The butterflies of Mt. Ainos

The order Lepidoptera is named after a particular trait of its wings. Even though they are membranous, like in other insects, they are not transparent, since both their upper and lower surfaces are coated with overlapping scales. These are responsible for the colouration of the wings, as well as their correct weight balance that provides their flight capability. Each scale has a unique color, genetically determined for each species and partly differentiated in each individual, thus leading to the extensive color pattern variability that characterises Lepidoptera wings (Pamperis 2009).

The common name ‘butterflies’ refers in fact to those Lepidoptera species that belong to the Rhopalocera group. This group includes diurnal species, in contrast to the Heterocera group which mostly consists of nocturnal species (moths). Moths significantly outnumber butterflies in species richness. Accordingly, in Greece most of the 3,197 lepidopteran species are moths and just ca 235 species belong to butterflies. At least 10 taxa are Greek endemics and at least 30 species residing in Greece are deemed threatened on a European or global level. Forty-nine species are protected by Greek legislation and 11by European legislation (Pamperis 2009, Legakis & Maragou 2009).

A butterfly merely constitutes the adult stage (imago) of the insect’s life cycle, which is short, compared to the preceding larval and pupal stages. Butterflies are, preferentially, more active between 15 and 35 οC. Therefore, locating them becomes easier during warm, windless days. Their detailed study, however, requires a good knowledge of their life cycle, in order to, among other things, successfully locate and record them in the habitats they occupy.

The butterflies of Cephalonia have been satisfactorily studied during the last 30 years. The first important study was performed by Gaskin & Littler (1986), who recorded 29 species in total. In 1996, Gaskin supplemented that work by recording 16 additional species as new for Cephalonia. However, the most comprehensive study was undertaken by Efthymiatou-Katsouni (2006), who confirmed the occurrence of 49 species in Cephalonia, 14 of which constitute new findings. Recently, Maroulis & Xanthakis (2015) confirmed the existence of 31 species in the region of Paliki and in the National Park of Mt. Aenos. Finally, Pamperis (pers. comm.) reports that ca 63 species live on Cephalonia, i.e. more than 25% of the total of ca 235 that occur in Greece. These species are divided among five large Rhopalocera families (Pamperis 2009): Papilionidae (4 species), Hesperiidae (7 species), Pieridae (13 species), Lycaenidae (15 species) and Nymphalidae (24 species). Among the butterflies of Cephalonia, one subspecies, Hipparchia volgensis delattini (Fig. 53) is a European endemic. Moreover, four species, Pseudophilotes vicrama, Hipparchia fagi, Ηipparchia statilinus and Thymelicus acteon, are evaluated as Near Threatened (NT) in Europe, according to the criteria of IUCN (2001).

In general, the butterflies cannot regulate their body temperature on their own, but rely on the accumulation of solar radiation, in order to attain any temperature increase. The dark brown colouration of the wing surface of several butterfly species, e.g. of Hipparchia volgensis delattini, which has been located on Mt. Roudi of the National Park, is considered to enhance the quick body temperature increase, thus achieving the desired activation of these butterflies at a shorter time, when compared to other species. In addition, Pararge aegeria gathers heat from sunrays that reach clearings or manage to penetrate the thick foliage of the Cephalonian Fir trees of the National Park and, accordingly, defends the advantageous spots it has occupied against any potential adversary that may try to claim it.

During the summer months, many butterfly species gather at the National Park of Mt. Aenos, showing preference to several plant species. For instance, the flowers of the thyme species, Thymus holosericeus, attract numerous, impressively coloured butterflies that belong to Argynnis paphia, Gonepteryx cleopatra or Iphiclides podalirius. Around Quercus coccifera stands, swarms of the species Neozephyrus quercus can be observed. Also, the forest meadows of the National Park support easily noticed species, such as Polyommatus icarus, Lasiommata megera, Lasiommata maera, Colias croceus, Spialia orbifer, Satyrium ilicis, Papilio machaon etc. Contrary to that, species, such as those of the genus Hipparchia, are hardly noticed e.g. resting on tree trunks, thanks to their excellent camouflage. Among the latest important observations on the Lepidoptera of Cephalonia is the fact that individuals of Vanessa cardui (Painted Lady) appear to go through their whole life cycle (from egg to adult stage) in Cephalonia, instead of adults being temporary and not locally breeding visitors that migrate from Africa, as previously considered (Maroulis & Xanthakis 2015).

During mating, the butterfly bodies remain affixed with each other and do not separate until the completion of the reproduction act. The unusually long duration of the reproductive process is due to the fact that the male seals the abdominal opening of the female with a keratinous projection it builds, thus hampering the female from mating with another male. This structure is called ‘sphragis’, named after the Greek word that means ‘seal’ (Pamperis 2009).

Adult butterflies feed on nectar, which they gather with their sucking, curling proboscis, from deep flower areas. Therefore, they contribute significantly to plant pollination and fertilisation, since they inadvertently transfer pollen from stamens to the ovary. Nevertheless, butterfly larvas feed on parts of their host plants (they possess chewing mouthparts), often causing significant damage to cultivations. For example, Pieris brassicae larvae feed on plants of the Brassicaceae family. The females place their fertilised eggs on plant parts or on the ground. Following hatching, the small larvae will massively feed on leaves and other parts of their host plant, grow in size, undergoing several moulting stages, until they turn into pupae and then, following metamorphosis, into adult butterflies (Pamperis 2009).

The natural enemies of the butterflies do not actually constitute a real danger that could lead to their extinction. Contrary to that, biodiversity loss, in relation to habitat degradation, the abandonment of traditional cultivation practices on the island, fires, the use of insecticides, illegal woodcutting and, in many cases, the removal of butterflies from their natural population in order to supplement personal or scientific collections constitute the most immediate threats for the survival of butterflies. For the protection of these insects, particularly of those that are rare or endemic species, usually sought after by avid collectors, the Presidential Decree 67/1981 “On the protection of indigenous flora, fauna and habitats” is in effect.

Within the framework of the recently conducted recording of Lepidoptera species in the National Park of Mt. Aenos by members of the scientific personnel of the Management Body of the National Park, in collaboration with Mr. Christos Maroulis, wildlife photographer, a poster was created on the “Butterflies of the National Park of Mt. Aenos”. The availability of such posters for the visitors of the National Park supports the Environmental Information/Awareness Raising activities that the Management Body has been implementing for several years, as outlined previously.