Springtail swarms


I bought a set of extension tubes this year to get more detail in my close-up my photos. I have tried them out on my camera’s 100 mm macro lens sometimes with good results. It’s a learning process with lots of duds, but I like the increased magnification on the shots that do turn out. With the extension tubes I’ve been taking many photos of lichens, mosses, fungi, bark, and wood grain. As the seasons move along I will be looking at the finer details of leaves and flowers.

Last month I saw hundreds springtails swarming on an old spruce log and decided to go in for some closeups. The shots taken with 31 mm and 21 mm extension tubes added to a 100 mm macro aren’t as sharp as I’d like but good enough considering how small (about 1 mm) they are and how fast they move. If they sense danger they can jump 100 times their body length which would be 10 cm.

A springtail that caught my attention was the larger (about 1.5 mm) light brown hirsute one with darker brown markings on its body segments. I’d seen this type before crawling in lichens on trees on warm the winter days. Named Entomobrya nivalis, it is a springtail that normally lives in the canopies of forest trees. Taxonomically they are placed in the family Entomobryidae in the order Entomobryomorpha one of the three orders of the hexapods in the subclass Collembola.

The other springtails with the black bodies are probably a species of Hypogastrura a genus with 169 species, 112 of which occur in the US and Canada, in the family Hypogastruridae also in the order Entomobryomorpha. These look similar to ones in photos of H. tooliki but without observing specimens under higher magnification it is only a guess. Hypogastrura are common inhabitants of leaf litter and soil. While there was plenty to eat on the surface of the log (spores, algae, fungi) the springtails weren’t there for eating. Instead, large swarms like these in the early spring are mating swarms. You can see these on mild days after snow melt when hundreds or even thousands of springtails find each other and congregate on damp wood, moss, leaves, twigs, and fungi. When a mass of springtails is large enough you can here hear the clicking sound they make as they jump. All you need to do is get close to to ground and listen.


Devil's urn and springtails
Springtails (Hypogastrura sp.) on devil’s urn fungus (Urnula cratarium). This shot was taken with the 100 mm macro lens and no extension tubes.

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