Male Mating Posture and Courtship Coloration of the Temperate Marine Tubesnout,Aulorhynchus flavidus(Gill)

Abstract

Species that engage in sexual reproduction often exhibit dynamic physical features and behavioral actions that serve to signal conspecifics. Body posture, vocalizations or the incorporation of bright coloration are typically used to establish dominance (Wiley 1973, Warner 1975, Clarke and Faulkes 1997, Peterson and Jacobs 2002) alert conspecifics of nearby threats or foraging opportunities (Godin and Morgan 1985, Beauchamp and Heeb 2001, Le Roux et al. 2009, Townsend et al. 2011) and for breeding purposes (Wiley 1973, Hagen et al. 1980, Christy 1983, Gibson 1989, DeMartini and Sikkel 2006). In many species females select a male based on their behavioral display of some desirable trait or their ability to express dominance or competitive superiority over other potential mates (DeMartini and Sikkel 2006). Such criteria are often not mutually exclusive in that particular features or actions may act to deter competitor males while simultaneously attracting females (Hagen et al. 1980, Cairns 1982). Understanding such physical characteristics or behavioral signals improves our knowledge of reproductive systems within and among taxonomic groups. Reproductive strategies have been well documented in the marine realm, including monogamous pairs (Whiteman and Cote 2004), large broadcast breeding aggregations (Coleman et al. 1996, Colin 1996, Carolsfeld et al. 1997), sneak copulation (Pilastro and Bisazza 1999, Hurtado-Gonzales and Uy 2010) and nesting species (Limbaugh 1964, Wiley 1973). Limbaugh (1962) previously described the nesting habitat for the temperate marine tubesnout, Aulorhynchus flavidus (Gill), but male mating behavior has not been characterized. A proposed description of male mating behavior is reported here from observations of A. flavidus on display at the Aquarium of the Pacific (AOP) in Long Beach, California during early May, 2013. Male A. flavidus pelvic fins are red in color (Fig. 1A) and are thought to remain that way year round (Love 2011). The heads of males are also dark blue to black with a prominent iridescent blue patch on their snout (Fig. 1B). Iridescent blue spots/coloration have also been observed along the full body length of males (Love 2011) while females are a drab brownish color throughout (Fig. 2). Although typically found at depths of 20 m, and as deep as 37 m (Love 2011), the preferred nesting habitat of A. flavidus is the upper blades of the macrophyte Macrocystis pyrifera. While bright coloration is common to tropical waters, it is disfavored in temperate marine habitats due to low light penetration at depth. The conspicuous coloration of males may be apparent only when actively breeding in the upper water column where red light is still present. It appears the pelvic fins are often folded up against the body (Fig. 1B) and covered partially by the pectoral fins when they are not actively displaying them. The anterior underside of male threespine stickleback (Gasterosteus aculeatus), another gasteriform species, are also red (Hagen et al. 1980) and both species breed in shallower water than they are typically found (,20– 30 m depth). Similarities in external morphology despite differences in breeding habits Bull. Southern California Acad. Sci. 113(3), 2014, pp. 176–179 E Southern California Academy of Sciences, 2014