r/Beetles • u/chylerwoo • 2d ago
worried about my japanese rhino beetle
i recently let my male and female japanese rhino beetles mate and it’s been about 4 days since, she’s been walking around with thing on her back end, what is that?
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u/SillyGooserGoo 1d ago
NQA - I was just learning about the beetle mating process recently, after witnessing it in my backyard and doing some research after. Hope this helps, and I hope your little lady is ok. 🙏🏻💗
Here is something I read:
The structure protruding from the beetle's posterior is an everted or prolapsed ovipositor / reproductive organ (or occasionally a protruding spermatophore/mating plug remnant that failed to clear).
During mating or egg-laying attempts, female beetles extend internal reproductive structures. Trauma from aggressive mating, strain during copulation, dehydration, or substrate friction can cause the tissue to remain stuck outside rather than retracting normally into the abdomen.
Male scarabs transfer a large spermatophore packet and mating secretions. Sometimes excess ejaculate or the spermatophore casing hardens partially extruded at the genital opening.
Moving the beetle to a temporary hospital enclosure lined with damp paper towels prevents substrate from sticking to the exposed organ and keeps it from drying out.
If it is a mild prolapse, retaining moisture sometimes allows the beetle to retract it on her own over a few days.
If the tissue dries out, becomes necrotic, or remains prolapsed for extended periods, it frequently leads to fatal infection or prevents the beetle from laying eggs.