%0 Journal Article
%T Stealth Effect of Red Shell in Laqueus rubellus (Brachiopoda, Terebratulida) on the Sea Bottom: An Evolutionary Insight into the Prey-Predator Interaction
%A Yuta Shiino
%A Kota Kitazawa
%J ISRN Zoology
%D 2012
%R 10.5402/2012/692517
%X The selective advantage of empire red coloration in the shell of Laqueus rubellus (a terebratulid brachiopod) was examined in terms of prey-predator interactions. The study was based on a comparison of benthic suspension feeders living at a depth of about 130£¿m in Suruga Bay, Japan, with special reference to their visibility under visible and near-infrared light conditions. Almost all species exhibited red coloration under visible light, while only the shell of Laqueus was dark under infrared light, similar to rocks and bioclasts. Given the functional eyes of macropredators such as fishes and coleoids, which are specialized to detect light in the blue-to-green visible spectrum, and even the long-wavelength photoreceptors of malacosteids, Laqueus should avoid both visible and infrared detection by predators inhabiting the sublittoral bottom zone. This fact suggests that terebratulids have evolved the ability to remain essentially invisible even as the optic detection abilities of predators have improved. The present hypothesis leads to the possibility that the appearance of marine organisms is associated with the passive defensive strategy, making possible to provide a lower predation risk. 1. Introduction Most organisms in natural settings live within a competitive framework, and this reciprocal interaction has been the driving force in evolutionary arms races [1]. Predator-prey interactions are an interesting subject for research on evolutionary arms races because the corresponding adaptations of prey and predator demonstrate how organisms survive to enhance and/or modify their behavioural and functional performances within a biotic community [2]. If either the predator or the prey cannot adapt to relevant changes in the other, extinction may occur. Benthic suspension feeders, such as bivalves, brachiopods, and some echinoderms, have been exposed to predation for macropredators throughout the Phanerozoic. They have developed several strategies toward off-potential predators. For example, some bivalves exhibit thickened valves that physically protect them against predator attacks [3¨C5], while others exhibit enhanced burrowing or swimming ability [6¨C8]. Crinoids and ophiuroids have evolved the ability to autotomise and regenerate tentacles that are bitten off by predators [9¨C11]. In contrast, rhynchonelliformean brachiopods are immobile sessile organisms with comparatively thin shells [12, 13] that appear to have evolved neither physical, physiological, nor behavioural defences against predators. Among rhynchonelliformean brachiopods, terebratulids are
%U http://www.hindawi.com/journals/isrn.zoology/2012/692517/