BIOLOGY EXPERIMENTS CHILDREN

(Jacob Rumans) #1

youngGreekpeasantgirl namedArachnehadtheaudacityto challengethe
goddessAthenato aweavingcontest. YoungArachnewasmostskillful, and
in a fitofjealousrage, Athenachangedthe girl into a spider!
Thefemale lays her eggsandwrapsthemup in acocoonofsilkthread
which she herselfspins. She uses the same threadas for herweb. Thisis
howit is produced: Agland in the spider'sabdomenproduces a silk fluid.
When this fluid isforced out ofthe spider'sbody, it hardensinto athin,
delicatebutstrongthreadofsilk assoonas it comesintocontactwiththe air.
Eachkindofspiderspins a webthatis characteristicofits species. Some
webs areextremely elaboratewith perfectarchitecturalsymmetryandform.


Manyfinethreadsseem to radiatefrom a centralpoint. Otherwebs are so
simplethatthey consistofonly three orfoursupportingthreads. A lovely
sight is adew-coveredwebsparklingin themorningsunlight.
Anunusualtypeofweb is a"nest"builtin the softearthby thetrap-door
spider. Itis a sac-like nest with ahingedlidthatcan only beopenedby the
spiderwho builtit. Thenest is so successfullycamouflagedthatwhen the
trapdooris closed, it blendsintothesurroundingground. Theownerlurks
behindthe door. Whenan unsuspectinginsectcrawls nearit, thetrapdoor
isquicklyopened and thensnappedshut behindthe insect. Ofcourse, he
becomesthespider'smeal.
Thespider'sweb servesmanypurposes. Itis thehomeoftheadultsand
thebirthplaceoftheyoung. Itserves as asnarefor thenaturalenemies which
thespiderkillsanduses for food. Ahungryspiderwillstandquietlyatone
endofhis web,waitingfor a fly ormosquitoto become trappedin itsthreads.
While the insectstrugglesto free itself, thespiderstings his victim,paralyzing
him, beforesuckingouttheinsect'slife-fluids.
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