Study reveals mechanism behind reproductive synchrony in locusts

BEIJING, March 21 (Xinhua) -- Chinese researchers have found that pheromones may play a role in reproductive synchrony among migratory locusts.

Reproductive synchrony occurs in many group-living animals. For migratory locusts, it is critical for maintaining locust swarms and the population density of the next generation. However, the underlying mechanism remains largely unexplored.

Researchers from the Institute of Zoology under the Chinese Academy of Sciences and other institutes found that female locusts living in swarms showed more synchronous sexual maturation and egg-laying than females without companions or with olfactory deficiency.

They also found that female locusts have maturation synchrony only when male adult locusts are in the swarm. A volatile aggregation pheromone called 4-vinylanisole emitted by male adults played a key role in inducing female sexual maturation synchrony.

Meanwhile, the pheromone only affected young female locusts three to four days after emerging as an adult from the pupa, while older females who were five to six days old as the adults had no response to the pheromone.

In further studies, the researchers identified that pheromone 4-vinylanisole could significantly elicit juvenile hormone, a critical endocrinal hormone regulator of insect development and physiology, triggering sexual maturation in younger locusts. The level of juvenile hormone did not show much change in older female locusts.

The findings have been published in the journal eLife.

The researchers said their findings highlight a "catch-up" strategy. Female locusts living in swarm synchronize their maturation and egg-laying by the time-dependent endocrinal response to the pheromone 4-vinylanisole. The study will be helpful in the understanding of swarming behavior among locusts.