Range Of Behavioral Strategies Research Articles

Lateralized motor behaviour in the righting responses of the cane toad (Rhinella marina)

ABSTRACT This paper reports a series of tests for fore- and hind-limb preferences used by cane toads, Rhinella marina, to assist returning to the righted position after being overturned. We confirm the strong and significant right-handedness reported in this species, which under certain conditions exceeded 90% right-hand preference at the group level. Toads were tested under a variety of conditions including horizontal and inclined surfaces, with and without the opportunity for the forelimbs to grasp a support, in order to assess the effects of different vestibular and proprioceptive input on the strength and direction of fore- and hind-limb preferences. A range of behavioural strategies indicated learning effects; however, the strength or direction of limb preferences did not increase significantly with experience, even in toads retested multiple times. Comparisons with the mammalian condition for limb preferences are discussed with relevance to practice effects and established limb preferences, and to effects associated with arousal or stress. In contrast to the expectation that handedness in toads represents intentional or voluntary preferences, the presence of lateralized central pattern generators in the toads is postulated to explain the different forms of lateralization revealed by our tests.

Side-impact collision: mechanics of obstacle negotiation in sidewinding snakes

Snakes excel at moving through cluttered environments, and heterogeneities can be used as propulsive contacts for snakes performing lateral undulation. However, sidewinding, which is often associated with sandy deserts, cuts a broad path through its environment that may increase its vulnerability to obstacles. Our prior work demonstrated that sidewinding can be represented as a pair of orthogonal body waves (vertical and horizontal) that can be independently modulated to achieve high maneuverability and incline ascent, suggesting that sidewinders may also use template modulations to negotiate obstacles. To test this hypothesis, we recorded overhead video of four sidewinder rattlesnakes (Crotalus cerastes) crossing a line of vertical pegs placed in the substrate. Snakes used three methods to traverse the obstacles: a Propagate Through behavior in which the lifted moving portion of the snake was deformed around the peg and dragged through as the snake continued sidewinding (115/160 runs), Reversal turns that reorient the snake entirely (35/160), or switching to Concertina locomotion (10/160). The Propagate Through response was only used if the anterior-most region of static contact would propagate along a path anterior to the peg, or if a new region of static contact could be formed near the head to satisfy this condition; otherwise, snakes could only use Reversal turns or switch to Concertina locomotion. Reversal turns allowed the snake to re-orient and either escape without further peg contact or re-orient into a posture amenable to using the Propagate Through response. We developed an algorithm to reproduce the Propagate Through behavior in a robophysical model using a modulation of the two-wave template. This range of behavioral strategies provides sidewinders with a versatile range of options for effectively negotiating obstacles in their natural habitat, as well as provide insights into the design and control of robotic systems dealing with heterogeneous habitats.

Combined foraging strategies and soldier behaviour in Nasutitermes aff. coxipoensis (Blattodea: Termitoidea: Termitidae)

A range of behavioural strategies and sensory abilities allows animals to minimize costs involved in food search. By building a network of tunnels and presenting a large number of soldiers (i.e., trophically dependent individuals), Nasutitermes spp. termites feature behaviours that imply additional costs during this process. Here we evaluated N. aff. coxipoensis foraging strategies focusing on the role of soldiers during foraging. Field experiments were carried out via nests transplantation to dune areas, and laboratory experiments evaluated termite responses to sternal gland chemical signals from workers and soldiers. N. aff. coxipoensis presented primarily nocturnal foraging. Soldiers typically initiated foraging; however, in established trails, the number of workers was always higher than that of soldiers. The number of trails remained constant over time, while the number of tunnels increased linearly over time. A higher proportion of tunnels originated in surrounding areas than directly from the nests. At observation points with tunnels, there were more stationary than walking soldiers; the opposite was true at observation points without tunnels. In mixed groups, the workers chose to follow soldier chemical signals, and in these groups, soldiers were the first to follow trails. Our results allowed us to identify a not common foraging strategy in termite species; which included the establishment of trails followed by construction of tunnels. Such foraging strategies occur predominantly at night and soldiers play a key role in the foraging process. This foraging strategy reported here seems to be employed to optimize energetic gain.

Variation in social structure alters queen body mass and productivity in the desert seed-harvester ant Messor pergandei

Parent–offspring conflict theory predicts conflict between parents and their offspring over per-offspring resource investment. Across the range of the desert seed-harvester ant, Messor pergandei, daughter queens use three different social strategies during colony founding that are expected to alter the optimal level of parental investment. To test whether social strategy variation is associated with shifts in body mass, we surveyed queen live mass over 3 years at 25 sites that spanned the range of behavioral strategies and founding group sizes. To test whether reduction in parental investment into individual offspring negatively impacts their productivity, queens were individually isolated and allowed to produce a single worker cohort under common garden conditions. Queen live mass was highly variable, from 24 mg on average at the site with the lightest queens to 1.5 times that size, 37 mg, at the site with the heaviest queens. As predicted by parent–offspring conflict over investment, solitary colony founding sites contained the heaviest queens, followed by secondary monogyny. Polygynous queens were lightest, with a strong negative relationship between group size and live mass. Reductions in body mass had a negative effect on queen productivity across all queen social types; however, queens from sites where queen–queen aggression is typical were significantly more efficient at brood rearing, resulting in lower mass loss during founding per unit offspring biomass. This may represent an adaptation to queen competition to gain a strength advantage over potential rivals.

Behavior Therapy for Stereotypic Movement Disorder in Typically Developing Children: A Clinical Case Series

Stereotypic movement disorder (SMD) is characterized by repetitive, rhythmic, episodic movement and is associated with distress and functional impairment. A range of behavioral strategies have been implemented for the treatment of stereotypies, but research on the effectiveness of behavior therapy in typically developing children is limited. The following case series describes the implementation of behavior therapy for 3 typically developing children (ages 12 to 14) with SMD. Results showed significant reductions in the frequency and intensity of the stereotypies. Future refinement and testing of a behavior therapy protocol is recommended.

Adaptation to disability in chronic obstructive pulmonary disease: neglected relationships to older adults' perceptions of independence

Purpose: This study extends understanding of the relationship between disability and independence in older adults with COPD.Methods: An interviewer-administered questionnaire was used to examine disability, adaptation, perceptions of independence, and self-efficacy in a sample of 50 community-dwelling older adults. Odds ratios were used to investigate relationships between variables.Results: Participants used a wide range of behavioural strategies to adapt to their disability including: limiting activities, optimizing performance (e.g. taking rests), compensating for lost function (e.g. using equipment), and obtaining help from others. The relative use of these adaptations varied across five domains of activity: personal care, in-home mobility, household activities, community mobility, and valued activities. Most participants felt very or extremely independent in all domains. In personal care, those who reported greater disability (O.R. = 0.26), more frequent attempts to optimize performance (O.R. = 0.57), or greater reliance on help from others (O.R. = 0.79) were significantly (p < 0.05) less likely to feel very or extremely independent.Conclusions: The relationship between disability and perceptions of independence depends on the nature of the activity and is influenced by factors that are amenable to study and intervention. In particular, the vast array of behavioural strategies available to older adults with COPD enables them to feel highly independent despite disability.