Sensorial Hierarchy in Octopus vulgaris's Food Choice: Chemical vs. Visual.

Valeria Maselli,Massimo Aria,Maria Buglione,Al-Sayed Al-Soudy,Gianluca Polese,Anna Di Cosmo

doi:10.3390/ani10030457

Abstract

Simple SummaryColeoids are cephalopods endowed with a highly sophisticated nervous system with keen sense organs and an exceptionally large brain that includes more than 30 differentiated lobes. Within this group, Octopus vulgaris, well known as an intelligent soft-bodied animal, has a significant number of lobes in the nervous system dedicated to decoding and integrating visual, tactile, and chemosensory perceptions. In this study, we aimed to understand the key role of chemical and visual cues during food selection in O. vulgaris. We first defined the preferred food, and subsequently, we set up five different problem-solving tasks, in which the animal’s choice is guided by visual and chemosensory signals, either alone or together, to evaluate whether individual O. vulgaris uses a sensorial hierarchy. Our behavioural experiments show that this species does integrate different sensory information from chemical and visual cues during food selection; however, our results indicate that chemical perception provides accurate and faster information leading to food choice. This research opens new perspectives on O. vulgaris’ predation strategies.Octopus vulgaris possesses highly sophisticated sense organs, processed by the nervous system to generate appropriate behaviours such as finding food, avoiding predators, identifying conspecifics, and locating suitable habitat. Octopus uses multiple sensory modalities during the searching and selection of food, in particular, the chemosensory and visual cues. Here, we examined food choice in O. vulgaris in two ways: (1) We tested octopus’s food preference among three different kinds of food, and established anchovy as the preferred choice (66.67%, Friedman test p < 0.05); (2) We exposed octopus to a set of five behavioural experiments in order to establish the sensorial hierarchy in food choice, and to evaluate the performance based on the visual and chemical cues, alone or together. Our data show that O. vulgaris integrates sensory information from chemical and visual cues during food choice. Nevertheless, food choice resulted in being more dependent on chemical cues than visual ones (88.9%, Friedman test p < 0.05), with a consistent decrease of the time spent identifying the preferred food. These results define the role played by the senses with a sensorial hierarchy in food choice, opening new perspectives on the O. vulgaris’ predation strategies in the wild, which until today were considered to rely mainly on visual cues.

Highlights

IntroductionThe sensory systems of animals are crucial to detect environmental cues, and they are processed throughsystems the nervous systemare to generate appropriate behaviours [1], such asthey findingThe sensory of animals crucial to detect environmental cues, and are food, avoiding predators, identifying conspecifics, locating suitable habitat, and attracting mates [2,3,4].In processed through the nervous system to generate appropriate behaviours [1], such as finding food, aquatic as on land, chemical cues affect not suitable only individual behaviour and mates population avoidingsystems, predators, identifying conspecifics, locating habitat, and attracting dynamics, and community organisation and ecosystem function.In aquatic systems, as on land, chemical cues affect individual behaviour and populationUse ofbut sensory modalitiesorganisation may be related the ecology of the species, as prey or predator.dynamics, community and to ecosystem function.Animals different sensory modalities to search forecology food such as chemical, tactile, Use use of sensory modalities may be related to the of the species, asvibrational, prey or predator.sound, heat, and visual senses [5].Among them, while vision enables marine animals to swim directlyAnimals use different sensory modalities to search for food such as chemical, vibrational, tactile, sound, to food items when they[5].see Among it, chemoreception is vision essential to detect and locate food items,directly especially heat, and visual senses them, while enables marine animals to swim to for animals active at night or in the deep ocean [6,7,8]
Our study investigated the priority given to chemical vs. visual perception to establish the sensorial hierarchy in food choice by O. vulgaris
All octopuses touched the three kinds of food provided, exhibiting no significant differences in the first touch for the proposed foods (Table 1, Figure S2, Table S1)

Summary

Introduction

The sensory systems of animals are crucial to detect environmental cues, and they are processed throughsystems the nervous systemare to generate appropriate behaviours [1], such asthey findingThe sensory of animals crucial to detect environmental cues, and are food, avoiding predators, identifying conspecifics, locating suitable habitat, and attracting mates [2,3,4].In processed through the nervous system to generate appropriate behaviours [1], such as finding food, aquatic as on land, chemical cues affect not suitable only individual behaviour and mates population avoidingsystems, predators, identifying conspecifics, locating habitat, and attracting dynamics, and community organisation and ecosystem function.In aquatic systems, as on land, chemical cues affect individual behaviour and populationUse ofbut sensory modalitiesorganisation may be related the ecology of the species, as prey or predator.dynamics, community and to ecosystem function.Animals different sensory modalities to search forecology food such as chemical, tactile, Use use of sensory modalities may be related to the of the species, asvibrational, prey or predator.sound, heat, and visual senses [5].Among them, while vision enables marine animals to swim directlyAnimals use different sensory modalities to search for food such as chemical, vibrational, tactile, sound, to food items when they[5].see Among it, chemoreception is vision essential to detect and locate food items,directly especially heat, and visual senses them, while enables marine animals to swim to for animals active at night or in the deep ocean [6,7,8]. The sensory of animals crucial to detect environmental cues, and are food, avoiding predators, identifying conspecifics, locating suitable habitat, and attracting mates [2,3,4]. In processed through the nervous system to generate appropriate behaviours [1], such as finding food, aquatic as on land, chemical cues affect not suitable only individual behaviour and mates population avoidingsystems, predators, identifying conspecifics, locating habitat, and attracting dynamics, and community organisation and ecosystem function. See Among it, chemoreception is vision essential to detect and locate food items,directly especially heat, and visual senses them, while enables marine animals to swim to for animals active at night or in the deep ocean [6,7,8]

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