Speckled Wood (Early Stages)
Posted: Mon Sep 29, 2014 11:38 am
This butterfly is seen in a variety of habitats, including gardens, but is at its best in dappled woodland clearings where males are often seen endlessly sparring for territory. The fact that this is the only species in the British Isles which can overwinter as both a larva or pupa, results in a series of overlapping generations throughout the following season. As such, adults can be seen anytime from early March through to early November. My latest personal sighting was on 25th November 2021 in Crawley, Sussex and my earliest on 24th February 2019 at Ferring Rife on the Sussex coast.
There are a number of sub-species, but this report relates to ssp.tircis in its southerly range.
The primary larval food plants are grasses like Cock’s-foot (Dactylis glomerata), Common Couch (Elytrigia repens), False Broome (Brachypodium sylvaticum) and Yorkshire-fog (Holcus lanatus).
THE EGG AND LARVA
It was commonly thought that eggs were laid singly, but from personal observations, they are also sometimes laid in pairs on plants that vary in location from deep shade to more open positions. In Crawley, Sussex on 24th April 2009, I watched as a female oviposited on the underside of a blade of grass. She visited three different clumps, which were in full sun, and on each occasion laid a pair of eggs rather than the usual singleton. I observed another pair of eggs being laid in a shady location in Woldingham, Surrey on 13th June 2010 and again at Gatwick, Sussex on 30th April 2019.
On 25th May 2014 I rescued an egg laid in a semi-open location on a grass verge. Two further eggs laid in a shady position under a tree were rescued from the council strimmer on 13th June 2014. Then, on 23rd July 2014 a female laid an egg in my Crawley garden on a plant which was in permanent deep shade.
Typically, an egg will hatch after 7-10 days, after developing a dark spot at its apex. This is the head of the developing larva which becomes visible through the transparent eggshell.
Of the four larva reared, one consumed the empty eggshell upon emerging and one did not. The behaviour of the other two was not recorded.
First Instar
The freshly emerged larva is approximately 2.5mm long, with a black head and a very pale body, but it develops a pale green colour after its first meal on the host plant. The first instar can pass in as little as 4 days, but it usually takes around 10. The following sequence shows the development of an individual larva (except where dates indicate otherwise).
Second Instar
This stage can also pass in just 4 days, but on average it is around 6. Here it develops a green head, pale stripes on its body and the characteristic forked tail.
Third Instar
This stage averages around 7 days.
After each moult of their development it was noted that the fresh larvae invariably turned round as if to eat the old larval skin, but it was always left untouched.
Fourth Instar
It takes approximately a further 8 days for the larva to become fully grown, at which point it achieves a length of around 25mm. As it nears maturation, the pale stripes fade from the body and it takes on an overall pale green colouration. It then suspends itself in preparation for pupation.
Part two to follow
There are a number of sub-species, but this report relates to ssp.tircis in its southerly range.
The primary larval food plants are grasses like Cock’s-foot (Dactylis glomerata), Common Couch (Elytrigia repens), False Broome (Brachypodium sylvaticum) and Yorkshire-fog (Holcus lanatus).
THE EGG AND LARVA
It was commonly thought that eggs were laid singly, but from personal observations, they are also sometimes laid in pairs on plants that vary in location from deep shade to more open positions. In Crawley, Sussex on 24th April 2009, I watched as a female oviposited on the underside of a blade of grass. She visited three different clumps, which were in full sun, and on each occasion laid a pair of eggs rather than the usual singleton. I observed another pair of eggs being laid in a shady location in Woldingham, Surrey on 13th June 2010 and again at Gatwick, Sussex on 30th April 2019.
On 25th May 2014 I rescued an egg laid in a semi-open location on a grass verge. Two further eggs laid in a shady position under a tree were rescued from the council strimmer on 13th June 2014. Then, on 23rd July 2014 a female laid an egg in my Crawley garden on a plant which was in permanent deep shade.
Typically, an egg will hatch after 7-10 days, after developing a dark spot at its apex. This is the head of the developing larva which becomes visible through the transparent eggshell.
Of the four larva reared, one consumed the empty eggshell upon emerging and one did not. The behaviour of the other two was not recorded.
First Instar
The freshly emerged larva is approximately 2.5mm long, with a black head and a very pale body, but it develops a pale green colour after its first meal on the host plant. The first instar can pass in as little as 4 days, but it usually takes around 10. The following sequence shows the development of an individual larva (except where dates indicate otherwise).
Second Instar
This stage can also pass in just 4 days, but on average it is around 6. Here it develops a green head, pale stripes on its body and the characteristic forked tail.
Third Instar
This stage averages around 7 days.
After each moult of their development it was noted that the fresh larvae invariably turned round as if to eat the old larval skin, but it was always left untouched.
Fourth Instar
It takes approximately a further 8 days for the larva to become fully grown, at which point it achieves a length of around 25mm. As it nears maturation, the pale stripes fade from the body and it takes on an overall pale green colouration. It then suspends itself in preparation for pupation.
Part two to follow