BBC Wildlife - UK (2020-05)

BENHOARE

Editorialconsultant

STUART BLACKMAN

Sciencewriter

A L E XM O R S S

Botanist

Q&A

ED DREWITT

Naturalist

E L L E NH U S A I N

Filmmaker

This month’s panel

We solve your

wildlife mysteries.

Email your questions to

[email protected]

More amazing facts at

discoverwildlife.com

HELENPILCHER

Sciencewriter

Red jungle fowl: Sta

an Widstrand/Wild Wonders of China/NPL; primroses:

Natural Visions/Alamy; Darwin: traveler1116/Getty; snake: cowyeow/Flickr

C

harles Darwin travelled the world,

but also spent countless hours

observing nature in Britain (see p12).

One common wildflower in his garden

and local woods long perplexed him.

Why did primroses appear in two

quite different forms? So-called ‘pin’

types had a long style (the stalk-

like female part of the flower)

but short, hidden stamens (the

pollen-bearing male part of the

flower). ‘Thrum’ versions

had a short, hidden style,

but long, prominent

stamens. Darwin spent years

painstakingly collecting, marking

and experimenting with pollen and

seeds from hundreds of primroses,

and found that the two forms had

different pollen. They could not self-

pollinate, thus helping to achieve

cross-pollination. Darwin described

this as “One of the most

surprising facts I have ever

observed,” adding that “No

little discovery of mine

ever gave me so much

pleasure.” Alex Morss

M

any people call a snake

‘poisonous’ when they mean

‘venomous’. The latter involves

injecting prey with a toxin

(venom), whereas the

former is secreting a

defensive toxin (poison)

that an attacker would

prefer not to touch. Just

two groups of snakes

are known to be

poisonous. North

American garter

snakes appear to

acquire toxins when

they eat newts, at

least temporarily.

Asia’s keelback snakes also obtain

toxins from prey, this time toads,

but retain the noxious chemicals

in special glands in their neck.

This has been known for a while,

but recently scientists discovered a

twist in the tale. One species, the

groove-necked keelback of China

and Vietnam, feeds on earthworms

instead of toads, yet still boasts the

unpleasant deterrent. Earthworms

don’t possess toxins, so where is this

snake getting them? The researchers

found it supplements its wormy diet

with firefly larvae, which, like toads,

manufacture the deadly substances

it needs. Ben Hoare

Which ower had Darwin

scratching his head?

Are any snakes poisonous?

BOTANY

REPTILES

Primroses were

once a puzzle for

Charles Darwin,

but one that he

managed to solve.

The groove-necked
keelback becomes
poisonous due to its
diet of firefly larvae.