Top 20 Most Common Insects in Croatia

It rests with closed wings when not in flight.

Limenitis reducta has a wingspan of 46–54 mm. The upperside of the wings is brown black with metallic blue shine, large transversal band of white markings and a submarginal line of small blue dots. The blue sheen varies with the angle of light. The ground colour of underside of the hindwings is red, with a silvery basal area, a row of white markings and a row of black spots. A few white cell spots are also present on the underside of the forewings. The caterpillars can reach a length of 1.1 in. They are light green to dull green on the back, red brown on the underside. On the back there are numerous brown thorns.

Melanargia galathea has a wingspan of 1.8–2.2 in. In these medium-sized butterflies the upper side of the wings is decorated with white and gray-black or dark brown markings, but it is always gray-black or dark brown checkered in the basal and distal areas. The underside is similar to the upper side but the drawings is light gray or light brown. On the underside of the hindwings is present a row of gray eye spots. The males and the females are quite similar, except that some females may have a yellowish nuance on the underside of the wings. The larvae are a lime-green colour, with a dark green line running down the middle of their back. The caterpillars are about 3 cm long. They are green or yellow with some lighter and darker narrow longitudinal lines. The head is always light brown.

Colias croceus has a wingspan of 46–54 millimetres (1.8–2.1 in). The upperside of the wings is golden to orange yellow with a broad black margin on all four wings and a black spot near the centre forewing. Usually these butterflies settles with its wings closed, consequently the black margin of the uppersides of the wings is difficultly visible. The underside lacks the black borders and is lighter, with a more greenish tint, particularly on the forewings. In the forewing underside is the same dark spot as on the upperside, but often with a light centre; the hindwing underside has a white centre spot, often with a smaller white or dark dot immediately above it. Sometimes, a row of black dots occurs on the underwings' outer margins, corresponding to where the black border ends on the upperside. Females differ from the males in having yellow spots along the black borders on the upperside. In flight, Colias croceus is easily identifiable by the intense yellow colouring, much brighter than that of the lemon-yellow male common brimstone which also lacks black markings. Like all Colias species they never open their wings at rest. In a small proportion of females (about 5%) the golden upperside colouration is replaced by a pale cream colour. These females have been distinguished as form helice. The pale form helice does not seem to be that distinct as intermediates exist and the variation is to some extent related to humidity during development, with dryer conditions producing paler colouration. These pale forms helice can be confused with Berger's clouded yellow (Colias alfacariensis) and the rarer Pale clouded yellow (Colias hyale). Even the palest C. croceus tends to have more black on the upperside however, in particular on the hindwings. Young caterpillars are yellow-green, with a black head. Later they become completely dark green, with a white red spotted lateral line after the third moult. The pupae are green and have a yellow side stripe. This species is rather similar to Colias myrmidone, Colias chrysotheme, Colias erate, Colias hyale, Colias alfacariensis, Colias caucasica, Colias aurorina.

Named after its resemblance to hummingbirds, the hummingbird hawk-moth feeds on nectar-rich, tube-shaped flowers. This large, fast, buzzing insect is known for its ability to learn colors; its food preferences are based on visual recognition. It is a migratory species that starts its journey in Africa. The hummingbird hawk-moth is considered a lucky omen.

Ischnura elegans can reach a body length of 2.5 - 3.5 cm and a wingspan of about 3.5 cm. Hindwings reach alength of 1.4 - 2 cm. Adult male blue-tailed damselflies have a head and thorax patterned with blue and black. There is a bi-coloured pterostigma on the front wings. Eyes are blue. They have a largely black abdomen with very narrow pale markings where each segment joins the next. Segment eight, however, is entirely pale blue. At rest, the wings of most damselfly species are held back together, unlike dragonflies, which rest with their wings out flat. The thorax of juvenile males has a green tinge. Female blue-tailed Damselflies come in a variety of colour forms.Juveniles may be salmon pink, form rufescens; violet, form violacea and a pale green form. The colour darkens as the damselfly ages. Mature females may be blue like the male, form typica; olive green thorax and brown spot, form infuscans or pale brown thorax and brown spot, form infusca-obseleta.

The body length of larvae is variable and highly dependent on environmental conditions. The final stage (F-0-stage) larvae are 3.5 - 4.5 mm and weigh about 4 mg, slightly below the banded demoiselle. Calopteryx virgo can reach a body length of 5 - 5 cm, with a length of hindwings of 3 - 4 cm. These large, dark damselflies have small hemispherical eyes located laterally on the head, two pair of wings similar in shape and a slender abdomen. The basal area of the wings is transparent, otherwise wings are uniformly colored. The wings are also traversed by a dense network of veins. This species presents an evident sexual dimorphism in colour pattern. The male usually has much more extensive pigmentation on the wings than other Calopteryx species in its range: in the south east of its range (the Balkans and Turkey) the wings are entirely metallic blue while in other areas, there are clear areas at the base and tip of the wing. Immature males show brown wings, as the metallic blue wing color develops only with age. They have metallic blue-green bodies and blue-green eyes. The female has dark brown iridescent wings, a white patch near the tip of the wings (called a pseudopterostigma) and a metallic green body with a bronze tip of the abdomen.

Often confused for the ladybug, multicolored asian ladybeetle (Harmonia axyridis) is a separate species that, unlike the ladybug, is a household pest. It is considered particularly annoying for its habit of returning to places from which it is removed. One of the most variable species in the world, there are many different colors and patterns multicolored asian ladybeetle may display, making identification potentially difficult.

The males are blue in colour with a white border. Females are brown in colour becoming blue towards the body, with orange crescents towards the edges of the wings. Both males and females have pale brown undersides with black spots and orange crescents . The caterpillar reaches 1.6 cm in length, has a dark green body with dark spines , and yellow bands along the back and sides .