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Vernacular Name , RHINOCEROS (aka: Grants' rhinoceros beetle, western )

Male Female Size Comparison

Male Female

GEOGRAPHIC RANGE Southwestern United States (Arizona, western New Mexico, southern Utah) and northern Mexico (Chihuahua).

HABITAT Leaf litter, plants, and fallen logs. can be found in rotting wood, especially sycamore.

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CONSERVATION STATUS • IUCN: Not Evaluated (2012) • Not endangered.

COOL FACTS • This behemoth of an is North America’s heaviest scarab beetle, found in the mountains of the American southwest where adults feed on the sap of ash trees. • Rhinoceros are herbivorous named for the horn-like projections on and around the heads of males. • Males use their horns to fight each other for access to females, attempting to pry their opponents off the branches. Size is important and it varies, notably among individuals depending on how well they fed as developing larvae: • Another name given to some of these insects is the Hercules beetle, because they possess strength of a herculean proportion. Adults of some species can lift objects 850 times their weight! That would be equivalent to a human lifting 9 fully grown male elephants! • Basically, this beetle has evolved the insect-equivalent of a large, grasping claw, but rather than it being an appendage located on an arm, it has been developed as extensions of the head and thorax! • Sexual dimorphism is prominent: the males and females are very different in appearance. In fact, for a long time, people thought that the two sexes were a different species because of their extremely different sizes and the absence of the claws on the female. • Though such beetles as this may appear fearsome or even dangerous, they are actually quite harmless to humans. • Natives eat them because it is assumed that the “gigantic powers” of these beetles will be transferred to those who consume them. • “Beetle” comes from old English “biten”, meaning “to bite, chew and gnaw”. • Beetles comprise 40% of all insects and 6X the number of ALL vertebrates.

DIET • In wild: herbivorous. The adults feed on ash tree sap; larvae eat decaying plant matter. • In captivity: rotten wood, compost and decaying leaves.

LONGEVITY • In wild: about 2 years; much of this may be spent in the larval stage. • In captivity: about 2 years.

ENEMIES - DEFENSE • Enemies: lizards, birds. • Defense: - when disturbed, rhinoceros beetles can produce hissing squeaks. - the horns are used a bit like pry bars during disputes with other males over mates.

MATING - CARE OF THE YOUNG • Mating: the horns of the male rhinoceros beetle are used to drive other males away from a female beetle during mating rituals. Beetle, Rhinoceros 3/6

• Clutch: females lay about 50 eggs which hatch into larvae. Larvae develop in rotten wood or decaying foliage. • Larvae Stage: larvae go through three stages: L1, L2 and L3 (larval instars: aka grubs). Then they build a pupal cell out of dirt and oral secretions and shed again to become a pupa. It is during this phase that you can see the adult beetle is finally taking shape. The larval period, from the time the egg hatches until the adult emerges, takes 12-18 months.

Beetle: Complete Metamorphosis

• Adult stage: lasts about 9 months.

SOCIAL INTERACTION • They are solitary and territorial. • Communication: when disturbed, rhinoceros beetles can produce hissing squeaks. These aren’t actually vocal noises. Instead, they’re produced when the beetle rubs their abdomen and wing covers together.

LIFE STYLE • Activity Period: nocturnal. They spend most of the daylight hours beneath the soil and come to the surface at night. • Locomotion: they are good walkers and capable flyers. • One of the uses for extreme strength is for the beetles to dig themselves into leaf litter and soil to escape danger. Their horns also help them to do this. • Both sexes are attracted to light.

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PHYSICAL

Anatomy of a Beetle

Like most other insects, beetles bodies are divided into 3 sections; the head, the thorax, and the abdomen.

• Size: 1.77”-3.00”. Males can reach more than 3″ in length (including the long “horn” on the thorax). • Sexual Dimorphism: males larger; females do not have horns. • Color: tan, yellow, brown and black. • Horns: curved to meet each other and look like pincers. They can make up more than half the body length of these beetles. There is much variation in body size, which affects the extent to which the horns are developed. This is related primarily to the amount and nutritional quality of the food which the beetle consumed as a larva. - The underside of the upper, thoracic horn is lined with a thick pile of fine brown hairs. - The upward curving lower horn on the head (called the "cephalic" horn) has several sturdy notches on it, and can be moved upward against the longer, downward curving one (called the "thoracic" horn) which projects from the beetle's dorsal shield of the thorax. • Wings: there are 2 distinct sets of wings. - The first set is called “elytra” and is the main characteristic of a beetle. They are not true wings, but are hard casings designed to protect the real wings underneath from abrasion, desiccation, parasites and predators. These front wings will expand out at nearly 90 degrees and, thus, expose the hind wings underneath. • The hind wings are soft, thin and membranous. The beetles use these to fly.

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• Sensory Organs. - Antennae: 2, which the beetles use to help sense the world around them. They are thread- like with a club-like end. - Eyes: large, compound eyes made up of several small photoreceptors (as if it is one eye made up of hundreds or thousands of smaller ones) that give them a 360-degree view. This type of eye gives less resolution than the vertebrate eye, but it gives acute perception of movement. • Legs: long, thin leg segments especially modified for running.

TAXONOMY Phylum / Subphylum Arthropoda / Invertebrate Class Insecta Order Coleoptera Family / species granti

• “Coleoptera” means “sheathed-winged” insects.

REFERENCES - Hutchins, Michael, Arthur V. Evans, Rosser W. Garrison, and Neal Schlager (eds). 2004. Grzimek’s Life Encyclopedia. Second Edition. Vol. 3: Insects. Farmington Hills, MI: The Gale Group. - Klausnitzer, Bernhard: 1981. Beetles. New York, NY. Exeter Books. - Dynastes granti: http://museum.unl.edu/research/entomology/Guide/Scarabaeoidea/Scarabaeidae//Dynastin ae-Tribes/Dynastini/Dynastes/D-granti/D_granti.html - http://myrmecos.wordpress.com/2010/02/05/friday-beetle-blogging-dynastes-granti-the-western- hercules-beetle/ - http://en.wikipedia.org/wiki/File:Fiddler_beetle_morphology_diagram.svg - http://en.wikipedia.org/wiki/File:Life_cycle_of_stag_beetle.svg - http://www.ehow.com/info_10043424_anatomy-rhinoceros-beetle.html - http://www.entomology.umn.edu/cues/4015/morpology/ - http://www.squidoo.com/beetles-for-kids - http://bugguide.net/node/view/139578 - http://www.nwf.org/Wildlife/Wildlife-Library/Invertebrates/Rhinoceros-Beetles.aspx - http://www.insectidentification.org/insect-description.asp?identification=Western-Hercules-Beetle

Prepared by: Dave Schaffer, docent Date: 11-16-12 Photos by: Map by: Dave Schaffer - Bob Sloane, docents 1) On branch and thumb -Matthew R. Moore U. of Nebraska State Museum - Division of Entomology 2) Other photos - myrmecos.wordpress.com – See references for full information 3) Graphics – See references Approved by PZ: Marina Haynes. Curator, KZU Date: 12-18-12 Formatted by: Dave Schaffer, docent Date: 11-16-12

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