BBC Wildlife - UK (2020-08)

Q&A

This month’s panel

We solve your

wildlife mysteries.

Email your questions to

[email protected]

More amazing facts at

discoverwildlife.com

BENHOARE

Editorialconsultant

ELLENHUSAIN

Wildlifefilmmaker

LAURIEJACKSON

Wildlifetourleader

HELENSCALES

Marinebiologist

GILLIANBURKE

Naturalist& TVpresenter

LAURENPHARR

Ornithologist

EDDREWITT

Naturalist

RICHARD JONES

Entomologist

H

ealthy tropical reefs look
like lush underwater
gardens, covered in rainbow-
hued hard and soft corals,
with psychedelic fish flitting
around. Corals get their
colours from single-celled
algae inside them, which
contain photosynthetic
pigments that harness the
sun’s energy and thus provide
food. What about the fishy
multitudes? Some evolved
colour as camouflage – for
example, the pink pygmy
seahorse hides in coral fans.

Cleaner wrasse use their blue-

and-yellow stripes to advertise

their services to other fish.

Meanwhile, fangtooth

blennies deploy colour for

deception – they mimic the

cleaners, but rather than

nibble parasites off visiting

fish, take bites of skin instead.

But when sea temperatures

rise, this ecosystem’s vibrancy

rapidly drains away. Heat-

stressed corals eject their

algae and lose colour, a

phenomenon called coral

bleaching. Helen Scales

H

overflies may be

renowned for it, but

many other insects do it

too, including bees, wasps,

beetles and other types of fly,

all of which land vertically

on flowers, helicopter-

style. But the best hoverfly

hoverers are those that guard

a 3D territory in mid-air. It

might be a shaft of sunlight

across a woodland path, a

sheltered open space against

a hedgerow, or a small

forest clearing. The resident

hoverfly will hang in the air,

stock still, a few metres

off the ground. Every now

and again, it suddenly

buzzes out sideways to

inspect an intruder or check

out a potential mate.

The front of a male

hoverfly’s head is virtually all

eyes – two huge hemispheres

that touch each other. This

gives the insect all-round

vision to monitor its

hovering position and track

the flight paths of other

insects crossing its precious

air space. Richard Jones

What makes coral reefs

so full of colour? Why do hoveries hover?

MARINE LIFE

ENTOMOLOGY

Coral digital composite: Georgette Douwma/Getty;

hoverfly: Michael Durham/NPL; mandrill: Thomas Marent/Minden/NPL

80 BBC Wildlife August 2020