Swarm of Bees on Bali Mandara Toll Road: BKSDA's Explanation

A video circulating online shows a swarm of bees flying over the Bali Mandara Toll Road, causing concern among passing motorists, especially motorcyclists, on Sunday (19/4/2026). The Bali Natural Resources Conservation Agency (BKSDA) has provided a scientific explanation.

The head of BKSDA Bali, Ratna Hendratmoko, explained that in entomological studies, bees are social insects with adaptation mechanisms to environmental changes, often due to weather variations.

Ratna stated that bees are ectothermic animals whose body temperature regulation heavily depends on their surroundings.

“The phenomenon of colony movement (swarming) aims to find a new nest. It commonly occurs when the old habitat no longer supports them; there are changes in environmental conditions (temperature, humidity, or disturbances); or the bee colony grows and requires new space. This phenomenon can also be examined from an ecological perspective as a response of organisms to ecosystem dynamics,” said Ratna in a written statement to detikBali.

BKSDA Bali, she added, has coordinated and consulted with an academic figure from Udayana University’s Faculty of Mathematics and Natural Sciences, Prof Ni Luh Putu Eswaryanti, to verify this phenomenon.

“She verified that the transitional season, intense heat, and wind can trigger bee colony movement to more favourable locations,” she continued.

Moreover, the Bali Mandara Toll Road is located near the mangrove area of Tahura Ngurah Rai, which is a natural habitat for insects like bees.

“Which utilise nectar from mangrove flowers. The infrastructure of the Bali Mandara Toll Road structures (underpasses or tunnels) provide protection from rain, strong winds, extreme temperature changes, and minimal disturbances from predators, making it an ideal place to build nests,” explained Ratna.

Nevertheless, Ratna continued, no motorists were injured due to the phenomenon, although the bees’ activity is aggressively massive. However, traffic conditions have also started to become conducive.

Ratna concluded that this phenomenon is not unusual but part of the bees’ adaptation process to environmental changes. She urged the public not to panic.

“This phenomenon generally lasts for a short time. The public is expected to remain vigilant but not to worry excessively,” she emphasised.