Social Behavior of Adult Laboratory-Reared Cuttlefish, Sepia pharaonis
MetadataShow full metadata
The cuttlefish Sepia pharaonis is widely distributed in the Indo-Pacific from the Red Sea to Japan and Australia, and is commercially important as a food resource. Given the interest in commercially culturing this species, knowledge of its reproductive behavior is most needed. However, studying cuttlefish reproductive behavior is hampered by the lack of anatomical features that distinguish males from females. Thus, behavioral differences and body patterns were examined in 18 captive, socially interacting, adult cuttlefish, Sepia pharaonis, over a four-month period to determine if they provided a reliable indicator of sex. Four groups of cuttlefish were identified on the basis of size, display patterns, and mating behavior: large males, average-sized males, small males, and females. Large and average-sized males used the Intense Zebra Display 94.7% of the time observed, made flamboyant postures 100% of time observed, and were highly. aggressive towards other males and females. In contrast, small males did not use elaborate patterning (used a muted Zebra Display instead), did not make flamboyant postures, and were not aggressive towards other males or females. They rarely exhibited the Intense Zebra Display (5.3%), but faint stripes were always visible on their fourth arms. Females were usually mottled with very faint stripes visible on their mantle; they completely lacked stripes on their fourth arms. Females never approached males or other females aggressively. Posthumous dissection of all cuttlefish verified that the use of these differences in body patterning and posture provided a highly reliable method of identifying males from females. Subsequent analysis of videotaped data also demonstrated differences in reproductive success between the different size classes of males. While there was a trend for the largest males and smallest males to mate most frequently compared to average-sized males, this trend was not significant. Also, while large males seemed to have longer duration matings compared to small males (mean duration 213 sec vs. 98.5 sec), small sample sizes precluded the use of statistical tests to determine if these differences were significant. Only large and average-sized males interacted; small males were rarely approached, possibly due to their muted body patterns and female-like behaviors. Behavioral transition sequences were calculated for malemale approaches and matings, which demonstrated predictable outcomes for these interactions based on the sequences of the behaviors displayed. Mating behavior in Sepia pharaonis differed from that of S. officinalis in that two male mating strategies were observed and pre-copulatory guarding of females was more common.
CitationFoster-Aitchison, E. (2001). Social behavior of adult laboratory-reared cuttlefish, Sepia pharaonis (Unpublished thesis). Southwest Texas State University, San Marcos, Texas.
This item is restricted to the Texas State University community. TXST affiliated users can access the item with their NetID and password authentication. Non-affiliated individuals should request a copy through their local library’s interlibrary loan service.