Determining mechanisms that allow species coexistence is crucial for understanding community structure and biodiversity of ecosystems. Two species of octopus, Octopus vulgaris (common octopus) and Macrotritopus defilippi (Atlantic longarm octopus) inhabit a tropical sandy habitat in South Florida; it is unknown how these species coexist. This study examines if these species coexist by feeding on different prey (diet partitioning) or feeding at different times (temporal partitioning). Using SCUBA, prey remains were collected from dens of both species to determine their diets. Supplemental video footage was also used to identify prey items. Both species of octopus were video-monitored for 24h periods to determine foraging times.
Results/Conclusions
O. vulgaris’s diet consumption consisted of bivalves (62%), gastropods (23%), and crustaceans (15%). Prey items were collected from 18 O. vulgaris dens for a total of 39 specimens and of those, 13 species were identified. M. defilippi’s diet consumption consisted of crustaceans (89%) and bivalves (11%). Prey items were collected from 7 M. defilippi dens for a total of 9 specimens and of those, 2 species were identified. Octopuses preyed on the same species of bivalve (Laeuicardium mortoni) and crustacean (Cryptosoma balguerii), indicating diet overlap. However, O. vulgaris forages during nighttime hours while M. defilippi forages in morning and mid-afternoon periods suggesting temporal partitioning. A total of 10 dens were monitored for each species to find their foraging activities. O. vulgaris was observed foraging during nocturnal hours with the highest percent foraging activities at 10:00PM (80%) and 1:00AM (75%). M. defilippi was observed foraging mainly during diurnal hours with the highest percent foraging activities at 9:00AM (60%) and between 1:00PM – 2:00PM (60%). This study will provide baseline data for conservation requirements of these octopus species and similar sand-dwelling organisms, which use this habitat as a nursery, and contribute to the general knowledge base of niche partitioning.