Behaviour and mimicry in the juvenile and subadult life stages of the mesopelagic squid Chiroteuthis calyx

Abstract

Cephalopods are common inhabitants of the deep ocean's mesopelagic zones worldwide, yet very little is known about their behaviour due to the inaccessibility of this environment. Recent studies suggest that, contrary to historical predictions, deep-sea cephalopods exhibit a wide array of visual behaviours. We used in situ footage from remotely operated vehicles, coupled with laboratory observations to assemble the first behavioural ethogram for the juvenile and subadult life stages of the mesopelagic squid, Chiroteuthis calyx. The number of behavioural components we described is comparable to or exceeds those recognized in ethograms of shallow-water teuthids. We used the ethogram to make a detailed behavioural comparison between the juvenile and subadult life stages, and found distinctly different patterns. Behavioural and morphological differences between the two life stages support the hypothesis that juvenile C. calyx mimic the abundant siphonophore Nanomia bijuga, in order to deter predation.

Energy-Rich Mesopelagic Fishes Revealed as a Critical Prey Resource for a Deep-Diving Predator Using Quantitative Fatty Acid Signature Analysis

“…this is C. calyx which has been classified in some studies as a midwater migrator (Roper and Young, 1975), since it undergoes ontogenic migration (i.e., depth distribution becomes deeper with age). However, adult C. calyx typically do not migrate into the epipelagic zone (Burford et al, 2014).…”

Myogenic activity and serotonergic inhibition in the chromatophore network of the squids, Dosidicus gigas (Family Ommastrephidae) and Doryteuthis opalescens (Family Loliginidae)

“…Chromatophore displays of living squid (chromogenic behaviors) have been described for other families (Moynihan, 1983a,b;Bush et al, 2009;Burford et al, 2014;Rosen et al, 2015), but comparative work on anatomy and control mechanisms is lacking.…”

Running the Gauntlet: Assessing the Threats to Vertical Migrators

“…Dynamic variables are rife in the deep pelagic habitat and they occur on day-to-day time scales, seasonally, episodically, and in patterns we cannot yet resolve or link to any particular explanation. Despite the vagaries imposed by such variability, one great value of a multi-decadal time series is that consistent and repeating patterns emerge during analysis which can reveal some of the fundamental ecological characteristics of the animals that comprise these vast communities (Robison et al, 2005;Zeidberg and Robison, 2007;Burford et al, 2015).…”

“…Chiroteuthis calyx exhibits a complex behavioral repertoire, especially for an animal that lives perpetually in a habitat of little or no ambient illumination (Burford et al, 2015). The fourth arm on each side of C. calyx is thicker and longer than the other three, and has a groove through which the slender feeding tentacle is deployed.…”