The Hungerford’s crawling water beetle (Brychius hungerfordi) occurs in small to medium sized streams and is most commonly found in pools immediately below obstacles like beaver dams, culverts, and artificial barriers. Despite their aquatic habitat, Hungerford’s crawling water beetles are actually clumsy swimmers, preferring to crawl when possible. The adult beetle is only about the size of a grain of rice, roughly 4mm long and 2 mm wide. Spotting this beetle requires patience and a good eye. It is distinguished by its yellowish-brown colour and series of dark narrow stripes running lengthwise across the wing covers.
Females tend to be larger than males. Males can be distinguished by their front legs, where the first three segments carry small tufts of hair and thickened tarsal segments used to grasp females during mating.
Like all beetles, Hungerford’s crawling water beetle undergoes complete metamorphosis with four distinct life stages: egg, larva, pupa, and adult. They breed sometime in spring and early summer, and the female will typically lay her eggs within filamentous algae and aquatic plants. They hatch within 8 to 14 days and are completely independent; there is no parental care. The entire development from egg to adult typically takes about 7 weeks, depending on water temperature, and they live up to 18 months in the wild.
The provincial Recovery Strategy for Hungerford’s crawling water beetle calls for a number of conservation measures, including identifying threats to existing populations, working with farmers to reduce agricultural runoff, working with landowners to steward aquatic habitat and investigating the possibility of translocating beetles.
For those living near known populations, protecting stream integrity is critical, this means avoiding the use of pesticides that contaminate water, preventing erosion and sedimentation, maintaining riparian vegetation, and reporting any beaver control activities to wildlife agencies. Even outside their range, supporting legislation that protects aquatic habitats and water quality benefits countless species like this one.
Q: Why is Hungerford’s crawling water beetle so endangered?
A: The beetle’s extremely limited range combined with its specialized habitat requirements makes it uniquely vulnerable. Any pollution, stream modification, or habitat destruction directly impacts the entire species. Beaver control programs, logging, dredging, culvert installation, and water pollution have all contributed to declining populations.
Q: Can Hungerford’s crawling water beetle fly?
A: Unlike many beetles, crawling water beetles have reduced flight capability. Their hindwings are rolled together rather than folded, making sustained flight difficult. This limits their ability to colonize new streams and escape deteriorating habitat.
Q: How do Hungerford’s crawling water beetles survive winter?
A: Both larvae and adults have been found overwintering in streams. Adults have been collected year-round, even beneath ice. Larvae bury themselves in damp soil adjacent to the stream, where they remain dormant until temperatures rise in spring.
Q: What eats Hungerford’s crawling water beetles?
A: Fish, tadpoles, and other aquatic insects prey on adult beetles. The larvae appear to have few documented predators, though they remain vulnerable to any fish species introduced to their streams for sport.
Q: Why are they called "crawling" water beetles?
A: Despite living in water, these beetles are inefficient swimmers. Instead of gliding or darting like diving beetles, they crawl along the bottom and edges of streams, using their short legs to clamber over rocks and through vegetation.
Q: Could Hungerford’s crawling water beetle be bred in captivity for reintroduction?
A: This is an ongoing consideration for conservation. No successful long-term captive breeding program currently exists, partly because their specialized feeding requirements (particularly their apparent dependence on Dichotomosiphon tuberosus algae) make rearing difficult. Efforts to understand their complete life cycle continue.
