Stereotypic behaviour is not limited to terrestrial taxa: A response to Rose et al

This comment is in response to a recent review of stereotypical behavior in captive exotic animals (Rose et al., 2017). Negative stereotypical behavior occurs across most if not all taxa, including notable aquatic invertebrates. A useful discussion of animal suffering cannot occur if we continue to ignore phylogenetically distant animals, especially when relevant information is becoming more easily available. Those interested in animal welfare and suffering must devise a plan and means to ensure all taxa are represented in such surveys and in the literature, and that their behaviors are assessed in ways meaningful to the species

Team colours matter when playing away from home: aggression biases in geographically isolated Mbuna cichlid populations

The rocky shore habitats of the African Great Lakes support high densities of cichlid fishes, including many closely-related/ecologically similar species. Aggressive behaviours between conspecifics, and perhaps heterospecifics, influences this unusually high level of species coexistence. In dichotomous choice aggression trials, male Maylandia thapsinogen were presented simultaneously with two heterospecific intruders (Maylandia emmiltos and Maylandia zebra). M. thapsinogen were significantly more aggressive towards intruders from an allopatric species (similar orange dorsal fin colour - M. emmiltos), than towards a different allopatric species (blue dorsal fin - M. zebra). Aggression biases disappeared when colour differences were masked using monochromatic lighting. A second experiment compared female aggression biases between M. emmiltos with M. thapsinogen, species similarly coloured to one another, the former possessing a yellow, as opposed to a black throat as the latter does. M. thapsinogen preferentially attacked females of their own species in full but not monochromatic light, while female M. emmiltos showed no significant bias in aggression under any lighting. Responses were not affected by olfactory cues provided by the stimulus fish. These results indicate that divergence in colour might facilitate species co-existence in some cases, but not all, which could be important should populations re-join through lake level drops

Field observations on the behavioural ecology of the stout bobtail squid Rossia macrosoma (Cephalopoda: Sepiolidae) from Scottish waters

Abstract: Bobtail squids (Cephalopoda: Sepiolidae) are emerging model organisms for a wide range of genetic, anatomical, neurophysiological and behavioural studies. However, the knowledge about their behavioural ecology is scarce and derives mainly from laboratory-based studies, whereas observations from the wild are rare. Here, we use photo and video footage collected through the Cephalopod Citizen Science Project to describe the hunting, burying, mating and spawning behaviour of the stout bobtail squid Rossia macrosoma (Delle Chiaje, 1830) from Scottish waters. Based on our long-term observations, we were able to determine a spawning period from August to November based on different behavioural traits for this species. Furthermore, we observed R. macrosoma to be able to adhere a sand grain layer (‘sand coat’) to its dorsal mantle. This behavioural feature has only been reported for two genera of the sepiolid subfamily Sepiolinae so far, and therefore represents the first of this kind for the subfamily Rossiinae. Lastly, we identified a local sea urchin species as an active predator of egg batches of R. macrosoma and discussed the cryptic egg laying behaviour of this bobtail squid species in terms of its protective traits to avoid egg predation

The Evolution of Fangs, Venom, and Mimicry Systems in Blenny Fishes

Venom systems have evolved on multiple occasions across the animal kingdom, and they can act as key adaptations to protect animals from predators. Consequently, venomous animals serve as models for a rich source of mimicry types, as non-venomous species benefit from reductions in predation risk by mimicking the coloration, body shape, and/or movement of toxic counterparts. The frequent evolution of such deceitful imitations provides notable examples of phenotypic convergence and are often invoked as classic exemplars of evolution by natural selection. Here, we investigate the evolution of fangs, venom, and mimetic relationships in reef fishes from the tribe Nemophini (fangblennies). Comparative morphological analyses reveal that enlarged canine teeth (fangs) originated at the base of the Nemophini radiation and have enabled a micropredatory feeding strategy in non-venomous Plagiotremus spp. Subsequently, the evolution of deep anterior grooves and their coupling to venom secretory tissue provide Meiacanthus spp. with toxic venom that they effectively employ for defense. We find that fangblenny venom contains a number of toxic components that have been independently recruited into other animal venoms, some of which cause toxicity via interactions with opioid receptors, and result in a multifunctional biochemical phenotype that exerts potent hypotensive effects. The evolution of fangblenny venom has seemingly led to phenotypic convergence via the formation of a diverse array of mimetic relationships that provide protective (Batesian mimicry) and predatory (aggressive mimicry) benefits to other fishes. Our results further our understanding of how novel morphological and biochemical adaptations stimulate ecological interactions in the natural world

The behavioural ecology of aggression in Lake Malawi haplochromine cichlid fish

Aggression is ubiquitous in the animal kingdom and a major field of investigation within the area of behavioural ecology. The haplochromine cichlid fish have been used extensively in studies relating not only to the behavioural ecology of aggression but also with respect to how aggression may play a role in the spectacular diversity found within the African Great Lakes. In the first half of this thesis, I investigate the nature of aggression within the rock dwelling fish of Lake Malawi. Aggression biases within polymorphic populations are initially investigated with field work determining the consequences of rare morph advantage. This is followed by experiments determining which cues males and females may use; lastly a pair of recently diverged allopatric species is studied to determine what may happen should secondary contact occur. The second half of this thesis focuses on the behaviorual ecology of female aggression. Females exhibiting the ancestral condition of post brood care are compared to a species with the more derived condition of no post release care. Non-maternal aggression is investigated with comparisons of the type of behavior used by males and females. When and why females are aggressive is also investigated. The results of this thesis suggest that overall a common morph bias may exist in some populations and the consequences are manifested in a rare morph advantage. Colour is important in aggression biases but potentially not limited to the dorsal region. Females and males use different kinds of aggressive behaviors and brooding females are able to vary levels of aggression towards different types of threat.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Use of a translucent refuge for Xenopus tropicalis with the aim of improving welfare

Xenopus tropicalis is an increasingly important animal model in a variety of biological research fields. In many countries legislation exists to promote and increase welfare wherever possible, including the ability to view animals during daily husbandry with minimal stress to the animal. X. tropicalis (n = 16) refuge use was investigated; it was found that the animals significantly preferred black opaque overhead cover to open-ended pipes or closed-off ceramic plants pots in refuge choice experiments. This experiment was repeated by replacing the opaque black overhead cover with red filters. A significant preference for overhead cover was seen for the red translucent cover compared with other available refuges, suggesting that X. tropicalis may adopt translucent refuges due to their visual inabilities. The inability of frogs to see certain wavelengths of light may allow staff to view them whilst simultaneously providing the refuge of choice

Can cephalopods vomit? Hypothesis based on a review of circumstantial evidence and preliminary experimental observations.

In representative species of all vertebrate classes, the oral ejection of upper digestive tract contents by vomiting or regurgitation is used to void food contaminated with toxins or containing indigestible material not voidable in the feces. Vomiting or regurgitation has been reported in a number of invertebrate marine species (Exaiptasia diaphana, Cancer productus, and Pleurobranchaea californica), prompting consideration of whether cephalopods have this capability. This “hypothesis and theory” paper reviews four lines of supporting evidence: (1) the mollusk P. californica sharing some digestive tract morphological and innervation similarities with Octopus vulgaris is able to vomit or regurgitate with the mechanisms well characterized, providing an example of motor program switching; (2) a rationale for vomiting or regurgitation in cephalopods based upon the potential requirement to void indigestible material, which may cause damage and ejection of toxin contaminated food; (3) anecdotal reports (including from the literature) of vomiting- or regurgitation-like behavior in several species of cephalopod (Sepia officinalis, Sepioteuthis sepioidea, O. vulgaris, and Enteroctopus dofleini); and (4) anatomical and physiological studies indicating that ejection of gastric/crop contents via the buccal cavity is a theoretical possibility by retroperistalsis in the upper digestive tract (esophagus, crop, and stomach). We have not identified any publications refuting our hypothesis, so a balanced review is not possible. Overall, the evidence presented is circumstantial, so experiments adapting current methodology (e.g., research community survey, in vitro studies of motility, and analysis of indigestible gut contents and feces) are described to obtain additional evidence to either support or refute our hypothesis. We recognize the possibility that further research may not support the hypothesis; therefore, we consider how cephalopods may protect themselves against ingestion of toxic food by external chemodetection prior to ingestion and digestive gland detoxification post-ingestion. Reviewing the evidence for the hypothesis has identified a number of gaps in knowledge of the anatomy (e.g., the presence of sphincters) and physiology (e.g., the fate of indigestible food residues, pH of digestive secretions, sensory innervation, and digestive gland detoxification mechanisms) of the digestive tract as well as a paucity of recent studies on the role of epithelial chemoreceptors in prey identification and food intake

Prospective severity classification of scientific procedures in cephalopods: Report of a COST FA1301 Working Group Survey

Cephalopods are the first invertebrate class regulated by the European Union under Directive 2010/63/EU on the protection of animals used for scientific purposes, which requires prospective assessment of severity of procedures. To assist the scientific community in establishing severity classification for cephalopods we undertook a web-based survey of the EU cephalopod research community as represented by the participants in the COST Action FA1301-CephsInAction. The survey consisted of 50 scenarios covering a range of procedures involving several cephalopod species at different life-stages. Respondents (59 people from 15 countries) allocated a severity classification to each scenario, or indicated that they were unable to decide (UTD). Analyses evaluated score distributions and clustering. Overall, the UTD scores were low (7.0 ± 0.6%) and did not affect the severity classification. Procedures involving paralarvae and killing methods (not specified in Annexe IV) had the highest UTD scores. Consensus on non-recovery procedures was reached consistently, although occasionally non-recovery appeared to be confused with killing methods. Scenarios describing procedures above the ‘lower threshold’ for regulation, including those describing behavioural studies, were also identified and allocated throughout the full range of severity classifications. Severity classification for scenarios based on different species (e.g., cuttlefish vs. octopus) was consistent, comparable and dependent on potentially more harmful interventions. We found no marked or statistically significant differences in the overall scoring of scenarios between the demographic sub-groups (age, gender, PhD, cephalopod experience). The COST Action FA1301 survey data provides a basis for a prospective severity classification for cephalopods to serve as guide for researchers, project assessors and regulators

Microplastics presence in cultured and wild-caught cuttlefish, Sepia officinalis

Amongst cephalopods microplastics have been reported only in jumbo squid gut. We investigated microplastics in the digestive system of wild cuttlefish (Sepia officinalis) as they are predators and prey and compared the stomach, caecum/intestine and digestive gland (DG) of wild and cultured animals, exposed to seawater from a comparable source. Fibers were the most common type (≈90% of total count) but were ≈2× higher in relation to body weight in wild vs. cultured animals. Fibers were transported to the DG where the count was ≈2× higher /g in wild (median 1.85 fibers/g) vs. cultured. In wild-caught animals the DG was the predominant location but in cultured animals the fibers were more evenly distributed in the digestive tract. The potential impact of microplastics on health of cuttlefish is discussed. Cuttlefish represent a previously unrecognized source of microplastic trophic transfer to fish and finding fibers in cultured animals has implications for aquaculture