- Last updated on 2012.12.29 by Frans Janssens
Checklist of the Collembola: Note on a case of lethal predation in Dicyrtoma fusca (Collembola: Dicyrtomidae) from Holland

Frans Janssens, Department of Biology, University of Antwerp, Antwerp, B-2020, Belgium
Matty P. Berg, Department of Ecological Science / Animal Ecology, VU University, AMsterdam, 1081HV, The Netherlands
Jan J. van Duinen,, The Netherlands



Methods and material

Fig.0. Dicyrtoma fusca from Holland
Reference specimen
2012.11.22 © van Duinen, J.
On December 19, 2012, a specimen of Dicyrtoma fusca (Lubbock, 1873) was found that was immobile, completely white, appearing translucent and 'empty'.
All specimens were observed and photographed in situ.


The specimen was found in a recently reforesterisated part of the nature reservate "De Zwatte", near to Schoonloo, in Holland. Never before such specimens were observed in that regio. Lots of other specimens of Dicyrtomina saundersi (Lubbock, 1862) and Dicyrtoma fusca (Lubbock, 1873) (fig.0) with a normal habitus were observed at that same location.

Fig.g1. Dicyrtoma fusca from Holland
Fronto-lateral aspect
2012.12.19 © van Duinen, J.
Fig.g2. Dicyrtoma fusca from Holland
Dorsal aspect
2012.12.19 © van Duinen, J.
The specimen is completely white, and appears to be translucent (fig. g1 & g2). The internal body tissues seem to be removed.
Fig.ant. Dicyrtoma fusca from Holland
Reduced antenna
2012.12.19 © van Duinen, J.
Fig.eye. Dicyrtoma fusca from Holland
Ocelli of composed eye
2012.12.19 © van Duinen, J.

The antennae are shortened (fig. ant). As if they shrunk. The 4th antennal segment appears to be intact.

The composed eye with 8 ocelli (fig. eye).


Fig.aca. Dicyrtomina ornata from the UK
Predated by a nymph of Trombidiidae
2012.12.21 © Barton, T.
It is assumed that the specimen has been attacked by a predator that liquifed the body tissues and then sucked up the liquified body tissues. What remains is the empty unliquified exoskeleton. Due to the power of the suction, the exocuticula of the antennae did shrink telescopically, effectively shortening the antennae.

Candidate predators are trombidiid mites (Acari: Trombidiidae). Adult Allothrombium are generalized predators and can probably feed on most of the small arthropods that they can handle (Zhang, 1991a cited by Zhang, 1998:144), whereas those of Trombidium feed exclusively on the eggs of Collembola (Robaux, 1974 cited by Zhang, 1998:144). However, few experimental tests on feeding ranges have been published. (Zhang, 1998:144).

A trombidiid mite inserts its chelicerae into the prey and the mouth sucks body fluid through the wound (modified after Zhang, 1998:148). The remains of the prey are a pale and empty exocuticula. On December 21, 2012, in the UK, England, London, Richmond, Toby Barton observed and photographically recorded a nymph of a trombidiid mite sucking empty a specimen of Dicyrtomina ornata (Nicolet, 1842). The head of the prey turned completely white after being sucked empty (fig. aca).



We would like to thank Toby Barton for his permission to use his picture as illustration.