Flora and fauna

That's the bedrock on it Langøya which makes the flora and fauna on the island so rich. The mineral-rich limestone bedrock on Langøya also means that microorganisms, which break down dead plant material, get good growing conditions and less humus is formed than is common elsewhere in Norway. Common humus-dependent species such as heather and blueberries are therefore rare Langøya. However, the lack of humus means that no soil is developed that can store moisture from the rain during dry periods. Plant species to thrive on Langøya must therefore be able to withstand very dry growing conditions.

Langøya has a very favorable climate by Norwegian standards. The summers are long and hot and the winters mild. Therefore, we find many species that normally have a southern distribution in Norway. Mistletoe is a good example of this.

You can still see clear traces of previous agricultural activity on Langøya. In the north of the island, the landscape used to be more open than now, and after the cessation of agriculture, the areas here have been covered with lush forest consisting of deciduous trees mixed with spruce and pine. However, there are still small, open, flower-rich meadows where the farmhouses have stood. Here you can still find old garden plants such as apple trees, daylilies and Whitsunday lilies.

An interesting phenomenon is that the old open pits in the north of the island have now grown into new ones. They are now covered by a short-growing pine forest with a very interesting flora in the forest floor. It is here, among other things, that we find the finest instances of the flyflower orchid. This is one of Langøyas main botanical attractions.

The fauna on Langøya

This part of the Oslofjord has previously been little visited by entomologists. The most popular island was probably Tofteholmen, which was visited by insect collectors as early as the 1800th century, and in 1953 an excursion was organized there in connection with the ninth Nordic entomological meeting. The excursion must have been rained out. Unfortunately was not Langøya equally popular.

One of Norway's greatest entomologists was the beetle researcher Thomas G. Münster (1855-1938). He traveled around the country and beach collecting beetles. In the collections at the Zoological Museum in Oslo, you can see that he visited Langøya several times in the 1920s. However, the yield was relatively meager. It is only after 1987 that the insect fauna on Langøya have been more thoroughly investigated, and close to 2000 species have now been found. Most of this material is in the collections at the Zoological Museum in Oslo and Bergen.

Digger wasp and flyflower

In few places in Norway is the strange fly flower as common as on Langøya. Here it almost pops off the puck. The interaction between this orchid and the burrowing wasp Argogorytes mystaceus is perhaps one of the most amazing things our northern nature can produce of strange adaptations. The orchid's flowers have developed a particularly clever way of luring in the poor male wasps, so that they can help with the pollination. The orchids do not offer nectar or pollen as is common with flowers. Instead, they offer cheating ladies. They don't exactly look anything like the female digger wasps, but they smell right, and that seems to be enough.

Experiments carried out in Sweden showed that the males were more attracted to the flowers than to the real females. Probably because the flowers smell stronger and have stronger colors than the female wasps. When a male settles on a flower to mate with it, pollen is deposited on the wasp. The wasp then carries this with it and will then pollinate flowers it visits afterwards. Flueblom depends on these wasps for them to be pollinated. The wasps, on the other hand, manage well without the plant, and are therefore found far outside the distribution area of ​​flyflower. The ant inside the fly flower in the picture below is probably more likely to be considered a nectar thief, than that it has been tricked by the plant kingdom's inflatable barbara.

Digger wasps in the genus Mystaceus are predatory wasps that feed on cicadas. The female wasp is specialized to catch only these insects and brings them "home" to an ingenious walkway system in the ground. Here, cells are set up which they fill up with paralyzed cicadas. These cells act as larval chambers. When the cell is filled with cicadas, she lays one egg and then seals the cell. Here, the caterpillar has enough food to grow large. It hatches early next summer. If it is a male, it flies out to hunt flyflowers and female wasps. Much research has been carried out on the digger wasps. They are not true social wasps, but their societies have certain degrees of sociality. For example, closely related females can jointly help each other fill up the larval chambers.

When: the flower meadows glitters in gold

You go ashore on Langøya on a warm midsummer night, with a bit of luck one can observe hundreds of tiny twinkling lights, almost like tiny nuggets of gold glittering in the grass. These are Santa worms. Actually, we are not talking about worms, but females of a special beetle species - Lampyra noctiluca. This belongs to the family of fireflies, and in Norway we only have this one representative of the family. At the back of the body, this wingless and highly inconspicuous female beetle has a small light organ. Here there are special cells that contain the substance luciferin. When this is affected by the enzyme luciferase and water, an oxidation takes place, and energy is released. In fact, close to 95% of this energy escapes as light. For comparison, it can be mentioned that the sun releases only 35% of its energy as light. Next to the light cells are uric acid crystals which act as reflectors for the light rays. Luciferin is also used in medical research, where radioactive markers have been replaced, such as radioactive iodine, with such light markers instead. Luciferin has thus been used as a marker for both insulin, myoglobulin and thyroid hormone. This is a school example of how important it is to take care of biological diversity in nature. You never know what you might find useful in time.

Picky butterflies

The butterfly fauna on Langøya is unique nationally. Close to 600 species have so far been identified here, and several of these are very rare. Many species thrive where it is warm and are therefore found on Langøya. Nevertheless, the main reason for this diversity is probably that well over half of our 2109 butterfly species are only linked to one or a very few plant species.

Since Langøya is known for its rich flora, then this is logically connected. Important in this context are both the limestone soil and the island's climatically favorable location. Two very interesting plant species that should be mentioned in this context are field wormwood and true wormwood. Both of these are common on Langøya. More than ten different small butterfly species are exclusively associated with field wormwood, while a few fewer are found on true wormwood. Several of these butterflies are very rare, and they will not be able to survive where the host plants do not grow. Another exciting species is licorice moth, which has two species of sac moth in addition to licorice moth bluewing, which only has this plant on its menu. The Norwegian subspecies of licorice bluewing is almost extinct in Norway. The last location it has been found is a secret location on one of the islands in the Oslofjord, but it is not Langøya. Krattalantfjærmollen is a characteristic small butterfly on Langøya. The larvae develop exclusively on scrubland, and the butterfly has only been detected in a very few Oslofjord locations.

There is hardly an herb, a shrub or a species of tree that does not have one or more butterfly species associated with it. Species associated with rare plants are of course dependent on the plants' existence. If a plant species disappears, this in turn could cause several insect species to disappear at the same time. In some cases, the growing location of the plant must also be correct. The krushøymol sack moth is exclusively linked to the krushøymol plant, but it is only found where the plant grows exposed on beaches. The butterfly therefore does not follow the plant inland. It is therefore not enough that a plant is present for the corresponding butterfly to be found there.

Of the beautiful diurnal butterflies, some are extra eye-catching and beautiful. One such stately species is the emperor's coat (Argynnis paphia). It is relatively uncommon this far up the fjord, but it thrives on the islands in the outer Oslofjord. Sometimes the species can be found as far north as Oslo, but it thrives best in southern Norway. The larvae develop exclusively on violets, and the eggs are laid in late summer on violet species, especially forest violets. The tiny larvae overwinter, preferably in a crack in the bark of the nearest tree. As soon as the violet leaves start to shoot in the spring, they start eating. Then it goes blow by blow until the pupa stage. Inside the pupa, all the caterpillar's organs break down and the beautiful butterfly is formed. One summer's day the pupa bursts open, and out crawls a shaggy creature. The wings are inflated and dried, and the very next day the butterfly is ready for its first flight.

Many nocturnal butterflies can also be very beautiful. Unfortunately, these are not the kind you usually see, because they are mostly only out at night. During the day, they sit hidden in the vegetation, or the pattern makes them blend in with the background.
One of the most beautiful is the narrow dusk meter Plagodis dolabraria. This is a relatively uncommon species that is widespread in south-eastern Norway. It has only been worn once Langøya, but is relatively common on the neighboring island of Mølen.

Unique insect fauna

On Langøya 20 parasitic wasp species have been found which in Norway have only been detected on this unique island. Most of these species are previously known from Central Europe or Russia. At the same time, the dancing fly Platypalpus norvegicus can be mentioned. This was named on the basis of some specimens caught on Ostøya in Bærum. The Latin name tells us that it is from Norway. It has later been proven at a few other locations in the Oslo Fjord area included Langøya, but it has not yet been found outside Norway's borders.

Bills

The beetle fauna on Langøya also includes several unusual species. The small leaf beetle Aphtona pallida has only been detected here in Northern Europe. Its larvae are attached to stork beaks, probably blood stork beaks. This species is also listed on the national list of threatened animal species.

Flies

That a dry island which Langøya also hiding freshwater insects is perhaps somewhat surprising. But as long as there are a few small streams and puddles, this is enough for certain species to develop. As many as 41 species of spring flies (Trichoptera) have been detected on the island, and several of these are very rare in Norway. Several of the species have only been found a few times in the Oslofjord area. One of the reasons why they exist on Langøya, it may be that they are vulnerable to acid rain, so that they eventually only manage in areas with calcareous soil.

Spiders

The spiders are voracious hunters who hunt both high and low in nature - some with webs, others without. One of those that hunts without a web is the crab spider Misumena vatia, which is probably the most common spider on Langøya. It likes to hide in yellow flower crowns where it waits for prey. When an unsuspecting insect comes to roost, it jumps over it and squirts it full of digestive juices using its hollow jaws. The insect is slowly digested in its own body, and eventually the spider can suck in its meal.

The spider fauna on Langøya is very interesting nationally. Close to a hundred species have been detected on the island, and one of these, the small carpet weaver Entelecara congenera, has only been detected here in Norway. It should be added that spiders are not insects, but arthropods. Nevertheless, the entomologists also include these in their field of study.

Many other insects are found exclusively here in Norway Langøya, but it would be too much to mention all of these. Most of them are southern, so-called continental species, which have their northernmost distribution in the Oslofjord area. Although we know parts of the insect fauna well Langøya, then it is quite clear that the island hides many more entomological secrets.