scholarly journals Early life differences in behavioral predispositions in two Alligatoridae species

2021 ◽  
Author(s):  
Stephan A. Reber ◽  
Jinook Oh ◽  
Judith Janisch ◽  
Colin Stevenson ◽  
Shaun Foggett ◽  
...  

AbstractBehavioral predispositions are innate tendencies of animals to behave in a given way without the input of learning. They increase survival chances and, due to environmental and ecological challenges, may vary substantially even between closely related taxa. These differences are likely to be especially pronounced in long-lived species like crocodilians. This order is particularly relevant for comparative cognition due to its phylogenetic proximity to birds. Here we compared early life behavioral predispositions in two Alligatoridae species. We exposed American alligator and spectacled caiman hatchlings to three different novel situations: a novel object, a novel environment that was open and a novel environment with a shelter. This was then repeated a week later. During exposure to the novel environments, alligators moved around more and explored a larger range of the arena than the caimans. When exposed to the novel object, the alligators reduced the mean distance to the novel object in the second phase, while the caimans further increased it, indicating diametrically opposite ontogenetic development in behavioral predispositions. Although all crocodilian hatchlings face comparable challenges, e.g., high predation pressure, the effectiveness of parental protection might explain the observed pattern. American alligators are apex predators capable of protecting their offspring against most dangers, whereas adult spectacled caimans are frequently predated themselves. Their distancing behavior might be related to increased predator avoidance and also explain the success of invasive spectacled caimans in the natural habitats of other crocodilians.

2021 ◽  
Author(s):  
Alexandra Rodriguez ◽  
Martine Hausberger ◽  
Patricia Le Quilliec ◽  
Laurence Henri ◽  
Philippe Clergeau

To understand the processes involved in biological invasions, the genetic, morphological, physiological and behavioral characteristics of invasive populations need to be understood. Many invasive species have been reported to be flying species. In birds, both invaders and migrants encounter novel situations, therefore one could expect that both groups might react similarly to novelty. Here we analyzed the behavioral responses of individuals from three populations of European starling Sturnus vulgaris: a population settled for centuries in a rural region, a population that recently colonized an urban area, and a population of winter migrant birds. We conducted a social isolation test, a novel environment test, a novel food test and a novel object test to explore their reactions towards novelty. We identified and characterized different behavioral profiles for each test. The group of migratory adults appeared to be less anxious in social isolation than the group of urban young. Urban and migrant groups entered the novel environment sooner than rural birds. Shy, bold and intermediate individuals were observed in all three groups when presented with novel food. Finally, the proportion of shy individuals which did not touch the novel object was higher than the proportion of bold individuals in the rural group. Our study emphasizes that neophilia or boldness present in migrant and invasive populations may facilitate the occupation of novel habitats. Our analysis also suggests that mixed reactions of neophobia ensure behavioral flexibility in a gregarious invasive species.


Animals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 1383
Author(s):  
Megan Elizabeth Corgan ◽  
Temple Grandin ◽  
Sarah Matlock

It is dangerous for both riders and horses when a horse suddenly startles. Sometimes horses do this in familiar environments because familiar objects may look different when rotated. The purpose of this study was to determine whether horses that had been habituated to a complex object (children’s playset) would react to the object as novel when rotated 90 degrees. Twenty young horses were led past the playset 15 times by a handler. Next, the rotated group was led past the rotated playset 15 times. Each time the horse was led by the object was a pass. The behavioral responses observed and analyzed were ears focused on the object, nostril flares, neck raising, snort, avoid by stopping, avoid by moving feet sideways, and avoid by flight. An increasing reactivity scale was used to quantify behavioral responses. A two-sample t-test was performed on the reactivity scores comparing the first pass by the novel object to the first pass by the rotated object. The horses in the rotated group reacted to the rotated orientation similarly to the first exposure (p = 0.001, α < 0.05). Being aware of potential reactions to changes in previously familiar environments can help keep the handler safer.


2017 ◽  
Vol 45 (3) ◽  
pp. 581-609 ◽  
Author(s):  
Sarah J. OWENS ◽  
Justine M. THACKER ◽  
Susan A. GRAHAM

AbstractSpeech disfluencies can guide the ways in which listeners interpret spoken language. Here, we examined whether three-year-olds, five-year-olds, and adults use filled pauses to anticipate that a speaker is likely to refer to a novel object. Across three experiments, participants were presented with pairs of novel and familiar objects and heard a speaker refer to one of the objects using a fluent (“Look at the ball/lep!”) or disfluent (“Look at thee uh ball/lep!”) expression. The salience of the speaker's unfamiliarity with the novel referents, and the way in which the speaker referred to the novel referents (i.e., a noun vs. a description) varied across experiments. Three- and five-year-olds successfully identified familiar and novel targets, but only adults’ looking patterns reflected increased looks to novel objects in the presence of a disfluency. Together, these findings demonstrate that adults, but not young children, use filled pauses to anticipate reference to novel objects.


2021 ◽  
Vol 15 ◽  
Author(s):  
Cesar Sierra ◽  
Ilario De Toma ◽  
Lorenzo Lo Cascio ◽  
Esteban Vegas ◽  
Mara Dierssen

The use of mouse models has revolutionized the field of Down syndrome (DS), increasing our knowledge about neuropathology and helping to propose new therapies for cognitive impairment. However, concerns about the reproducibility of results in mice and their translatability to humans have become a major issue, and controlling for moderators of behavior is essential. Social and environmental factors, the experience of the researcher, and the sex and strain of the animals can all have effects on behavior, and their impact on DS mouse models has not been explored. Here we analyzed the influence of a number of social and environmental factors, usually not taken into consideration, on the behavior of male and female wild-type and trisomic mice (the Ts65Dn model) in one of the most used tests for proving drug effects on memory, the novel object recognition (NOR) test. Using principal component analysis and correlation matrices, we show that the ratio of trisomic mice in the cage, the experience of the experimenter, and the timing of the test have a differential impact on male and female and on wild-type and trisomic behavior. We conclude that although the NOR test is quite robust and less susceptible to environmental influences than expected, to obtain useful results, the phenotype expression must be contrasted against the influences of social and environmental factors.


2021 ◽  
Author(s):  
Elizabeth Morin-Lessard ◽  
Krista Byers-Heinlein

Previous research suggests that English monolingual children and adults can use speech disfluencies (e.g., uh) to predict that a speaker will name a novel object. To understand the origins of this ability, we tested 48 32-month-old children (monolingual English, monolingual French, bilingual English-French; Study 1) and 16 adults (bilingual English-French; Study 2). Our design leveraged the distinct realizations of English (uh) versus French (euh) disfluencies. In a preferential-looking paradigm, participants saw familiar-novel object pairs (e.g., doll-rel), labeled in either Fluent (“Look at the doll/rel!”), Disfluent Language-consistent (“Look at thee uh doll/rel!”), or Disfluent Language-inconsistent (“Look at thee euh doll/rel!”) sentences. All participants looked more at the novel object when hearing disfluencies, irrespective of their phonetic realization. These results suggest that listeners from different language backgrounds harness disfluencies to comprehend day-to-day speech, possibly by attending to their lengthening as a signal of speaker uncertainty. Stimuli and data are available at https://osf.io/qn6px/.


2018 ◽  
Author(s):  
Damien Marechal ◽  
Véronique Brault ◽  
Alice Leon ◽  
Dehren Martin ◽  
Patricia Lopes Pereira ◽  
...  

ABSTRACTIdentifying dosage sensitive genes is a key to understand the mechanisms underlying intellectual disability in Down syndrome (DS). The Dp(17Abcg1-Cbs)1Yah DS mouse model (Dp1Yah) show cognitive phenotype and needs to be investigated to identify the main genetic driver. Here, we report that, in the Dp1Yah mice, 3 copies of the Cystathionine-beta-synthase gene (Cbs)are necessary to observe a deficit in the novel object recognition (NOR) paradigm. Moreover, the overexpression ofCbsalone is sufficient to induce NOR deficit. Accordingly targeting the overexpression of human CBS, specifically in Camk2a-expressing neurons, leads to impaired objects discrimination. Altogether this shows thatCbsoverdosage is involved in DS learning and memory phenotypes. In order to go further, we identified compounds that interfere with the phenotypical consequence of CBS overdosage in yeast. Pharmacological intervention in the Tg(CBS) with one selected compound restored memory in the novel object recognition. In addition, using a genetic approach, we demonstrated an epistatic interaction betweenCbsandDyrk1a, another human chromosome 21 gene encoding the dual-specificity tyrosine phosphorylation-regulated kinase 1a and an already known target for DS therapeutic intervention. Further analysis using proteomic approaches highlighted several pathways, including synaptic transmission, cell projection morphogenesis, and actin cytoskeleton, that are affected by DYRK1A and CBS overexpression. Overall we demonstrated that CBS overdosage underpins the DS-related recognition memory deficit and that bothCBSandDYRK1Ainteract to control accurate memory processes in DS. In addition, our study establishes CBS as an intervention point for treating intellectual deficiencies linked to DS.SIGNIFICANT STATEMENTHere, we investigated a region homologous to Hsa21 and located on mouse chromosome 17. We demonstrated using three independent genetic approaches that the overdosage of the Cystathionine-beta-synthase gene (Cbs) gene, encoded in the segment, is necessary and sufficient to induce deficit in novel object recognition (NR).In addition, we identified compounds that interfere with the phenotypical consequence of CBS overdosage in yeast and in mouse transgenic lines. Then we analyzed the relation between Cbs overdosage and the consequence of DYRK1a overexpression, a main driver of another region homologous to Hsa21 and we demonstrated that an epistatic interaction exist betweenCbsandDyrk1aaffecting different pathways, including synaptic transmission, cell projection morphogenesis, and actin cytoskeleton.


2017 ◽  
Vol 284 (1847) ◽  
pp. 20162108 ◽  
Author(s):  
Pete C. Trimmer ◽  
Sean M. Ehlman ◽  
Andrew Sih

Human activity alters natural habitats for many species. Understanding variation in animals' behavioural responses to these changing environments is critical. We show how signal detection theory can be used within a wider framework of state-dependent modelling to predict behavioural responses to a major environmental change: novel, exotic species. We allow thresholds for action to be a function of reserves, and demonstrate how optimal thresholds can be calculated. We term this framework ‘state-dependent detection theory’ (SDDT). We focus on behavioural and fitness outcomes when animals continue to use formerly adaptive thresholds following environmental change. In a simple example, we show that exposure to novel animals which appear dangerous—but are actually safe—(e.g. ecotourists) can have catastrophic consequences for ‘prey’ (organisms that respond as if the new organisms are predators), significantly increasing mortality even when the novel species is not predatory. SDDT also reveals that the effect on reproduction can be greater than the effect on lifespan. We investigate factors that influence the effect of novel organisms, and address the potential for behavioural adjustments (via evolution or learning) to recover otherwise reduced fitness. Although effects of environmental change are often difficult to predict, we suggest that SDDT provides a useful route ahead.


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