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Correspondence

Subject: Photographing live Dicyrtomina ornata in culture.

From: Keith Brocklehurst.
Date: Sun, 18 April 2005

During late autumn of 2004 I had the good fortune to observe and sample a thriving population of the sminthurid, Dicyrtomina ornata var. saundersi, in a strip of low-growing thyme next to and overhanging a low stone retaining wall. Collection was by net and pooter. They were accompanied by smaller numbers of Entomobrya nivalis and E. nicoleti. Largely by chance, I came upon a way of keeping them still under the stereomicroscope making digital photography of them almost leisurely and comfortable. This happened a few months after I had finally purchased a Meiji FL-150 fibre optic light source which I knew did not stimulate some springtail species in culture like focussed tungsten light does.

I try to keep springtails alive in plastic screw-topped jars and normally feed them and add distilled water to the culture base of DIY filler every other day; after three warm days without attention I put in about six drops of distilled water. The water soaked in rapidly as I watched . Within a few seconds all the dicyrtominas had collected in the moist circles, stopped moving and extended their two long vesicles from their ventral tube. Some had laid them out left and right tidily on the media surface; a few I was fortunate to observe temporarily getting their vesicles tangled up with antennae or legs. I realized they were 'drinking'; exactly how I was not sure, but thought the bright transparent vesicles might be using capillarity. Then I managed to get my Nikon 995 on one eyepiece and record some of them before they had drunk their fill. It was quite simple to get three live specimens in one camera frame. I still await a plentiful collection of this or any other sminthurid to refine and repeat the experiment and record more completely.

Previously I had met the long extruded vesicles of Dicyrtomina ornata, but only in preserved specimens. Apparently immersion in alcohol causes this extrusion. I assume that long vesicles of the ventral tube are present only in some sminthurids; but certainly I have seen species of Entomobrya in culture behave similarly, except that no long vesicles were detected viewed from the dorsal side. They were certainly immobilized for several minutes and could have been absorbing water through the two terminal lobes of the ventral tube.

Here are some labelled photographs of some of the events described above.


















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WelcomeThe PMSThe Study GroupWhat are Springtails?Collecting TechniquesObservation Techniques Cultures Identification Springtails of the MonthPhoto GalleryCorrespondence Related SitesE-mail PMS Main Site