www.ukbutterflies.co.uk

At about August time of year, one was sometimes seeing annual wild flower meadows raked bare and seed deposited for next years flush of pretty flower heads.
Were there any United Kingdom butterfly species, that had evolved, to primarily complete their life cycles, needing and using native, annual wild flowers, rather than native perennial (came back year after year from same root source) or biennial (flower and seeded biannually after sowing)?
(by needing to complete a life cycle, I was referring mainly to caterpillar (larval) food plants that were needed as a food source, rather than flower head nectar for butterflies.

Hi Phil
I'm not aware of any. Annual wildflowers tend to be transitory and unreliable habitat, without very specific human management.

Before the advent of herbicides, annual wildflowers tended to be the odd flowers mixed in with farmers crops. Before agriculture, they would only grow for a year or so in disturbed ground, for example where animals had disturbed earth or there had been a land slip or fallen tree.

I'm sure there will be the odd insect that can cope with such unreliability, but I'm not aware of any butterflies.
Best Wishes
Paul

A simplified way of looking at it, was that a butterfly species that appeared in the summer as an adult butterfly, needed a leaf that over-wintered to hide or sustain larva.
Specifically looking at how native species evolved with dependant relationships, some annual flora might not have completed their life cycle at all by flowering and seeding, if leaves were stripped bare first, as energy from leaves was put into flowering.
Perennials and biennials had a seasonal time (and evolved time) to develop root systems that withstood grazing by fauna, to leaf back again afterwards from energy stored in the root.

Kind Regards

selbypaul wrote: ↑Mon Aug 31, 2020 8:27 am Hi Phil
I'm not aware of any. Annual wildflowers tend to be transitory and unreliable habitat, without very specific human management.

Charlock or Wild Mustard
was classed as an annual that might have over-wintered as a seedling and was a primary larval food source, for the Green-veined White, species Pieris napi
In a “normal” climate unchanged year, Charlock generally flowered from May to July and seeded from August, but flowering may have began as early as April in plants that germinated the previous autumn.
This might be important information and/or understanding for people wanting to see three annual broods of Pieris napi which over-wintered as a pupa, but generally not on it’s host plant.
Additional reading and my understanding, compiled and composed from here on January 13th 2021:
https://www.gardenorganic.org.uk/weeds/charlock

“and those that go onto overwinter, usually pupate away from the food plant and low down in vegetation, although they will pupate on tree trunks and even fences on occasion.”
Reference:
Page 103, Green-veined White, Life Cycles of British & Irish Butterflies,
by Peter Eeles

If Wild Mustard was see as an arable farm weed, plant with discretion, as where to sow.
Wild Mustard might have been seen as an appropriate yellow flowering, Wild flower annual, where soil was raked bare every year (late summer or Autumn), as part of a management plan, in a broader or and/or longer diverse habitat, that included perennial & biennial wild flowers.

Post Script
I wanted to be careful not to use the word discreet, in a context in place of discretion. If for example, one purchased wild flower seed, a nice idea might have been, to know what species were included and even some advice given as where to plant. Apparently the Wild Mustard seed can stay dormant in unploughed ground for many years. In an urban context a “brownfield site” might not have an arable field for miles of it’s locality and in a rural environment, the plant might have been considered for wide field margins.

That's really interesting Phi, thanks for sharing!