Spring in a snapshot

Walking through the hills of central Italy in early March, we notice that something is changing: the sun is more enveloping, the green of the meadows brighter and the air, still crisp, is tinged with scents that the nose thought it had forgotten. Confirmation that spring is beginning arrives when, on the brown of the hillsides, clear white and pink speckles appear: these are the plants of the Prunus genus, the first tree species to bloom after the long winter rest. The best known is certainly the cherry, Prunus avium, with its majestic, fragile white flowers, but it is not alone: there are many species in this genus that populate our hillsides and gardens. the almond tree, the apricot tree up to the laurocerasus, Prunus laurocerasus, of which many of the hedges surrounding our homes are made. There are many species of pollinators that become active with the appearance of these blooms, the first precious sources of nectar and pollen, let's discover them!

Among the most famous pollinators that we can find among the foliage of the flowering Prunus, the bumblebees, genus Bombus, are certainly the best known. Characterised by a rounded body and thick hair, bumblebees are social apoids and, like the honey bee Apis mellifera, live in colonies organised in castes comprising both reproductive individuals, queen and males, and numerous worker individuals represented by the female workers. Among the best-known species we have Bombus terrestris recognisable by its characteristic black and yellow banded livery with a white abdomen tip. The onset of spring coincides with the moment when the queens, fertilised the previous year, emerge from their winter hibernation and begin tirelessly searching for a site to establish a new colony. You may encounter them as they scour the ground in search of cavities in which to settle and you will recognized them by their large size (20-22 mm) and their deep buzzing sound.

When, in a forest on a Prunus, your eye is caught by a bumblebee too small to be a queen, you may be looking at something different. Mallota fuciformis, despite its appearance, is a dipteran like flies and mosquitoes and belongs to the Syrphidae family. It is a saproxylic insect in that in its larval stage it feeds on dead wood, but as an adult it likes to feed on Prunus flowers. As its appearance suggests, it is a skilled mimic, an ability that enables it to defend itself from predators when they, mistaking it for a stinging insect like the bumblebee, prefer to stay away. This technique is called Batesian mimicry and consists of the imitation by a harmless species of a dangerous one. The features that belie this hoverfly's disguise are its short antennae, fly-like eyes and wings, one pair instead of two and endowed with spurious vein, a feature common to all sirphids.

Osmia cornuta loves Prunus so much that it is employed in the artificial pollination of almond trees and rosaceae more generally. This species of solitary bee is characterised by a massive head, prominent mandibles and a two-tone livery: black in the first half of the body and brick red in the second half. The males flicker first, between late February and early March, and we recognise them by a tuft of light-coloured hairs on the clypeus (face). A few weeks later, the females also appear, larger than the males and with a black clypeus: you can observe them mating and then with the ventral clypeus sprinkled with pollen, intent on procuring food for their offspring. Osmia is also called the mural bee because it nests in pre-existing cavities from which it makes a series of cells lined and separated by mud, used as cement. In each chamber it lays an egg and stores a generous amount of pollen that will serve as nourishment for its offspring.

The butterflies are certainly the most conspicuous pollinators and it is easy to notice their fluttering. Vanessa atalanta, also known as vulcano, is a nymphalid and appears early on the spring scene, but is never actually gone: individuals of this species winter as adults finding shelter in the vegetation. It is not uncommon to spot them in January during particularly clear and warm days. In the spring, the volcano seeks out its nurse plant, the ortica, and lays eggs there from which bruchi will hatch, which, feeding on the plant, will grow until they pupulate and become adult butterflies. The cleopatra also overcomes winter in the adult stage. Gonepteryx cleopatra is a large butterfly of the pieridae family with thin leaf-like wings with pronounced orange haloes in males and peach shades in females. It lives a long time, as it flickers in June, but the adult over

As the days pass, temperatures rise and the equinox makes spring official. The days grow longer and April arrives. The flowers on the "Prunus" give way to leaves, new trees and shrubs take centre stage sporting majestic blossoms and intense fragrances while the meadows are tinged with a thousand colours. The horse-chestnuts unleash their cob-like blossoms on city boulevards while the oaks and the nuts express themselves more subtly with unisexual flowers both male and female, unobtrusive to the untrained eye. The Juda tree stands out with its deep fuchsia and the glycine bursts forth, lilac and fragrant. In the meadows the taraxacum Taraxacum officinale, the flowers of Crepis and the ranunculus Ranunculus acris bring a hint of yellow, the small veronica Veronica persica brings blue and Salvia pratensis adds a touch of purple. And new pollinators enter the field...

If the appearance of Osmia cornuta coincides with the flowering of Prunus, that of Osmia bicornis is marked by the flowering of plants of the genus Quercus. The pollen produced by the male flowers of these trees, in the form of threadlike catkins, may go unnoticed by the human eye, but it represents an abundant resource that is particularly prized by these lone bees. In order to distinguish the two species of Osmia, which appear extremely similar in both appearance and habits (both are called worm bees), we must consider the period of flickering (which varies according to latitude) and we can observe the colour of the body: Osmia bicornis, in fact, appears more blonde in the posterior part of the body while maintaining a tawny colouration.

It sounds like a small helicopter when a wood bee approaches, so intense and persistent is its buzz. The bees of the genus Xylocopa, three species in Italy, are large insects with black-bright colouring with brown to violet highlights and dark wings. They have a very extensive diet and at this time of year they go crazy for wisteria and Judas tree flowers, where they can be seen intent on feeding on nectar or collecting pollen. The carpenter bee or woodcutter is so called because it digs tunnels in the wood that it uses as nests. It is considered a solitary bee, but exhibits forms of presociality in which the offspring of the founder bee, once they become adults, remain in the nest and help keep it tidy while leaving the foraging duties to the matriarch. It is mistakenly called the black hornet, but it has nothing to do with the hornets of the genus Wasp: Xylocopa is a apoid like bumblebees and osmias.

The aurora, Anthocharis cardamines is an iconic butterfly of the month of April. White in colour, it clearly stands out against the bright green grass thanks to the bright orange spots that males display on the tips of their forewings (a feature absent in females). We only find it at this time of year because it is a univoltine species, i.e. it only makes one generation a year, and flies from April to May. White are the butterflies of the genus Pieris, such as the lesser cabbagefly Pieris rapae, which begin to abound in meadows and clearings as early as March. Unlike the aurora, the cabbagebirds, so called because they use cabbage as a nourishing plant, are polivoltine because they make three to five generations a year, making them among the most frequent species to observe.

Spring is a magical season, perfect for marvelling at the abundance and variety of plant species and pollinators that we are lucky enough to enjoy in our country. biodiversity is fundamental not only as a source of beauty, but also because it is the basis of the resilience of ecosystems. Unfortunately, however, there are many factors that undermine biological diversity in general and the survival of pollinators in particular: habitat degradation, overexploitation of resources, invasive species, climate change and pollution are the main ones. The human contribution can be crucial, which is why it is important to set up protected sites for the protection of pollinator insects. This need is met by the 3Bee Biodiversity Oases: urban and agroforestry habitats designed to allow pollinators to have refuges and native flora.