bees and wasps, females perch on objects close to the host nests and, once a returning host is detected, they follow it in flight at a fi...

Hymenoptera evolved structures on the legs which are able to remove particles from their antennae through grooming behaviour. The antenna cleaner (strigil) consists of an apical and modified protibial spur (calcar, composed of a trunk and a velum) and a modified basitarsus including a fine comb made up of setae and a notched inner surface. In "Tere...

BACKGROUND Pistachio (Pistacia vera L.) is a commercially important tree in the Mediterranean basin, where there is a considerable increase in cultivation, especially in Spain. Because of its recent introduction as a crop in the country (1980s), studies on the pests of pistachio in Spain are still rare. Here, we studied the leaf beetle Labidostomis...

Insects are highly involved in accidental introductions in non-native areas. Potential distribution modelling is routinely used to predict the dynamics of such range expansions, giving insights on which areas are climatically suitable for establishment. However, even in areas where climatic conditions are unsuitable, colonization may be still possi...

Sicily (Italy) is an important hotspot diversity for bees and new species records are constantly reported for the island. Here, we rediscovered after 45 years without records, the occurrence in Eastern Sicily of Lasioglossum marginatum (Brull e 1832) confirmed by DNA barcoding. This is the only known species of eusocial sweat bees (Halictidae) with...

Pollinators of most of the plants cultivated in the Mediterranean regions of Europe are still unknown. We provide new data and we review previously available information on bees (Apoidea) associated with three economically important crops in Spain: melon (Cucumis melo L.), watermelon (Citrullus lanatus (Thunb.) Matsum. & Nakai) and almond (Prunus d...

The wasp family Chrysididae (cuckoo wasps, gold wasps) comprises exclusively parasitoid and kleptoparasitic species, many of which feature a stunning iridescent coloration and phenotypic adaptations to their parasitic life style. Previous attempts to infer phylogenetic relationships among the family’s major lineages (subfamilies, tribes, genera) ba...

Total list of bee species collected on flowers (i.e. by netting) of melon, watermelon and almond in Spain, with locality and morpho-ecological traits.

Since alien species may threaten native ecosystems when becoming invasive, one of the main challenges is try to predict their potential spread. Despite bees are essential pollinators and provide important ecosystem services in their native areas, outside these areas they could represent a risk for the local bee fauna, e.g. by competing for resource...

Most data about parasitoids of the genus Melittobia (Hymenoptera: Eulophidae) in Europe, where only the native M. acasta (Walker, 1839) and the alien M. australica Girault, 1912 occur, come from studies carried out in the central-northern part of the continent. In the present study, we provide new information on both species in the Iberian Peninsul...

The vast majority of species of velvet ants (Hymenoptera: Aculeata: Mutillidae) are ectoparasitoids of immature stages of other aculeate Hymenoptera (bees, wasps and ants). Due to their cryptic, furtive behaviour at the host nesting sites, however, even basic information on their biology, like host use diversity, is still unknown for entire subfami...

Mating behaviour in insects is largely mediated by chemical signals emitted by one sex and recognized by the other (sex pheromones). A particular type of integumentary gland produces a sex pheromone in the antennae of male Cynipoidea (Hymenoptera), a rich and diverse wasp group consisting of species forming galls on plants, species which act as inq...

The alien cynipid wasp Dryocosmus kuriphilus Yasumatsu, 1951 is a serious pest of chestnuts ( Castanea spp.) in Japan, North America and Europe, causing fruit losses while inducing galls in buds. While D. kuriphilus galls have a recognizable and roughly invariable globular shape, their size varies, reaching up to 4 cm in diameter. Among other facto...