Fregate Beetle Census 2024: What We Found
This year’s beetle census on Fregate Island brought exciting insights into the population of the critically endangered Fregate beetle (Polposipus herculeanus). Found only on Fregate, this beetle plays a key role in keeping the island’s ecosystem healthy, helping to break down organic material and return nutrients to the soil.
Our 2024 survey aimed to estimate the population size and distribution of these unique beetles across different habitats on the island, including areas dominated by banyan trees, coconut forests, and mixed woodlands. We used a method called “mark and recapture” to estimate how many beetles live in each area. This year, we focused on seven habitats and left out some others where we didn’t expect to find any beetles.
What We Discovered
After gathering data, we calculated that there are approximately 61,008 Fregate beetles living across the island. The beetles seem to prefer mixed woodland areas, with a population of over 18,000 in this habitat. On the other hand, the coconut forests, which were the smallest habitats surveyed, had the fewest beetles, with just 444 found there.
Interestingly, we also noticed that deadwood—fallen and decaying wood—attracted the highest number of beetles. In fact, beetles were seen on deadwood more than three times as often as on living trees! Of the living trees, cinnamon trees were the most popular with the beetles, followed by banyan and coconut trees.
Why This Matters
The findings of this census are important for understanding the role of different habitats in supporting the Fregate beetle population. It’s clear that deadwood is crucial for the beetles’ survival, offering them food and shelter. This means that conservation efforts need to focus on maintaining deadwood and reducing invasive plants that might make the habitat less suitable for these beetles.
Going forward, we plan to expand native and endemic plant species and reduce homogenous habitats, like the coconut forests, to help the beetle population grow and thrive.
With these results, we’re better equipped to protect this fascinating species and keep Fregate’s ecosystem healthy for generations to come!
