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Bug Spotlight!

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U.C. Riverside
Department of Entomology
Photo by: G. Ballmer(c)
Xixuthrus ganglbaueri Lameere by Doug Yanega  

The female in this photo is the first known specimen of this species since it was first described in 1912; she will become the neotype specimen for the species, since the original specimen was lost.  This is one of three species of Xixuthrus that occur in Fiji (the other two are X. heros (Heer) and X. terribilis Thomson), and they are all rare and mysterious, despite their enormous size (from 8-15 cm [or about 3-6 inches], making them the second largest beetles in the world ─ only Titanus giganteus is larger).  Highly prized, specimens of the adults of any of the three Fijian species will sell for hundreds or even thousands of dollars each, and they are few and far between.  As a result, most reside in private collections, rather than museums.  Reasons for the apparent rarity of the three Fijian Xixuthrus are still uncertain, but their scarcity may be due to life history characteristics associated with their large size, or food plants.  Their larvae are considered special delicacies, on those rare occasions when they are encountered by Fijians, so there are no known specimens of the larvae, and those who have found them haven't made note of the tree species involved.  Recent field surveys by the Wildlife Conservation Society and the Fiji Department of Forestry, however, have found giant larval tunnels averaging 5 cm in diameter in a threatened species of native hardwood, with grubs in living trees with some dead wood.  Hopefully they can get adults, at some point, to confirm that they're Xixuthrus.  The larvae may therefore require very large and/or rare host trees, and such trees are uncommon in Fiji 's cyclone forests and are becoming increasingly rare as widespread logging actively targets big trees. A review of known localities for the beetles initially suggests they may require intact native lowland forest, as older specimens are from (or adjacent to) forested areas, and most recent collections have come from adults flying to lights situated adjacent to natural lowland forests, which are rapidly disappearing due to logging and clearance for agriculture.  Of course, entomological surveys are few in Fiji , thanks largely to the rugged, inaccessible terrain and high rainfall, so the rarity of Xixuthrus may also be due, in part, to limited collections in remote areas.  Nonetheless, the clearest threat to their survival is habitat loss, rather than collecting.     

                                                            

(c)2006  ERM-UC Riverside