It was a slightly cloudy day in mid-May when I decided to visit the northern part of Istria (Croatia), between Mount Ucka (Fig. 1) and the mountainous plateau of Cicaria, which is an extension of the Dinaric Alps. The area is mostly uninhabited, wild and largely untouched. Flower-rich wheat meadows are dominant here; in the past they were (most probably) pastures. Today they provide habitats for bees, butterflies, grasshoppers, spiders, mammals, reptilians and so on. Among flowers, I recognized Polygala nicaensis, members of the genera Ajuga and Ranunculus, various orchid species and, of course, grasses. Among orchids, I found Orchis puprpurea (Fig. 1 and 2), Orchis tridentata (Fig. 3), the very common and widespread Orchis morio, the delicate Cephalanthera longifolia and the non-photosynthetic Neottia nidus-avis, which prefers shady places along the nearby deciduous woodland.
Given the altitude and the higher soil moisture level, the plant communities present here are the typical sub-mediterranean ones. Therefore, I had the pleasure to meet some butterfly species for the first time, one of those meriting a special attention: Everes alcetas (Fig. 4) or the Provencal short-tailed blue. It is a member of the Lycaenidae family which, although occuring sporadically, it is common across the central Europe.
In general, they feed on plants of the genus Medicago, Coronilla varia and Galega officinalis where they lay their eggs. They prefer bushy and sunny places but in Istria are very local and spotted by me only in this location.
One butterfly species that I encountered in the same area is the marsh fritillary (Euphydryas aurinia), a member of the Nymphalidae family (FIg. 5 and 6). This species is in decline in Europe, and is protected under law in the United Kingdom. However I managed to see them quite abundantly in many sites around Istria; perhaps because their habitat – the damp heathy grasslands – is still pretty intact in this region.
This is a widespread species, present in the central and southern Europe. However, it is very local and in Istria I found it only here. Larvae feed on members of the Aristolochia genus and in some areas, for instance in Hungary, it is restricted to only one Aristolochia species: the Birthwort (Aristolochia clematitis). The wings are yellow, a bit paler in females, covered with a gaudy pattern of several black bands and spots, with a distinctive black sinuous line at the margin. On the edge of the hindwings there are several blue and red warning spots. The body is black, with red warning spots at the side.
Spring days in the Mediterranean region in May are ideal for observing butterflies and other insects, because during this period most of the plants are in full blossom. Therefore, I try not to miss any potential day for wandering with my dog in search of opportunities for a good picture. During one of these sunny and warm days of May, while trekking on Marlera, I spotted a beautiful sample of Glaucopsyche alexis or, Green-underside Blue, a member of the Lycaenidae family. It was resting on a herbaceous plant, most probably of the Linum genus. However, their life history is accomplished on several members of the Fabaceae family and the larvae are attended by various ant species, as typical for this family of butterflies. This species is widespread and common in many European regions, and it can be easily recognised by the metallic greenish-blue flush on the light-grey hind underside wing. In the specimen on the picture (Photo 1 and 2) it is extended to the edge but in some populations it can be reduced.
Eggs are laid on a flower which will later be eaten by the larvae. The colour of the larvae is variable and depends on the colour of the flower they feed on. It can be greenish, dusky-pink or even bright yellow if they consumed the yellow flowers of Spartium junceum.
Larvae is whitish prior the pupation and at this stage it is attended by various ant species (Lasius, Formica, Myrmica, Camponotus etc.).
When I was living in Ližnjan, a small village on the south-eastern side of the Istrian peninsula facing the Kvarner Gulf , I used to go every day for a walk along the sea and the surrounding inland, hosting the typical garrigue and macchia plant communities. That was a quite relaxing way of spending my afternoons – walking my dog and photographing everything that caught my senses. One might think that visiting the same place every day would be quite boring, and indeed it can be so – if one does not pay attention to the little details. After a decade spent photographing nature, I could notice even the slightest changes in the light intensity and direction, and their impact on the way I experience the landscape in from of me.
I especially loved visiting Marlera, a plain area with intact garrigue and macchia vegetation and a paradise for insects and birds.
One beautiful and sunny day in May, I went there for the usual walk along the sea. I was lucky that the sky was so limpid that I could see the Cres and Losinj islands of the Kvarner Sea quite well and even the outlines of the mount Ucka, 80 km distant, were clearly visible. While crossing the garrigue along the way, my attention was caught by the shimmer of a wide whitish carpet spread a couple of square meters in front of me. I was quite astonished, because I´ve never seen something like this before. As I approached it in order to investigate it better, I realised that it was Anthemis tomentosa, or the Woolly Chamomile, in full blossom; that’s a daisy-like species that is very rare in this region. I´ve heard about the presence of this species in this area by two well-known local botanists (Claudio Pericin and Slavko Brana), however I have not been able to find its the exact location, even though I tried many times. In fact, this is a very local species that can be found only in this spot on Marlera and in another one at the tip of the Kamenjak peninsula, but only in Marlera it creates such vast veils of beauty at the border of the jagged and rocky coast. I decided to stay here for a while, take some pictures and enjoy the flowers along with the picturesque view of the navy blue sea and the islands of Cres and Losinj in the background. It was so soothing and pleasant just to be here, walk and mindfully feel my surroundings with all my senses and notice every detail around me. The ripples of the sea, the thousands of blue shades, that sometimes are soft but other times are interrupted by a dark, almost black blue that gives the impression of an abyss, but actually is just Posidonia oceanica, a marine plant which creates dense meadows that appear very dark from the surface. Nature is so rich of opportunities in every moment, so it is important is to be alert, and notice the patterns of colours and shapes, feel the wind, smell the air and sense the temperature.
I decided to come close to the plants and to observe in more detail the flower peps to feel the scent and watch the insects coming – bees, spiders, butterflies, ants etc. Their camomile-like look creates a beautiful contrast with the blue of the sea in the background. Once at home I decided to learn more about this species so I discovered something really interesting in a scientific publication: the essential oils produced by this plant have been tested against Gram-positive bacterial species, and an antibacterial activity has been detected, therefore it has a big potential as antibiotics in medicine and in the cosmetic industry http://www.ncbi.nlm.nih.gov/pubmed/23157016.
While continuing my tour of exploration, I encountered a day-flying moth Zygaena filipendula (Six Spot Burnet) on a Knautia head flower.
The vivid red spots on a dark green metallic background on the fore wings are actually a warning sign for potential predators, indicating that they are poisonous. In fact, their entire body contains cyanogenic glycosides, amino acid-derived toxic substances produced by various plants as a defence mechanism against grazers.
The sequestration of the toxic compounds takes place during the larval stage from their food plants, however they are able to synthesize those products in small amount by themselves.
Another surprise was the quite uncommon orchid species, Anacamptis coriophora (Bug Orchid), known also as Orchis fragranas Pollini (Foto 5), a name still in use by some authors, due to the vanilla-scented flowers. It is a nectar-producing species which attracts honeybees, several bumblebee species and some moths of the genus Zygaena.
Foto 5. Two specimens of Anacamptis coriophora
Photo 5. Two specimens of Anacamptis coriophora
Butterflies of the family Lycaenidae are rather frequent in this period of the year, so I saw various species flying around. Among them I was lucky to be able to catch with my camera the beautiful Silver-studded Blue (Plebejus argus, Photo 6, 7 and 8), the Common Blue (Pollyommatus Icarus, Foto 9 and 10) and the Adonis Blue (Lysandra bellargus, Photo 11).
Plebejus argus is widespread and locally common across Europe, Asia and as far as Japan, however threatened due to habitat reduction in the UK. He has a wide variety of food plants (Calluna, Erica, Lotus, Tymus etc).
Interacts with ants in the larval stages: pupation often taking place in the ant´s nest where they are protected from enemies; in exchange they secrete the honeydew-like liquid which is delicious for ants (mutualism).
It is always associated with Lasius ants and emerging adults are attractive to Lasius workers, a very unusual behaviour because they are normally attacked or ignored by them.
Polyiommatus icarus curiosities:
The larva feeds on plants of the Leguminosae family. These plants are rich in flavonoids which they sequester on their wings in order to increase its reproductive fitness. One study made by Burghardt et al. (2000, 2001) shows that females sequestered flavonoids in their wings 59% more efficiently than males.
According to him, the flavonoids accumulated in the wings by the females is used in visual communication, since flavonoid rich females are more attractive to males than flavonoid-free females.
The chrysalis is olive green/brown and formed on the ground, where it is attended by ants, which will often take it into their nests. The larva creates a substance called honeydew, which the ants eat while the butterfly lives in the ant hill.
The preferred habitat of the Lysandra bellargus (Adonis blue) is calcareous grasslands with hot and dry conditions.
In the 1980s, 70% of their colonies had gone extinct in UK, however recently a dramatic recovery has been observed thanks to increased grazing and warmer temperatures.
One research showed that the sexes prefer flowers with different nectar compositions: males of both generations preferred flowers with high proportions of sucrose and high amounts of total sugar, whereas females preferred flowers with high portions of glucose in their nectar, and, in the spring generation, flowers rich in amino acids.
Flowers visited exclusively by males or females in spring differed significantly in their amino acid composition.
Larvae feed exclusively in nature on the leaves of two host plants, Coronilla varia and Hippocrepis comosa (both Fabaceae).