Western Cape's nightmare: fruit flies, roaches and wildfires

ARE insects the early indicators of a changing climate and what can we learn from their changing behaviour to help us prepare for what's to come?

- TRACY-LYNN RUITERS

WILDFIRES burning in the Kouga region. THERE is a notable increase in fruit flies and cockroaches in the Western Cape.

(Facebook Reuters)

As communities across South Africa grapple with changing weather patterns, scientists say insects are also providing visible clues about rising temperatures and environmental stress.

Professor Cang Hui, a Stellenbosch University academic and holder of the South African Research Chair in Mathematical and Physical Biosciences, said public observations of changing insect activity are consistent with well-established ecological responses to heat.

"Insects are ectotherms, meaning their body temperature, metabolism and behaviour are tightly linked to ambient temperature," Hui explained. "As temperatures rise, many species initially become more active and reproduce faster, but only up to a thermal limit. Beyond that, prolonged heat becomes physiologically stressful."

Residents have reported increases in cockroaches and fruit flies during recent heatwaves, while noticing fewer cricket calls. Hui said these patterns align with species-specific tolerances.

Cockroaches and fruit flies are highly heat-tolerant and thrive in warm, human-modified environments. Heatwaves often drive cockroaches indoors in search of water and cooler microclimates, increasing their visibility. Fruit flies, with their rapid life cycles, reproduce faster in warm conditions, particularly where organic waste ferments more quickly.