In the last post on Rilaena triangularis, I mentioned that there are only very few species of harvestmen that are adult around this time of year. One of them is Platynunus pinetorum, but this species is not very common in most northern European countries. Today I went looking for it in the forest, and hurray, I found one! Isn’t it a nice one? It came falling out a tree when I shook the lowest branch, and landed in my white umbrella. Once put on the grass it was very patient letting me take pictures. (Luckily, because my simple camera that only has auto-focus really likes to focus on everything except the thing that I have in mind…)
P. pinetorum originally occured in central Europe, but over the past two decades it has moved northwards. In Belgium it was first recorded in 1992 and in the Netherlands in 1998. Also in Germany, where it already occurred, the species is becoming more and more abundant. Only a few years ago (2010) there was a first sighting in Sheffield in the UK.
As already indicated by its name, this species is often found on coniferous trees, such as pine. This is the area where I was today, with nice low pine trees so that it’s easy to shake the branches.
P. pinetorum is a very good-looking harvestman, if I may say so. It is rather large (5-8 mm) and has a very dark colour. The body of a male is completely black, with brown legs, while the female is dark brown with a saddle of black and white (so, the one pictured here is a female). They have a row of white spikes running along the underside of the palps, pointing forward when the palps are drawn in (visible on the first two pictures above). On the picture below a view of it’s cute white belly.
One of the nice things about harvestmen is that some species can be found year-round. So excursions can be undertaken even in the midst of winter! I have a special bag containing the things I need when I go look for harvestmen. This is the equipment:
Notebook and pen
Plastic containers For examining or taking home specimens
Photo camera I take a picture of every specimen I find, so that more experienced people can check the determination before they are entered into the database of the Netherlands. Luckily there are so few species living here that they mostly can be recognized from a picture.
White umbrella A light-coloured umbrella is very handy to find specimens that sit in bushes or in the lower parts of trees. Open up the umbrella and place it upside down under the branches, then shake the braches or hit them a few times with a stick so that all invertebrates fall into the umbrella (like this).
Last weekend my husband and I set off to the IJssel river forelands to take a walk. And of course I had to look for harvestmen along the way.
I especially went looking for Astrobunus laevipes, a small harvestman (2,5 – 4 mm) with two rows of blunt spikes running over its back. It is an originally southern European species, that has been found for the first time in the Netherlands in 20031. It is expected to live along the IJssel, but the area has not been searched often so it has not (yet) been found. We turned over many small rocks, but unfortunately weren’t able to detect one.
This pile of rocks however was home to a number of Phalangium opilio:
At the end of the walk we found 3 specimens of Mitopus morio, which made me very happy as I had not seen this species before.
One male was carrying a parasitic mite larva on its leg:
The female looked a bit faded, perhaps she had to molt one more time:
So, al in all, a nice walk, harvestmen-wise and otherwise!
1. H. Wijnhoven (2003) De hooiwagen Astrobunus laevipes nieuw voor Nederland (Opiliones: Phalangiidae). Nederlandse Faunistische Mededelingen 19: 73-78. Link to article.