Summer wedge-shaped beetle hunting

Inspired by this post

Background: Wedge-shaped beetles are in the family Ripiphoridae and represent one of the few groups of beetles that are entirely parasitic. In the genus Ripiphorus that I am most interested in, all species are probably parasitizing ground-nesting bees, especially Halictidae and Apidae:Emphorini. Females lay eggs in a flower bud and the larvae hatch into a form called triangulins, that latch onto a foraging bee and get a free ride back to the nest.

Why you should help: Ripiphorus has been known to science since 1791. Throughout the following 232 years. there are only about 10 records per year, and that includes 700 iNaturalist observations uploaded since 2012 (a rate of over 60/year). Many species outside of Europe are known only from an original description and a few hundred year-old specimens. In North America, it has been 75 years since the last published work I’m aware of on this genus, so I have decided to work on a modern account of species.

How you can help: Get out and observe flowering plants, especially Asteraceae like goldenrod, this summer and fall. If you see a bizarre, wasp-like beetle that is 3-10 mm in length (1/8 to 1/2 inch), take as many pictures as possible. All angles are helpful, especially side views that clearly show the hind leg and top views that capture color of wings and elytra.

Example of useful angle: truncate (shortened) first segment of her hind tarsus is visible.

If you are able and willing to collect specimens for research, that is also welcome, but not necessary.

Thanks for reading,


I saw my first Ripiphorus last year and was so intrigued when I spotted them - I was like, wait, is that a…beetle?

Very neat creatures and glad that you are looking into them. I’ll keep my eyes out! Are there any conservation concerns with collecting? I know so little and they seemed rare so I didn’t want to collect any when I first saw.


The adults are short-lived, days to weeks, so it’s a tough call on collecting without disrupting mating and ovipositing. Overall, they don’t appear to be in decline.


This is really interesting! Do you have a project for these? And any other tips on finding them? I’d love to help!

Not an iNaturalist project, but you can search all the observations. All I can recommend is be an active observer in areas with lots of flowers and small bees.

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