Castiarina nasuta

4 A jewel beetle at Murrumbateman, NSW

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Identification history

	Castiarina nasuta	7 Dec 2023	MarkH
	Castiarina nasuta	7 Dec 2023	SimoneC

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User's notes

This lone jewel beetle attempted to mate with a Lycid beetle that it mimics. After being initially unsuccessful it tried a second time before flying off. The Lycid did not seem to notice/care See https://canberra.naturemapr.org/sightings/4533873

5 comments

living wrote:

14 Dec 2023

OMG, interesting observation, totally blown away!

MatthewFrawley wrote:

16 Dec 2023

I'm going to have to look more closely at Lycid beetles from now on, I had no idea there was a jewel beetle that mimics them. I wonder what the evolutionary purpose of that is? Perhaps someone more learned can explain.

Harrisi wrote:

16 Dec 2023

There are numerous jewel beetles that mimic lycid beetles in our region...at least 5 come to mind, all are represented on CNM. Jewel beetles also mimic other types of beetle too

SimoneC wrote:

16 Dec 2023

@RogerF has a discussion of the mimicry of Lycid beetles in his book Insects of South-Eastern Australia. Lycids taste bad, and so do a lot of other insects that mimic them. Others like the Jewel beetles don’t taste bad. Given the Jewel beetle’s inability to identify an appropriate mate (at least in this case), and the vastly greater number of Lycids vs Jewel beetles. C. nasuta could be wasting a great deal of energy and reducing their reproductive output per mating - that means they must receive a huge benefit in the form of protection from predators for the mimicry to be maintained as strongly as it is. We would expect that over evolutionary time they should eventually be selected to be able identify their own species a bit more successfully too

RogerF wrote:

16 Dec 2023

Just to clarify this issue. !) There are several species of jewel beetle that mimic Porrostoma 2) they are examples of Mullerian mimicry whereby several distasteful species mimic each other 3) Jewel beetles are quite toxic and contain the chemical buprestin whose formula has been elucidated by the late Barry Moore, biochemist at CSIRO Entomology (as was). I photographed a Pelecorhynchus fulvus fly in ANBG yesterday that is a Batesian mimic of Porrostoma ie it's tasty, this fly also 'walks' across flowers like a beetle. Its also interesting that the black line on the elytra of this species of Jewel beetle mimics the separation of the lycid wing cases. There are 13 species of Castiarina that are reported by Shelley Barker to be lycid mimics. I have never seen such attempted cross mating.

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