Any Plant Biologists out there?

Why are the flowers of so many spring pllants yellow?

IIRC it's to do with bees (bumblebees?) being the first on the wing and they can't see red but can see UV light. Or something. Probably.

Sex. Plants evolved to attract insects with colour and nectar. Insects, especially bees, get covered in sticky pollen whilst collecting nectar and transfer it to other plants, improving the gene pool. Over the same time bees evolved to detect flower colours, which helps them find the nectar.

Dave

White vies fairly well with the yellow.. snowdrops and then blackthorn lighting up the hedgerows around here with the damsons. Pears and crab apples just behind. They compete with the daffs and primroses and then gorse and aconites but the wood anemones are out too.
I'd guess white flowers light up in UV. Moths?
The wild garlic will cover white swathes around here soon and the first bluebells and violets are bringing alternative colour.

pgk

There are a few theories, see here and here.

Thor

Is it a natural thing or actually a human thing, most of the yellow flowers we see are daffs planted by people rather than primulas and cow slips that tend to be more natural plantings

There are more bluebells and fritillaries out in my garden at the moment than the small amount of primula & cowslip

I've got a saphora (Sun King) in my garden that is covered in yellow flowers for about 6 weeks from mid march onwards. It attracts lots of bumble bees every year. Later on in summer the very much not yellow hardy fuchsias (Lady's Eardrops?) attract honey bees.

Martin C

Everything in nature is probability and has already been done over millions of years

If we assume most colours have already been tried then yellow attracted the most diverse array of insects and was the most successful reproductive colour

The shoebill has 2 hatchlings and always starves one to death.

Shoebills who try to bring up 2 hatchlings have been out-competed and remain extinct so far

UV rays I think because I have noticed over the years that flies are attracted to white surfaces, couldn't understand why we got a lot of flies setting on our white cladding when we moved into our current house, also on a white car and caravan we had, bit of googling came up with the UV theory.

Bill D.

And the first butterfly is also yellow (Brimstone), in the UK

Bee see in UV, flowers look different to them

The visual colour receptor ranges vary between species. Iirc there is a night flowering cactus that gets illuminated by moonlight and can attract moths from as much as a mile away. Not that there is much competition in the desert...