For my master thesis, I studied the prey preferences and microhabitat use of the coral-eating snail Drupella cornus in the northern Red Sea.
Population outbreaks of this coral predator have the potential to destroy wide areas of coral reef and have caused significant damage on many reefs including Ningaloo Reef in Western Australia. During a 2-month fieldtrip to the Egyptian Red Sea, I analyzed for the first time if prey preferences are independent of coral availability using resource selection ratios and extensive Scuba surveys.
I found that both juvenile and adult snails prefer specific species of Acropora independent of their abundance, and that an ontogenetic habitat shift (and thus also shift in prey selectivity) occurs at a size of 2 cm. As a consequence, the two life stages differ in their ecological impact on coral communities. Using mesocosm experiments, I also provided the first experimental evidence that intraspecific attraction plays a major role in prey selection of D. cornus, which may contribute to the formation of population outbreaks.