Rare 2nd breed

Commonly, the Small Tortoiseshell has a single breed each year. Due to the location of Finland the species only has a 2nd breed in years with good weather conditions.

After two bad years the Small Tortoiseshell has declined in population. In 2015 I hardly spotted this butterfly at all. In summer 2016 the species has taken a great leap back. Early summer the first breed turned to adult butterflies. They were flying in large numbers. But that’s not all. Recently, I’ve noticed a high number of caterpillar nests, too. During a check at a farm I noticed caterpillars in almost all instars. This means a 2nd breed will continue to grow the population this summer.

It’s one of the most common butterflies. Nevertheless, it’s always a pleasure to take a close look at the beauty of this “ordinary” insect.

Species check at the farm

Today, I wanted to take a different approach searching for caterpillars and butterflies. Instead of searching for a particular species I selected a small location. I then spent about an hour at that location, the Haltiala farm in Helsinki, trying to spot as many species as possible.

No rare species today, but it was a good day and it was great to see that the ordinary butterfly species do very well at the moment. What I found was young caterpillars of the Elephant hawk-moth (Deilephila elpenor), lots of caterpillars of the Red admiral (Vanessa atalanta), caterpillars of the Small tortoiseshell (Aglais urticae) in almost all instars, Large whites (Pieris brassicae) that most likely migrated to Finland recently and of course, European peacocks (Aglais io).

The Small Tortoiseshell

The Small Tortoiseshell (Aglais urticae) is a butterfly that most people recognize. When not by name then by its looks. The reason is simple: It is one of the widest spread and most common butterflies across Europe.

Regardless of being a common species there is an interesting fact that can be observed in Finland. In some years, it’s the most common species and appears everywhere. Then suddenly, there might be a year when people hardly make any sightings at all.

Overwintering as adult the Small Tortoiseshell is a really early butterfly to wake up in spring. They also breed early and develop fast which allows them to fly in up to three generations even as north as in Finland.

2014 has been been a poor year for this species. Even the lepidopterists can only speculate what has caused the Small Tortoiseshell to almost disappear after a cold period early summer. I sighted many individuals of this species early spring. Next, I spotted a normal amount of caterpillar “nests”. But suddenly, it was quiet. By the time the butterflies should have hatched I only saw three individuals in late summer.

That the butterfly had a hard time this year can also be seen in my captures. All expect one are from spring. I waited for the fresh and colorful specimens to fly in high summer. But they never came.

The Small Tortoiseshell is probably the best butterfly species for learning how to rear caterpillars. They’re relatively easy to take care of, are not too demanding and their food plant, nettles, are easily available. They develop fast which makes it more convenient if you want to show this spectacle to your kids (who may not have the patience to wait for a chrysalis to overwinter). Keep an eye on nettles nearby. They form a web around their nest at the very early stage which makes it simple to track them down.

Though I didn’t raise any caterpillars of this species in 2014 I didn’t hesitate to get a close look with my camera whenever I found caterpillars. Here’s some shots showing the development from small caterpillars to chrysalis.

1 out of 100

The title of this post may refer to my attempts in finding a caterpillar I’m after. However, it’s actually standing for the loss in individuals on the journey from egg to butterfly.

Today I tried another time finding caterpillars of the Purple Emperor (Apatura iris), Lesser Purple Emperor (Apatura ilia), Scarce Tortoiseshell (Nymphalis xanthomelas) and Mourning Cloak (Nymphalis antiopa). And again, it was only caterpillars of moths, the Small Tortoiseshell (Aglais urticae) and the Common Brimstone (Gonepteryx rhamni) that I found.

Nevertheless, the search will continue. Here’s the footage from today, a 4 hours trip into the greenery. To start with, a spider generated a rather dramatic scenario feeding on the colony of young Small Tortoiseshell caterpillars. Remember, 1 out of 100.

Here’s a series of other caterpillars I spotted today.

At the end even the sun started to shine and for the first time since a couple weeks I got some butterfly shots as well.

Needle in the haystack

This weekend I was after caterpillars. The weather was slightly better again, but not sunny enough to get butterflies fly. I spent two hours out on Saturday and almost three hours on Sunday. No luck on the caterpillar quest.

On Sunday, I only focused on finding the larvae of the Purple Emperor (Apatura iris) or the Lesser Purple Emperor (Apatura ilja). I also tried to spot a caterpillar of the Lesser Marbled Fritillary (Brenthis ino) whenever Meadowsweet (Filipendula ulmaria) was around. Nothing!

I headed towards a biotope which is supposed to host at least the Lesser Purple Emperor. And I kept my eyes primarily on Goat Willow (Salix caprea). All I found were a couple caterpillars of moths (and again Small Tortoiseshells). I must check one more biotope next weekend. The species will soon enter the chrysalis stage of the metamorphosis, and it would be really cool finding some caterpillars before that.

Unfortunately I’m not that good determining caterpillars of moths. Therefore, most of the species below are undefined.

Kicking off the search

Just a couple days ago I came across the first caterpillars this spring. This has been a good sign to see how far nature’s cycle has progressed, and gave green light to start looking for keepers.

I’ve set myself 11 targets for this season. By targets, I’m referring to species from which I’ll particularly try to find caterpillars and raise these all the way to the adult butterfly. Time to kick-off the caterpillar quest.

Today, I made a first attempt. There wasn’t that much around yet. I found three colonies of Small Tortoiseshell (Aglais urticae) caterpillars. In one case the caterpillars just hatched. The small size of these caterpillars indicated it may be too early to look for other species. They may not have hatched yet, or are simply too small to be found.

While I also came across a construction site where my favorite biotope is being bulldozed I checked if there’s any Alder Buckthorn (Rhamnus frangula) around. Alder Buckthorn is the food plant of the Common Brimstone (Gonepteryx rhamni). The caterpillars were pretty small, but since that piece of forest will be turned over soon, I decided to grab some with me.

Bottom line, with the Common Brimstone caterpillars the first target is accomplished. And there’s finally some life in the terrarium.

The first caterpillars

The Common Brimstone (Gonepteryx rhamni) may often be the first butterfly to be sighted in early spring. When it comes to caterpillars, it’s generally the Small Tortoiseshell (Aglais urticae) that appears first.

Caterpillars of the Small Tortoiseshell are not only present early, they’re also easy to sight from distance. Living in colonies they build a web at a very early stage (see photos). Later on, once they’ve grown in size, they will start moving more individually. The web is only present during the early stage, but it remains on the nettles for weeks giving hint that caterpillars can be found.

If you have any intention to raise caterpillars yourself try finding some of this particular species. They’re easy to raise and don’t require too much care-taking. Some fresh nettles every second day or so and they’re happy.

One tip though. The younger the caterpillars you find, the better chances you have to get butterflies. Older caterpillars have an increased risk of being infected by parasites. This means it may not be a butterfly hatching from the chrysalis, but a nasty parasitoid wasp. Nevertheless, regardless on what will hatch, you’ll be able to get a real close-up on nature. A fascinating play which is particularly fun for kids to watch and learn.

Unfortunately, I was only equipped with my iPhone when I found this colony. I’ll try to get better photos with my DSLR¬† when I get the chance.