Life Cycle of the Orange-tip

 A true harbinger of Spring, the Orange-tip (Anthocharis cardamines) breeds in my garden (on garlic mustard) most years and 2020 afforded me the time to monitor its life cycle almost on a daily basis during May and June.

This species overwinters as a pupa and the adults are usually on the wing from early-April until late-June. In good years, they can emerge as early as mid-March and a small partial second brood can sometimes occur in August or September.

The usual foodplants are Garlic Mustard and Lady's Smock and the female will lay her eggs on the stems just below the flower heads. The young larva will then feed mainly on the fresh seed pods when it hatches, having first eaten its egg-shell.

The developing larvae will go through five instars (stages between skin shedding) before it pupates. It will remain a pupa for about ten months until the adult butterfly emerges the following Spring. 

Of the following images, those of the developing larvae were taken during 2020. I have delved into my photo library for the other images.

Orange-tip (Anthocharis cardamines)

Male

Female

Mating pair.

Female ovipositing on garlic mustard.

The freshly laid ovum is white.

After a day or so the ovum turns orange.

A day old larva eating its egg-shell.

1st. instar larva.

2nd. instar larva.

3rd. instar larva.

4th. instar larva.

5th. instar larva. 

The following images of a final instar larva preparing to pupate, were taken on three consecutive days and show the very subtle changes occuring. Sadly, this larva perished before it could make the final change to a pupa.

 

The following images are of pupae photographed in 2008.

Pupa (brown form)

Pupa (green form)

Larval Development and Parasitism in the Large White Butterfly

 Back in early spring, just as we were entering lockdown, the weather was gloriously warm and sunny. Like many other amateur entomologists, I spent a lot of time in the garden watching the comings and goings of butterflies and other insects. 

Garlic Mustard is a wild plant that is regularly used as a foodplant by several species of Pieridae butterflies and in late April, I watched a female Large White (Pieris brassicae) ovipositing on the underside of a garlic mustard leaf. This would provide a good opportunity to monitor larval development, hopefully through to pupation and the emergence of a summer brood of Large Whites. 

The parasitic wasp Cotesia glomeratus specialises in laying its eggs in the larvae of the Large White (P. brassicae) and can sometimes kill large numbers of caterpillars but the predator-prey cycle always ensures that, over time, numbers of predator and prey species are kept in balance.

Large White (Pieris brassicae) 

(female ovipositing on garlic mustard)

(egg batch on garlic mustard)

(egg batch showing developing larvae, one day before hatching)

(1st. instar larvae, one day after hatching )

(2nd. instar larvae, with 3rd. or 4th. instar larva wandering along leaf edge)

The following sequence of images show a 5th. instar larva being pestered by attendant Cotesia wasps. The larva is clearly aware of its peril and constantly made attempts to keep them away.

The following image is of a 5th. instar larva with a Cotesia wasp on its back, injecting its eggs.

This final image shows a 4th. or 5th. instar larva surrounded by the pupal cocoons of the Cotesia larvae that have emerged from its body. You can also see a Cotesia larva in the process of emerging from the 5th. segment of the caterpillars body.

This small colony of Large White larvae was overwhelmed by the onslaught wrought by the parasitoids and I am pretty certain that none survived to pupation.

Some Moths during November

 I have probably put the moth-trap out for the last time this season. The catches were low during November and now that December has arrived and night-time temperatures have dropped, it is time to put the trap away until early spring.

Here are a few images of species seen during November.

December Moth (Poecilocampa populi) (female)

November Moth (Epirrita dilutata)

Northern Winter Moth (Operophtera fagata) (male)

Feathered Thorn (Colotois pennaria) (male)