Behavior & BiologyCoconut Rhinoceros Beetle

Adult Feeding Sites• Adultsfeedonlivingpalmtreesfortheirsweetsapintheheart.

• Leaves are damaged as a result of adultsburrowing past new emerging leaves in thecrown.

Adult Breeding Sites• Afterfeeding,adultswillseeksitestobreed.• Females lay their eggs in dead standingcoconut trees, and other decaying organicmatter.

• Grubs will spend their whole life-cycle inorganicmatter.

• Alllifestagescanbefoundinthesebreedingsites.

Facts to Remember• Alllifestagescanbefoundinbreedingsites.• Grubsarebeneficialinbreakingdownorganicmatterforcompost.

• AdultbeetlesaretheONLYonesthatfeedandcausedamagetopalmtrees.

• GrubsDO NOTfeedonlivepalmtrees.• Someadultslayeggsontreetopsandgrubsfeedindeadorganicmatteratthebaseofthefronds.

• Adults feed on the sap of palm trees anddamageemergingleavesastheyboreintotheheartofthetree.

For More InformationCoconutRhinocerosBeetleProgramCollegeofNatural&AppliedSciencesAgricultureandLifeScienceBuildingRm.105UniversityofGuamUOGStationMangilao,Guam96923Phone:(671)735-2085/0Fax:(671)734-1244

www.cnas-re.uog.edu

PreparedbyIanIriarte,RolandQuitugua,OlympiaTerral,AubreyMoore,andMarianaSanders.LastUpdatedSeptember14,2015.

This publication ismade possible through a grant from the USDAForestService.

Scientific NameOryctesrhinoceros

Common NamesAsiaticRhinocerosBeetleCoconutRhinocerosBeetle

Where are they from?TheCoconutRhinocerosBeetle(CRB)isnativetoSoutheastAsia,primarilyinIndonesiaandthePhilippines.During thepast century, theyhavebeen introduced intomany Pacific Islands likeFiji, Palau, Samoa, and Tonga because of theincreaseinairandseatrade.Itwasfirstdetectedin Tumon, Guam in 2007 andOahu, Hawaii in2013.

How did they get here?Itisstillunknown,however,itwasmorelikelybroughtinbyshippingcontainerholdingconstructionmaterials.

Life CycleThebeetlehasfourlifestages:egg,larvae,pupa,and adult (Figure 3). The female rhino beetlelaysabout100eggs(inherlifetime)indecayingorganic matter. Once hatched, the grubs feedonorganicmatter,helpingtobreakitdownintocompost. After about 60 days, grubs begin topupateandtransformintoanadultbeetle.

Figure 3. Coconut rhinoceros beetle life cycle.

Instar Grubs• Liveinbreedingsiteswithingreenwastepilesorpilesofdecomposingmaterial.• Spendall of their timeeatingandproducingwasteinordertogrowanddevelop.• Growforabout2–3monthsfromafirst-instartoathird-instargrub.• Eachinstarstageisdeterminedbythesizeoftheirheadcapsulesratherthanbodysize.

Adult Beetles• Onetotwoinchesinlength,blacktoreddishblack in color with reddish hairs around thebody,andpossessasinglepredominanthorn.

• Adultsaretheonlyonesthatcausedamagetococonutandotherpalmstrees.

• Bore into trees using their horn and spikedlegstofeedonthesweetsapintheheartofthepalm.

• Arenocturnalandareactiveatsunset.• Canflyupto2milesatatime.• Onlyfeedfortwotothreedaysatatime.• After feeding theyexit the treeandflyoff tomateingreenwasteororganicmatterpiles.

Figure 1. Male coconut rhinoceros beetle.

Figure 2. Female coconut rhinoceros beetle.

Male or female? How can I tell?

Note. The amount of nutrition each beetleconsumesinthegrubstageoftheirlife-cycleplaysaroleinthebodyandhornsize.

Males• Usuallylargerhorn.• Littletonoreddish

hairsontheirposteriorends.

Females• Usuallysmallerhorn.• Posteriorendsfully

coveredinreddishhairs.