Another 5500 to 7000 species (depending on the source, and for sure not final) of animals we hardly know. That’s thrips, order Thysanoptera.
‘Thrips’ literally means wood worm, without them being worms – of course. A common name for some species of thrips is thunderbugs. Or thunderworms. There are plenty of cute names for thrips in Germany, like Hommelmösche or Gnudd. Dutch say blaaspotigen.
When I found these large thrips on a piece of dead wood in Singapore, I did not think of worms. For a second I thought I finally found some scorpions. Baby black forest scorpions. Size, color and behaviour gave me that first impression.
In fact some species of thrips seem to mimic other animals, and mine held the first pair of legs like scorpion holds the claws, and the tube like back looked like a scorpion’s tail. There were dozens of thrips on that old mossy tree stem, plus plenty of other interesting animals. That’s how valuable rotting wood is for nature.
The adult, black “scorpion thrips” were approx. 10mm in size. Have a look at the photos, there is one small juvenile to the right front, with a nice red band on a pale yellow body.
The identification was almost impossible for me. I was already happy when I found out these were thrips. The only thrips I knew before was the thunderworms from Germany, which are so tiny I had no idea how they look like, apart from black tiny, yes, worms.
The fact that many species of thrips are considered crop eaters, or pests, makes it even harder to get information that is not just about killing thrips. There aren’t many enthusiasts around. Probably gardeners and farmers are the only people who know about thrips. But I found one very knowledgeable enthusiast, whom I would like to thank again for his support: Dr. Manfred Ulitzka. Have a look at his website!
https://www.thrips-id.com/de/sammlung/ He was able to determine the genus of my thrips.
It’s a Dinothrips species (obviously the spines on the male’s back allow this characterisation), from the subfamily Idolothripinae, family Phlaeothripidae. The exact species is impossible to determine from photos. It would require DNA analysis.
Fungi and their spores are the main food source, which is good for them. There were lots of fungi on their home wood! Thrips can be herbivores, predators, parasites, and mixed forms. They can be found around the world, except for the coldest areas. Most can fly, but poorly, and often males have no wings.
The genus Dinothrips was described in 1908 by the British entomologist Richard S. Bagnall, and contains 6 species. ‘Dino means’ terrible he mentioned in a foot note, probably he chose the name because of these spines, or the huge size? In ‘On some new genera and species of Thysanoptera‘ Bagnall explained that around 200 species were known in 1908, but he foresaw that the order is huge and might have well over 1000 species. He was right! On page 186 and 187 our genus comes up. Large, massive and curious (?), 7 to 12mm, from the Malay archipelago, ‘head with the cheeks profusely set with spines’. Three genera existed in the family, Dinothrips, Macrothrips, and Machatothrips. Dinothrips are further described on page 190 to 192. He described D. sumatrensis very detailed. I’m always fascinated how much passion these entomologists had and have. In 1908 Ford started to sell the T model, and the Tunguska asteroid hit Siberia. Wilbur Wright demonstrated the Model A in Le Mans, France, the first time the public world would see an aeroplane. And Richard S. Bagnall described thrips. There’s a biography written by Louise Berridge about Ragnall. He obviously had health issues which limited his mobility severely. The author quotes Randall saying tiny creatures make a resticted area seem much larger.
There are two suborders in the order Thysanoptera: Terebrantia (with the majority of species) and Tubulifera. Tubulifera are considered larger, and bearing a tube-like last segment of the abdomen. Currently Phlaeothripidae is the only extant family of Tubulifera.
Thrips are considered a sister group to real bugs (Hemiptera), which has ten times more species. Picmybug has a sister, Picmythrips! Two unique features of thrips are these:
1 Their mandibles, the jaws so to say, are asymmetrical. The right mandible is either smaller than the left, or absent. There’s not too much asymmetry in nature, so that’s quite remarkable! Wikipedia’s list of asymmetry in nature mentions for example sperm whales with only a single left nostril, flounders, snails, hermit crabs, and thrips.
2 Thrips have a different way of flying. Wright? Earlier I mentioned they are poor flyers, but I guess evolution left them with the best way to fly for their needs. While most insects use a method creating a ‘leading edge vortex’, thrips fly with the ‘clap and fling’ mechanism. It is also called Weis-Fogh mechanism, named after a Danish entomologist who was into aerodynamics. While I’m trying to get a handle on the mechanisms of insect flight, I realise I’m not into aerodynamics. Not yet. Thrips’ tiny body size seem to have to do with the clap and fling flight. When biologists count you in as aeroplankton, you know you’re tiny, and unable to control your directions. Tiny poor flyers.
And there lies a story about the name thunderbugs. The tiny sisters of our giant thrips use thermals to travel. A warm sunny day is travel time for thrips. When rain or thunderstorms develop, thermals decline, and the tiny thrips sink. It also has to do with an increasing field strength, resulting in the thunders finally. They do not exactly indicate thunders, since they start landing when the change of weather is already obvious for us.
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