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Journal: Behavioural processes


Through the removal of parasites, dead skin and mucus from the bodies of visiting reef fish (clients), cleaner fish have a significant ecosystem function in the ecology of coral reefs. Cleaners gain nutrition from these interactions and through offering a ‘service’ are afforded protection from predators. Given these benefits, it is unclear why more fish do not engage in cleaning, and why part-time cleaning strategies exist. On coral reefs, dedicated species clean throughout their life, whereas some species are facultative, employing opportunistic and/or temporary cleaning strategies. Here, we investigate the cleaning behaviour of a facultative species to assess the relative importance of this interaction to the cleaner. Using a combination of focal and event sampling from a coral reef in Tobago, we show that cleaning is not an essential food source for facultative juvenile blue-headed wrasse (Thalassoma bifasciatum), as cleaning rate was unrelated to their foraging rate on the substrate. These wrasse displayed two cleaning strategies: stationary versus wandering cleaning, with cleaning frequency being highest for stationary cleaners. A specific cleaning location facilitated increased cleaning frequency, and wrasse cleaning rate decreased as cleaner or client abundance increased. We also compared juvenile blue-headed wrasse cleaning behaviour to a resident dedicated cleaner, the sharknose goby (Elacatinus evelynae), and showed that, in comparison, juvenile wrasse clean a narrower client range, predominately cleaning three species of gregarious free-ranging surgeonfish (Acanthurus spp.). The wrasse, however, frequently approached these clients without cleaning, which suggests that their selective cleaning strategy may be driven by the acquisition of a particular parasitic food source. Juvenile blue-headed wrasse are generalist foragers, and may thus be limited in their cleaning behaviour by their nutritional requirements, the availability of a suitable cleaning site, and fish density, which ultimately means that they do not adopt more dedicated cleaning roles within the reef community.

Concepts: Algae, Fish, Symbiosis, Coral, Coral reef, Ecosystem, Cnidaria, Caribbean


Domestic cats (Felis silvestris catus) engage in a variety of relationships with humans and can be conditioned to engage in numerous behaviors using Pavlovian and operant methods Increasingly cat cognition research is providing evidence of their complex socio-cognitive and problem solving abilities. Nonetheless, it is still common belief that cats are not especially sociable or trainable. This disconnect may be due, in part, to a lack of knowledge of what stimuli cats prefer, and thus may be most motivated to work for. The current study investigated domestic cat preferences at the individual and population level using a free operant preference assessment. Adult cats from two populations (pet and shelter) were presented with three stimuli within each of the following four categories: human social interaction, food, toy, and scent. Proportion of time interacting with each stimulus was recorded. The single most-preferred stimulus from each of the four categories were simultaneously presented in a final session to determine each cat’s most-preferred stimulus overall. Although there was clear individual variability in cat preference, social interaction with humans was the most-preferred stimulus category for the majority of cats, followed by food. This was true for cats in both the pet and shelter population. Future research can examine the use of preferred stimuli as enrichment in applied settings and assess individual cats' motivation to work for their most-preferred stimulus as a measure of reinforcer efficacy.

Concepts: Sociology, Mammal, Motivation, Cat, Gestation, Preference, Felidae, Felis


In recent years red-footed tortoises have been shown to be proficient in a number of spatial cognition tasks that involve movement of the animal through space (e.g., the radial maze). The present study investigated the ability of the tortoise to learn a spatial task in which the response required was simply to touch a stimulus presented in a given position on a touchscreen. We also investigated the relation between this task and performance in a different spatial task (an arena, in which whole-body movement was required). Four red-footed tortoises learned to operate the touchscreen apparatus, and two learned the simple spatial discrimination. The side-preference trained with the touchscreen was maintained when behaviour was tested in a physical arena. When the contingencies in the arena were then reversed, the tortoises learned the reversal but in a subsequent test did not transfer it to the touchscreen. Rather they chose the side that had been rewarded originally on the touchscreen. The results show that red-footed tortoises are able to operate a touchscreen and can successfully solve a spatial two-choice task in this apparatus. There was some indication that the preference established with the touchscreen could transfer to an arena, but with subsequent training in the arena independent patterns of choice were established that could be evoked according to the test context.

Concepts: Psychology, Educational psychology, Learning, Knowledge, Tortoise, Tortoises, Geochelone, Red-footed tortoise


Few quantitative descriptions of parturition behavior have been reported in wild nonhuman primates because the majority of births occur at night. We have recorded a daytime birth event of a primiparous black-and-white snub-nosed monkey (Rhinopithecus bieti). The partum stage lasted 4min 30 s, and the female skillfully severed the umbilical cord, ingested the placenta, and held and licked the newborn infant. During this period, the laboring female received delivery assistance from a multiparous female in same one-male unit (OMU) and female juveniles from same OMU showed great interesting during the partum. Our case study suggested that there might be considerable individual variation in birth-related behaviors.

Concepts: Pregnancy, Childbirth, Infant, Fetus, Primate, Placenta, Old World monkey, Colobinae


Echolocating bats are known to produce terminal buzz calls during pursuit and capture of airborne prey, however the use of buzz calls while drinking on the wing has not been previously investigated. In this study I recorded the first empirical evidence that bats produce terminal phase buzz calls while drinking on the wing. Every drinking pass recorded during this study was characterized by a terminal buzz which bats emitted immediately prior to touching the water surface with their mouth. The characteristic frequency (the frequency at the end or flattest portion of the pulse) of echolocation call sequences containing drinking buzzes varied from 25-50kHz, suggesting multiple bat species present at the study site emit buzzes while drinking on the wing. As feeding buzz calls appear to be ubiquitous among echolocating bat taxa, the prevalence of drinking buzzes clearly warrants further investigation. Drinking buzzes could potentially be used to document rates of drinking by bats in the same way that feeding buzzes are used to infer foraging activity.

Concepts: Animal echolocation, Bat, Flight, Wing, Flying and gliding animals, Microbat, Bats, Vesper bat


Optimality theory predicts that females tend to maximize their offspring survival by choosing the egg-laying site. In this context, the use of conspecific cues allows a more reliable assessment of the habitat quality. To test this hypothesis, Tetranychus urticae Koch is an appropriate biological model as it is a phytophagous mite living in group, protected against external aggression by a common web. Experiments were conducted to determine the respective influence of substrate (living substrate: bean leaf vs. non-living substrate: glass plate), silk and presence of conspecific eggs on the egg-laying behavior of T. urticae females. On both living and non-living substrates, the presence of silk positively influenced the probability of a female to lay an egg, but had no influence on the number of eggs deposited. The egg-laying behavior was mainly determined by the nature of the substrate with mites laying fewer eggs on a non-living substrate than on a living one. The presence of a conspecific egg had no impact on either the probability of laying an egg or on the oviposition rate. This study showed a high variability among females in their fecundity and egg-laying performance. The physiology of females (individual fecundity), the egg-laying substrate and to a lesser extent the presence of silk impacted on the decision of spider mites to lay eggs.

Concepts: Chicken, Acari, Arachnid, Tetranychus urticae, Spider mite, Tetranychus, Acariformes, Agricultural pest mites


It is commonly assumed that cats actively avoid eliminated materials (especially in multi-cat homes), suggesting regular litter box cleaning as the best defense against out-of-box elimination. The relationship between previous use and litter box appeal to familiar subsequent users is currently unknown. The purpose of this study was to investigate the relationship between previous litter box use and the identity of the previous user, type of elimination, odor, and presence of physical/visual obstructions in a multi-cat household scenario. Cats preferred a clean litter box to a dirty one, but the identity of the previous user had no impact on preferences. While the presence of odor from urine and/or feces did not impact litter box preferences, the presence of odorless faux-urine and/or feces did - with the presence of faux-feces being preferred over faux-urine. Results suggest neither malodor nor chemical communication play a role in litter box preferences, and instead emphasize the importance of regular removal of physical/visual obstructions as the key factor in promoting proper litter box use.

Concepts: The Key, Household, Cat, Preference, Income quintiles, Home, Cleanliness


Animalsreadily learn the timing between salient events. They can even adapt their timed respondingto rapidly changing intervals, sometimesas quickly as a single trial. Recently, drift-diffusion models-widely used to model response times in decision making-have been extended with newlearning rules that allow themto accommodate steady-state interval timing, including scalar timing and timescale invariance. These time-adaptive drift-diffusion models (TDDMs) work by accumulating evidence of elapsing time through their driftrate, thereby encoding the to-be-timed interval. One outstanding challenge for these models lies in the dynamics of interval timing-when the to-be-timed intervals are non-stationary. On these schedules, animals often fail to exhibit strict timescale invariance, as expected by the TDDMs and most other timing models. Here, we introduce a simple extension to these TDDMs, where the response threshold is a linear function of the observed event rate. This new model compares favourably against the basic TDDMs and the multiple-time-scale (MTS) habituation model when evaluated against three published datasets on timing dynamics in pigeons. Our results suggest that the threshold for triggering responding in interval timing changes as a function of recent intervals.

Concepts: Time, Function, Model, Linear function, Enharmonic, Renaissance music, Music theory


We investigated suboptimal choice between different work requirements in pigeons (Columba livia), namely the sunk cost effect, an irrational tendency to persist with an initial investment, despite the availability of a better option. Pigeons chose between two keys, one with a fixed work requirement to food of 20 pecks (left key), and the other with a work requirement to food which varied across conditions (center key). On some trials within each session, such choices were preceded by an investment of 35 pecks on the center key, whereas on others they were not. On choice trials preceded by the investment, the pigeons tended to stay and complete the schedule associated with the center key, even when the number of pecks to obtain reward was greater than for the concurrently available left key. This result indicates that pigeons, like humans, commit the sunk cost effect. With higher work requirements, this preference was extended to trials where there was no initial investment, so an overall preference for the key associated with more work was evident, consistent with the work ethic effect. We conclude that a more general work ethic effect is amplified by the effect of the prior investment, that is, the sunk cost effect.

Concepts: Costs, Choice, Preference, Microeconomics, Columbidae, Rock Pigeon, Sunk costs, Psychology of previous investment


Leyhausen’s (1979) work on cat behaviour and facial expressions associated with offensive and defensive behaviour is widely embraced as the standard for interpretation of agonistic behaviour in this species. However, it is a largely anecdotal description that can be easily misunderstood. Recently a facial action coding system has been developed for cats (CatFACS), similar to that used for objectively coding human facial expressions. This study reports on the use of this system to describe the relationship between behaviour and facial expressions of cats in confinement contexts without and with human interaction, in order to generate hypotheses about the relationship between these expressions and underlying emotional state. Video recordings taken of 29 cats resident in a Canadian animal shelter were analysed using 1-0 sampling of 275 4-second video clips. Observations under the two conditions were analysed descriptively using hierarchical cluster analysis for binomial data and indicated that in both situations, about half of the data clustered into three groups. An argument is presented that these largely reflect states based on varying degrees of relaxed engagement, fear and frustration. Facial actions associated with fear included blinking and half-blinking and a left head and gaze bias at lower intensities. Facial actions consistently associated with frustration included hissing, nose-licking, dropping of the jaw, the raising of the upper lip, nose wrinkling, lower lip depression, parting of the lips, mouth stretching, vocalisation and showing of the tongue. Relaxed engagement appeared to be associated with a right gaze and head turn bias. The results also indicate potential qualitative changes associated with differences in intensity in emotional expression following human intervention. The results were also compared to the classic description of “offensive and defensive moods” in cats (Leyhausen 1979) and previous work by Gourkow et al. (2014a) on behavioural styles in cats in order to assess if these observations had replicable features noted by others. This revealed evidence of convergent validity between the methods However, the use of CatFACS revealed elements relating to vocalisation and response lateralisation, not previously reported in this literature.

Concepts: Scientific method, Psychology, Cat, Emotion, Felidae, Tongue, Felis, Cat communication