The number of scarab pests has risen steadily (Jackson and Klein, 2006Jackson and Klein, 2006:
Jackson TA, Klein MG. 2006. Scarabs as pests: a continuing problem. The Coleopterists Bulletin 60 (5): 102-119.). Once established, scarab pests are extremely difficult to dislodge, and a full range of technologies and controls is needed for their eradication (Jackson and Klein, 2006Jackson and Klein, 2006:
Jackson TA, Klein MG. 2006. Scarabs as pests: a continuing problem. The Coleopterists Bulletin 60 (5): 102-119.).
The coconut rhinoceros beetle (Oryctes rhinoceros) causes distinctive damage in palm leaves and 50% mortality in afflicted coconut trees (Gressitt, 1953Gressitt, 1953:
Gressitt J. 1953. The coconut rhinoceros beetle ( Oryctes rhinoceros ) with particular reference to the Palau Islands. Bernice P. Bischop Museum, Bulletin 212: 157. full text (accessed 2015)). In Guam, coconut palm losses exceeded $US 2.5 million between 2007 and 2009 (Moore, 2009Moore, 2009:
Moore A. 2009. Guam coconut rhinoceros beetle (CRB) eradication program semi-annual progress report. University of Guam Cooperative Extension Service. 13 pp.). In December 2013, this destructive beetle was discovered breeding on Oahu island in Hawaii (Hawaii Department of Agriculture, 2014Hawaii Department of Agriculture, 2014:
Anonymous. 2014. Destructive beetles found on Oahu coconut trees. Hawaii Department of Agriculture. Available from http://hdoa.hawaii.gov/blog/main/crb/ (accessed May 21 2015).). The beetle poses a threat to the coconut palm, a tree that is deeply integrated into Hawaii’s traditions, culture, and economy. Some of Hawaii’s most persistent and economically significant pests are foreign scarab species. The long-established Chinese rose beetle (Adoretus sinicus) is an agricultural and horticultural pest with a palate for more than 250 plant species (McQuate and Jameson, 2011McQuate and Jameson, 2011:
McQuate G and Jameson M. 2011. Sex determination in the Chinese rose beetle, Adoretus sinicus , and overview of Adoretus species of biosecurity concern. Journal of Insect Science 64: 1-18. full text (accessed 2015)). Widespread invasivesinvasives:
a species that has recently arrived to a new location, usually via human activity, causing notable economic and/or ecological damage
such as Protaetia species and oriental beetle (Anomala orientalis) (Reding and Klein, 2007Reding and Klein, 2007:
Reding M and Klein M. 2007. Life history of oriental beetle and other scarabs, and occurrence of Tiphia vernalis in Ohio nurseries. Journal of Entomological Science 42 (3): 329-340.) trouble the agriculture and economy in regions where they are introduced. Additionally, tourism is threatened by scarab turf pests such as the southwestern masked chafer (Cyclocephala pasadenae), plate-faced beetle (Temnorhynchus retusus), and Hybosorus roei.
Conservation of native scarabs and the conservation impact of non-native scarabs is an additional concern. Island archipelagos and isolated montane regions harbor many unique scarab beetles. The flightless, endemicendemic:
in biogeography, a species that occurs only in a given location
Hawaiian stag beetles (Apterocyclus species: Lucanidae) of Kauai have become increasingly rare, with two of the five species now thought to be extinct (Paulsen and Hawks, 2014Paulsen and Hawks, 2014:
Paulsen M and Hawks D. 2014. A review of the primary types of the Hawaiian stag beetle genus Apterocyclus Waterhouse (Coleoptera, Lucanidae, Lucaninae), with the description of a new species. ZooKeys 433: 77–88. DOI: 10.3897/zookeys.433.8022). Further, non-native scarabs are known to damage rare, native plants on both Hawaii and Guam. On Hawaii, the Chinese rose beetle (Adoretus sinicus) is known to feed on the endangered plants such as kauila (Colubrina oppositifolia), Kauai hau kuahiwi (Hibiscadelphus distans) and ko'oloa'ula (Abutilon menziesii) (Howarth, 1985Howarth, 1985:
Howarth F. 1985. Impacts of alien land arthropods and mollusks on native plants and animals in Hawaii [pp. 149-179]. In: Hawaii's Terrestrial Ecosystems: Preservation and Management. University of Hawaii Publishing, Honolulu, Hawaii, USA. full text (accessed 2015)). On Guam, the oriental flower beetle has been reported as a pest of the endangered Micronesian cycad (Cycas micronesica) (Marler and Muniappan, 2006Marler and Muniappan, 2006:
Marler T and Muniappan R. 2006. Pests of Cycas micronesica leaf, stem, and male reproductive tissues with notes on current threat status. Micronesica 19: 1-9. full text (accessed 2015)).
How many scarabs are in Hawaii? Seventy-one species of scarab beetles (chafers, hide beetles, dung beetles, stag beetles, and rhino beetles) are recorded from Hawaii (Nishida, 2002Nishida, 2002:
Nishida G (editor). 2002. Hawaiian terrestrial arthropod checklist, fourth edition. Bishop Museum Technical Report 22: 1-313.; McQuate and Jameson, 2011McQuate and Jameson, 2011:
McQuate G and Jameson M. 2011. Sex determination in the Chinese rose beetle, Adoretus sinicus , and overview of Adoretus species of biosecurity concern. Journal of Insect Science 64: 1-18. full text (accessed 2015); Paulsen and Hawks, 2014Paulsen and Hawks, 2014:
Paulsen M and Hawks D. 2014. A review of the primary types of the Hawaiian stag beetle genus Apterocyclus Waterhouse (Coleoptera, Lucanidae, Lucaninae), with the description of a new species. ZooKeys 433: 77–88. DOI: 10.3897/zookeys.433.8022). A full checklist of Hawaiian scarabaeoids is available. Only five of these species are native to Hawaii (the Hawaiian stag beetles). Your observations and specimens can assist in advancing our knowledge of Hawaiian scarabs. You can report scarab observations to our iNaturalist project.
How many scarabs are in Guam? Twenty-two scarab beetles (chafers, hide beetles, dung beetles, stag beetles, and rhino beetles) are reported from Guam. Like Hawaii, only a small minority of these species are believed to be native. The majority of Guam's scarabs are widespread adventivesadventives:
a species that has recently arrived to a new location; may or may not be invasive
such as the Chinese rose beetle (Adoretus sinicus). A full checklist of Guamanian scarabaeoids is available.
What if I find a coconut rhino beetle in Hawaii? Report the coconut rhinoceros beetle (CRB) to the pest hotline at 808-832-0585 (local call in Hawaii) or to our iNaturalist project. The citizen science project “Help Save Hawaii’s Coconut Trees” also needs your input.
What native scarabs are known from Hawaii or Guam? Both Hawaii and Guam have some naive scarabaeoid beetles. Guam has both native stag beetles (Lucanidae) and native scarabs (Scarabaeidae). The Marianas stag beetle (Figulus integricollis), can be found in rotting tree logs on Guam and the Northern Mariana Islands (Bourquin, 2002Bourquin, 2002:
Bourquin O. 2002. Invertebrates recorded from the Northern Mariana Islands status 2002. CNMI Invertebrate Collection Crees-Northern Marianas College, Saipan.), and the Caroline Islands chafer (Lepidiota carolinensis), is native to many islands across Micronesia including Guam (Cartwright and Gordon, 1971Cartwright and Gordon, 1971:
Cartwright O and Gordon R. 1971. Insects of Micronesia Coleoptera: Scarabaeidae. Insects of Micronesia 17: 256-296.). The Hawaiian island of Kauai is home to a fascinating radiation of stag beetles in the genus Apterocyclus (the Hawaiian stag beetles). These native stag beetles were once common across the island and occurred from sea level to the montane koa forests (Paulsen and Hawks, 2014Paulsen and Hawks, 2014:
Paulsen M and Hawks D. 2014. A review of the primary types of the Hawaiian stag beetle genus Apterocyclus Waterhouse (Coleoptera, Lucanidae, Lucaninae), with the description of a new species. ZooKeys 433: 77–88. DOI: 10.3897/zookeys.433.8022), and their larvaelarvae:
the immature form of an insect; in scarabs, also called grub or white grub; preceded by the egg stage, followed by the pupal stage
could be found by the hundreds in the soil around koa trees (Van Dyke, 1922Van Dyke, 1922:
Van Dyke E. 1922. A study of the lucanid Coleoptera of the Hawaiian Islands. Proceedings of the Hawaiian Entomological Society 5: 39–49. full text (accessed 2015)). Now, however, these beetles are confined to highland koa forests, and two of the five species may be extinct (Paulsen and Hawks, 2014Paulsen and Hawks, 2014:
Paulsen M and Hawks D. 2014. A review of the primary types of the Hawaiian stag beetle genus Apterocyclus Waterhouse (Coleoptera, Lucanidae, Lucaninae), with the description of a new species. ZooKeys 433: 77–88. DOI: 10.3897/zookeys.433.8022).
Are there native dung beetles in Hawaii or Guam? It appears that Hawaii does not host any native dung beetles. The tiny dung beetle Ataenius pacificus was described from Hawaii, but it is originally from the U.S. mainland and was accidently transported to Hawaii. The dung beetles Canthon balteatus and Canthidium muticum were also described from "Hawaii", however this appears to be an error in the original descriptions of the species (Liebherr et al., 2010Liebherr et al., 2010:
Liebherr J, Casale A, Rewin T, Nall G. 2010. On the provenance of Boheman's "Eugenies Resa" Carabidae
(Coleoptera) allegedly described from Hawaii. The Coleopterists Society 64: 221-229. DOI: http://dx.doi.org/10.1649/0010-065X-64.3.221.7). Both are known from the Neotropics, and neither species has ever been collected in Hawaii. It is unclear if Guam hosts any native dung beetles. The tiny dung beetle Airapus yasumatsui is recorded from Guam and the Marianas (Cartwright and Gordon, 1971Cartwright and Gordon, 1971:
Cartwright O and Gordon R. 1971. Insects of Micronesia Coleoptera: Scarabaeidae. Insects of Micronesia 17: 256-296.), but the validity of this species is problematic. Until the taxonomy of this tiny beetle is resolved, the question of a native Guamanian dung beetle remains uncertain.
Are Hawaiian scarabs in need of conservation? Sadly, two of the five species of endemicendemic:
in biogeography, a species that occurs only in a given location
Hawaiian stag beetles may be extinct (Paulsen and Hawks, 2014Paulsen and Hawks, 2014:
Paulsen M and Hawks D. 2014. A review of the primary types of the Hawaiian stag beetle genus Apterocyclus Waterhouse (Coleoptera, Lucanidae, Lucaninae), with the description of a new species. ZooKeys 433: 77–88. DOI: 10.3897/zookeys.433.8022). These showy and large beetles (some over 2 cm) are icons for Kauai’s native Acacia koa forest. All species are flightless, rare, and dependent upon vanishing native Hawaiian habitat. These native stag beetles suffer from a combination of habitat loss and heavy predation from non-native rodents (Howden, 2008Howden, 2008:
Howden H. 2008. In past years - XIII 1970–1974. Scarabs Newsletter 30: 15–21.) and probably pigs. LarvaeLarvae:
the immature form of an insect; in scarabs, also called grub or white grub; preceded by the egg stage, followed by the pupal stage
could once be found by the hundreds in soil around decaying koa trees (Van Dyke, 1922Van Dyke, 1922:
Van Dyke E. 1922. A study of the lucanid Coleoptera of the Hawaiian Islands. Proceedings of the Hawaiian Entomological Society 5: 39–49. full text (accessed 2015)). All species are in urgent need of conservation and study.
Are checklists available for scarabaeoid beetles of Hawaii and Guam? Yes! We provide a checklist to Hawaiian scarabaeoids as well as a checklist to Guamanian scarabaeoids.
Authors: J.B. Dunlap, M.L. Jameson, E.L. Engasser, P.E. Skelley, A.J. Redford
Content last updated February 2016
idtools.org
Lucid mobile app for Android and iOS | tool images at ITP Node
