Imagine meeting a beetle the size of a hotdog (including the bun), with mandibles strong enough to bite a pencil in half! Not real, you say? Oh yes, it is! The Giant Fijian Longhorn Beetle (Xixuthrus heros) is (likely) the second largest beetle in the world. This goliath of the insect world is only found in the tropical rainforests of the Fijian island of Viti Levu. It is rarely seen but is sometimes attracted to the artificial lights of houses. Given its size, the wing flapping can be heard from a distance.
Generally, we know very little about the world’s insects – creatures such as beetles, bugs, and butterflies – compared with other species which are often considered more “charismatic” – such as mammals and birds. Yet just like mammals and birds, invertebrates (animals without a backbone) are also threatened by human impact, and our lack of knowledge impedes our ability to provide efficient conservation action for these incredibly important species.
One of the reasons why we know so little is that we are vastly outnumbered; for example, more than 35,000 species of longhorn beetle have been described by science, out of more than 350,000 species of described beetles overall. For comparison, there are just over 60,000 vertebrate species (all fish, amphibians, reptiles, birds, and mammals combined!). Gathering knowledge on these species-rich groups is a long, difficult process, due in part to them living in remote and understudied regions like the tropics.
At the Indianapolis Zoo’s Global Center for Species Survival, we are hoping to help change this – one species assessment at a time. One example is the South Pacific Terrestrial Invertebrate Project, which aims to increase the number of Red List assessments for terrestrial invertebrates from Melanesia (specifically Fiji, New Guinea, and Solomon Islands). This project is led by researchers at Kutztown University, with the support of the IUCN SSC Terrestrial and Freshwater Invertebrate Red List Authority (TIRLA), species experts in Fiji, and Global Center Freshwater Conservation Coordinator Dr. Monika Böhm (coordinator of TIRLA).
Red List Assessments
Wait – what are Red List assessments? Red List assessments underpin conservation work around the world. The International Union for the Conservation of Nature (IUCN) established a system to assess the risk of extinction for species of animals, fungi and plants, and this system – the IUCN Red List of Threatened Species – allows conservationists to prioritize actions in the field and communicate the state of our natural world to diverse audiences – from politicians to the general public. At present, only about 1% of the species assessed for the IUCN Red List are beetles, although beetles account for around a quarter of the world’s described species.
This month, the Giant Fijian Longhorn Beetle was added to the IUCN Red List, together with two other species of rather large Xixuthrus from Fiji, thanks to the efforts of Kutztown University researchers Greg Setliff and Dave Waldien. When COVID prevented their original plan for a student field trip to Fiji to study bats and bugs, it opened a new opportunity: a Red Listing initiative for South Pacific invertebrates. By enlisting the help and enthusiasm of Kutztown undergraduate students Shannon Keller and Zachary Glass, Red Listing is now underway for dozens of species, in international collaboration with Hilda Waqa-Sakiti from the University of South Pacific and Sajana Lal of the Fijian Ministry of Forestry, who are experts on the beetle fauna of the island.
So how is this hot dog-sized, pencil-biting beetle doing? The team has assessed the species as Endangered (at a very high risk of extinction) because it only occurs over a very small area and is threatened by habitat loss through logging of large trees, conversion of native forest to agricultural land, and cyclones. The species requires large trees for its larva to develop (ca. 80 cm diameter or slightly wider than a child’s hula hoop), so losing these large trees will hit the species hard, especially since the larva may take up to ten years to develop inside the tree. Specimens of this giant species have also been collected for international trade, and while this species has been protected on the Fijian Endangered Species List since 2002, it is not protected by international treaties such as CITES – the Convention on International Trade in Endangered Species of Wild Fauna and Flora – which aims to prevent species from becoming threatened or extinct because of international trade.
Thankfully, the Kutztown University team and partner networks such as TIRLA are now hoping to catalyze conservation planning and action in Fiji for this extraordinary giant and other invertebrates. With so many unknowns still to shed light on – like what tree species larvae develop best in, how far the adults can travel, how long they live, or whether and how fast populations may be declining – the team will conduct much-needed field research once they can travel to Fiji to try to further expand our knowledge and allow for effective protection of the species.
This blog was a collaboration between experts with the Global Center for Species Survival and Kutztown University researchers Greg Setliff and Dave Waldien.
Published Dec. 14, 2021