Antarctica's Only Native Insect Adapts to Extreme Climate with Unique Dormancy Strategy

Antarctica's Only Native Insect Adapts to Extreme Climate with Unique Dormancy Strategy
by Riko Seibo
Tokyo, Japan (SPX) Feb 18, 2025

When thinking of Antarctic wildlife, penguins often come to mind, yet the continent is also home to a unique flightless midge, Belgica antarctica, the only known insect native to the region. This tiny species has evolved remarkable survival strategies to endure the harsh Antarctic environment. A new study led by researchers at Osaka Metropolitan University has provided crucial insights into how this midge navigates the extreme climate through distinct dormancy mechanisms.

Professor Shin G. Goto from the Graduate School of Science and Dr. Mizuki Yoshida, a former graduate student now a postdoctoral researcher at Ohio State University, led an international team that uncovered the insect's ability to alternate between two forms of dormancy-quiescence and obligate diapause-during its two-year life cycle.

Quiescence is an immediate, reversible dormancy triggered by adverse conditions, allowing an organism to resume activity as soon as the environment becomes favorable. In contrast, obligate diapause is a predetermined period of dormancy that occurs at a fixed point in an organism's life cycle, a rare phenomenon among insects from temperate regions.

Dr. Yoshida explained, "We were able to establish a method for rearing the Antarctic midge over six years to better understand its environmental adaptation mechanisms."

The study found that larvae of the Antarctic midge typically develop into their second instar stage by their first winter, at which point they enter quiescence. This adaptation enables them to resume development immediately when temperatures temporarily rise. By their second winter, the larvae reach their fourth and final instar but do not pupate. Instead, they enter obligate diapause, ensuring synchronized adult emergence during summer, a critical period for reproduction.

Professor Goto added, "We determined that for the Antarctic midge, obligate diapause ends with the onset of low temperatures in winter so that the larvae all pupate simultaneously and emerge as adults at the same time. Although such seasonal adaptation strategies involving multiple overwintering periods using both quiescence and obligate diapause have not been documented in other organisms, we believe insects in extreme environments such as the Arctic and high altitudes may employ similar mechanisms."

Research Report:Obligate diapause and its termination shape the life-cycle seasonality of an Antarctic insect