Dynamic Courtship Signals and Mate Preferences in Sepia plangon

Abstract

Communication in cuttlefish includes rapid changes in skin coloration and texture, body posture and movements, and potentially polarized signals. The dynamic displays are fundamental for mate choice and agonistic behavior. We analyzed the reproductive behavior of the mourning cuttlefish Sepia plangon in the laboratory. Mate preference was analyzed via choice assays ( n = 33) under three sex ratios, 1 male (M): 1 female (F), 2M:1F, and 1M:2F. We evaluated the effect of modifying polarized light from the arms stripes and ambient light with polarized and unpolarized barriers between the cuttlefish. Additionally, to assess whether a particular trait was a determinant for mating, we used 3D printed cuttlefish dummies. The dummies had different sets of visual signals: two sizes (60 or 90 mm mantle length), raised or dropped arms, high or low contrast body coloration, and polarized or unpolarized filters to simulate the arms stripes. Frequency and duration (s) of courtship displays, mating, and agonistic behaviors were analyzed with GLM and ANOVAs. The behaviors, body patterns, and their components were integrated into an ethogram to describe the reproductive behavior of S. plangon . We identified 18 body patterns, 57 body patterns components, and three reproductive behaviors (mating, courtship, and mate guarding). Only sex ratio had a significant effect on courtship frequency, and the male courtship success rate was 80%. Five small (ML < 80 mm) males showed the dual-lateral display to access mates while avoiding fights with large males; this behavior is characteristic of male “sneaker” cuttlefish. Winner males showed up to 17 body patterns and 33 components, whereas loser males only showed 12 patterns and 24 components. We identified 32 combinations of body patterns and components that tended to occur in a specific order and were relevant for mating success in males. Cuttlefish were visually aware of the 3D-printed dummies; however, they did not start mating or agonistic behavior toward the dummies. Our findings suggest that in S. plangon , the dynamic courtship displays with specific sequences of visual signals, and the sex ratio are critical for mate choice and mating success.

The brain structure and the neural network features of the diurnal cuttlefish Sepia plangon

“…This early vision-related capability, presumably prepares these species for the post-hatching environment such as camouflage among coral, rubble or shallow coastal environments (e.g., seagrass meadow). 19 On the other hand, nocturnal S. officinalis and S. japonica often burry in sand to conceal the body outline during daytime and are more active hunting and interacting at night 4 , 7 and therefore do not need the OPL size or complexity seen in the diurnal species ( Figure 3 E).…”

“…Both chromatic and hydrostatic (papillae) systems are regularly used in the formation of cuttlefish body patterns for camouflage and courtship display. 1 , 3 , 12 , 13 , 16 , 19 For instance, S. plangon uses 34 chromatic components combined with 3 textural and 14 postural components for dynamic courtship displays (11 patterns used by female; 18 by male). 19 In contrast, squid mainly rely on chromatic components such as S. lessoniana assembling 27 chromatic components during reproductive interactions (7 patterns by female; 12 by male).…”

“…1 , 3 , 12 , 13 , 16 , 19 For instance, S. plangon uses 34 chromatic components combined with 3 textural and 14 postural components for dynamic courtship displays (11 patterns used by female; 18 by male). 19 In contrast, squid mainly rely on chromatic components such as S. lessoniana assembling 27 chromatic components during reproductive interactions (7 patterns by female; 12 by male). 77 The complexity of camouflage tricks cuttlefish and squid demonstrate is also substantial, but again the former outstripping the latter.…”

“…1 , 10 , 11 , 12 , 13 In fact, cuttlefishes spend most of their time in camouflage mode but may also rapidly switch body patterning to emphasize their presence, produce startle threats, attract mates or indeed cheat rival males. 1 , 14 , 15 , 16 , 17 , 18 , 19 The ability to alter their visual appearance is driven by neurally controlled chromatophore (colors) and muscular hydrostat (papillae) systems coordinated by circuits from a set of brain lobes; the optic lobe (OPL), the lateral basal lobe (lB) and the chromatophore lobe (Ch)). 12 , 20 Despite some recent attempts to prove otherwise, 21 several previous studies have shown cuttlefish to be colorblind, 10 , 17 , 22 , 23 their camouflage achieved through intensity, pattern and textural match alone on a baseline palette of ocean floor colors.…”

Ritualized ink use during visual courtship display by males of the sexually dimorphic cuttlefish Sepia andreana

“…These morphological characteristics enable males to gently stimulate a large area of female skin simultaneously. Although tactile communication in which males touch females with the tips of the arms during courtship has been reported for a few cuttlefish species (Hanlon & McManus, 2020; López Galán et al., 2020), Stroking with the unique sexually dimorphic arms of S. andreana would provide stimulation very different from that produced by the typical short and tapering arms of other cuttlefish species, and consequently appears to be an extreme form of a tactile courtship signal that facilitates female acceptance and enhances species recognition.…”