Unexpected Consequences of an Invasive Succulent
Researchers in Japan have uncovered a subtle yet profound way that a non‑native succulent can reshape animal behavior. The study, published in Basic and Applied Ecology, focused on the blue‑winged butterfly Tongeia fischeri, commonly called Fischer’s Blue, whose larvae traditionally feed on the native stonecrop Orostachys japonica.
Feeding on a foreign host
When the team from Osaka Metropolitan University reared caterpillars on the exotic Sedum sarmentosum, the larvae appeared to thrive. Growth rates, pupal weight and egg‑laying choices showed no obvious disadvantage, suggesting that the invasive plant could serve as an alternative food source.
Shifts in wing coloration
The surprise emerged after the butterflies reached adulthood. Photographs taken under normal light and under ultraviolet (UV) illumination revealed stark differences. Individuals raised on the native host displayed a slightly yellowish underside and reflected less UV light. In contrast, those fed on the introduced succulent showed a greyer hue and a pronounced increase in UV reflectance.
UV patterns are invisible to humans but crucial for butterfly communication. The wing surface functions as a visual “business card” that helps males locate suitable mates. A change in UV reflectance can therefore alter the odds of successful courtship.
Male response to altered wings
Field experiments confirmed the hypothesis: male Tongeia fischeri approached and made contact more frequently with females that had developed on the native plant. Those raised on Sedum sarmentosum attracted fewer suitors, indicating that the altered wing signal reduced their attractiveness.
Broader ecological implications
Lead author Karen Hisai warns that invasive plants can disrupt ecosystems in ways that extend far beyond direct competition for space or nutrients. Even when they provide a viable food source, they may indirectly impair reproductive success of native insects.
Co‑author Norio Hirai adds that such hidden threats could accelerate the decline of already vulnerable species. Understanding these nuanced interactions is essential for crafting effective management strategies against invasive flora.
By shedding light on the invisible ripple effects of plant invasions, the study underscores the importance of preserving native plant‑insect relationships.
Source: https://scientias.nl/deze-invasieve-plant-verandert-de-kleur-van-vlindervleugels/
