I first found this caterpillar - or one of its "siblings" - a couple of days ago, and after posting photos to a Facebook forum I had it at least tentatively identified as the larva of a Scarlet Tiger moth. If true, this would be Extremely Exciting, because I've never seen a Scarlet Tiger; though they're a kind of cousin of the Cinnabar moth, which we do have in the village, and whose numbers I tried to swell last summer by allowing a self-seeded ragwort plant to grow in the garden (with this happy result, though whether those caterpillars will successfully pupate into moths remains to be seen).
I posted my photos and the tentative ID to iRecord, and promptly received an automated warning that this was an unlikely record and would need to be checked by someone who knows what they're talking about - which at the time of writing this blog hasn't yet happened. The record was flagged because in the UK this species is most common in the south-west corner of England; but it's not unknown in the SP zone in which we live, as indicated in an interactive map which I accessed from the Scarlet Tiger page of the UK Moths web site, so I'm not especially concerned. One of the things I enjoy about being involved in the citizen science project that is iRecord is that the work of rank amateurs such as myself is scrutinized by experts, and I always take the verification process as an opportunity to learn. I currently have 1426 entries on the site, of which some are still awaiting checking; but of those that have been verified, only one has so far been rejected as incorrect, and several which were initially flagged by the system as outside of the known range or period of that particular species were later verified - which gives me the satisfaction of thinking that in a minuscule way I've contributed to the sum of human knowledge.
Anyhoo - back to this caterpillar. Today I found two of it - and I daresay there are more hidden within the mess that is my front garden flower bed. This is the second individual, and R (despite being squeamish, and slightly repulsed by the image) has chosen this shot because he found it interesting that it shows the prolegs, via which the larva is climbing the stem of the forget-me-not to get to the buds it seems to prefer to eat. Prolegs are not proper legs in the sense that they're not jointed limbs, but are rudimentary structures with multiple hooks at the ends, which a caterpillar uses to cling on to plant surfaces. According to Wikipedia they work via hydraulics, which is an intriguing statement but not one on which the site expands.
I've also posted a shot of the first caterpillar to Facebook, showing it expressing what seemed like displeasure at being interrupted in its work of munching through my flowers, by waving two of its six true legs at me. As soon as I moved the macro back a little, it stopped rearing up and went back to eating: the bud that's slightly to the left of it in that photo was gone within a few seconds.