History

It was well known in Yorkshire untill 1816  when it crashed but recovered strongly with  a warming cliamte in 1830's  up till the 1870 while spreading well up into Scotland  during this time. The UK population then crashed  after Krakatoe and the following cold period 1879-1895 except  for parts of Glos and Hereford where it remained common in the hopyards. It returned to Yorkshire in the warm period of the 1930 and 40's. but in  50's and 60's it declined once again as it became cooler to become almost absent apart from early Autumn wanderers until about 1982 when the current expansion recommenced and continues at an ever increasing rate and in 2023  greatly outnumbered Small Tortoiseshell and even Peacock in the Vale of York to reach and all time high .  The contrast with Small Tortoiseshell is stark who is  increasingly confined to cooler areas during the current  run of hot summers. 

The Comma spends most of its life pretending to be something else, larvae have a chalky stripe  half way down its back which makes it look uncanningly like the lime of a birds dropping while the adults underwings are practically indistinguishable from a dead leaf ; a master of mimicry.  Topside it is very similar in looks to a Small Tortoiseshell, but with scalloped wings and a more even orange brown coloration lacking blue spots.  It can also be confused with Wall Brown and some Fritillaries.  The Comma’s undersides vary from dark brown to near black, with a marbling of ochre and bronze green, and the usually distinctive white C mark on the hindwing.  When seen, wings closed, on a dried bracken leaf everything makes sense as the mimicry with the scalloped edges and subtle marbling and colouration is perfection. Its no surprise that it is often seen in number where bracken abounds  in woodlands clearings. The pupa has a set of silver mirrors  likely to confuse potential predator by reflecting the movement of its approach.

Males and females are very similar, but females tend to be larger with less ragged edges and a more even dark coloration on the underside.  Up to 40% of the first brood have brighter, more golden orange upperparts and much paler underparts with less strongly scalloped wings.  These are known as the hutchinsonii form, after Emma Hutchinson (b 1820/d 1906) who was first to breed them and discover that only this colour form produced the second brood.

The Comma has a flexible life cycle, which allows it to capitalize on favourable weather conditions. The butterfly can be seen at any time of the year, occasionally awakening on warm winter days. The butterfly emerges from hibernation in March, giving rise to the next generation which appears at the end of June and start of July.

Females lay 10 to 25 eggs on each suitable day, which hatch after 2 to 3 weeks, becoming intrically marked, brown larvae with a white splodge helping to disguise them as bird droppings.  The 1st brood larval period lasts around 4 to 7 weeks depending on which colour form is involved.  Pupae resemble withered leaves and hang from a pad of silk under a leaf or branch of the foodplant with a number of silver mirrors.

First brood adults come in two forms – the normal dull brown form with dark undersides go on to hibernate (the darker colouration offering better camouflage during winter).  The hutchinsonii form, which have lighter undersides and brighter uppersides as they have no need as they will not hibernate, go on to produce a second brood in late summer.  

The proportion of the two forms seems to be determined by daylight length during the larval stage (although Emmet & Heath (1989) suggest succulence of foodplant also plays a part). Poor food quality is important to all Teh vanessids teh more succulent the higher the fecundity while poor dry food wil inhibit  sexual maturity triggering hibernation almost immediatly.   First brood larvae, which develop before the solstice, are likely to be hutchinsonii.  Those developing as day length shortens will grow more slowly and emerge later as the normal darker form whose prime purpose is to hibernate successfully in readiness for mating the following spring.

Although major variation is rare, over 30 aberrations have been described.  Ground colour can vary considerably from almost white (ab albus Frohawk) or pale straw yellow (ab dilutus Frohawk), to examples where the dark markings join together (ab suffusa Tutt), or the hindwing is almost black (ab reichenstettenis Fettig).  The amount of ochre and metallic green on the underside may vary as can the ‘comma’ mark in size or shape.  More rarely it may even be missing (ab extincta Rebel).