Presence Of Novel Objects Research Articles

Conspecific alarm calls prevent the attenuation of neophobia behavior in wild-caught house sparrows (Passer domesticus)

Some individuals respond to new objects, foods, or environments with wariness (neophobia), whereas others are willing to approach and explore. Because novel stimuli can represent both dangers and resources, group-living species may show adaptive plasticity in neophobia in response to social cues. To better understand how conspecific calls can influence neophobia in a highly gregarious species, we exposed individual house sparrows (Passer domesticus) to either conspecific alarm calls (n = 12), conspecific contact calls (n = 12), or no playback (n = 12) and measured latency to feed in the presence of novel objects. We also measured novelty responses with no sound the week before and after the sound treatment week for all individuals. Relative to no playback and contact calls, we predicted that conspecific alarm calls would increase neophobia behavior during the acoustic trial and that these effects would persist the week after exposure. Instead, we found that individuals in the contact call and no playback groups became less neophobic as weeks progressed, while the alarm call group showed no attenuation of neophobia. There was a significant interaction between week and treatment, where neophobia responses over the three weeks were significantly different for individuals exposed to alarm calls compared to the contact and no playback groups combined. These results suggest that house sparrows learn social information about potentially threatening stimuli from conspecific alarm calls; here, that novel objects may be dangerous.

Exploring differences in neophobia and anti-predator behaviour between urban and rural mountain chickadees

Abstract Urbanization is changing natural landscapes worldwide, pushing species to quickly acclimate or adapt if they are to survive in urban environments. Mountain chickadees (Poecile gambeli) readily nest in both urban and rural environments without suffering apparent reproductive costs. However, whether urban-nesting chickadees are successful in these environments due to differences in behaviour between urban and rural birds remains untested. We examined the behavioural responses of urban and rural nesting mountain chickadee females when presented with a novel object (red plastic cup) or simulated predator (imitation squirrel model) at the nest. Behavioural responses depended on both the type of model and the habitat. As expected, mountain chickadees responded more strongly to squirrel models than novel objects; however, the magnitude of the difference in response depended on habitat. Urban birds seemingly ignored the novel object, spending little time investigating, and re-entering the nest box quickly. In contrast, rural birds spent more time reacting to the novel object and alarm calling within 5 m of the nest. When presented with a predator model, the urban birds reacted relatively more strongly (compared to the novel stimulus) than rural birds, spending more time within 5 m of the nest and alarm calling. These results suggest that either mountain chickadees in urban environments quickly acclimatize to the presence of novel objects or, potentially, that less neophobic birds disproportionately settle in urban environments or experience positive selection in urban areas. Either way, reduced neophobia may aid in mountain chickadees’ ability to readily and successfully nest in such habitats.

Learn Fast, Segment Well: Fast Object Segmentation Learning on the iCub Robot

The visual system of a robot has different requirements depending on the application: it may require high accuracy or reliability, be constrained by limited resources or need fast adaptation to dynamically changing environments. In this work, we focus on the instance segmentation task and provide a comprehensive study of different techniques that allow adapting an object segmentation model in presence of novel objects or different domains. We propose a pipeline for fast instance segmentation learning designed for robotic applications where data come in stream. It is based on an hybrid method leveraging on a pre-trained CNN for feature extraction and fast-to-train Kernel-based classifiers. We also propose a training protocol that allows to shorten the training time by performing feature extraction during the data acquisition. We benchmark the proposed pipeline on two robotics datasets and we deploy it on a real robot, i.e. the iCub humanoid. To this aim, we adapt our method to an incremental setting in which novel objects are learned on-line by the robot. The code to reproduce the experiments is publicly available on GitHub.

Novel objects alter immediate early gene expression globally for ZENK and regionally for c-Fos in neophobic and non-neophobic house sparrows

Neophobia – an animal’s reluctance to approach novel objects, try new foods, or explore unfamiliar environments – affects whether animals can adapt to new environments and exploit novel resources. However, despite its importance, the neurobiological mechanisms underlying this personality trait are poorly understood. In this study, we examined regional brain activity using the expression of two immediate early genes (IEGs), ZENK and c-Fos, in response to novel objects or control conditions in captive house sparrows (Passer domesticus, n = 22). When exposed to novel objects, we predicted that we would see differential IEG activity in brain regions involved in regulating stress and emotion (hippocampus, medial ventral arcopallium, lateral septum), reward and learning (striatum), and executive function (NCL) between neophobic and non-neophobic individuals. To classify birds by phenotype, we used behavior trials that tested willingness to approach a food dish in the presence of several different novel objects, habituation to one novel object, and willingness to try several different novel foods. We then exposed birds to a new novel object or a control condition and assessed protein expression of two IEGs in neophobic vs non-neophobic individuals after this final exposure. An analysis of average sparrow feeding times in the presence of novel objects showed a bimodal distribution of neophobia behavior. There was also high repeatability of individual novel object responses, and average responses to all three trial types (novel object, novel food, and habituation to a novel object) were significantly correlated. Although we saw no differences between neophobic and non-neophobic birds in IEG expression in response to novel objects in any of the 6 brain regions examined, there was a significant global decrease in ZENK expression and a significant increase in c-Fos expression in the medial ventral arcopallium and the caudal hippocampus in response to novel objects compared to controls, suggesting that these two regions may be important in novelty detection and threat perception. Additionally, there was no object effect in the rostral hippocampus, which supports the hypothesis that the avian hippocampus may have a rostrocaudal functional gradient similar to the septotemporal gradient in mammals.

A transient reduction in circulating corticosterone reduces object neophobia in male house sparrows

Aversive reactions to novelty (or “neophobia”) have been described in a wide variety of different animal species and can affect an individual's ability to exploit new resources and avoid potential dangers. However, despite its ecological importance, the proximate causes of neophobia are poorly understood. In this study, we tested the role of glucocorticoid hormones in neophobia in wild-caught house sparrows (Passer domesticus, n = 11 males) by giving an injection of the drug mitotane that reduced endogenous corticosterone for several days or a vehicle control, and then examined the latency to feed when the food dish was presented with or without a novel object in, on, or near the dish. Each sparrow was exposed to multiple novel object and control trials and received both vehicle control and mitotane treatments, with a week between treatments to allow the drug to wash out. As found previously, all novel objects significantly increased sparrows' latency to feed compared to no object present. Reducing corticosterone using mitotane significantly reduced the latency to feed in the presence of novel objects. In control trials without objects, mitotane had no significant effects on feeding time. Although we have shown that corticosterone affects neophobia, further studies using specific receptor agonists and antagonists will help clarify the neurobiological mechanisms involved and determine whether baseline or stress-induced corticosterone is driving this effect. These results suggest that increased glucocorticoids (e.g., due to human-induced stressors) could increase neophobia, affecting the ability of individuals to exploit novel resources, and, ultimately, to persist in human-altered environments.

Existence of wild brown rats (Rattus norvegicus) that are indifferent to novel objects.

Exposure to novel objects typically evokes avoidance behavior in wild animals, which is called neophobia. We previously found that wild brown rats (Rattus norvegicus) that were trapped in a park in downtown Tokyo, Japan, exhibited neophobia. We also found that this behavior was accompanied by the activation of the basolateral complex of the amygdala (BLA). Previous studies have suggested that genetic factors are the primary determinants of neophobia. Since rats in cities form populations with distinct genetic characteristics, it is reasonable to assume that wild rats caught at different locations in urban centers will exhibit different levels of neophobia. Here we assessed the intensity of neophobia in wild rats trapped at a wholesale market in Tokyo. Although we performed exactly the same experiment in which neophobia was observed in wild rats trapped at the park, the presence of novel objects did not affect the behaviors of wild rats trapped at the market. Conversely, laboratory rats showed approach and exploratory behaviors as seen in the previous study, suggesting that the experiment was performed appropriately. Compared to the laboratory rats, the lack of behavioral changes in the wild rats was accompanied by fewer Fos immunoreactive cells in the BLA. In addition, the numbers of Fos immunoreactive cells in the bed nucleus of the stria terminalis and ventromedial hypothalamus were similar between the two types of rats. The results demonstrated the existence of wild rats that were indifferent to novel objects.

Behavioural polymorphism in wintering white-throated sparrows, Zonotrichia albicollis

Behavioural polymorphisms associated with morphs with a known genetic basis are interesting to study since they provide a model system to investigate the molecular basis of complex behaviours. White-throated sparrows are one of such rare models, presenting two morphologies and behavioural types, tan and white, caused by a chromosomal rearrangement. The behavioural differences have been mainly studied during reproduction, defining two morph-specific breeding strategies and different levels of aggression between morphs. Outside of the breeding season, the morphological differences are less apparent, morphs are more difficult to distinguish and the behavioural polymorphism is poorly understood. In this study, we caught wild individuals during the winter, determined their morph by genetic analysis, and analysed the differences in behaviour between morphs when encountering a novel object under standardized conditions in captivity. White morphs are more aggressive during reproduction; therefore, we expected them to be less affected by the presence of the novel object than tan morphs; animal personality research shows that more aggressive individuals are less affected by the presence of novel objects (i.e. neophilic). Contrary to our expectations, white morphs were more neophobic than tan morphs, and within morphs, males were more neophobic than females. Furthermore, white morph individuals and males of both morphs suffered greater weight loss during captivity compared to tan morphs and females, respectively, suggesting that the response to captivity-induced stress differs between morphs and between sexes. Finding behavioural differences between morphs not related to reproduction implies a broader impact of the effects of the chromosomal rearrangement on the behavioural polymorphism in this species.

Physiological outcomes of calming behaviors support the resilience hypothesis in horses

To manage a stressful stimulus animals react both behaviorally and physiologically to restore the homeostasis. In stable horses, a stressful stimulus can be represented by social separation, riding discomfort or the presence of novel objects in their environment. Although Heart Rate Variability is a common indicator of stress levels in horses, the behavioral mechanisms concurrently occurring under stressful conditions are still unknown. The sudden inflation of a balloon was administered to 33 horses. Video-recording of self-directed behaviors (snore, vacuum chewing, snort, head/body shaking) and monitoring of heart activity (HR and SDRR) were conducted for five minutes before (Pre-test) and after the stimulus administration (Stress-test). During the Stress-test, only snore and vacuum chewing increased and a significant increase was also recorded in both HR and SDRR. Moreover, the snore variation between the two conditions showed a significant correlation with the variation of both HR and SDRR. With the snore acting as stress-releasing behavior to restore basal condition, the homeostasis recovered via the enactment of such behavior could be physiologically expressed by an increasing vagal activity. Hence, the capacity to maintain homeostasis (resilience) could correspond to a prevalence of parasympathetic control on heart activity, intervening when certain behaviors are performed.

Urbanization and its effects on personality traits: a result of microevolution or phenotypic plasticity?

Human-altered environmental conditions affect many species at the global scale. An extreme form of anthropogenic alteration is the existence and rapid increase of urban areas. A key question, then, is how species cope with urbanization. It has been suggested that rural and urban conspecifics show differences in behaviour and personality. However, (i) a generalization of this phenomenon has never been made; and (ii) it is still unclear whether differences in personality traits between rural and urban conspecifics are the result of phenotypic plasticity or of intrinsic differences. In a literature review, we show that behavioural differences between rural and urban conspecifics are common and taxonomically widespread among animals, suggesting a significant ecological impact of urbanization on animal behaviour. In order to gain insight into the mechanisms leading to behavioural differences in urban individuals, we hand-raised and kept European blackbirds (Turdus merula) from a rural and a nearby urban area under common-garden conditions. Using these birds, we investigated individual variation in two behavioural responses to the presence of novel objects: approach to an object in a familiar area (here defined as neophilia), and avoidance of an object in a familiar foraging context (defined as neophobia). Neophilic and neophobic behaviours were mildly correlated and repeatable even across a time period of one year, indicating stable individual behavioural strategies. Blackbirds from the urban population were more neophobic and seasonally less neophilic than blackbirds from the nearby rural area. These intrinsic differences in personality traits are likely the result of microevolutionary changes, although we cannot fully exclude early developmental influences.

Structure and Possible Functions of Constant-Frequency Calls in Ariopsis seemanni (Osteichthyes, Ariidae)

In the 1970s, Tavolga conducted a series of experiments in which he found behavioral evidence that the vocalizations of the catfish species Ariopsis felis may play a role in a coarse form of echolocation. Based on his findings, he postulated a similar function for the calls of closely related catfish species. Here, we describe the physical characteristics of the predominant call-type of Ariopsis seemanni. In two behavioral experiments, we further explore whether A. seemanni uses these calls for acoustic obstacle detection by testing the hypothesis that the call-emission rate of individual fish should increase when subjects are confronted with novel objects, as it is known from other vertebrate species that use pulse-type signals to actively probe the environment. Audio-video monitoring of the fish under different obstacle conditions did not reveal a systematic increase in the number of emitted calls in the presence of novel objects or in dependence on the proximity between individual fish and different objects. These negative findings in combination with our current understanding of directional hearing in fishes (which is a prerequisite for acoustic obstacle detection) make it highly unlikely that A. seemanni uses its calls for acoustic obstacle detection. We argue that the calls are more likely to play a role in intra- or interspecific communication (e.g. in school formation or predator deterrence) and present results from a preliminary Y-maze experiment that are indicative for a positive phonotaxis of A. seemanni towards the calls of conspecifics.

Novelty Responses in a Bird Assemblage Inhabiting an Urban Area

AbstractNeophobia, or the hesitancy to approach a novel food item, object, or place, is an important factor influencing the foraging behavior of animals. Environmental factors (e.g. rapid anthropogenic changes, migration into new habitats) are associated with novelty in feeding ecology and may affect neophobic responses. Mechanisms that underlie the differential neophobic response may involve complex interactions with the environment: post‐fledging experience in a greater diversity of habitats or in habitats that are more complex may contribute to reduced neophobia. In a previous study, it was observed that some urbanized species, in particular house sparrows (Passer domesticus) and shiny cowbirds (Molothrus bonariensis) show high levels of neophobia. This study was carried out in a suburban marsh of Cortaderia selloana, a relatively simple and predictable ecosystem as compared to urban areas. For this reason, in the present study, we explored novelty responses of bird species inhabiting an urban area, representing a complex environment. The results were compared to those obtained previously in the suburban marsh. We found unexpectedly high levels of neophobia in house sparrows, but shiny cowbirds showed a somewhat neophilic response. In the presence of novel objects, house sparrows tended to enter the feeders alone, while shiny cowbirds tended to forage in groups. We found no differences in latencies to forage or in visit duration between habitat types, but the proportion of individuals that visited the feeders when novel objects were present was lower in the urban area for house sparrows and eared doves (Zenaida auriculata). The results are discussed in the context of invasion success and feeding innovation in shiny cowbirds.

Experimental analysis of novelty responses in a bird assemblage inhabiting a suburban marsh

Suburban areas in the Pampas region of Argentina are inhabited by several bird species that sharply differ in their ability to exploit human-modified, urban areas. This bird assemblage includes species restricted to natural grasslands (e.g., Great Pampa Finch, Embernagra platensis (J.F. Gmelin, 1789)) as well as generalist, highly cosmopolitan species such as House Sparrow, Passer domesticus (L., 1758). We explored the role of certain aversive responses to novelty in shaping the marked differences in ecological plasticity among species in the assemblage. In field experiments, we tested for differences in feeding in the presence of artificial objects near feeders regularly replenished with seeds. In spite of their granivorous diet, some non-urbanized species did not use the feeders, possibly because of an extreme degree of aversion to novel situations. The group of birds that visited the feeders included both urbanized (N = 8) and non-urbanized (N = 2) species. We found that the presence of novel objects discouraged visitation to an otherwise attractive food source, although neophobia was weak for most species. However, we found unexpectedly high levels of neophobia in highly generalist, urbanized species such as House Sparrow and Shiny Cowbird, Molothrus bonariensis (J.F. Gmelin, 1789). This response is discussed in the context of the influence of post-fledging development in a relatively simple and predictable ecosystem versus that in urban areas.

Novelty and individual differences influence neophobia in orange-winged Amazon parrots (Amazona amazonica)

Environmental enrichment both improves the welfare of captive animals and increases the validity of research using these animals. Enrichment programs have been shown to prevent or reduce the development of behavioral vices, stereotypy, and fearfulness. However, the protocols used in enrichment studies can be inconsistent: under some protocols, enrichments are provided but not changed, while under others, enrichments are rotated frequently. Enrichment experiments to date have also largely ignored the influence of individual differences on fearfulness. The aim of this study was to determine whether frequent rotation of enrichment objects (“high novelty”) was more effective than simply providing enrichment objects (“low novelty”) in reducing neophobia in juvenile orange-winged Amazon parrots and to determine whether individual differences significantly affected neophobia. Thirty-four juvenile orange-winged Amazon parrots received both an 11-week high-novelty (HN) treatment and an 11-week low-novelty (LN) treatment, which were given in random order. Neophobia was assessed by measuring birds’ latency to feed from a dish of highly favored food in the presence of various novel objects at approximately 10-day intervals. Our results indicate that the HN treatment significantly reduced neophobia in juvenile orange-winged Amazons. We also found that both individual variation in fearfulness and the novel object used for testing significantly affected birds’ latency to feed in the presence of novel objects. Our results indicate that rotation of enrichment objects is more effective than simply providing enrichments in reducing fearful behavior in parrots. The effect of rotating enrichments was strong enough to overcome approximately four-fold differences in birds’ latency to feed in the presence of different novel objects and even greater individual differences in neophobia. However, we also found that in highly fearful individuals, HN actually increased birds’ latency to feed in the presence of novel objects. Our results indicate that rotation of enrichment objects is more effective than simply providing enrichments in reducing fearful behavior in parrots, but that both enrichment object properties and individual differences should be carefully considered in the design of future enrichment studies and protocols.

Differences between two psychogenetically selected lines of rats in a swimming pool matching-to-place task: long-term effects of infantile stimulation.

The present study explored the effects of infantile stimulation (i.e., neonatal handling or NH) on the performance of 18-month-old Roman high-avoidance (RHA/Verh) and low-avoidance (RLA/Verh) rats in a swimming pool matching-to-place (SPMP) test. This test (also called repeated acquisition and place learning-set paradigm) consists of administering pairs of consecutive trials in the Morris water maze. The difference between each "odd" and the consecutive "even" trial of a trial pair is considered to be a measure of working memory. The same rats were first tested for exploration and novelty-seeking in a hole-board test in the presence of novel objects, which showed that RHA/Verh rats were more explorative than their RLA/Verh counterparts, and that NH treatment augmented exploration in RLA/Verh rats, generally eliminating the genetically-based differences between the lines. RHA/Verh rats performed less efficiently than RLA/Verh rats in the SPMP test, and NH facilitated acquisition in the early stages of training in both rat lines, an effect that was presumably due to an improvement in the acquisition of spatial reference information. Performance during training also indicated that RHA/Verh rats showed less differentiated behavior between odd and even trials, indicating a relative working memory deficit at advanced ages in that rat line.

Neophobia, aversion to open space, and ecological plasticity in Song and Swamp sparrows

The Song Sparrow (Melospiza melodia) is a habitat generalist and successful colonist of habitats altered by man and of small islands. The Swamp Sparrow (Melospiza georgiana) is more restricted in its habitat distribution, occurring primarily in marsh or marsh-like habitats. In field experiments I examined the role of certain aversions in shaping the apparent difference in ecological plasticity found in these species. I tested for differences in aversion to feeding in the presence of novel objects and away from cover and found that such conditions greatly reduced the visitation rate of Swamp Sparrows but not Song Sparrows to feeding stations. I found no differences between the species in the degree to which feeding rate, visit length, or group size changed between areas with and without cover. Neither did I find a difference in feeding behavior or flight speed in the two species. I suggest that the increased hesitancy that Swamp Sparrows show for foraging away from cover or at novel objects reflects selection to reduce exploratory behavior away from preferred habitat types in this more stereotyped species.

Locomotor and electric displays associated with electrolocation during exploratory behavior in mormyrid fish

In the presence of a novel stimulus such as an aluminum or a plastic rod mormyrid fish ( Marcusenius cyprinoides and Gnathonemus petersii) exhibit characteristic motor probing acts (PMAs): ‘chin probing’, ‘radial’ and ‘lateral va-et-vient’, ‘lateral probing’, ‘tangential probing’, and ‘stationary probing’. During the display of these PMAs the fish maintain characteristic probing distances from the object which were 4.5 cm for the metal and 2.5–3.7 cm for the plastic stimulus. G. petersii with their electric organ rendered inoperative (‘silent fish’) no longer exhibited ‘radial’ and ‘lateral va-et-vient’. Regardless of the nature of the stimulus the probing distances were shorter in ‘silent’ fish and ranged from 1.8 to 2.6 cm. During the display of PMAs intact fish changed their variable electric organ discharge rate to a unique and stable, regularized rate, with the interdischarge interval maintained at 28–30 ms. The fish's electric and non-electric (motor) probing behavior in the presence of novel objects (and following their removal during phantom PMAs) is discussed in light of theories on exploratory behavior.

Effects of prepubertal ovariectomy on the development of scent glands, scent marking, and aggressive behaviors of female tamarin monkeys ( Saguinus fuscicollis)

The effects of prepubertal ovariectomy on scent gland development, scent marking behavior, and on social interactions with strange adult conspecifics were studied in adult females cohabiting with intact males. Eight females were ovariectomized and eight underwent control surgery at 6 months of age. All were returned to their families after surgery and allowed to reach sexual maturity. At 18 months of age, each female was permanently paired with an adult, intact male. When the subjects were 21 months old, the social interactions of all pairs with strange adults were tested in a situation analogous to a territorial encounter. The scent marking activities of the subjects and their mates were studied during “territorial encounters,” in trial-free control situations, and in the presence of novel objects. Ovariectomy prior to puberty retarded the development of the scent gland but did not inhibit it completely. Social interactions with strange conspecifics were also affected. Ovariectomized females showed fewer threat displays than did control females, but there was no significant difference in the amount of injurious aggression both female groups directed at the strangers. Under all testing conditions, ovariectomized females tended to scent mark less frequently with the circumgenital-suprapubic gland than did controls. This difference was statistically significant only under some of the testing conditions. Intact females scent marked more frequently than their males but ovariectomized females did so only under trial-free testing conditions. The sternal scent gland was used very infrequently by all subjects and there was no difference in marking activity between males and females or between ovariectomized and control females.

Responses of protein malnourished rats to novel objects.

Rats deprived of normal amounts of protein early in life and then rehabilitated were placed in an open field in the presence of either familiar or novel objects. In the presence of the familiar objects, the experimental animals did not differ from controls. In the presence of the novel object, animals with a history of early malnutrition were less active than controls. The data are consistent with other findings that indicate that the rat suffering early malnutrition reacts more emotionally to environmental stimulation.