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- Title
- Mechanisms of Coexistence Between Two Octopus Species In A South Florida Lagoon.
- Creator
- Bennice, Chelsea, Brooks, W. Randy, Florida Atlantic University, Charles E. Schmidt College of Science, Department of Biological Sciences
- Abstract/Description
-
Theoretically, sympatric species must partition resources or space to allow for coexistence. Determining empirically the specific resources each species exploits and species’ interactions (e.g., intra- and interspecific competition) can sometimes be challenging, thus the data are relatively sparse for certain taxa. This paucity of data exists for octopuses. Therefore, I chose to study niches of two sympatric octopuses (Octopus vulgaris and Macrotritopus defilippi) in an intracoastal habitat....
Show moreTheoretically, sympatric species must partition resources or space to allow for coexistence. Determining empirically the specific resources each species exploits and species’ interactions (e.g., intra- and interspecific competition) can sometimes be challenging, thus the data are relatively sparse for certain taxa. This paucity of data exists for octopuses. Therefore, I chose to study niches of two sympatric octopuses (Octopus vulgaris and Macrotritopus defilippi) in an intracoastal habitat. Specifically, I assessed (1) spatial distribution of octopus home or “den” space, (2) habitat association, (3) octopus abundance, (4) foraging activity periods, (5) diet, and (6) associated substrates and behaviors used during foraging events. Octopus den locations were marked by GPS to quantify spatial patterns of both species and their spatial relationship to each other. Habitat associations were measured by quantifying photoquadrats of den and surrounding habitats. For foraging activity periods, a video camera was placed near an octopus den for 24-h observation to determine when each octopus species leaves/returns from foraging. Underwater video recording was used to determine associated foraging substrates and behaviors for both species. Prey remains from octopus’ dens and video recordings indicating prey consumption were used to determine diets of the two octopus species. Video recordings from the 24-h camera and foraging behavior events also provided observations of intra- and interspecific interactions. Results revealed that the two species are interspersed throughout the shallow Florida lagoon and are both abundant during the spring months (March, April, May). Although both species are interspersed throughout the lagoon, their den and surrounding habitat association differed. O. vulgaris was associated with hard bottom and M. defilippi was associated with soft bottom, thus they may not compete strongly for habitats. Each species used different foraging strategies and different primary prey, which may also lessen competition and facilitate coexistence. O. vulgaris had peak foraging activity during night hours, foraged mostly on hard bottom and mainly consumed bivalves while M. defilippi had peak foraging activity during day hours, foraged mostly on soft bottom and mainly consumed crustaceans. Octopuses also had species-specific foraging behaviors, with O. vulgaris using parachute attack and M. defilippi using flounder swimming and tripod stance. Additional intra- and interspecific interactions were video recorded and included: fishes following octopuses, predation attempts, agonistic encounters, cannibalism, and tactile communication. This study identified ecological and behavioral components that may facilitate coexistence of these sympatric species, provided insight into cephalopod niches and ecology, and provided baseline conservation requirements for sand-dwelling cephalopods, both of which may be using this site as a mating and nursery habitat.
Show less - Date Issued
- 2019
- PURL
- http://purl.flvc.org/fau/fd/FA00013185
- Subject Headings
- Octopuses, Sympatry (Biology), Coexistence of species, Lagoons--Florida
- Format
- Document (PDF)
- Title
- DIETARY VARIABILITY IN A GROUP OF MIXED-SPECIES CERCOPITHECUS MONKEYS (CERCOPITHECUS MITIS, C. ASCANIUS AND C. MITIS X C. ASCANIUS) IN MKENKE VALLEY, GOMBE NATIONAL PARK, TANZANIA.
- Creator
- Crawford, Sarah, Detwiler, Kate M., Florida Atlantic University, Dorothy F. Schmidt College of Arts and Letters, Department of Anthropology
- Abstract/Description
-
This research represents the first multi-year investigation of the feeding ecology of Gombe’s Cercopithecus populations. The main goal of this study was to identify dietary overlap and distinctiveness among the phenotypes in our study group, a mixed species group of guenons comprised of C. ascanius, C. mitis, and C. ascanius x C. mitis hybrids. Field assistants collected feeding data using ad libitum observations as well as instantaneous scan sampling at 30-minute intervals from July 2014 to...
Show moreThis research represents the first multi-year investigation of the feeding ecology of Gombe’s Cercopithecus populations. The main goal of this study was to identify dietary overlap and distinctiveness among the phenotypes in our study group, a mixed species group of guenons comprised of C. ascanius, C. mitis, and C. ascanius x C. mitis hybrids. Field assistants collected feeding data using ad libitum observations as well as instantaneous scan sampling at 30-minute intervals from July 2014 to December 2018. A total of 63 plant species were identified in our group’s diet. Results indicate that a significant difference exists between the diets of each phenotype. The results also found an unusually high percentage of invertebrate eating (54%) in our group. These findings suggest that invertebrates are an important food resource for the Gombe study group and may help facilitate coexistence in an environment where there are many sympatric primate species.
Show less - Date Issued
- 2019
- PURL
- http://purl.flvc.org/fau/fd/FA00013295
- Subject Headings
- Cercopithecus, Gombe National Park (Tanzania), Phenotype, Sympatry (Biology), Animals--Food
- Format
- Document (PDF)
