Biology 342 Fall 2014
Emily Merfeld & Nicolette Tapia
The Development of Camouflage
Cephalopods develop through three general stages: from eggs to paralarvae, from paralarvae to subadults, and from subadults to adults (Robin 2014). Cuttlefish development is unique in that juveniles in the subadult stage are miniature replicas of the adult: from birth they start to show complex patterning behaviors similar to that of adult cuttlefish, as camouflage in the cuttlefish is an innate behavior, not learned. However, cuttlefish do show plasticity in response to the environment throughout development, especially through differences perceived by the visual system, and the speed of maturation of patterning that cuttlefish show at birth is dependent on the visual enrichment of the embryonic environment, and experience with different visual patterns can lead to different concealment patterning in adulthood (Lee 2015, 2010; Poirier 2005) (Figure 2). The visual system of the cuttlefish is fully developed at birth and the cuttlefish is the only known animal to learn visual images as embryos, such as prey, which affects their learning and preferences as adults (Buresi 2014; Darmaillacq 2008). Response to visual cues can be measured by mantle contractions, which have been recorded in stage 25 embryos, one of the last stages of embryotic development, lending itself to the complexity of the visual system (Romagny 2012). The visual system of the cuttlefish is extremely important as it mediates many behaviors, such as the patterning system and visual lateralization used in hunting (Jozet-Alves 2012).
Figure 1. Visual representation of some of the 34 components of cuttlefish patterning.
The produced patterns used in camouflage are built from specific components: 34 chromatic, 6 textural, 8 postural, and 6 locomotor (Figure 1). Juvenile cuttlefish are only missing 8 of the chromatic and 2 of the postural components. Even though cuttlefish are already endowed with many of the mechanisms for patterning at birth, their patterning does develop over time and can be observed through behavior and modulated by the environment. Young cuttlefish primarily use patterning for concealment, whereas adult cuttlefish extend the use of patterning to interspecific and intraspecific signaling. With maturation, males develop the ability to produce a characteristic zebra pattern, which is used to attract mates (Hanlon and Messenger 1998). The majority of cuttlefish reproduce in their second year of life, and the remainder reproduce in their first year (Gauvrit 1997).
Cuttlefish eye. Image: http://www.sciencebuzz.org/blog/eye-beholder-cuttlefish-embryos-remember-prey
Cuttlefish embryo. Image: http://sciworthy.com/science-news/science-authors/let-me-hatch/