Some Moths during January and February

 The overnight temperatures during January and February have been generally mild for the time of year, with only three consecutive sub-zero nights in early January. By the middle of the month, a particularly mild few nights, with a pause in the incessant rain, encouraged me to get the moth-trap out. Towards the end of February, more mild and dry nights were suitable for the moth-trap.

Quite a few of the Geometridae species that breed during the winter months, or early in the season, have females that are flightless. This is more than just a coincidence but I can only conjecture the reason why. With predation reduced to a minimum (for example, bats and dormice are hibernating) and with very little competition for egg laying sites, negating the need for females to wander, then it possibly makes sense for females to become flightless in order to produce more eggs. They probably pupate on or near the foodplant and when they emerge, there is little risk in waiting nearby to be found by a male, mated and crawling off into the foliage to lay their eggs.

The first four species that follow, all have flightless females.

Pale Brindled Beauty (Phigalia pilosaria) (male)

Dotted Border (Agriopis marginaria) (male)

Spring Usher (Agriopis leucophaearia) (3 males)

This species is very variable in its ground colour but its markings are usually constant and visible.

March Moth (Alsophila aescularia) (male)

Grey Shoulder-knot (Lithophane ornitopus lactipennis)

This individual was tempted out of hibernation in mid-January.

Totricodes alternella

On 4th January, after a very cold night, I went out into the garden with a hot kettle in order to melt the ice in the bird bath. After I started pouring, I noticed this icicle (measuring about 12 cms.) which had grown vertically upwards from the edge of the ice. I stopped pouring and dashed off to get my camera before the icicle melted through at its base. I assume it was caused by the expanding surface ice forcing water up at the edge of the bath! I have seen horizontal icicles before (on top of Scafell Pike in winter) but I think this one is a first for me.

Large White Larvae during Winter

 The Large White (Pieris brassicae) is mainly a double brooded butterfly in Britain but in good years, it can produce a third brood, with larvae found late in the season. The latest example that I had previously found was on 12th November 2008, when I came across a colony of 5th instar larvae on Rye Levels.

On 19th December 2025 (as reported in an earlier post) I happened upon a colony of 4th and 5th instar brassicae larvae, numbering about 40 caterpillars, feeding on Rape (Brassica napus) on Pevensey Levels. I decided to observe their progress over the following weeks.

With a warming climate in south-east England, our winters are generally damp and mild and freezing overnight temperatures are less frequent than they used to be. During early January, I noted just three consecutive nights with sub-zero temperatures (down to minus 2 degrees) but this had little effect on the larvae, with only two dead caterpillars found limp in the foliage.

During my vigil, there was no evidence of parasitic attack and by 2nd February 2026 (my last visit) there were only eight fully mature larvae still feeding. I am confident that the vast majority of the larvae completed their development unmolested by predators and had wandered off to pupate.

The main predator of P. brassicae is the parasitic wasp Cotesia glomerata, the adults of which inject their eggs into the larval host. The development of the parasitic larvae within the living caterpillar is rapid and their emergence from the dying host is made obvious by the presence of their yellow cocoons around the dead caterpillar.

The life cycle of Cotesia glomerata is currently synchronised with the spring and summer broods of Pieris brassicae. Unless glomerata is able to extend its season by taking advantage of our warming climate, then it appears that any third brood larvae of P. brassicae have every chance of avoiding such parasitic attack. 

Larval skin-shedding stem (1st January 2026)

The following images are all of mature 5th instar larvae showing evidence of feeding.

(14th January)

(18th January)

(28th January)

Pierids in Sussex

 The white and yellow butterflies in Britain all belong to the Pieridae family. 

Of those species that occur in Sussex, most are common and widespread and found in a range of habitats.

 However, one is a rare resident, only to be found in a few small colonies in the north-west of the county.

Wood White (Leptidea sinapis)

This species is our rarest Pierid in the county and only occurs in a few areas in north-west Sussex.

(males)

(females)

(courtship)

Clouded Yellow (Colias croceus)

This species is a migrant to Britain, occurring annually in varying numbers. Some years it can arrive in huge numbers and produce summer and autumn broods. In other years it can be a rare sight.

(female)

(female, form helice)

This pale form accounts for about 10% of the female population.

(male)

(mating)

Brimstone (Gonepteryx rhamni)

The Brimstone hibernates as an adult butterfly and is one of our first species to be seen on the wing during late winter and early spring sunshine.

(males)

(female)

(mating)

Large White (Pieris brassicae)

This is a common and widespread species. Together with the next species, it can cause serious damage to garden cabbage crops.

(females)

(male)

(mating)

Small White (Pieris rapae)

This common and widespread butterfly is also a cabbage crop pest.

(females)

(male)

(mating)

Green-veined White (Pieris napi)

This cousin of the previous two species is certainly not a garden pest. It is more akin to the next species in its choice of habitat, preferring to wander along field margins, verges and woodland edges, looking for foodplants such as garlic mustard and lady's smock.

(males)

(females)

(mating)

Orange-tip (Anthocharis cardamines)

This pretty little butterfly is a true harbinger of spring, emerging from its overwintering pupa from late March to late May.

(males)

(females)

(mating)