Our one-of-a-Kind Residents
Our one-of-a-Kind Residents
The Fregate Beetle, also known as the Giant Tenebrionid Beetle (Polposipus herculeanus), is one of the island’s most unique residents, and Fregate Island is the only place in the world where this species lives freely in the wild. Every year, we carry out a census to better understand the population size, habitat use, and demographics of this remarkable insect.
Why We Count
The census provides crucial data to help us protect the Fregate Beetle. By estimating population numbers, mapping their distribution across different habitats, and tracking density on different tree species, we can detect shifts over time.
How We Do It
Our monitoring covers the seven habitat types known to be suitable for Fregate Beetles. Within each habitat, transects were set up and carefully surveyed. A 100m tape defined each transect, with all trees within 2m on either side recorded. Trees were identified to species level, measured, and marked, while Fregate Beetles were counted and measured during evening visits, which is when they are most active. This year, more transects than ever before were included, giving us greater accuracy compared to earlier surveys.
What We Found
- Population size: An estimate of over 100,000 beetles (±9,300) live on Fregate Island.
- Distribution: Beetles were found across all seven habitat types.
- Most abundant habitat: Mixed woodland, with 67.5% of the total population.
What It Means
With a population of over 100,000 individuals, the Fregate Beetle remains secure on the island — but its survival depends on careful monitoring and habitat protection. This year, a more precise estimate was possible, which allows for a clearer picture of the population and strengthens our long-term monitoring efforts.
