Gifu University study reveals butterfly larvae survival strategy

Researchers at Gifu University have discovered a specific survival strategy used by swallowtail butterfly larvae to avoid parasitism. A study published in the ‘Journal of Insect Behavior’ reveals that final-stage larvae engage in wandering behavior, moving an average of more than 20 meters away from their host plants before pupating.

The study focused on the relationship between the distance from host plants, such as citrus trees, and the parasitism rates by wasps like Cotesia glomerata. Findings showed that while larvae remaining on or near the host plant were frequently parasitized, those that moved 5 meters or more away showed no confirmed parasitism.

Experiments using a Y-shaped olfactometer indicated that the wasps are specifically attracted to the scent of the pre-pupa. This suggests that by moving away from the host plant, the larvae successfully evade wasps that use plant-related scents or immediate larval scents to locate hosts. The research team aims to further identify the specific volatile substances released during the pre-pupa stage to understand the chemical mechanisms of this avoidance behavior.