Hi all,
As previously noted, I found a Comma larva on a hazel shrub at the end of July. Here follows a full account of my observations:
On a cloudy morning on 26 July 2017, I unexpectedly found a Comma
Polygonia c-album larva on Hazel
Corylus avellana in a narrow ride in Millennium Wood, Stevenage.
- Comma 3rd instar larva on hazel 26Jul17
- Habitat - hazel on left and nettles on right 27Jul17
Up until 14 August, I visited the site each day, at around 7 am, and occasionally at other times as well. The larva exhibited some interesting behaviour perhaps not previously witnessed for this species in the UK. The larva was in its third instar when I discovered it but I did not notice any significant leaf damage at the time. Each day, wherever the larva was stationed, nearly always resting under a leaf, and the same one over two or more days, there was always some feeding damage most likely to be by the larva itself.
- Comma 3rd instar larva on hazel 31Jul17
The larva constructed a tent by folding a leaf for protection against the elements as well as predators perhaps like the Red Admiral larvae would do on nettles. There is no evidence, as far as I know, that Comma larvae behave in a similar way on nettles. A moult took place on 31 July or thereabouts then the fourth and final instar larva took a slightly lower position on the Hazel to start feeding again.
- Comma larva in hazel leaf tent 3Aug17
- Comma larva 4th instar 6Aug17
- Hazel leaf damage and tent (bottom left) 8Aug17
- Comma larva under hazel leaf 8Aug17 (pm)
- Comma larva under hazel leaf 10Aug17
On 12 August, the larva prepared itself for pupation about a foot lower than its last feeding platform.
- Comma larva preparing for pupation 12Aug17
Pupation was successfully completed within a day but sadly the pupa expired by 14 August, presumably through predation.
- Comma pupa on hazel 13Aug17
It is not known if the larva in its first two instars fed or the egg was previously laid on the Hazel. There are nettles in close proximity so it is possible that the egg was laid on one of these nettles then soon after hatching the young larva located to the Hazel shrub which was about 2 metres in height. If it had located to the Hazel was it because of lack of nitrogen or other nutrients in the nettle leaves? The nettles looked healthy and were not significantly infested with other larvae of any kind so competition for good quality food is unlikely to be a factor. The larva was probably the progeny of Comma
hutchinsoni adults many of which were on the wing in the last week of June in the area. It is known that offspring larvae from the
hutchinsoni generation develop faster than from other broods and the life cycle is often completed in around 6 weeks which may be correlated with higher temperatures but the possibility that host-plant quality is a factor cannot be discounted. The expansion of the Comma in the last 100 years is thought to be associated with the change in host-plant preferences from hops to nettles and elms, and climate change. Perhaps Hazel can be added to the list. Is Hazel the preferred host-plant choice, in some localities, and unique to
hutchinsoni females?
Interestingly, on 19 August I found another Comma pupa on the same Hazel shrub higher up, at eye-level. This raises the possibility that this Is a sibling of the Comma pupa which had just expired and therefore eggs being laid by a single female but there is no known evidence that this plant has ever been used for egg-laying in the wild.
- Second Comma pupa on same hazel shrub 20Aug17
ATB
Peter
