Home > Species > Insects SPECIES - INSECTS Native Hylaeus Bee - Photo: S Plentovich INSECT SURVEY STRATEGY FOR HAWAII’S OFFSHORE ISLETS The insects (terrestrial arthropods actually) of Hawaii’s offshore islets are, in general, poorly known. The species lists for offshore islets are incomplete and much work remains to be done. Many of the offshore islets are small and difficult to access, which has tended to deter collectors. It is their isolation, however, that makes these sites potentially interesting, since they have been shielded from many of the alien species invasions and human activities that have decimated native coastal plant, seabird, and insect populations in most of the main Hawaiian Islands. Researchers have been rewarded, although all too rarely, when native and endemic (i.e., found only in Hawaii) species are collected on the islets. Perhaps the best example was the 1968 collection of a new species of endemic flightless weevil, Rhyncogonus kapapa, found only on 9.5 acre Kapapa Islet in Oahu’s Kaneohe Bay. Since beginning in 2000, Offshore Islet Restoration Committee (OIRC) surveys have identified just over 20 endemic insect species on offshore islets, including rare yellow-faced bees (Hylaeus anthracina). Increasing the scope of islet insect surveys is an important part of OIRC’s biological survey efforts. This effort, however, must be focused to meet the constraints of logistics, funding, and human safety. Collecting time on offshore islets is usually limited, transportation (often helicopters) can be expensive, and researchers frequently risk their lives working in dangerous locations. The costs and benefits of conducting insect surveys must be carefully considered, especially since all islets surveyed to date have been dominated by introduced species. Multiple species of invasive ants are present on most islets, to the detriment of native insects. Even on islets with native-dominated plant communities, healthy seabird colonies and abundant marine resources, most insects collected are aliens. Despite these negative considerations, there are several excellent reasons to continue to survey and study insects on offshore islets. First, rare native species deserve all the protection that resource management agencies and their allies can provide. Many native coastal insects are federally designated species of concern and they must be surveyed and mapped before protection strategies can be developed. Second, alien insects have profound effects on islet ecosystems and their presence or absence can make or break efforts to restore native plants and seabirds. For example, seabird colonies are affected by alien ants, such as Big-headed ants (Pheidole megacephala) and Fire ants (Solenopsis geminata), that attack chicks, eggs, and even the webbing of the birds’ feet. Mosquitos carry a variety of diseases, including avian pox and avian malaria, which can sicken or kill a variety of birds. In addition, the success of plant restoration projects can hinge on the presence or absence of native pollinators and the alien insects that eat them. Detecting insects like the Schistocerca nitens grasshopper that recently devoured much of the native vegetation on Nihoa provides restoration planners with important information. Lastly, offshore islet ant eradication studies like the one being carried out by the University of Hawaii (see description under the Projects section of this website) may provide management tools for controlling aggressive ant species that are a limiting factor in restoring coastal ecosystems. Clearly, insect surveys and studies on islets must be intelligently focused. Priorities will include identifying and surveying those islets with the greatest potential to support native insects; developing management techniques to control the most destructive alien insects; and carefully surveying insect fauna on islets where active plant and seabird restoration is being planned. The arthropods shown below are classified as either endemic or introduced. These terms are defined as follows: Endemic: Native only to Hawaii Introduced: Non-native species brought by humans either intentionally or accidentally Native Hawaiian Bee Hylaeus species Endemic and Rare Native Hylaeus Bee - Photo: S Plentovich   Bees in the Hylaeus genus, also known as yellow-faced bees, are native to Hawaii and are important pollinators of native plants.   There are about 60 species of Hylaeus in Hawaii and some of these, like Hylaeus anthracina , are found in coastal areas.   Hylaeus have recently been found on some of Oahu's offshore islets and are also known from Kaena Point. Bees in this genus are becoming increasingly rare and several species are already extinct due to habitat loss and the presence of alien ants and other insects. Loss of any remaining Hylaeus species will affect the native plant species that rely on them for pollination. Big-headed Ants Pheidole megacephala Introduced and Invasive Big-headed ants attack Seabird Chick - Photo: C Vanderlip   Big-headed ants are one of several invasive ant species in Hawaii (Hawaii has no native ants). As the photograph shows, they can swarm on seabird chicks in addition to eating native plant seeds and killing native insects. Studies are currently underway to see if ants can be effectively controlled or eradicated from offshore islets. Two other invasive ant species that are known to damage native species on our offshore islets are Fire ants ( Solenopsis geminata ) and Yellow crazy ants ( Anoplolepis gracilipes).  It is especially important that visitors to offshore islets not bring ants with them, since once they are established they can cause a great deal of ecological damage and are very hard to get rid of. Hawaiian flightless weevil Rhyncogonus species Endemic and Rare Rhyncogonus vestitus - Photo: S Plentovich   Weevils in the Rhyncogonus genus are found on several Pacific oceanic islands, but Hawaii is fortunate to have several endemic species, found nowhere else in the world. Most Hawaiian Rhyncogonus are endemic to single islands, like Rhyncogonus kapapa which was discovered on tiny Kapapa Island in Kaneohe Bay in the 1960s. Intensive surveys recently discovered small numbers of Rhyncogonus vestitus on Oahu's Kaohikaipu Islet (see photo). However, Rhyncogonus are now very rare in Hawaii and are continuing to disappear due to habitat destruction and a variety of alien species, including ants. These weevils are flightless, nocturnal, and tend to feed only on a small range of native host plants. When their host plants are destroyed or removed, the weevils cannot survive.   > Back to top of page Home  Islets  Species  Projects  Outreach  Links  About Us