A Couple of Garden Butterflies

13th August 2012
There's not been much butterfly activity in the garden so far this summer, even for the more common species like the Large White (Pieris brassicae). This, and the Small White (Pieris rapae) are both referred to a "cabbage whites" as they often choose cabbage (and other brassica plants) on which to lay their eggs. They do choose other plants though, including Nasturtiums, and this is what they have chosen in our garden. I had seen lots of the characteristic clusters of yellow eggs on the underside of Nasturtium leaves and over the last few days, there has been considerable additional Large White activity and egg laying.

The Large White has two; sometime three broods a year and the female pictured left, is likely to be from the second brood. Second brood adults develop from first brood eggs laid during May and June. Here she has positioned herself on the edge of a nasturtium leaf and her abdomen can be seen dipping down (or up in this case!) onto the leaf underside. She lays her eggs singly at the rate of about four per minute, forming clusters of typically around 40, but it can be more.

The Large White female can be distinguished from the male by the presence of two black dots and a black dash on the upper fore-wing. These are absent in the male. The Large White can be distinguished from the Small White by size and by the arrangement of the black marking at the apex of the fore-wing. This curves round onto the "base" of the fore-wing in the Large White but is mainly restricted to the "edge" in the Small White.

Here's a close-up view of the eggs (ova) of the Large White butterfly. These are yellow and rather skittle-shaped. Each egg is laid onto the surface of the leaf; directly next to and touching previously-laid eggs. This produces the typically-arranged egg cluster. The eggs usually take 2-3 weeks to develop before hatching into larvae (caterpillars). Larvae moult four times and then leave the food plant to pupate. A pupa (chrysalis) of the early broods will take an additional two weeks or so to develop, before emerging as an adult (imago). The late-brood pupae will over-winter and emerge as adults the following spring.

The Large White is found throughout the British Isles. Additionally, our local population is sometimes supplemented by adults flying across from the continent.

Unlike the Large White, the Gatekeeper (or Hedge Brown) Butterfly (Pyronia tithonus) has just one brood a year, with adults being active late July to mid-September; peaking in early August. Gatekeepers are included in "The Browns" or family Satyridae; many having prominent false "eyes" on the upper or lower surface of the wings.

Gatekeepers are orange and brown and both sexes have three or four small white spots on the underside of the hind-wing. The false "eye" on the for-wing though, in both sexes, typically includes two prominent white spots, and this forms a useful distinguishing feature. The somewhat similar Meadow Brown usually has a single white spot in the "eye" or may have a second much smaller subsidiary spot. Gatekeepers are found throughout the British Isles but are more common in the south.

This Gatekeeper is feeding on Eryngium flowers. These flowers are attracting a large number of bees and hoverflies to the garden too.

[Click on any image for a larger version]

Leave a comment

Your Name
Your Email
Your Comment
No info required here, please press the button below.