Considerable Variation In Behaviour Research Articles

Characterizing group and individual engagement in intergroup encounters between small groups of ring-tailed lemurs (Lemur catta) on St. Catherines Island, USA.

Primate species exhibit considerable variation in behavior and outcomes during intergroup encounters (IGEs). Social group characteristics, like group size, and individual traits, such as sex, rank, and reproductive status, within those groups can influence both IGE engagement and outcomes. To better understand the impact of group heterogeneity on IGEs, we must examine individual strategies to elucidate individual costs and benefits of engaging in these interactions. Here, we present a descriptive study of the IGEs between two small social groups of ring-tailed lemurs (Lemur catta) on St. Catherines Island, GA, USA. We distinguish between dyadic and multiple-individual interactions between groups to compare collective and individual agonistic engagement. All encounters occurred when the East Road group (N = 7 individuals) traveled from the center of their home range to the boundary with Windmill group's (N = 5 individuals) home range, indicating that East Road might have been actively testing this boundary for access to food resources, sleeping trees, and mating opportunities. We also found notable individual variation in participation during IGEs. The daughters of the highest-ranking females were the most-engaged in dyadic intergroup and intragroup aggression, had high "win" rates during intergroup dyadic encounters, and engaged in intergroup multiple-individual interactions at high levels. These findings indicate that they might value their home range more as "potential alphas" compared to other group members. Dominant females were the most engaged in multiple-individual interactions, suggesting that they contribute heavily to collective action that might result in a gain or loss of access to resources. Finally, these two small groups might be equally matched despite the two-individual group size disparity due to individual free-riding strategies. Future research should focus on individual strategies during IGEs to characterize the complex decisions and trade-offs that influence participation.

On the behaviour of an under-studied population of bottlenose dolphins in the Southern Adriatic Sea

AbstractPerhaps the world's best-known cetacean, the bottlenose dolphin shows considerable variation in behaviour between and within populations in relation to differences in natural and anthropogenic conditions. Drivers of behavioural variation need to be identified to understand the dynamics of wild dolphin populations. Little research has been published on the bottlenose dolphin population found in the Southern Adriatic Sea. Using a set of spatial, temporal and social predictors, we aimed to investigate what variables are related to the behaviour of an under-studied population of bottlenose dolphins along the coastline of Montenegro. We present the results of a year-long study monitoring the behaviour of bottlenose dolphins along coastal Montenegro. We considered the effect of topography, seasonality and group size. A large proportion of travelling (55%) small groups (mean 4, range 1–9) in shallow waters (<50 m) was observed. We showed that seasonality alone explained behaviour best, with surface-feeding and socializing-resting increasing in autumn and winter. Group size was found to be a result of behavioural choice. We suggest seasonal changes in environmental conditions and anthropogenic pressure may explain the recorded behavioural pattern. This research points to the necessity of increased collaboration in the region to help understand complex patterns in behaviour and habitat use of local dolphin populations if effective conservation measures are to be developed.

Factors influencing individual participation during intergroup interactions in mountain gorillas

In group-living species, encounters with extragroup rivals can be one of the riskiest actions in which individuals participate. Different group members often have different incentives to participate during intergroup interactions, and individuals with fewer payoffs of competition, including those of the smaller sex and/or lower rank, may ‘free-ride’ to avoid the costs of conflict. However, there is little evidence for how different types of intergroup interactions (e.g. interactions that do not involve conflict) can influence the participation of individuals. We examined the ecological, demographic and social predictors of individual participation in interactions between 14 fully habituated mountain gorilla groups in Volcanoes National Park, Rwanda from 2003 to 2015. The probability of an individual participating decreased with group size but remained relatively high in aggressive interactions and in multimale groups, illustrating the potential for ‘load lightening’ among group members. Males with fewer mating opportunities participated less often than males with more mating opportunities; however, male participation was significantly higher than female participation across all types of intergroup interactions. Females were more likely to be involved in aggressive interactions with solitary males, possibly to avoid the potential cost of infanticide if a resident male is killed or injured. Both sexes demonstrated more affiliative behaviours towards familiar groups, indicating a benefit of maintaining social relationships with familiar groups. Individuals show considerable variation in behaviour during intergroup interactions, and our results suggest that this variation is primarily driven by intergroup familiarity and individual reproductive benefits, both of which may have long-term consequences for individual fitness.

Effects of emergence time and early social rearing environment on behaviour of Atlantic salmon: consequences for juvenile fitness and smolt migration.

Consistent individual differences in behaviour have been well documented in a variety of animal taxa, but surprisingly little is known about the fitness and life-history consequences of such individual variation. In wild salmonids, the timing of fry emergence from gravel spawning nests has been suggested to be coupled with individual behavioural traits. Here, we further investigate the link between timing of spawning nest emergence and behaviour of Atlantic salmon (Salmo salar), test effects of social rearing environment on behavioural traits in fish with different emergence times, and assess whether behavioural traits measured in the laboratory predict growth, survival, and migration status in the wild. Atlantic salmon fry were sorted with respect to emergence time from artificial spawning nest into three groups: early, intermediate, and late. These emergence groups were hatchery-reared separately or in co-culture for four months to test effects of social rearing environment on behavioural traits. Twenty fish from each of the six treatment groups were then subjected to three individual-based behavioural tests: basal locomotor activity, boldness, and escape response. Following behavioural characterization, the fish were released into a near-natural experimental stream. Results showed differences in escape behaviour between emergence groups in a net restraining test, but the social rearing environment did not affect individual behavioural expression. Emergence time and social environment had no significant effects on survival, growth, and migration status in the stream, although migration propensity was 1.4 to 1.9 times higher for early emerging individuals that were reared separately. In addition, despite individuals showing considerable variation in behaviour across treatment groups, this was not translated into differences in growth, survival, and migration status. Hence, our study adds to the view that fitness (i.e., growth and survival) and life-history predictions from laboratory measures of behaviour should be made with caution and ideally tested in nature.

Implementing Realistic, Nonlinear, Material Stress–Strain Behavior in ANSYS for the Autofrettage of Thick-Walled Cylinders

High-pressure vessels are autofrettaged to introduce favorable, compressive, residual stresses around their inner diameters. The efficacy of autofrettage is limited by a phenomenon called the Bauschinger effect, which describes the early onset of nonlinearity during unloading in a material that has previously been subjected to initial deformation. The degree of prestressing achieved determines the fatigue life of the vessel, hence, high fidelity prediction of the stress field developed is essential for accurate prediction of fatigue life. This requires precise representation of material behavior within the autofrettage model used. This paper describes the adaption and development of USERMAT, a user programmable feature within ANSYS (ANSYS Finite Element Program, ANSYS, Inc., Southpointe, 275 Technology Drive, Canonsburg, PA), to create a framework to represent realistic behavior of candidate gun steels. A number of materials including A723 were modeled to investigate and validate the framework. A723 was then used in simulations of both a uni-axial test and hydraulic autofrettage. These results are compared with spreadsheet data from the material-fit equations and equivalent results from the Hencky program, respectively. Close agreement was observed between the results in both cases, indicating the model is an effective means of representing the considerable variation in behavior between loading and unloading in candidate steels.

THE COMPOSITION OF THE INTERIOR OF COMET 73P/SCHWASSMANN-WACHMANN 3: RESULTS FROM NARROWBAND PHOTOMETRY OF MULTIPLE COMPONENTS

We present analyses of and results for multiple components of Comet 73P/Schwassmann-Wachmann 3 at two apparitions. A total of eight nights of narrowband photometry were obtained during the comet's 2006 apparition from February 25 to September 24 at Lowell Observatory. The comet's very close passage of Earth and sporadic outbursts allowed us to successfully measure the primary body, "C," as well as components "B," "G," and "R." We additionally include four nights of narrowband photometry from 1995, obtained at Perth Observatory between October 19 and November 21, one to two months after the initial fragmentation event and outburst. We determined production rates for OH, NH, CN, C3, and C2, along with a proxy for the dust production, A(θ)fρ, and our 2006 measurements show considerable variation in behavior among the components, and for the gas species as compared to the dust grains. The two components having the best temporal coverage, C and B, both exhibit evidence for strong seasonal effects with larger production rates prior to perihelion than after. Because C showed little or no evidence of outbursts, its derived active area (based on water production rates) appears to be dominated by ice vaporizing from the nucleus; the fractional active area of the total nucleus surface varied from 56% (2006 February) to 125% (May) and back down to 11% (September) following perihelion. Except for when Component B was in outburst, C always had higher production rates than B, implying a significantly larger effective active area on its nucleus' surface. Unlike the gas species, dust production showed large and varying trends with both aperture size and with time, implying a significant change in the properties of the dust grains during the 2006 apparition. Due to the fragmentation event in 1995, the majority of active surfaces on the various components observed in 2006 are freshly exposed from the interior of Schwassmann-Wachmann 3's nucleus, thus permitting us to directly probe the chemical composition of the relatively pristine interior. Relative abundances, expressed as production rate ratios between gas species, were compared among the four components and to values determined prior to the fragmentation, as well as to those measured in other comets. Our measurements indicate each component, to within the uncertainties, has the same composition and that this composition is consistent with that measured in the pre-fragmented nucleus. Moreover, C2 and C3 are both strongly depleted when compared to the majority of comets, placing Schwassmann-Wachmann 3 among the more extreme comets within the carbon-chain depleted class identified by A'Hearn et al. With the material released from the interior of the comet yielding comparable depletions of carbon-chain molecules as the original surface of the nucleus, we conclude that carbon-chain depletion is not caused by evolution of the surface, and so must instead reflect the primordial composition at the time and location that the comet accreted.

Limits, Variability, and General Behavior of Statistical Predictability of the Midlatitude Atmosphere

AbstractThe nature of statistical predictability is analyzed in a T42 global atmospheric model that is able to adequately capture the main features of the midlatitude atmosphere. Key novel features of the present study include very large prediction ensembles and information theoretic techniques. It is found globally that predictability declines in a quasi-linear fashion with time for short-term predictions (3–25 days), while for long ranges (30–45 days) there is an exponential tail. In general, beyond 45 days the prediction and climatological ensembles have essentially converged, which means that beyond that point, atmospheric initial conditions are irrelevant to atmospheric statistical prediction.Regional predictions show considerable variation in behavior. Both of the (northern) winter storm-track regions show a close-to-quasi-linear decline in predictability toward a cutoff at around 40 days. The (southern) summer storm track shows a much more exponential and considerably slower decline with a small amount of predictability still in evidence even at 90 days. Because the winter storm tracks dominate global variance the behavior of their predictability tends to dominate the global measure, except at longer lags. Variability in predictability with respect to initial conditions is also examined, and it is found that this is related more strongly to ensemble signal rather than ensemble spread. This result may serve to explain why the relation between weather forecast skill and ensemble spread is often observed to be significantly less than perfect. Results herein suggest that the ensemble signal as well as spread variations may be a major contributor to skill variations. Finally, it is found that the sensitivity of the calculated global predictability to changes in model horizontal resolution is not large; results from a T85 resolution model are not qualitatively all that different from the T42 case.

Predicting the dynamics of animal behaviour in field populations

Many species show considerable variation in behaviour among individuals. We show that some behaviours are largely deterministic and predictable with mathematical models. We propose a general differential equation model of behaviour in field populations and use the methodology to explain and predict the dynamics of sleep and colony attendance in seabirds as a function of environmental factors. Our model explained over half the variability in the data to which it was fitted, and it predicted the dynamics of an independent data set. Differential equation models may provide new approaches to the study of behaviour in animals and humans.

Waiting time information services: what are the implications of waiting list behaviour for their design?

In some countries, patients requiring elective surgery can access comparative waiting time information for various surgical units. What someone can deduce from this information will depend upon how the statistics are derived, and how waiting lists behave. However, empirical analyses of waiting list behaviour are scarce. This study analysed three years of waiting list data collected at one hospital in Sydney, Australia. The results highlight various issues that raise questions about using particular waiting time statistics to make inferences about patient waiting times. In particular, the results highlight the considerable variation in behaviour that can exist between surgeons in the same specialty, and that can occur over time.

Popliteal Vessels in Knee Surgery A Magnetic Resonance Imaging Study

Popliteal artery injury during surgery of the knee is rare but can have devastating consequences. The position of knee flexion has been thought to be protective for the popliteal artery, allowing it to fall back from the knee joint. No prior study has provided in vivo cross sectional evidence of the behavior of the popliteal vessels during knee flexion with the effect of gravity. Magnetic resonance imaging was used in nine volunteers to measure the distance of the popliteal artery and veins from the posterior proximal tibia at two levels corresponding to the levels of osteotomy in total knee arthroplasty and in high tibial osteotomy. Scans were taken with the knee in full extension and at 90 degrees flexion with the patient in the supine position, allowing for the effect of gravity. Considerable variation in behavior of the vein and the artery was observed at the high tibial osteotomy cross sectional level and the total knee arthroplasty cross sectional level. In two knees at the high tibial osteotomy cross sectional level and in two knees at the total knee arthroplasty cross sectional, level the artery moved closer to the posterior tibia with knee flexion. Even with the effect of gravity included, knee flexion does not guarantee removal of the popliteal vessels from potential harm during surgery of the knee.

Nature watch

Bats are placental mammals that have achieved true flight. After mating and fertilisation, the egg is implanted in the wall of the uterus and the foetus undergoes development over a gestation period. After birth, the young are protected and given shelter, suckled, and possibly instructed before weaning and eventual independence. Within this period, bats show considerable variation in behaviour which is generally linked to climate and feeding habits. This article explains the behaviour associated with different breeding systems in different climatic regimes.

Behavioural variability in marine larvae

AbstractDespite increasing recognition of the importance of larval settlement, recent models have concentrated on small and large scale hydrodynamic effects as determinants of larval settlement. Implicit in most of these discussions is the assumption that variability in larval behaviour either does not exist, or is unimportant.We present evidence that this is an inaccurate description of larval behaviour at the time of settlement. There exists considerable variation in behaviour at a number of scales, even under controlled laboratory conditions. For almost all species examined, responses to attractive and discrete stimuli were non‐uniform. The causes of variability in larval behaviour both within and between populations are largely unexplored. We suggest that variable behaviour, in response to discrete stimuli, may be a selectable trait. If so, the manifestation of such variability in individuals within a population is simply the expression of an adaptive trail. By this reasoning, differences in larval behaviour between populations are evidence for varying selective pressures. We conclude with an examination of possible consequences to a population, arising from variable larval behaviour.

AIDS and the Social Relations of Intravenous Drug Users

Gauging the impact of AIDS on intravenous drug users requires analysis of the cultural, political, and racial contexts of American society in which drug use is embedded. Considerable variation in behavior among drug injectors and noninjectors in different cities over time further complicates an understanding of the dynamics of drug use. AIDS has prompted many IV drug users to change their behavior, though not all users have reduced the risks of transmitting HIV infection. While expanded harm-reduction strategies and drug abuse treatment systems may help limit the epidemic's spread, weak federal support, constrained hospital resources, and racial stigma inhibit more direct action needed to stem the negative social and personal consequences of drug use.

Behavioral Interactions between Ants and Their Parasites

Ectoparasitic and endoparasitic arthropods of ants include species of Acarina (Antennophoridae, Uropodidae, Macrochelidae), Strepsiptera (Myrecolacidae), Hymenoptera (Formicidae, Diapriidae, Eucharitidae), and Diptera (Phoridae). Variation in the style of ectoparasitism is illustrated by the different lifestages involved and differing effects on the hosts by parasitic ants and eucharitids. Considerable variation in behavior occurs between related genera and species of phorids emphasizing the danger of over-generalization on the relationships of ants and their parasites.

Factors affecting the rate and extent of heat release during the immersion of powdered coals in alkanols

The heats of immersion of both bituminous coals (Virginia-C and Kentucky-Blend) and subbituminous coals (Wyodak) in alkanols have been determined micro-calorimetrically. Studies have been made of the effects on immersional heat release of varying outgassing conditions and prior extraction of the coal samples with methanol. Investigations of the heat release and the rate of heat release across the range of simple alkanols containing from one to ten carbon atoms show considerable variation in behaviour, with the butanol isomers revealing particularly striking differences. The observed values of the heats of immersion are interpreted in terms of limited alcohol accessibility to the pore structure of the coals.

Protonation of anion intermediates in metal-ammonia reduction: 1,2- vs. 1,4-dihydro aromatic products

The competition between 1,3-cyclohexadienes and 1,4-cyclohexadienes during metal-ammonia reduction has been examined. The former is usually regarded as a thermodynamic product and the latter as a kinetic product although, in actuality, little thermodynamic difference exists between these two isomers. 1,4-Cyclohexadiene was found to undergo proton abstraction with potassium or sodium amide in ammonia at -50/sup 0/C but not with lithium amide. Similarly, 1,3-cyclohexadiene reacts only with potassium amide and not with sodium or lithium amide. Consequences relating to the formation of conjugated and nonconjugated products during metal-ammonia reduction are discussed. The reaction of dihydronaphthalenes with various amides is also presented and again there is considerable variation in behavior. This has led to improved synthetic schemes for the selective production of 1,2-dihydro- and 1,4-dihydronaphthalenes as well as tetralins. Finally, protonation sites in pentadienyl type anions are considered. 4 tables.

Liposarcoma of paratesticular origin: a case report.

SummaryA liposarcoma of paratesticular origin is reported; this is the 12th recorded case. A survey of previously published cases suggests that there is a considerable variation in behaviour, but that they are probably less malignant than the commoner testicular neoplasms, and that orchidectomy with high ligation and excision of the spermatic cord is adequate.

Apparatus for the Measurement of Gaseous Conditions inside an Apple Fruit

IT was noticed in the course of studies of the behaviour of apples which had been coated with various oil-water emulsions (see e.g. Hulme, 1949) that some of the fruits exhibited symptoms of physiological diseases typical of fruit stored in low concentrations of 02 and high concentrations of C02 (see Kidd and West, 1927). This suggested that the effect of skin-coatings on the storage behaviour of the fruit was related to their effect on the composition of the atmosphere within the fruit and that to study these effects it was necessary to measure the content of C02 and Oa within the fruit. Considerable variation in behaviour was observed in fruit treated with the