Nederlands English

Order: Opiliones, Harvestmen

There are seven pages, this page with general information and four pages with the species. Furthermore two pages with foreign sightings during holidays:

General information

Harvestmen are not toxic.

Harvestmen are often called spiders but they are a separate order. Harvestmen have no possibility to spin a web, they can't produce silk. What also is missing are the venom glands that spiders do have. The story that the harvestmen are very toxic is consequently not true. To defend themselves they can release a smelly liquid.

Harvestmen have no venom glands and are non-toxic
Harvestmen have no venom glands and are non-toxic

Food

Rilaena triangularis, juvenile, eats a springtail
Rilaena triangularis, juvenile, eats a springtail

Harvestmen are generally omnivores. So they eat both vegetable and animal food, although there are species that only eat animal-based feeds. Often it are scavengers and they live further from decaying plants, small invertebrates etc. They reduce their food with the shears that are on the chelicerae. Below on the picture of a dead male D. ramosus that I've found in a spider's web you can clearly see how this looks like. It are a kind of lobsters scissors. It consists of three parts, the first part is pointing forward, the second downward and forms with the third the scissors. I have laid down the dead animal on its back, so you can see the scissors well. Often the chelicerae are increased on the males. A good example is the male Phalangium opilio, which you can recognize at a great distance at the great chelicerae.
In addition to the cheliceren there are the pedipalps, on the picture they put forward and walk out of view. In the Dicranopalpus ramosus the pedipalps are forked, on which you can identify the species. Often are they differed in male and female, in D. ramosus the male has thin pedipalps, the female pedipalps are thick and hairy.
Further you see on both sides the four walking legs, i.e. the attachments, because this animal misses a number of legs.

strekpoot, Dicranopalpus ramosus ♂
strekpoot, Dicranopalpus ramosus ♂

Molting

Like all other arthropods the harvestmen have to shed their skin. After several times they are adult and then stop molting. For molting they hang somewhere and crawl out of their old skin, such as the harvestman on the photo. Normally the harvestmen has a lot (8) of legs now it's a bunch, eight legs from the newly shed animal and eight of the old skin. You often find empty skins under the hollow side of pieces bark that lay on the ground.

Dicranopalpus ramosus
Dicranopalpus ramosus

Reproduction

Harvestmen life generally a year and reproduction goes through eggs. Internal fertilization takes place, at the mating are the animals facing each other. The females put the eggs with a ovipositor in the ground or on damp places such as in crevices in the bark of trees. Most species come through the winter in the egg phase. On the photos below, a female Leiobunum spec A and Platybunus pinetorum with ovipositor, a male Platybunus pinetorum with visible reproductive organ and mating of Opilio saxatilis.

Leiobunum spec A, ovipositor visible
Leiobunum spec A, ovipositor visible

Platybunus, ovipositor visible
Platybunus pinetorum, ovipositor visible

Platybunus pinetorum ♂
Platybunus pinetorum ♂

Platybunus pinetorum ♂
Platybunus pinetorum ♂

Opilio saxatilis
Opilio saxatilis

Opilio saxatilis
Opilio saxatilis

Opilio saxatilis
Opilio saxatilis

Opilio saxatilis
Opilio saxatilis

a spider and a harvestman

spider
spider

harvestman
harvestman

The difference between harvestmen and spiders is that harvestmen are so on the eye a ball with legs, spiders have always two body sections, are clearly two pieces with the legs on the front part. The eyes of harvestmen lay on a hillock on top of the body, they have two eyes, spiders usually have six or eight eyes.

Daddy longlegs:

In English the Opiliones are called harvestmen or daddy longlegs. The last name is confusing because that is also used for a spider and for the craneflys.

cranefly
cranefly_daddy longlegs

Pholcus spider
Pholcus spider_daddy longlegs

harvestman
harvestman_daddy longlegs

Mites

Harvestmen often suffer from parasitic mites. On the legs but also on the body. It are the larvae of the Velvet mite, see my page diversen for photographs of the mite, sorry the text there is in Dutch.

Platybunus pinetorum with mite
Platybunus pinetorum with mite

Mitopus morio with mites
Mitopus morio with mites

Mitopus morio with mites
Mitopus morio with mites

Rilaena triangularis, juvenile with mite
Rilaena triangularis, juvenile with mite

Pseudoschorpion

Pseudo Scorpions are very small Arachnids that live off small arthropods. In order to move over larger distances, they keep themselves sometimes stuck to the legs of large insects such as beetles and flies. Mid May 2018 several are on Platybunus pinetorum near Schoonoord. The Pseudo Scorpions use the harvestman only as a means of transport, they go hitch-hiking.

Platybunus pinetorum with Pseudoschorpions
Platybunus pinetorum with Pseudoschorpions

Platybunus pinetorum with Pseudoschorpion
Platybunus pinetorum with Pseudoschorpion

Platybunus pinetorum with Pseudoschorpion
Platybunus pinetorum with Pseudoschorpion

cranefly with Pseudoschorpions
cranefly with Pseudoschorpions

Species

In The Netherlands there are now 33 species. Worldwide approximately 7000 species. An overview of the Dutch species from 1975 mentions 21, (Spoek 1975). pdf English. The last years there have been 12 species introduced. This are species from the South of Europe and North Africa that extend to the North.
Below is a list in order of first performance with at the back the author who described the first sighting in The Netherlands with sometimes the possibility to download this document from the website of Naturalis.nl, natur-in-nrw.de, and eis-nederland.nl:

1991 Opilio canestrinii (Thorell, 1876) (Weele 1993)
1993 Dicranopalpus ramosus (Simon, 1909) (Cuppen 1994)
1997 Nemastoma bimaculatum (Fabricius, 1775) (Wijnhoven 1997)
1997 Trogulus nepaeformis (Scopoli, 1763) (Wijnhoven 1998ab
1998 Platybunus pinetorum (C.L. Koch, 1839) (Wijnhoven 1998ba)
2002 Leiobunum sp. A (Wijnhoven et al. 2007) (pdf)
2003 Astrobunus laevipes laevipes (Canestrini, 1872) (Wijnhoven 2003) (pdf)
2004 Nelima sempronii Szalay, 1951 (Wijnhoven 2005) (pdf)
2006 Nelima doriae (Canestrinii, 1871) (Wijnhoven 2007) (pdf)
2012 Leiobunum religiosum Simon, 1879 (Noordijk & Bink 2014) (pdf)
2014 Trogulus nepaeformis (Wijnhoven 2014)

 

Thanks

I would like to thank Joost Vogels, Arp Kruithof and Hay Wijnhoven for the enormous amount of information they have provided me through the forum of waarneming.nl. By this my interest in the harvestmen became strongly stimulated.

 

literature:

List of the Dutch species: