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Rhantus suturalis, pupal stage 02-09-2007
enlarge Rhantus suturalis, pupa
THE larva OF THE PREVIOUS PAGE HAS TOTALLY CHANGED AFTER A WEEK. It has become a pupa. Under the pupal skin the perfect beetle is almost ready. I don't know whether the larva has a moult just before the pupal stage.
detail appendages head, collar and abdomen of the pupa
The large compound eyes of the beetle are visible through the pupal skin. Also the legs and wings have developed. After some hours the pupal skin will tear open, along the seam which is just visible on the neck shield. Then the beetle emerges from the pupa, so the pupal stage is very short compared to, for example, a butterfly pupa that often hibernates for months. The Rhantus beetles have a short developing time. As is written on the larva page this is necessary because the little pools which are their habitats, often dry out quick and the beetle must be ready to fly.
On the "snout", head and back the pupa has stiff hairs that carry it, so it lies free from the surrounding mud. This probably avoids fungus and keeps the air around the pupa fresh while the pupa is resting motionless until the beetle starts stirring in it's envelope.

The fresh beetle is weak with floppy legs. And it is probably has a light-yellow colour at first, like all insects after a moult. I sadly missed the light-yellow stage, it last just a few hours I guess. The hardening of the beetle last longer, that's why she stays safely under leaf in the pupation hole.

Below the entire process: digging a hole and pupation. It takes less than two weeks!

Rhantus suturalis, larva in pupation hole Rhantus suturalis, pupa in pupation hole 02-09-2007 Rhantus suturalis, beetle in pupation hole 04-09-2007


Page track: INDEX » diving beetles » Rhantus suturalis » the pupa

All pictures on this site were made by Gerard Visser (Aadorp, 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 09-09-2007
rev 07-07-2008

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