MindanaoMimics

There’saspeciesofjewelweevilcalledPachyrhynchusreicherti.Itsblackandspottedbodyhasauniquepattern.Itselytraarefusedtogether.Itcannotfly.It’stootoughtobitethrough.Anditsstrongcolorsandmarkingstellpredatorstostay away.


WhenCabrasfirstspottedanewspecies,Metapocyrtuswillietorresi,shemistookitforPachyrhynchusreicherti.Ithassimilarcolorsandmarkings.Ithastough,fusedelytra.Neitherbeetlewouldmakeagoodmeal.So,whywasonecopyingthe other?


ThephenomenoniscalledMüllerianmimicry.That’swhentwoequallyharmfulthingshaveevolvedtoresembleeachother.Whenbeetleshavesimilarcolorsandpatterns,predatorslearnthattheyrepresentdangerous,foul-tasting,orevenpoisonousbeetles.Andpredatorsstay away.


Itdoesn’tendthere.Athirdbeetle,Doliopsdaugavpilsi,looksalotliketheothertwo.It’salonghornbeetle.Ithasasoft shell—onethatpredatorscouldeasilybite through.

Pachyrhynchus reicherti

Metapocyrtus willietorresi

Byhavingcolorsandpatternssimilartotheweevils,thelonghornstayssafe.ThisisBatesianmimicry.Anedibleinsectwithfewdefenseskeepspredatorsawaybylooking dangerous.

HereareafewexamplesofthebeetlesCabrassawduringherfieldworkonMindanao.Themimicsstronglyresembletheir models.

MODEL

Model: Metapocyrtus kitangladensis

MIMIC

Mimic: Coptorhynchussp.

MODEL

Model: Pachyrhynchus tikoi

MIMIC

Mimic: Metapocyrtussp.

Totestahypothesis,Cabrasusedfakebeetlesmadeofmodelingclay,liketheoneshownhere.Shewantedtoseeifpredatorswouldreacttothebeetle’swarning colors.

Testing aTheory

Cabraswonderedifshewastheonlyonebeingfooledbytheselook-alikes.Shetriedanexperiment.Sheandherteammadefakebeetlesfrommodelingclay.TheylookedlikePachyrhynchusreicherti.Shesetthemoutinplaceswherethesebeetleswerecommonandinplaceswheretheywerenot.Thenshesetupcamerastoseewhatwould happen.

Wherethebeetleswerecommon,predatorsavoidedtheclaybeetles.Theyhadlearnedwhatthosecolorsandpatternsmean.Intheplaceswherethebeetleswerelesscommon,morepredatorstriedtoattack.Theyhadnotyetlearnedtostay away.

acamera trap

InMindanao,therecouldbemanynewspeciesto discover.

Cabrasstillhasmanyquestionsshewantsanswersto.ButalotoflandonMindanaoisbeingclearedawayforfarmingandhouses.Infiveto10years,shemightnotbeabletofindthesebeetlesintheirnatural habitat.


Withtheclockticking,Cabrasisdoingherbesttodiscover,observe,andrecordthebiodiversitythatsheseesinMindanao.Fornow,hereyesaretrainedon weevils.