By Zoe Gentes
Editor’s Note: This article was originally published on the National Ecological Observatory Network Observatory Blog. Republished with permission.
It is always exciting when a new species is identified on a field site of the National Network of Ecological Observatories. In the Pu’u Maka’ala Nature Preserve (PUUM) in Hawai`i, researchers have confirmed the discovery of two previously undescribed species of beetles (ground beetles). Kip Will, Ph.D., of the University of California, Berkeley, and James Liebherr, Ph.D., of Cornell University recently published their findings in The Pan Pacific Entomologist: “Two new species of Mecyclothorax Sharp, 1903 (Coleoptera: Carabidae: Moriomorphini) from the island of Hawaii. »
The two new species are both members of Mecyclothorax, a highly diverse genus of beetles on volcanoes of the Hawaiian Islands and the Society Islands in French Polynesia. The new name Mecyclothorax neonoma and Mecyclothorax brunneonubiger bring the number of known Mecyclothorax species in Hawai`i to 241 (many of them have already been described and cataloged by Liebherr). Their discovery could provide new insights into the evolutionary history of the genus.
The road to discovery
Will is one of two researchers hired by the NEON program for the definitive identification of ground beetles. It studies ground beetles worldwide and provides identification for the NEON program for ground beetles found in the western United States, including Hawai`i. Liebherr is one of America’s top experts on ground beetles, especially those from the Hawaiian Islands. Over the past 20 years, he and his students have created the most comprehensive and authoritative guide to Hawaiian ground beetles to date. Will has completed his Ph.D. thesis at Cornell under the supervision of Liebherr.
Will first discovered the suspicious specimens in a group of ground beetles sent to him for identification by PUUM. “When the NEON samples arrived for identification, it was the first time I had worked seriously with Hawaiian ground beetles,” he says. He soon realized that two of the specimens did not match the species already described in Liebherr’s publications: “I said, hey, Jim, your key isn’t working, it must be something new!” He sent the specimens to Cornell, where Liebherr confirmed the identification of two new species. Finding new ground beetle species is part of these researchers’ journey, but these are the first new species of Hawaiian ground beetle identified with NEON samples.
Hawai’i is where Will discovered his love for the insect world. He served eight years in the US Army before beginning his scientific career; While stationed at Schofield Barracks in Hawai’i in the 1980s, he began volunteering at the Bishop Museum in Honolulu, which had a very active field entomology program at the time. He was seduced by the diversity of the insect world. “They had a fantastic collection there and the researchers were very excited,” says Will. “They hired me as a volunteer and took the time to explain everything.”
After leaving the military, Will earned a degree in entomology from Ohio State University and eventually a Ph.D. from Cornell. He spent a lot of time in the Southern Hemisphere, hunting ground beetles across South Africa, South America and Australia. “Beetles give me an excuse to go everywhere. Wherever they are, I will be there,” he said. The discovery of these two new species in Hawaiian samples allows it to close the circle of its entomological roots on the islands.
Shedding light on the evolutionary relationships among terrestrial beetles in Hawai`i
Will’s main interest in entomology is phylogenetics, or the evolutionary relationships between species. Carabids in general, and Mecyclothorax in particular, provide excellent opportunities for phylogenetic studies. According to Liebherr, the 241 known species of Mecyclothorax in Hawaii evolved over a period of 1.2 to 1.9 million years. “They don’t mess around when it comes to diversification,” he says.
Studying the differences between species and the habitats in which they are found can provide insight into their evolution and diversification. Many species are found in tiny evolutionary niches. During Liebherr’s field studies in Hawaii, he and his students identified 116 species of Mecyclothorax on a single volcano, including 74 species new to science. Volcanic islands, such as those found in Hawai’i, have many “microhabitats” that promote the rapid speciation of insects like Mecyclothorax. For example, individuals of a species may prefer riparian or aquatic habitats, leaf litter habitats on the forest floor, or arboreal microhabitats in epiphytic mosses or plants. In addition, ocean island species (especially wingless species such as those in the Mecyclothorax genus) often exhibit reduced dispersal abilities, and thus each volcanic ridge may harbor species different from those on an adjacent ridge. The two new species discovered at PUUM, for example, are among those most likely to be found in terrestrial forest habitats, making them more likely to be caught in the pitfall traps used by the program. NEON.
Different species of Mecyclothorax are recognized by distinct morphology, obvious streaks in their exoskeletons, species-specific shape of genitals, and other physical features, which also provide clues to species relationships. Will says: “The average person would just say, ‘There’s another little shiny brown beetle,’ but each species is unique based on its characteristics.” Species with more similar markings or morphology may be more closely related. Will explains, “We can look at current species distributions to find clues about how taxa of a particular fauna have come together over time. Looking at where we have representatives of related species on different volcanoes and knowing the age of each volcano can tell us how they diversified and how they ended up where they are.
Why care about carabids?
Ground beetles are found in virtually every ecosystem in the world, with an estimated 35,000 to 45,000 species worldwide and nearly 2,500 species known in the United States alone. They are also good environmental indicators. Many species are highly specialized for their habitats and very sensitive to changes in the environment. These characteristics make them ideal subjects for NEON data collection. The NEON program collects ground beetles in pitfall traps at land sites. Studying ground beetle populations across geographic regions and over time can provide information on climate and ecosystem changes and ecosystem dynamics.
Will explains: “The NEON program made a wise choice in sampling ground beetles. This is a group of insects that can be sampled uniformly to obtain short-term and long-term dynamics. They show just enough sensitivity to the ecosystem and climate change – they are resilient enough to survive some changes, but sensitive enough to show a response that we can learn from.
Ground beetles are found in large numbers in many habitats and play an important role in the ecosystem. Most are predators or scavengers. Some are the insect world’s top predators in their areas, making some species very useful for biopest control. Many are highly specialized, with unique adaptations that allow them to prey on specific prey such as hard-shelled snails or poison-spewing centipedes. These differences were what made beetles so fascinating to Will. “These are really important players in the ecosystem. If you want to have a robust ecosystem, they are part of it,” he says.
In the years to come, ground beetle data from the NEON program will allow researchers to closely monitor population trends in Hawai’i and across the country. One issue Will plans to keep an eye on in Hawai’i is the impact of invasive ground beetle species on native Hawaiian species – for example, the invasive species trechus obtuse, which showed itself in large numbers in the pit traps at PUUM. “That’s the beauty of consistent sampling year after year,” he says. “It allows us to see how populations fluctuate and where other native or non-native species move in or native species are pushed out. NEON allows us to see these changes over time. »
Zoe Gentes is a Senior Communications Specialist at Battelle with the National Ecological Observatory Network Program. Email: [email protected]