Meeting Abstract
Mexican Jumping Beans are popular novelty toys, but we have a poor understanding of the adaptive significance of their intriguing jumping behavior. Mexican Jumping Beans are comprised of moth larva (Laspeyresia saltitans) contained within the seedpod of a shrub (Sebastiana pavoniana). The larva inside the seed is responsible for the beans’ jumping motions. We examined avoidance of environments that may cause or indicate risk of overheating or desiccation. We placed beans at one end of arenas containing gradients of heat, light or moisture, and monitored their position for 24 hours. Beans selected cool or dark environments, actively avoiding warm or light environments, but did not respond to substrate moisture. We also documented repeatable variation in individual bean propensity to jump. Jumpier beans were more likely to escape lethally high temperatures, and the ability to jump at all increased survival of beans in the face of high temperatures. These findings suggest that the jumping behavior of the larvae contained in Mexican Jumping Beans allows them to survive in their desert environment by avoiding direct sunlight.
