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Hygrotus inaequalis 06-10-2008
Hygrotus inaequalis

A tiny, bulgy beetle, length about 2.7 mm. Very common in all kinds of ditches and ponds in the Netherlands. This specimen was found in a ditch on Terschelling (an island near the north coast of Holland). It is very similar to Hygrotus versicolor, but the black lines on the wingcases of that beetle seem to be merged to large blots on the species here. More typical is the punctuation of the wingcases: here there are large and deep dents, while versicolor has also smaller dents between these large ones. Protozoa have attached themselves to this beetle, probably bell animalcules of the Opercularia species.


Hygrotus inaequalis 06-10-2008 enlargement enlargement
Hygrotus inaequalis 06-10-2008
The picture at left and right show, better than the picture above, that the head is relatively small. Notice the small space in the corner under the wingcases, just behind the head: the beetle may fold it's legs in there, much in the same way as Hydrovatus ovatus. On the picture at left, where the beetle is resting below the surface, it has partially retracted it's legs. They may be further withdrawn in this corner and in that way are lying close to the body. This could be efficient during swimming because the water resistance is lower that way, but I don't know if the beetle makes use of that advantage. What I have seen is that the legs are fully retracted when the animal feels threatened, just like a Lady beetle does.

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COPYRIGHT:
All pictures on this site were made by Gerard Visser (Almelo, Netherlands), unless stated otherwise. All rights remain with him. These pictures may not be used for purposes any other than private viewing or printing. Do NOT hardlink to these pictures or place them on other websites without the author's approval. Should you need them for purposes which include third parties, you must ask the author permission by e-mail. People, who want to use this pictures for exhibitions or publications or educative material are much encouraged to do so, after approval as mentioned and giving the normal credits.
© G.H. Visser 15-10-2008
rev.03-11-2008

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