traveling treasures 2016 – the power of poison

5
Traveling Treasures 2016 – The Power of Poison Snake and Butterfly case Timber rattlesnake (Crotalus horridus) Light morph Like other snakes in the family Viperidae, timber rattlers are pit vipers. This means they have heat sensitive pit organs located between the nostrils and the eyes. They are sensitive to radiant energy and can distinguish very slight changes in temperature. Their main food source is small mammals but also eat birds. The prey is killed when bitten because the snake injects venom. They then swallow the prey whole. Range and Habitat: Timber and canebrake rattlesnakes have a wide distribution in the eastern United States but the species is absent from most of Florida. This snake occurs in a wide variety of terrestrial habitat including lowland cane thickets, high

Upload: others

Post on 01-Dec-2021

1 views

Category:

Documents


0 download

TRANSCRIPT

TravelingTreasures2016–ThePowerofPoisonSnakeandButterflycaseTimberrattlesnake(Crotalushorridus)

Lightmorph

LikeothersnakesinthefamilyViperidae,timberrattlersarepitvipers.Thismeanstheyhaveheatsensitivepitorganslocatedbetweenthenostrilsandtheeyes.Theyaresensitivetoradiantenergyandcandistinguishveryslightchangesintemperature.Theirmainfoodsourceissmallmammalsbutalsoeatbirds.Thepreyiskilledwhenbittenbecausethesnakeinjectsvenom.Theythenswallowthepreywhole.

RangeandHabitat:TimberandcanebrakerattlesnakeshaveawidedistributionintheeasternUnitedStatesbutthespeciesisabsentfrommostofFlorida.Thissnakeoccursinawidevarietyofterrestrialhabitatincludinglowlandcanethickets,high

areasaroundswampsandriverfloodplains,hardwoodandpineforests,mountainousareas,andruralhabitatsinfarmingareas.Theytypicallybecomereducedinnumbersinhighlyurbanizedorareasofhousingdevelopment.

TheOrianneSocietyTimberRattlesnakeFactSheethttp://www.oriannesociety.org/sites/default/files/fact-sheets/Timber%20Rattlesnake%20Fact%20Sheet.pdfFirsthandaccountofaTimberRattlesnakebite:http://www.venomousreptiles.org/articles/345?venomsid=f065e3fa57ac4a0dabcdb000f3c3b09cBandedkrait(Bungarusfasciatus)

Habitat:Livesinandaroundwetlands,openforests,agriculturallandshavinglow

vegetationandopenwaterbodiesetc.Strictlypreferswetsurroundingforits

activities.Usuallyfoundinplainsoflowtomoderateelevationsbutinmanypartsof

itsrangeitsfoundinelevationupto5000ft.

Snakevenomscontainamultitudeofbiologicallyactivetoxinsthatworktogetherforthecaptureofprey(takealookattheTablelistingthevarietyoftoxinsfoundinthevenomofthemany-bandedkrait).Theireffectsincludepro-andanti-bloodcoagulation,neurotoxicity,mycotoxicity,nephrotoxicity,cardiotoxicityandnecrotoxicity(localtissuedamage).Amongstthese,theneurotoxinsplayakeyroleinimmobilisingpreythroughparalysis,disorientationanddepressedrespiration.

Venomsoftencontaindifferentneurotoxinsthatworksynergisticallytocripplethenervoussystem.Neurotoxinscanbeclassifiedaccordingtotheirsiteofaction:pre-synapticneurotoxinsblockneurotransmissionbyaffectingacetylcholinetransmitterrelease;post-synapticneurotoxinsareantagonistsoftheacetylcholinereceptor.Togethertheseneurotoxinseffectivelyblockskeletalneuromusculartransmissionbycripplingreceptors,whileatthesametimeactingtodestroyanyneurotransmitterthatmightcompetewiththetoxinforreceptorbinding.Venomsoftencontainseveralpost-synapticneurotoxins,eachwithahighaffinityforanicotinicreceptorsubtype-inthiswaythevenomcancrippleasmanyreceptorsaspossible.Thepost-synapticneurotoxinsarefoundonlyinelapidsandseasnakes(Hydrophiidae).Inthemany-bandedkraitpicturedabove,apre-synaptictoxinisb-bungarotoxin,whilepost-synaptictoxinsarea-andk-bungarotoxins.

CentralAmericancoralsnake(Micrurusnigrocintus)

It ranges from southern Mexico through Central America (except Belize) to northwestern Colombia, and the westCaribbean. It is mainly found in lowland rain forest, lowland dry forest, thorn forest, lower montane wet (or moist) forest, and lower montane dry forest, usually at elevations up to 1,300m.[1] The Central American coral snake's venom contains a strong neurotoxin, causing neuromuscular dysfunction.[1]Coralsnakesaresmall,vibrantlycolored,highlyvenomoussnakes.Theyhavethesecond-strongestvenomofanysnake(theblackmambahasthemostdeadlyvenom),buttheyaregenerallyconsideredlessdangerousthanrattlesnakesbecausecoralsnakeshavealesseffectivepoison-deliverysystem.

Hasmainlypotentneurotoxicvenomwhichcanbeinjectedthroughapairofgrooved,upper,fixedfrontfangs.Duetothesmallsizeoftheirmouths,coralsnakebitestohumansusuallyoccuronafingerortoe,andusuallyduringattemptstocatchthesnake.Thisspeciesisabundantthroughoutmostofitsrange,andisthemaincauseofcoralsnakebitesofhumanswithinitsrange.Monarchbutterfly(Danausplexippus)Butterflyidentificationchart:

MonarchbutterfliesareknownfortheincrediblemassmigrationthatbringsmillionsofthemtoCaliforniaandMexicoeachwinter.NorthAmericanmonarchsaretheonlybutterfliesthatmakesuchamassivejourney—upto3,000miles(4,828kilometers).Theinsectsmustbeginthisjourneyeachfallaheadofcoldweather,whichwillkillthemiftheytarrytoolong.Fatteninglarvaebecomejuicy,colorfulcaterpillars,thencreateahardprotectivecasearoundthemselvesastheyenterthepupastage.Theyemergeasbeautifully

colored,black-orange-and-whiteadults.Thecolorfulpatternmakesmonarchseasytoidentify—andthat'stheidea.Thedistinctivepatternwarnspredatorsthattheinsectsarefoultastingandpoisonous.

Butterfliesthatemergefromchrysalides(pupastate)inlatesummerandearlyfallaredifferentfromthosethatdosoduringthelongerdaysandwarmerweatherofsummer.Thesemonarchsareborntofly,andknowbecauseofthechangingweatherthattheymustpreparefortheirlengthyjourney.

Onlymonarchsborninlatesummerorearlyfallmakethemigration,andtheymakeonlyoneroundtrip.Bythetimenextyear'swintermigrationbegins,severalsummergenerationswillhavelivedanddiedanditwillbelastyear'smigrators'greatgrandchildrenthatmakethetrip.Yetsomehowthesenewgenerationsknowtheway,andfollowthesameroutestheirancestorstook—sometimesevenreturningtothesametree.

It’sthedependencythatMonarchshaveonMilkweedsastheonlyfoodsourcefortheircaterpillarsthatmakesthisrelationshipsonoteworthy.Monarchs,likemanyspeciesofinsects,haveevolvedtospecializeintheirlarval(inthiscasecaterpillar)foodsourceinordertogainprotectionfrompredatorsthroughthechemicalstheyingestfromtheplantstheyeat.Milkweedscontaincardiacglycosides,whicharetoxictomanyspeciesofbirdsandmammals.Plantshaveevolvedthesechemicalstoprotectthemselvesfrombeingeaten,astrategythathaslargelybeensuccessfulfortheplants.Plantsareallaboutsurvivingandreproducing,tofurtherthecontinuedexistenceoftheirspecies.

Suchaplanforprotectionisnevercompletelyfoolproof,however.Monarchs,alongwithsomeotherinsectspecies,haveevolvedtobeabletodigesttheseplantsandsequesterthetoxinsintheirbodies,makingtheinsectunpalatableatbestandtoxicatworsttoanyoneinexperiencedenoughtoattempttoeatthem.Asaremindertobirdormammalpredatorswhosamplesuchaninsectandsurvivetoeatanothermeal,insectswiththesetoxinshavealsoevolvedtohavebrightwarningcolors,aneasytoremembersignaltopredatorstobewarebeforeattemptingsuchamealagain.InexchangeforthisprotectionobtainedfromeatingMilkweeds,Monarchsaregamblingthatthisfoodsourcewillcontinuetobeavailable.Withoutit,Monarchswon’tsurvive.