Hawk-moth saldo 2016

In summer 2016 my goal was to spot some caterpillars of Hawk-moth species that I haven’t come across recently. Here’s a wrap-up of all species I managed to find, including the the hummingbird hawk-moth (Macroglossum stellatarum) from which I received caterpillars from a friend.

There’s a lot of challenge left for next year. Nevertheless, it was nice to finally find caterpillars of the Privet Hawk-moth (Sphinx ligustri). Another nice surprise was to spot a caterpillar of the Eyed Hawk-moth (Smerinthus ocellatus). All in all, it has been 7 Hawk-moth species in summer 2016. And bottom line, it’s always a great moment when coming across caterpillars of hawk-moth.

Half-success with Sphinx ligustri

Since about two weeks I’ve had a special priority: To find caterpillars of the Privet hawk-moth (Sphinx ligustri). It’s the largest caterpillar that can be found in Finland and it almost looks like a gigantic candy.

The search has been exhausting and with my e-bike I’ve been riding several hundred kilometers, keeping a close eye on growth that the caterpillar accepts as food plant. While I was able to locate several other species of hawk-moths there was absolutely no trace of Sphinx ligustri.

Today, on the 5th birthday of our daughter we went for another visit to one of the children’s playgrounds nearby. I couldn’t resist checking some of the perennial herbaceous flowering plants decorating the playground. There it was, less than 500 meters from our home, an almost full grown caterpillar was feasting.

The caterpillars of the Privet hawk-moth are amazing. This is one of the species highly suitable for raising with kids. Unfortunately, the species also suffers great losses to parasites. The caterpillar found today was carrying over a dozen eggs of parasites on its skin. The truth is this specimen will never become a moth. Something else will hatch from the chrysalis. I’ll call this finding half-success.

Nevertheless, here’s some photos of the caterpillar. I’m sure we’ll find more over the next couple weeks. This one might be a bit early anyway.

First feeding traces

The spring weather has been amazingly warm recently. As a result, within just a week nature has gotten its green dress back. Also the first leafs of Salix caprea have grown, making it finally easier to track back caterpillars. With the first leafs also the first feeding traces could be found.

Just a random check on a couple bushes and I found it: my second caterpillar of the Purple Emperor (Apatura iris). It felt great seeing the caterpillar happily feeding on it’s first feast after the long winter. Here’s a couple photos of the great day.

Caterpillar of the Small Copper

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One of the caterpillar targets for this season has been to track down the Small Copper (Lycaena phlaeas). In late 2015, all I was able to find was empty egg shells. I knew the habitat was right, now it was just about timing.

A couple days ago spring came back. With raising temperatures it was clear that the caterpillars will become active again. This time, I even got lucky. After browsing tiny growth of Rumex I managed to find one. Just a single one, but that’s all I needed.

Here’s a couple photos of the mid-sized caterpillar (taken in captivity). It’s size is about 8mm, and after hibernation it will probably feed for another two weeks or so.

The quest for the Small Copper

This year one of my target caterpillars for raising is the Small Copper (Lycaena phlaeas). This butterflies is one of the smallest but most common species in our region. Nevertheless, finding caterpillars is a bit tricky.

As with many species of the Blues, caterpillars are tiny and well disguised. This counts for the Small Copper, too. I’ve been browsing through vegetation accepted as host plant every once in a while, with no results so far. In autumn 2015, however, I tracked down a habitat where I’ll continue my search this spring. Just nearby where we live, in a small rocky forest.

One afternoon I spent checking Rumex plants on those rocks, finding two empty egg shell. Caterpillars I found none, possibly they had already withdrawn for hibernation as it was later in autumn. I’m optimistic to find slightly larger caterpillars once the snow has gone and the warm spring sun gets the plants to grow again.

Look up!

Not always are caterpillars found on the ground. Occasionally, you can find some on the height of one’s eyes. But that’s not all, it may also be worth to have a look up.

The White-letter Hairstreak spends almost all of its life high up in elm trees. This includes the larval stage, therefor it’s possible to spot the caterpillars by standing right under the leafs of a tree. Then, have that look up to the bottom side of the leafs. This may requires a sunny day to get a good look. Some twigs hang almost down to the ground (see photo below), making it possible to get a close-up or collect a caterpillar for raising.

If you want to raise the species from eggs here’s a couple tips for tracking them down in winter.

The First Apatura Caterpillar

For a long time I’ve wanted to raise caterpillars of the Purple Emperor (Apatura iris) or the Lesser Purple Emperor (Apatura Ilia). Before getting that chance there was one challenge thought: Finding eggs or caterpillars.

After spending quite some time on the quest I finally found what I was after a couple days ago. A hibernating caterpillar of the Purple Emperor on Goat Willow (Salix caprea). Here’s some images on the specimen, including a photo of the growth where the larva was found (see red marking).

How to find eggs of the Orange Tip

The Orange Tip (Anthocharis cardamines) is a common butterfly (that counts at least up here in Finland) and finding eggs is not too difficult. However, as with any species, the time and place must be right.

The shape of the eggs is pretty similar to those of the Common Brimstone (Gonepteryx rhamni). Eggs will be around only for a short period as the caterpillars tend to hatch already after 5-7 days. Once you start seeing the first males flying, wait for another moment. I waited two weeks this spring after spotting the first male, and got lucky. The first female I actually sighted after first finding the first eggs.

Here’s a couple photos from my search this spring. I also tried to capture the larval habitat to show what kind of surrounding I found eggs in.

How to find eggs of the Black Hairstreak

Finding eggs of the Black Hairstreak (Satyrium pruni) is a bit more challenging compared to other hairstreaks that overwinter as egg. As the color changes duringĀ  winter the eggs also get better disguised.

Every species requires its own strategy for tracking down ova. In case of the Black Hairstreak, there are two tips I can provide: First, confirm the location is right. As with every species, searching at the right location is essential. Second, attention to detail. It may require a bit more experience searching for eggs to get results with Black Hairstreaks as eggs really are well hidden in disguise. Personally, I was inspecting the very same growth multiple times before I found eggs on a spot I thought I already checked before.

I got lucky when it comes to location. Just a week ago I met another lepidopterist on a different site. After catching up and having a really interesting talk he revealed me a spot where he knew Black Hairstreaks have a good population. And this tip made my day.

Knowing the right location I was also able to start the search. I knew in advance that this species requires more attention, a better look and serious focus to find eggs. I realized how challenging it was to find eggs after finding the first two (see photo below with three eggs, one of them an empty shell). But I also got an important hint on what to look for. A week later, I found a couple more.

Check the photos below for a view on the habitat. Usually, eggs were laid on the shadow side of growth with a height of 1-2.5 meters. They were found in a height 20cm above ground up to the height of my eyes, about 1.5-2 meters above ground.

How to find caterpillars of the Scarce Tortoiseshell

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In summer 2014 one of my primary targets was to find caterpillars of the Scarce Tortoiseshell, also known as Yellow Legged Tortoiseshell (Nymphalis xanthomelas). My aim was to get a closer view on this species rearing caterpillars to adult butterflies.

The Scarce Tortoiseshell is a rather occasional visitor in Finland. However, in 2013 the species mass migrated from East towards Finland. As a result, early spring 2014 this butterfly was one of the most sighted species in southern Finland. A great baseline to try tracking down caterpillars early summer.

Please note that all my knowledge and data has been collected during one summer and within one region only. Behavior may vary depending on location, and in a “normal” year finding caterpillars will most likely be difficult if not impossible (due to the lack of the species’ presence). Nevertheless, I’ve been browsing through the greenery nearby. Here’s my wrap up from the experience I collected.

Location 1: Caterpillar colony

This location relates to one of my season highlights last summer, finding the actual caterpillars. On a cold and windy day I got lucky. On June 19th, the caterpillars appeared late that summer which must have been a direct response to poor weather conditions.

I knew in advance this location would be good as I continuously spotted Scarce Tortoiseshells flying early spring. Since late May I started monitoring willow in this area. Though I had little knowledge what kind of breeding behavior this species would have.

The caterpillars were found on willow, Salix phylicifolia to be precise. They were feeding above a small ditch. I’ve once read that Mourning Cloaks (Nymphalis antiopa) prefer similar conditions. The ditch keeps the growth doing well while providing some level of humidity to the caterpillars above. This particular location has continuous and direct sunlight.

Location 2: Abandoned colony

This sight was located just about 50 meters across a field from location 1 (see photo in the conclusion). It is well possible this colony was laid by the same female as the caterpillars found nearby. In this case (actually my first finding on the search), there were no caterpillars left. Clearly visible from a distance were the feeding traces. A closer look also provided details such as twigs covered by web and moulted skins.

Compared to location 1 this colony must have been further developed already. Caterpillars on location 1 were just moulting to the last instar. Location 2 looked like moulting took place already some time ago. Perhaps the twig was abandoned as the adult caterpillars separated (which I believe is a common behavior for this species at this stage).

Here the facts about the location. Again, caterpillars were feeding on Salix phylicifolia, a common type of willow in Scandinavia. The differences to location 1 were that no ditch was nearby. The caterpillars fed on a twig hanging low and outside of the growth, which in this case was much older already. The sight has direct sunlight from noon until evening.

Location 3: Abandoned colony

Later on in summer 2014, around mid July, I accidentally sighted a third location where caterpillars had been feeding. This location took me by surprise as it was just around the corner where we live. I did spot adult butterflies flying in spring though, but I didn’t expect caterpillars this close.

This time it must have been already weeks since the caterpillars pupated, most likely the butterflies had already hatched as well. The habitat had very much in common with location 1. The caterpillars were, yet again, feeding on the same type of willow (Salix phylicifolia). The growth was located in a ditch with the twigs hanging over water. The location has direct sunlight throughout the day. This spot is just between a small road and a walking path. Just 50 meters away there’s apartment buildings and a much frequented street.

Conclusion

Based on my findings in 2014 the common conditions for all sightings were following: The caterpillars were feeding on Salix phylicifolia and they were located on twigs clearly separated from other growth of the plant. The “colonies” were located in a height of 20-50cm above ground. As in location 1 and 3 they fed on twigs growing in the ditch, which causes them to be located very low.

Direct sunlight and open terrain were other conditions matched at all sights. Nevertheless, location 2 was next to higher growth. Tracking down a twig with caterpillarsĀ (or traces left by them) was pretty easy, assuming the location was right. Caterpillars feed the twigs completely “naked”. Should there be caterpillars left they color the twig black as they feed in large numbers. Other traces are skins after moulting and a web covering the twig.

Due to the poor weather conditions in 2014 it was difficult to get hint on the exact time when caterpillars could be found. As a result, I had to accept finding abandoned sights as well. Despite of the butterfly flying in large quantities in spring the species almost disappeared in summer when the next generation was expected. Spring 2015 will show if there’s any individuals left, or if Finland has to wait for the next mass migration to enjoy the beauty of the Scarce Tortoiseshell again.

I’m definitely hoping to get another chance to raise these caterpillars. By the way, approximately 90% of the caterpillars had parasites. I was able to observe the larvae of some Tachinidae species leaving its host before building a snow-white cocoon, usually hanging at the tail of the dead caterpillar. Therefor, young caterpillars or eggs would be yet a better finding.