Ceratapion onopordi

This was found in a meadow and keyed straightforwardly using Duff.

Ceratapion onopordi showing close-ups of pronotum and base of elytra, antenna, and rostrum and frons, Wendling Beck Environment Project (Norfolk, UK), 21st July 2023

The next three were found by suction.

Ceratapion onopordi showing close-ups of base of elytra, humerus, antenna, pronotum and frons with base of rostrum, Wendling Beck Environment Project (Norfolk, UK), 25th August 2025

second Ceratapion onopordi, Wendling Beck Environment Project (Norfolk, UK), 25th August 2025

third Ceratapion onopordi, Wendling Beck Environment Project (Norfolk, UK), 25th August 2025

This came to light in 2022 and although it predated the ones above, I examined it afterwards. At first I was unsure if this one was onopordi or not as whilst the frons seemed more-or-less similar to the ones above, and the pronotum was strongly punctured, the gaps between the punctures on the pronotum were noticeably larger, the punctures themselves being slightly smaller. The rostral teeth weren't as angled as shown in Duff for gobbirostre, so if it wasn't onopordi then it would have to be carduorum, but at barely over 2.5mm it was small for that species. The rostral teeth (or bulge) seemed more than shown for onopordi, closer to that of carduorum, and this added to the difference in pronotal punctures was starting to tip the balance more towards carduorum, although I remained unconvinced given the similarity in the frons and only minor difference in pronotal punctures. I then found that in photos of gibborostre the rostral teeth were not as pointed as shown in Duff which, in view of the size, made me wonder if it could even be that.

Now rather confused, I turned to another Ceratapion from 2025 that was also waiting to be identified. This one had a clearly different frons pattern, the ridges being much finer and more parallel. The punctures on the pronotum were far shallower - rather hard to see at all. The differences between 2025 and 2022 individuals was vastly greater than the difference between the 2025 indidvidual and the onopordi shown above, and this reassured me that onopordi must be the correct identification for the 2022 individual. I had hoped to confirm this genitalically, but on dissection it proved to be a female. It was fully-winged (although Duff says that both onopordi and armatum have fully-winged and short-winged forms, it omits to say whether carduorum and gibbirostre have either or both).

Ceratapion onopordi showing base of elytra, pronotum (2 views), frons, frons and rostral tooth (2 views), antenna and fore tibia, North Elmham (Norfolk, UK), 17th August 2022