Copepod stocking for dengue fever control shows excellent mosquito-killing effect

Plankton in the cartoon "SpongeBob SquarePants," "Plankton," goes to great lengths to steal the secret formula for the Krabby Patty, but do you know what it likes to eat most in real life? The answer may be the Aedes mosquito that transmits dengue fever.

With two big antennae on top and an oval body, Plankton bears a 99% resemblance to the plankton "copepod," Cai Kunxian, host of the Vector-Borne Infectious Disease Laboratory at National Taiwan University College of Public Health, discovered that copepods, which are only 0.5~2 cm in body length, have an astonishing appetite and love to eat Aedes mosquito larvae, eating up to 40 wrigglers a day. After the laboratory released copepods in drains and basements in Tainan and Kaohsiung for half a year, the wriggler breeding rate fell from 50% to 10%, jokingly called "a hundred mosquitoes are not worth one copepod," and it is expected to become a sharp weapon for preventing and controlling dengue fever.

Biological control methods, paired with paradise fish and essential oils, work well

However, copepods must grow to adulthood to have strong predatory ability, which takes about 7.5~8.5 days, and due to their limited body size, they can roughly only prey on first- or second-instar wrigglers (first instar is about 10 days). Once the wrigglers grow a bit larger, the copepods can no longer eat them, so Cai Kunxian suggests pairing them with other fish for control at appropriate times.

In addition, essential oils extracted from Cinnamomum osmophloeum or Cryptomeria japonica can reduce the activity of wrigglers. If added at the appropriate time, they can increase the predation efficiency of copepods by 20~50%.

As the weather gets hotter and hotter, the dengue fever outbreak is also heating up