The co-extinction of interdependent species in relation to massive, long-term habitat disturbance has not been thoroughly investigated. Using logistic regression analyses, we examined the relationship between the loss of butterflies and their specific hostplants from the tropical island of Singapore and report the probable occurrence of their co- extinctions at the community level. Our simulation shows that the number of extinct butterfly species is expected to increase exponentially with that of extinct hostplants. The close association between butterflies and their hostplants suggests that the preservation of whole habitats is urgently needed if we are to avoid the possible cascading effects of species (co-)extinctions.