Blue butterflies in the Netherlands and Belgium
Two blue butterflies flutter on the terrace on a beautiful warm summer day. After careful observation, it turns out that one blue butterfly is slightly different from the other. The blue butterfly family (Lycaenidae) is also large. Worldwide there are more than 5200 types of blues consisting of butterflies and moths. There are thirteen types of blues in the Netherlands. But whether we will all see them in the garden?
- Family Lycaenidae
- The blues
- Which blue is it?
- Tree Blue
- Common Blue
- Brown blue
- Difference between brown blue and icarus blue
The butterflies of the family Lycaenidae are often quite small. The wingspan is on average 30 to 40 millimeters, with the largest butterflies having a wingspan of up to 50 millimeters. It is a large family that includes about 40% of all butterflies. The Lycaenidae family consists of:
- blues (thirteen species);
- beautiful butterflies (one species in Europe, not in the Netherlands) .;
- small pages (four kinds);
fire butterflies (five species).
The eyes are elongated and the colors are wonderful in this family. Of bright blue, green and fiery orange-red. Especially the males with their often iridescent wings. A colorful family!
In the past there were 25 types of blues in the Netherlands and Belgium. Which ones can still be seen, many of them are on the red list. The group of beautiful butterflies contained one species: the Hamearis lucina (primrose butterfly), which in the Netherlands has only been observed twice in South Limburg and in the Belgian Ardennes only in open thickets on limestone grasslands. Many blues have almost disappeared or are under threat.
Which blue is it?
The three types of blues that are most likely to detect them are:
- common blue
- tree blue
- brown blue
When we see a blue flutter at eye level past ivy or holly in the garden between buildings, it is usually the tree blue. The other blues need a specific living environment and are interesting for someone who is an expert in the field of butterflies, a lepidopterologist. Lepidopterology is a specialism within the study of insects or entomology) or someone who enjoys observing, photographing, determining and passing on to the database of butterflies.
The first blue that will be visible in the spring is the tree blue. This is often present in cities and villages and a blue butterfly in the garden is certainly a tree blue. The top of the wings is a powdery light blue with a wide to very wide black border along the forewings in the females and in the males this border is not that wide. The wings are trimmed with a white fringe-like edge, which is interspersed with black stripes on the forewings. The underside of the wings have a silvery white to light blue color with black dots here and there. The front wing length is approximately 14 millimeters.
The tree blue has a habitat near tree avenues, hedges, mixed forests, urban parks and gardens. The eggs are laid on flower buds or ripe seeds of holly, ivy and cardinals, among others. After three to five days the caterpillar hatches from the egg and eats from the flower buds or young fruits and only later on the leaves. After two to four weeks, the caterpillar pupates near the host plant. Pupation lasts 11 to 20 days and the first generation flies at the end of May – June and the second generation flies in August-September. The butterfly lives for 9 to 18 days. The tree blue hibernates as a pupa.
In the icarus blue there are differences in males and females. The wings of the male are blue at the top and brown of the female. Both have a nice white fringe along the wings. The male has a beautiful black slightly wavy edge, which ?? marked ?? is between the blue and the white fringe of the wings. The female’s rear wings have a beautiful orange look ?? spots. Orange round spots with a black tip surrounded by white, like beautiful sweet eyes. The black dot in the orange is missing from the front wing. Some females are completely brown but they can also have brown wings with blue, as if they have a blue powder on them.
The undersides of the wings are the same for the male and the female. Somewhat of a silver pearly color with flecks. Beautiful white circles with a black spot in them and with a row of orange spots on the outer edge of the wings. The row of orange spots are clearly accentuated by a thin black, curved line. On the underside of the forewing there are two root spots, which distinguish this species from other blues. Often the underside of the wings at the wing root is blue pollinated, as if there is light blue powder on it.
The biotope of the Common Blue are dry and poor grasslands (blue grassland), moderately to nutrient-rich grasslands and moist hay meadows. One of the reasons why a blue spotted in the garden can hardly ever be an icarus blue. The female deposits the eggs on many legume varieties, especially the clovers. Soon the caterpillars hatch from the eggs and start to eat the clover. After pupation we can see the first generation of icarus blues flying in April. First the striking blue males, as the females emerge a little later. On average, the Common Blue has two generations, but in a beautiful summer and late summer it is possible to see a third generation flutter in October. The Common Blue hibernates in a litter layer as a caterpillar that has already undergone a number of molts.
Both the male and the female have brown wings. Along the fore and hind wings there is a beautiful white blocky fringe edge and along the trailing edge of both wings a row of orange spots. Because the wing veins continue, the fringed edge is blocked. In the middle of both forewings, nicely parallel to each other, a black dot. The undersides of the wings have a light brown to gray color with beautiful white bordered black dots. Orange spots along the outer edge of the wings. As beautiful as peacock feathers. The male has blue pollination at the wing root, which is lacking in the female. The forewing length of the brown blue is approximately 13 millimeters.
The brown blue is seen less and less and is on the red list as sensitive. The butterfly can be found in areas with dry sandy grasslands and in river and coastal dunes. The host plant are the various stork species such as the lesser cranesbill and the common heronsbill. The brown blue hibernates as a half-grown caterpillar. At the beginning of June we can see the first generation of butterflies flying and in a warm summer and late summer the third generation can still fly in October.
Difference between brown blue and icarus blue
Many icarus blue females are brown on top with orange spots. These females look a lot like the brown blues. But there is a difference:
|Brown blue||Common Blue ♀|
|Checkered white fringe trim||Not checkered fringe edge|
|Orange dots clearly visible||The orange dots are not always clearly visible|
|No root spots, but often a white ‘wedge’ on the underside of the rear wing||Two carrot spots|
|No blue pollination||Blue pollination|
|The dots on the underside of the wings can form a triangle||The dots on the underside of the wing are lined up. But … at 5% again not!|
Identifying a blue butterfly properly remains difficult.
You can ask for help on the forum Waarneming.nl. Try to figure it out yourself first!
Blues and ants have a special bond. The caterpillars of various blues (tree blue, among others) let themselves be carried along by the worker ants in the ant’s nest where they are fed. In exchange, the caterpillars secrete a sweet substance that the ants feed on.