- Last updated on 2016.12.24 by Frans Janssens
Checklist of the Collembola: Note on the oviposition in Sminthurides aquaticus (Sminthurididae)

Frans Janssens, Department of Biology, University of Antwerp, Antwerp, B-2020, Belgium
Marie Louise Huskens, Opitterkiezel 223 bus 0.1, B-3960, Opitter, Belgium


It was observed that in Sminthurides aquaticus, the eggs are deposited in cuplike depressions of the epidermis of Lemna minor. The cups have been chewn out by the female, prior to laying the egg. The egg is covered with a faecal pellet.


In Collembola, the eggs are fertilised within the female before laying using stored sperm (Hopkin, 1997:140). Once the eggs have been laid, they are subject to a wide range of predation pressures, not least by Collembola themselves; thus there is a strong selective pressure to hide the eggs in crevices and make them as inconspicuous as possible. (Hopkin, 1997:142). Caretaking of the eggs by the females of Sminthurides aquaticus has been observed already in 1907 : Lemna minor is chewn out and eggs are deposited in it (Klugkist 1907 cited from Schaller, 1970:50). For this Sminthurides aquaticus was considered a parasite of Lemna minor.

Material and methods

Specimens were collected from the surface of a pool in Opitter, Limburg, Belgium, near to the Itterbeek and the Zuid-WillemsVaart. At 2016.MM.DD the specimens were gently blown into a shallow container, held tilted at the water surface, using a mouth operated aspirator in reverse fashion. The concentrated specimens were then transported to a small pond covered with Lemna minor in the garden of the second author and kept as such in culture for several months. Observations were performed indoors on a staged set-up. Photographs were made using a digital reflex camera Canon EOS 80D. A Canon MP-E 65mm lens was mounted on the camera using a set of Kenko extension tubes (12mm + 20mm + 36mm). Illumination was provided by a Canon Macro Ring Lite MR-14EX and a Falcon Eyes SLP-120LTV LED Lamp.


The indoors stage was set-up and after a short aclimatisation period the females started with their oviposition activities. At first the epidermis of Lemna minor was chewn out to form a shallow cuplike depression (fig.1). In such a cup, an egg was deposited (fig.2). Afterwards, the egg was covered with a faecal pellet (fig.3).
Fig.1. Sminthurides aquaticus ♀ chewing out a 'nest'.
Huskens, M.L. © 2016.07.28
Fig.2. Sminthurides aquaticus ♀ depositing egg.
Huskens, M.L. © 2016.07.28
Fig.3. Sminthurides aquaticus ♀ covering egg with faecal pellet.
Huskens, M.L. © 2016.07.28

At the end of the embryonic development, the eggshell is completely transparant revealing the fullgrown embryo ready to hatch (Fig.4).
Fig.4. Embryo's of Sminthurides aquaticus.
Huskens, M.L. © 2016.07.28


After the courtship ritual and spermatophore uptake, the female must moult before she can lay eggs (Falkenhan 1932 cited from Schaller, 1970:49). Oviposition occurs in batches of 1 to 6 eggs (Falkenhan 1932 cited from Schaller, 1970:49). In each intermoult oviposition period, in average 25, at most 66, eggs are laid (Falkenhan 1932 cited from Schaller, 1970:49). Eggs are deposited continuously when not moulting (Waldorf 1971 cited from Hopkin, 1997:142). Eggs are deposited in cuplike depressions of the epidermis of Lemna minor (Fig.1,2). The cups have been chewn out by the female. After deposition, the egg is covered by a faecal pellet (fig.3).