BBC Wildlife - UK (2020-04)

Wha

es:

Serg

oHanquet/B

osphoto/A

amy;

wood

ouse

cutout:

Bob

Poo

/Getty;

wood

ouse

portra

t:M

tsuh

ko

Imamor

/M

nden/A

amy

Mosquito: Larry West/FLPA; puya plant: Jean-Claude Malausa/Biosphoto/Alamy; sheep: Edwin Remsberg/Alamy; coot: Bob Pool/Getty

F

emalemosquitoesfamouslytake

vertebratebloodtogetproteinfor

theirdevelopingeggs.Butratherthan

beinghost-specifictohumans,for

example,mosquitobehaviourtends

tobehunting-specific.Thosebitingin

fieldsseeklarge,dark,CO2-exhaling

silhouettesagainstthehorizon.If

therearen’tanyfarmersorhikers

available,theblood-thirstyinsects

willhappilygoafterhorses,cowsor

pigs.Somemosquitospeciessearch

forhollowtrees,wheretheyfindbats;

somefocusonburrows,wherethey

biterabbits,foxesandbadgers.Others

specialiseintargetingbirdsontheir

nests.TheabundantspeciesCulex

pipiens, whichcausesussomuch

bother,infactmostly bites pigeons.

Richard Jones

Domosquitoes

bite us most?

ENTOMOLOGY

ORNITHOLOGY

BOTANY

N

otmany– because

youngbirdsneed

toavoidtheattentionof

predatorsanddon’trequire

fancyfeatherstoattract

mates– butcootsarea rare

example.Thefieryorange-

redplumageadorningthe

headsofcootchicksis the

resultofcarotenoidpigments

laiddownintheeggby

themother.Experiments

ontheAmericancoot

(whichprobablyapplyto

theEurasiancoot,too)have

shown that the first eggs

laidwithina clutchcontain

fewercarotenoidsthan

thelastones,meaningthe

brood’soldestchicksareless

colourfulthantheyoungest.

Bylabellingtheirchicksin

thisway,theparentsareable

todirecttheircaretowards

thosethatmostneedit.The

firstchickstohatchgeta

headstartontheirsiblings,

butbypreferentiallyfeeding

thebrightestones,theadults

canincreasethechancesthat

thewholebroodfledges.

Stuart Blackman

A

pparently,yes.Sheepandbirds

aresaidoccasionallytobecome

entangledonthehookedspinesofPuya

chilensis, a plantfromthedryhillsides

ofChile.Whentheunfortunateanimal

diesanddecomposes,theplantmay

absorbitsnutrients,effectivelyusing

thevictimasa fertiliser.Thevicious

spinesarelikelyalsotoprotecttheplant

itselffrombeingeatenbyherbivores.

P.chilensisbelongstothebromeliads,

a groupoftropicalandsubtropical

plantsthatmainlygrowintheforestsof

CentralandSouthAmerica.Bromeliads

haveformonthecarnivorefront–

three otherspeciestrapinsectsinpools

calledtanks,which

format the base

oftheirleafrosettes.Perhaps,likeour

Puya, theymaybe‘protocarnivorous’

ratherthanstrictlycarnivorous,

meaningtheycankillbutdon’tactually

digesttheproceeds.It’snot yet clear

whetheranyofthese

assassinsproduce

theenzymes

neededto

finishthejob.

Liz Kalaugher

Areanybabybirdsmore

colourful than their parents?

Is it true there’s a plant that kills sheep?

Ruminantsbeware:

don’tgettangled

upwithdeadly

Puya chilensis.

Humansaren’t

alwaysflavour

ofthemonthfor

mosquitoes.

Colourful

characters:

youngcoots

standoutfrom

the crowd.

Q&A

82 BBC Wildlife April 2020