Temporal pattern of locomotor activity in Drosophila melanogaster

The temporal pattern of locomotor activity of single Drosophila melanogaster flies freely walking in small tubes is described. Locomotor activity monitored by a light gate has a characteristic time-course that depends upon age and the environmental conditions. Several methods are applied to assess the complexity of the temporal pattern. The pattern varies according to sex, genotype, age and environmental conditions (food; light). Activity occurs clustered in bouts. The intrinsic bout structure is quantified by four parameters: number of light gate passages (counts) per bout, duration of a bout, pause between two successive bouts and mean bout period. In addition, the distribution of the periods between light-gate crossings (inter-count intervals) as function of inter-count interval duration reveals a power law, suggesting that the overall distribution of episodes of activity and inactivity has a fractal structure. In the dark without food, the fractal dimension which represents a measure of the complexity of the pattern is sex, genotype and age specific. Fractality is abolished by additional sensory stimulation (food; light). We propose that time-course, bout structure and fractal dimension of the temporal pattern of locomotor activity describe different aspects of the fly's central pattern generator for locomotion and its motivational control. Accepted: 10 October 1998     

Scan and focal sampling: reliability in the laterality for maternal cradling and infant nipple preferences in olive baboons, Papio anubis

We compared measures of laterality obtained by two observational sampling procedures (a 15-min focal-dyad sampling with continuous recording, and a scan and instantaneous sampling), using 10 mother-infant dyads of captive olive baboons. The two measures of lateral biases for maternal cradling, infant nipple preference, infant head position and maternal carrying, but not those for infant retrieval, were positively and significantly correlated. Our results clearly show that the two sampling procedures produce equally sensitive measures of lateral bias for both the maternal and the infant behaviours. They also provide evidence of asymmetries in mean bout length and therefore suggest that recording bouts is not necessarily the best measure of lateral bias. Taken together, these results show empirically that the scan and instantaneous sampling procedure does not lead to a lack of independence of data points, as previously assumed.     

The correspondence between proximal phalanx morphology and locomotion: implications for inferring the locomotor behavior of fossil catarrhines

Phalanges are considered to be highly informative in the reconstruction of extinct primate locomotor behavior since these skeletal elements directly interact with the substrate during locomotion. Variation in shaft curvature and relative phalangeal length has been linked to differences in the degree of suspension and overall arboreal locomotor activities. Building on previous work, this study investigated these two skeletal characters in a comparative context to analyze function, while taking evolutionary relationships into account. This study examined the correspondence between proportions of suspension and overall substrate usage observed in 17 extant taxa and included angle of curvature and relative phalangeal length. Predictive models based on these traits are reported. Published proportions of different locomotor behaviors were regressed against each phalangeal measurement and a size proxy. The relationship between each behavior and skeletal trait was investigated using ordinary least-squares, phylogenetic generalized least-squares (pGLS), and two pGLS transformation methods to determine the model of best-fit. Phalangeal curvature and relative length had significant positive relationships with both suspension and overall arboreal locomotion. Cross-validation analyses demonstrated that relative length and curvature provide accurate predictions of relative suspensory behavior and substrate usage in a range of extant species when used together in predictive models. These regression equations provide a refined method to assess the amount of suspensory and overall arboreal locomotion characterizing species in the catarrhine fossil record.     

Early locomotor behaviour in genetic stocks of chickens with different growth rates

Reduction in exercise increases the occurrence of lameness in meat-type chickens. Locomotor activity is dramatically reduced during the finishing period in chickens from fast-growing genetic types compared to slow-growing genetic types, but it is not known whether this difference is already present during the starting period and may be influenced by genetic factors. In order to define the effect of genetic origin on early locomotor behaviour, exercise was compared from 1 to 22 days of age in two meat-type chicken stocks differing in growth rate: male broilers (B) which grow fast and are often lame, and male "label rouge" chickens (L) which grow slowly and are rarely lame.Time budget (lying, standing, drinking, eating, walking) was measured by scanning in six repetitions of five birds (density=2.5 birds/m(2)) at 1, 8, 15 and 17 days of age. Standing bouts were analysed by focal sampling at 2-3, 6-7, 13-14 and 20-21 days of age.B chicks spent less time standing than L chicks at 15 days of age (B=13+/-2%, L=24+/-1%, P<0.01) and 17 days of age, and spent more time lying at 17 days of age (B=73+/-3%, L=60+/-4%, P<0.05).The major part (74%) of the total active time observed by focal sampling was linked to feeding activity. At 2 and 3 days, the activity of B chicks was half that of L chicks during standing bouts (duration of walking per bout: 19+/-4 s for B; 45+/-4 s for L, P<0.05). The activity observed by focal sampling during non-feeding bouts at 20-21 days was significantly correlated with the corresponding data recorded at 2-3 days in the same chicks in the B stock but not in the L stock.We concluded that (1) both B and L genetic stocks have the same overall activity during the first 3 days of age (scanning) but they exhibit different organisation and composition of standing bouts (focal sampling). (2) Genetic factors are probably involved in the expression of locomotor behaviour in very young chicks. (3) The correlations between the levels of activity at early and later ages suggest that selection of young mobile broiler chicks might increase activity at a later age and might therefore reduce the occurrence of leg abnormalities.     

The cross-sectional geometry of the hand and foot bones of the hominoidea and its relationship to locomotor behavior

Cheiridia are valuable indicators of positional behavior, as they directly contact the substrate, but systematic comparison of the structural properties of both metacarpals and metatarsals has never been carried out. Differences in locomotor behavior among the great apes (knuckle-walking vs. quadrumanous climbing) can produce biomechanical differences that may be elucidated by the parallel study of cross-sectional characteristics of metacarpals and metatarsals. The aim of this work is to study the cross-sectional geometric properties of these bones and their correlation with locomotor behavior in large-bodied hominoids. The comparisons between bending moments of metacarpals and metatarsals of the same ray furnished interesting results. Metacarpals III and especially IV of the knuckle-walking African apes were relatively stronger than those of humans and orangutans, and metatarsal V of humans was relatively stronger than those of the great apes. Interestingly, the relative robusticity of the metacarpal IV of the quadrumanous orangutan was between that of the African apes and that of humans. The main conclusions of the study are: 1) cross-sectional dimensions of metacarpals and metatarsals are influenced by locomotor modes in great apes and humans; 2) interlimb comparisons of cross-sectional properties of metacarpals and metatarsals are good indicators of locomotor modes in great apes and humans; and 3) the results of this study are in accord with those of previous analyses of plantar pressure and morphofunctional traits of the same bones, and with behavioral studies. These results provide a data base from which it will be possible to compare the morphology of the fossils in order to gain insight into the locomotor repertoires of extinct taxa.     

Complex mate searching in the satin bowerbird Ptilonorhynchus violaceus

Mate-choice studies typically focus on male traits affecting female mating decisions, but few studies seek to identify the behavioral rules females use when searching for mates. Current models suggest that females may either directly compare a set of males ("pooled comparison") or compare each male to an internal standard ("sequential-search rule") when judging the suitability of potential mates. Models also differ in other specific aspects, such as the predicted number of sampling bouts initiated and the tendency of females to return to males after previous visits. We monitored 63 female satin bowerbirds, Ptilonorhynchus violaceus, during mate sampling to reconstruct their search patterns. We found that females typically sampled several males and returned to the most attractive male for mating: a behavior consistent with the pooled-comparison tactic. Females, however, varied in the number of males sampled; some visited only one male before mating. We found that this variation can be explained by differences among females in the number of mates, the date mate searching is initiated, and long-term experience with males. Further, females were observed to initiate two distinct sampling bouts, with the rejection of most of their potential mates occurring before the start of the second sampling bout. This suggests that the choices of potential mates are narrowed prior to the second sampling bout and that the later visits may function to reconsider preliminary decisions made during the first sampling bout or to resolve decisions concerning the remaining potential mates. Our results indicate that mate searching is a complex process in which females use multiple sampling bouts to find suitable mates and in which several different factors influence their search behavior.     

Mechanisms of Change in the Ontogeny of Black-tailed Prairie Dog Time Budgets

This study examines the behavioral mechanisms underlying changes in the time allocation patterns of black-tailed prairie dog (Sciuridae: Cynomys ludovicianus) pups. Previous analyses of time budgets had revealed substantial differences between pups (young of the year) and adults, and that pup time budgets changed significantly over time. This paper shows that these differences were due to two mechanisms: pups generally differed from adults in the frequency of performance of different behaviors; however, changes in pup behavior over time were due to changes in both bout frequencies and durations. Other influences on bout durations were also examined. Time of day dramatically affected the duration of most behaviors, with vigilance bouts longest in the morning and feeding bouts longest in the evening. The presence of a pup's mother above ground and the height of the vegetation a pup was in had much less influence on bout durations. Multiple regression analyses were used to identify other potential influences (e.g., weather and social conditions) on bout lengths. Of these, the distance of a pup from the nearest burrow produced the strongest relationships.     

Dopamine modulates the rest period length without perturbation of its power law distribution in Drosophila melanogaster

We analyzed the effects of dopamine signaling on the temporal organization of rest and activity in Drosophila melanogaster. Locomotor behaviors were recorded using a video-monitoring system, and the amounts of movements were quantified by using an image processing program. We, first, confirmed that rest bout durations followed long-tailed (i.e., power-law) distributions, whereas activity bout durations did not with a strict method described by Clauset et al. We also studied the effects of circadian rhythm and ambient temperature on rest bouts and activity bouts. The fraction of activity significantly increased during subjective day and at high temperature, but the power-law exponent of the rest bout distribution was not affected. The reduction in rest was realized by reduction in long rest bouts. The distribution of activity bouts did not change drastically under the above mentioned conditions. We then assessed the effects of dopamine. The distribution of rest bouts became less long-tailed and the time spent in activity significantly increased after the augmentation of dopamine signaling. Administration of a dopamine biosynthesis inhibitor yielded the opposite effects. However, the distribution of activity bouts did not contribute to the changes. These results suggest that the modulation of locomotor behavior by dopamine is predominantly controlled by changing the duration of rest bouts, rather than the duration of activity bouts.     

Automatic monitoring of primate locomotor behaviour using accelerometers

Accelerometry data were transmitted by a radio collar attached to a hand-reared red-ruffed lemur housed in a large indoor/outdoor enclosure at Chester Zoo. An observer simultaneously recorded locomotor behaviour using a manually operated event recorder. Both data streams were recorded directly to hard disk to ensure accurate synchrony. Leaps were modelled using a y = x2 - x3 formulation for the take-off acceleration, to link peak acceleration to leap distance. Cyclic locomotor modes were analysed using power spectra and the modal frequency used to estimate stride periodicity. Comparison of the dual data shows that leaping behaviour can be recorded reliably, and acceleration magnitude provides accurate predictions of the distance travelled. Cyclic activities were less well characterised, but calibration should permit travel distance estimations equalling or bettering those from conventional techniques.     

Sex differences in adult chimpanzee positional behavior: The influence of body size on locomotion and posture

Focal animal instantaneous sampling of adult male and female chimpanzee positional behavior was conducted during a 7-month study in the Tai Forest, Ivory Coast, in order to determine whether there are sex differences in the locomotion, posture, substrate use, and height preference of sexually dimorphic adult chimpanzees, and if so, whether these differences support predictions based on body size differences. Results indicate that as predicted, adult male and female chimpanzees differ in their arboreal locomotor behavior, with the larger males using less quadrupedalism and more climbing, scrambling, and aided bipedalism than females during feeding locomotion. There is a sex difference in height preference as well, with female chimpanzees consistently using more arboreal behavior than males, primarily during resting. Although it has been previously demonstrated that separate primate species of differing body size differ in locomotor and postural activities (Fleagle and Mittermeier, 1980; Crompton, 1984), this study clearly demonstrates that body size differences within a species can also be correlated with differences in locomotor behavior. These findings may influence how we interpret sex differences in body size of extinct species. © 1993 Wiley-Liss, Inc.     

The effects of substratum on locomotor performance in lacertid lizards

Locomotion is important to animals because it has direct implications for fitness through its role in predator escape, prey capture, and territory defence. Despite significant advances in our understanding of animal locomotion, studies exploring how substrate properties affect locomotor performance remain scant. In the present study, we explore how variation in substrate (sand, slate, cork) affects locomotor performance in lacertid lizards that differ in morphology. Moreover, we explore whether substrate effects are the same for different types of locomotor performance (speed, acceleration, and stamina). Our results show that the substrate affected most types of locomotor performance studied but not always in the same way. Although substrate effects were species‐dependent for the maximal speed over 50 cm and the distance run to exhaustion, this was not the case for acceleration capacity. These results suggest that substrate texture differentially affects burst performance vs. longer duration measures of locomotor performance. Finally, straightforward relationships between habitat use and the substrate on which performance was maximized were not observed. This suggests that the evolution of locomotor capacity is complex and that animals may show compromise phenotypes allowing them to deal with a variety of substrates in their natural environment. © 2015 The Linnean Society of London, Biological Journal of the Linnean Society, 2015, ●●, ●●–●●.     

The locomotor behavior of Callicebus brunneus and Callicebus torquatus

This study presents data on the positional behavior of Callicebus torquatus and Callicebus brunneus collected from two different localities in Peru. C. brunneus primarily utilizes short-distance, bounding leaps, while C. torquatus relies predominantly on quadrupedal walking. Both species utilize small, horizontal and terminal branches more than any other substrate class. We relate the differences in locomotor behaviors between the two species to their utilization of different forest levels. C. brunneus tends to reside in the understory and brush layer forest levels. These more discontinuous strata necessitate higher frequencies of short-distance leaping. C. torquatus occupies the more continuous, interconnected canopy level, and much of its food is found in this level. Comparisons with other species show that Callicebus spp. locomote along smaller-sized, horizontal branches using quadrupedal progression and leaping.     

Modular diversification of the locomotor system in damselfishes (Pomacentridae)

As fish move and interact with their aquatic environment by swimming, small morphological variations of the locomotor system can have profound implications on fitness. Damselfishes (Pomacentridae) have inhabited coral reef ecosystems for more than 50 million years. As such, habitat preferences and behavior could significantly constrain the morphology and evolvability of the locomotor system. To test this hypothesis, we used phylogenetic comparative methods on morphometric, ecological and behavioral data. While body elongation represented the primary source of variation in the locomotor system of damselfishes, results also showed a diverse suite of morphological combinations between extreme morphologies. Results show clear associations between behavior, habitat preferences, and morphology, suggesting ecological constraints on shape diversification of the locomotor system. In addition, results indicate that the three modules of the locomotor system are weakly correlated, resulting in versatile and independent characters. These results suggest that Pomacentridae is shape may result from the interaction between (1) integrated parts of morphological variation that maintain overall swimming ability and (2) relatively independent parts of the morphology that facilitate adaptation and diversification. J. Morphol. 277:603–614, 2016. © 2016 Wiley Periodicals, Inc.     

Locomotor Ability and Wariness in Yellow-Bellied Marmots

Animals employ a variety of behaviors to reduce or manage predation risk. Often, these are studied in isolation, but selection may act on packages of behavior that are referred to as behavioral syndromes. We focused on yellow‐bellied marmots (Marmota flaviventris) and examined three commonly studied antipredator behaviors. We fitted general linear models to explain variation in maximum running speed, time allocated to vigilance and foraging during bouts of foraging, and flight initiation distance (FID). Marmot maximum running speed was influenced by the substrate run across; marmots ran fastest across dirt or low vegetation and slowest across stones or talus. Incline and several other variables shown to affect running speed in other marmot species failed to explain significant variation in yellow‐bellied marmots. From these results we expected marmots to be sensitive to substrate while foraging, but insensitive to incline. However, time allocated to foraging was affected by incline but not by substrate. In bouts of foraging observed in different habitats, and on different inclines, more time was allocated to foraging and less to vigilance on steep slopes and less on level ground. Substrate influenced FID. Marmots in tall vegetation were less tolerant of an approaching person than were those in shorter vegetation. Finally, we found significant correlations between the residuals from the maximum running speed model and the residuals from the time allocated to vigilance and foraging models. We found a tendency for marmots that ran slower than predicted to be less vigilant while foraging. We also found that relatively slow marmots engaged in more active foraging and less vigilance during foraging bouts. This finding suggests a ‘locomotor ability‐wariness while foraging’ syndrome. It also suggests that vulnerable individuals minimize their exposure while foraging.     

Circadian feeding and locomotor rhythms in pigeons and house sparrows.

Feeding and locomotor activities were measured simultaneously in homing pigeons (Columba livia) and house sparrows (Passer domesticus). Feeding, as well as locomotor activity, was found to be regulated by a circadian clock in both of these species. Implantation of melatonin-filled capsules or exposure to constant light abolished feeding and locomotor rhythms in both species. Removal of the pineal gland from pigeons did not abolish either rhythm, whereas pinealectomy abolished both feeding and locomotor rhythms in house sparrows. Although feeding rhythms were generally more robust than locomotor rhythms in both of these species, different feeding and locomotor free-running periods were not observed within any individual pigeon or house sparrow. These results are consistent with the hypothesis that each of these species has a single pacemaker that regulates the timing of feeding and locomotor activity, but they do not rule out the possibility that separate clocks regulate these behaviors.     

Evidence for the entrainment of breathing by locomotor pattern in human

In human, it has been shown that interactions between locomotor and respiratory patterns may lead to locomotor-respiratory couplings termed entrainment. In order to prove that this coupling is really an entrainment, we tried to show that it obeys one of the expected rules, i.e. that it evolves and is not present for all imposed locomotor frequencies. For that purpose, seventeen healthy volunteers were asked to run on a treadmill at 14 different locomotor rates (instead of 2 or 3 in previous works) for 40 s. All the subjects did not exhibit the same coupling and different relationships could be obtained: the most commonly observed was 2:1 (2 locomotor activities for a respiratory one) but other forms could appear (4:1 and even 5:2 or 3:2). When the coupling evolution was followed in the same subject, it did not appear for all locomotor frequencies but only for locomotor periods close to harmonics of respiratory ones (absolute coordination). On both sides of these values, it progressively evolved to relative coordination and to the lack of coordination. When two forms of absolute coordination were observed in a same subject, the phase relationships followed the rules of the entrainment. Compared to data obtained in quadrupeds, these results suggest that the entrainment of breathing frequency by the locomotor activity is due to central interactions between the respiratory and locomotor pattern generators and does not depend on a chemical regulation avoided here by short locomotor sequences.     

Central complex substructures are required for the maintenance of locomotor activity in Drosophila melanogaster

In Drosophila melanogaster, former studies based on structural brain mutants have suggested that the central complex is a higher control center of locomotor behavior. Continuing this investigation we studied the effect of the central complex on the temporal structure of spontaneous locomotor activity in the time domain of a few hours. In an attempt to dissect the internal circuitry of the central complex we perturbed a putative local neuronal network connecting the four neuropil regions of the central complex, the protocerebral bridge, the fan-shape body, the noduli and the ellipsoid body. Two independent and non-invasive methods were applied: mutations affecting the neuroarchitecture of the protocerebral bridge, and the targeted expression of tetanus toxin in small subsets of central complex neurons using the binary enhancer trap P[GAL4] system. All groups of flies with a disturbed component of this network exhibited a common phenotype: a drastic decrease in locomotor activity. While locomotor activity was still clustered in bouts and these were initiated at the normal rate, their duration was reduced. This finding suggests that the bridge and some of its neural connections to the other neuropil regions of the central complex are required for the maintenance but not the initiation of walking. Accepted: 21 June 1999     

Effect of locomotor approach on feeding kinematics in the green anole (Anolis carolinensis)

Squamates are well-known models for studying to examine locomotor and feeding behaviors in tetrapods, but studies that integrate both behavioral activities remain scarce. Anolis lizards are a classical lineage to study the evolutionary relationships between locomotor behavior and complex structural features of the habitat. Here, we analyzed prey-capture behavior in one representative arboreal predator, Anolis carolinensis, to demonstrate the functional links between locomotor strategies and the kinematics of feeding. A. carolinensis uses two strategies to catch living insects on perches: Head-Up Capture and Jump Capture. In both cases, lizards use lingual prehension to capture the prey and the kinematic patterns of the trophic apparatus are not significantly influenced by the selected strategies. Therefore, to capture one prey type, movements of the trophic structures are highly fixed and A. carolinensis modulates the locomotor pattern to exploit the environment. Predation behavior in A. carolinensis integrates two different behavioral patterns: locomotor plasticity of prey-approach and biomechanical stereotypy of tongue prehension to successfully capture the prey.     

An empirical evaluation of instantaneous and one-zero sampling of chimpanzee behavior

The behavior category in progress at theend of every 15 seconds of observation of chimpanzee behavior was recorded (instantaneous sampling) as was the occurrence or nonoccurrence of all defined categoriesduring every 15 second observation interval (one-zero sampling). The scores obtained using the above procedures were then correlated with the percent of net observation time, hourly rate, and mean bout duration of the behavior categories. One-zero sampling scores correlated very strongly with percent of net observation time and moderately with hourly rate and mean bout duration. Instantaneous sampling scores correlated very strongly with percent of net observation time and moderately with hourly rate and mean bout duration.     

Sex differences in the nursing relationship between mothers and pups in the Atlantic harbour seal, Phoca vitulina concolor

Sex differences in the dynamics of the relationship between harbour seal mothers and their pups were investigated. An index of pair proximity governance suggested that pups became increasingly responsible for maintaining the distance between the pair over the course of the nursing period. Male pups demonstrated a stronger tendency to control initiation distance than female pups. A Nursing Index utilizing suckling bout initiations and terminations revealed that, as weaning approached, pups became progressively more responsible for the continuance of nursing. Male pups exhibited more control than female pups, primarily through initiating a greater portion of the bouts. On-teat times averaged 4.08 min per bout, with no significant differences between male and female pups. Male pups, however. nursed a greater portion of haul-out time due to higher bout frequencies obtained through more bout initiations. Mothers did not preferentially reject attempts to nurse by pups of either sex. These results suggest that the tenet of parental investment theory suggesting male pups enjoy preferential investment may be misleading. In harbour seals. male pups seem actively to seek out resources, as opposed to any inherent strategy on the par1 of the mother.