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1.

001-es BibID:BIBFORM022957
Első szerző:Barta Zoltán (biológus, zoológus)
Cím:Sexual Conflict about Parental Care : the Role of Reserves / Zoltán Barta, Alasdair I. Houston, John M. McNamara, Tamás Székely
Dátum:2002
Megjegyzések:Parental care often increases the survival of offspring, but it is costly to parents. Because of this trade-off, a sexual conflict over care arises. The solution to this conflict depends on the interactions between the male and female parents, the behavior of other animals in the population, and the individual differences within a sex. We take an integrated approach and develop a state-dependent dynamic game model of parental care. The model investigates a single breeding season in which the animals can breed several times. Each parent's decision about whether to care for the brood or desert depends on its own energy reserves, its mate's reserves, and the time in the season. We develop a fully consistent solution in which the behavior of an animal is the best given the behavior of its mate and of all other animals in the population. The model predicts that females may strategically reduce their own reserves so as to "force" their mate to provide care. We investigate how the energy costs of caring and searching for a mate, values of care (how the probability of offspring survival depends on the pattern of care), and population sex ratio influence the pattern of care over the breeding season.
Tárgyszavak:Természettudományok Biológiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban
sexual conflict
parental care
offspring desertion
dynamic game
reserves
body mass regulation
Megjelenés:American Naturalist. - 159 : 6 (2002), p. 687-705. -
További szerzők:Houston, Alasdair I. McNamara, John M. Székely Tamás (1959-) (biológus)
Internet cím:Intézményi repozitóriumban (DEA) tárolt változat
DOI
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2.

001-es BibID:BIBFORM021579
Első szerző:Barta Zoltán (biológus, zoológus)
Cím:Annual routines of non-migratory birds : optimal moult strategies / Zoltán Barta, Alasdair I. Houston, John M. McNamara, Robert K. Welham, Anders Hedenström, Thomas P. Weber, Orsolya Feró
Dátum:2006
ISSN:0030-1299
Megjegyzések:In a periodically changing environment it is important for animals to properly time the major events of their life in order to maximise their lifetime fitness. For a non-migratory bird the timing of breeding and moult are thought to be the most crucial. We develop a state-dependent optimal annual routine model that incorporates explicit density dependence in the food supply. In the model the birds' decisions depend on the time of year, their energy reserves, breeding status, experience, and the quality of two types of feathers (outer and inner primaries). Our model predicts that, under a seasonal environment, feathers with large effects on flight ability, higher abrasion rate and lower energetic cost of moult should be moulted closer to the winter (i.e. later) than those with the opposite attributes. Therefore, we argue that the sequence of moult may be an adaptive response to the problem of optimal timing of moult of differing feathers within the same feather tract. The model also predicts that environmental seasonality greatly affects optimal annual routines. Under high seasonality birds breed first then immediately moult, whereas under low seasonality an alternation occurs between breeding and moulting some of the feathers in one year and having a complete moult but no breeding in the other year. Increasing food abundance has a similar effect.
Tárgyszavak:Természettudományok Biológiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban
Megjelenés:Oikos. - 112 (2006), p. 580-593. -
További szerzők:Houston, Alasdair I. McNamara, John M. Welham, Robert K. Hedenström, Anders Weber, Thomas P. Feró Orsolya
Internet cím:Intézményi repozitóriumban (DEA) tárolt változat
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3.

001-es BibID:BIBFORM018796
Első szerző:Barta Zoltán (biológus, zoológus)
Cím:Optimal moult strategies in migratory birds / Zoltán Barta, John M. McNamara, Alasdair I. Houston, Thomas P. Weber, Anders Hedenström, Orsolya Feró
Dátum:2008
Megjegyzések:Avian migration, which involves billions of birds flying vast distances, is known to influence all aspects of avian life. Here we investigate how birds fit moult into an annual cycle determined by the need to migrate. Large variation exists in moulting patterns in relation to migration: for instance, moult can occur after breeding in the summer or after arrival in the wintering quarters. Here we use an optimal annual routine model to investigate why this variation exists. The modelled bird's decisions depend on the time of year, its energy reserves, breeding status, experience, flight feather quality and location. Our results suggest that the temporal and spatial variations in food are an important influence on a migratory bird's annual cycle. Summer moult occurs when food has a high peak on the breeding site in the summer, but it is less seasonal elsewhere. Winter moult occurs if there is a short period of high food availability in summer and a strong winter peak at different locations (i.e. the food is very seasonal but in opposite phase on these areas). This finding might explain why only long-distance migrants have a winter moult.
Tárgyszavak:Természettudományok Biológiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban
optimal annual routines
moult
migration
birds
state-dependent dynamic models
dynamic programming
Megjelenés:Philosophical Transactions Of The Royal Society of London, Series B. - 363 : 1490 (2008), p. 211-230. -
További szerzők:McNamara, John M. Houston, Alasdair I. Weber, Thomas P. Hedenström, Anders Feró Orsolya
Internet cím:DOI
Intézményi repozitóriumban (DEA) tárolt változat
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4.

001-es BibID:BIBFORM018610
Első szerző:Barta Zoltán (biológus, zoológus)
Cím:Cooperation among non-relatives evolves by state-dependent generalized reciprocity / Zoltán Barta, John M. McNamara, Dóra B. Huszár, Michael Taborsky
Dátum:2011
Megjegyzések:For decades, attempts to understand cooperation between non-kin have generated substantial theoretical and empirical interest in the evolutionary mechanisms of reciprocal altruism. There is growing evidence that the cognitive limitations of animals can hinder direct and indirect reciprocity because the necessary mental capacity is costly. Here, we show that cooperation can evolve by generalized reciprocity (help anyone, if helped by someone) even in large groups, if individuals base their decision to cooperate on a state variable updated by the outcome of the last interaction with an anonymous partner. We demonstrate that this alternative mechanism emerges through small evolutionary steps under a wide range of conditions. Since this state-based generalized reciprocity works without advanced cognitive abilities it may help to understand the evolution of complex social behaviour in a wide range of organisms.
Tárgyszavak:Természettudományok Biológiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban
internal state
gratitude
tit for tat
anonymous partners
Egészség- és Környezettudomány
Megjelenés:Proceedings of the Royal Society. Series B. Biological sciences. - B : 278 (2011), p. 843-848. -
További szerzők:McNamara, John M. Huszár Dóra B. Taborsky, Michael
Pályázati támogatás:TÁMOP-4.2.1/B-09/1-KONV-2010-0007
TÁMOP
Viselkedésökológiai Kutatócsoport
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5.

001-es BibID:BIBFORM104124
035-os BibID:(cikkazonosító)20200622 (WOS)000540447000001 (Scopus)85084328509
Első szerző:Bauer, Silke
Cím:Environmental variability, reliability of information and the timing of migration / Silke Bauer, John M. McNamara, Zoltan Barta
Dátum:2020
ISSN:0962-8452
Megjegyzések:The timing of migration and migratory steps is highly relevant for fitness. Because environmental conditions vary between years, the optimal time for migration varies accordingly. Therefore, migratory animals could clearly benefit from acquiring information as to when it is the best time to migrate in a specific year. Thus, environmental predictability and variability are fundamental characteristics of migration systems but their relationship and consequence for migratory progression has remained unexplored. We develop a simple dynamic model to identify the optimal migration behaviour in environments that differ in predictability, variability and the number of intermediate stop-over sites. Our results indicate that higher predictability along migration routes enables organisms to better time migration when phenology deviates from its long-term average and thus, increases fitness. Information is particularly valuable in highly variable environments and in the final migration-step, i.e. before the destination. Furthermore, we show that a general strategy for obtaining information in relatively uninformative but variable environments is using intermediate stop-over sites that enable migrants to better predict conditions ahead. Our study contributes to a better understanding of the relationship between animal movement and environmental predictability-an important, yet underappreciated factor that strongly influences migratory progression.
Tárgyszavak:Természettudományok Biológiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban
folyóiratcikk
predictability
phenology
climate change
environmental variability
uncertainty
Megjelenés:Proceedings of The Royal Society B-Biological Sciences. - 287 : 1926 (2020), p. 1-8. -
További szerzők:McNamara, John M. Barta Zoltán (1967-) (biológus, zoológus)
Pályázati támogatás:NKFIH-1150-6/2019
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6.

001-es BibID:BIBFORM018765
Első szerző:Bauer, Silke
Cím:Animal migration : linking models and data beyond taxonomic limits / Silke Bauer, Zoltan Barta, Bruno J. Ens, Graeme C. Hays, John M. McNamara, Marcel Klaassen
Dátum:2009
ISSN:1744-9561
Megjegyzések:An international workshop on animal migration was held at the Lorentz Center in Leiden, The Netherlands, 2-6 March 2009, bringing together leading theoreticians and empiricists from the major migratory taxa, aiming at the identification of cutting-edge questions in migration research that cross taxonomic borders.
Tárgyszavak:Természettudományok Biológiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban
evolution of migration
migration strategies
currencies of migration
predictability
tracking of migrants
graphical user interface migration models
Megjelenés:Biology Letters. - 5 : 4 (2009), p. 433-435. -
További szerzők:Barta Zoltán (1967-) (biológus, zoológus) Ens, Bruno J. Hays, Graeme C. McNamara, John M. Klaassen, Marcel
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7.

001-es BibID:BIBFORM018795
Első szerző:Feró Orsolya
Cím:Optimal annual routines : New tools for conservation biology / Orsolya Feró, Philip A. Stephens, Zoltán Barta, John M. McNamara, Alasdair I. Houston
Dátum:2008
Megjegyzések:Many applied problems in ecology and conservation require prediction, and population models are important tools for that purpose. Formerly, the majority of predictive population models were based on matrix models. As the limitations of classical matrix models have become clearer, the use of individual-based models has increased. These models use behavioral rules imposed at the level of the individual to establish the emergent consequences of those rules at the population level. Individual behaviors in such models use an array of different rule types, from empirically derived probabilities to long-term fitness considerations. There has been surprisingly little discussion of the strengths and weaknesses of these different rule types. Here, we consider different strategies for modeling individual behaviors, together with some problems associated with individual-based models. We propose a novel approach based on modeling optimal annual routines. Annual routines allow individual behaviors to be predicted over a whole annual cycle within the context of long-term fitness considerations. Temporal trade-offs between different behaviors are automatically included in annual routine models, overcoming some of the primary limitations of other individual-based models. Furthermore, as well as population predictions, individual behaviors and indices of condition are emergent features of annual routine models. We show that these can be more sensitive to environmental change than population size, offering alternative, repeatable metrics for monitoring population status. Annual routine models provide no panacea for the problems of data limitations in predictive population modeling. However, as a result of their ability to deal with life-history trade-offs, as well as their potential for relatively rapid and accurate validation and parameterization, we suggest that annual routine models have strong potential for predictive population modeling in applied conservation settings.
Tárgyszavak:Természettudományok Biológiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban
environmental change
habitat degradation
individual-based models
migration
molt
optimality
population dynamics
Megjelenés:Ecological Applications. - 18 : 6 (2008), p. 1563-1577. -
További szerzők:Stephens, Philip A. Barta Zoltán (1967-) (biológus, zoológus) McNamara, John M. Houston, Alasdair I.
Internet cím:Intézményi repozitóriumban (DEA) tárolt változat
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8.

001-es BibID:BIBFORM018802
Első szerző:Hedenström, Anders
Cím:Migration speed and scheduling of annual events by migrating birds in relation to climate change / A. Hedenström, Z. Barta, B. Helm, A. I. Houston, J. M. McNamara, N. Jonzén
Dátum:2007
Megjegyzések:Empirical evidence for changed timing of migration in birds is emerging from both American and Euro-African migration systems. These changes are usually interpreted as a consequence of changes in climate. Responses in timing of migration and breeding may differ among species, and the adaptive significance is not well understood. There is a lack of theoretical understanding about time-shifts in life-history events due to climatic changes. In the present paper, we use 2 separate modelling approaches to investigate the effects of climate change on migration. We first use a simple model of flight speed and foraging to explore which factors may influence migration speed and stopover itinerary. Our second approach derives predictions based on an annual routine model, where behavioural strategies regarding timing of migration, breeding, moult and number of breeding attempts are modelled in an environment comprising 4 locations (breeding and wintering sites and 2 stopover sites). This approach takes account of interrelationships between behaviours and seasons as a step towards realistic modelling of migratory connectivity. Departure from the wintering site is advanced in relation to the advancement of spring if the moult is in summer, but not so for species with a winter moult, while arrival at the breeding site is advanced for both moult scenarios. Timing of breeding and number of successful broods were also affected by spring advancement, while start of moult is relatively unaffected by climate change. These optimal solutions under the modelled set of parameters are discussed with respect to current knowledge of the mechanisms underlying seasonal timing in birds.
Tárgyszavak:Természettudományok Biológiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban
Annual routines
Climate change
Phenology
Timing of breeding
Bird migration
Megjelenés:Climate Research. - 35 : 1-2 (2007), p. 79-91. -
További szerzők:Helm, B. Houston, A. I. McNamara, John M. Jonzén, N. Barta Zoltán (1967-) (biológus, zoológus)
Pályázati támogatás:OTKA
NF 61143
OTKA
T046661
Internet cím:DOI
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9.

001-es BibID:BIBFORM022923
Első szerző:Houston, Alasdair I.
Cím:The effect of foraging parameters on the probability that a dive is successful / Alasdair I. Houston, John M. McNamara, Jon E. Heron, Zoltán Barta
Dátum:2003
ISSN:0962-8452
Megjegyzések:In this paper, we investigate the foraging decisions of an animal that dives to obtain its food. It might seem reasonable to use the probability that the diver is successful in any dive as an indicator of habitat quality. We use a dynamic model of optimal prey choice to show that this interpretation of diving success is not generally valid. In particular, we show that diving success is not directly proportional to the overall rate of gain that can be achieved in an environment. Furthermore, some environmental factors can have a non-monotonic effect on the probability of success. For example, as the travel time to the foraging area increases, the probability of success may first increase and then decrease. We point out that the same conclusions are likely to apply in the context of mate choice, i.e. the probability of getting a mate may not be an indicator of the quality of the environment in terms of reproductive success
Tárgyszavak:Természettudományok Biológiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban
diving
optimal choice
probability of success
indicator
Megjelenés:Proceedings of the Royal Society. Series B. Biological sciences. - 270 : 1532 (2003), p. 2451-2455. -
További szerzők:McNamara, John M. Heron, Jon E. Barta Zoltán (1967-) (biológus, zoológus)
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10.

001-es BibID:BIBFORM018805
Első szerző:Houston, Alasdair I.
Cím:The effect of energy reserves and food availability on optimal immune defence / Alasdair I. Houston, John M. McNamara, Zoltán Barta, Kirk C. Klasing
Dátum:2007
ISSN:0962-8452
Megjegyzések:In order to avoid both starvation and disease, animals must allocate resources between energy reserves and immune defence. We investigate the optimal allocation. We find that animals with low reserves choose to allocate less to defence than animals with higher reserves because when reserves are low it is more important to increase reserves to reduce the risk of starvation in the future. In general, investment in immune defence increases monotonically with energy reserves. An exception is when the animal can reduce its probability of death from disease by reducing its foraging rate. In this case, allocation to immune defence can peak at intermediate reserves. When food changes over time, the optimal response depends on the frequency of changes. If the environment is relatively stable, animals forage most intensively when the food is scarce and invest more in immune defence when the food is abundant than when it is scarce. If the environment changes quickly, animals forage at low intensity when the food is scarce, but at high intensity when the food is abundant. As the rate of environmental change increases, immune defence becomes less dependent on food availability. We show that the strength of selection on reserve-dependent immune defence depends on how foraging intensity and immune defence determine the probability of death from disease.
Tárgyszavak:Természettudományok Biológiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban
immunity; state-dependence; dynamic programming; energy reserves
Megjelenés:Proceedings of the Royal Society. Series B. Biological sciences. - 274 : 1627 (2007), p. 2835-2842. -
További szerzők:McNamara, John M. Klasing, Kirk C. Barta Zoltán (1967-) (biológus, zoológus)
Pályázati támogatás:OTKA
NF 61143
OTKA
T046661
Internet cím:DOI
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11.

001-es BibID:BIBFORM104126
035-os BibID:(cikkazonosító)20201758 (WOS)000595340600008 (Scopus)85096348842
Első szerző:McNamara, John M.
Cím:Behavioural flexibility and reputation formation / John M. McNamara, Zoltan Barta
Dátum:2020
ISSN:0962-8452
Megjegyzések:Limited flexibility in behaviour gives rise to behavioural consistency, so that past behaviour is partially predictive of current behaviour. The consequences of limits to flexibility are investigated in a population in which pairs of individuals play a game of trust. The game can either be observed by others or not. Reputation is based on trustworthiness when observed and acts as a signal of behaviour in future interactions with others. Individuals use the reputation of partner in deciding whether to trust them, both when observed by others and when not observed. We explore the effects of costs of exhibiting a difference in behaviour between when observed and when not observed (i.e. a cost of flexibility). When costs are low, individuals do not attempt to signal that they will later be trustworthy: their signal should not be believed since it will always pay them to be untrustworthy if trusted. When costs are high, their local optimal behaviour automatically acts as an honest signal. At intermediate costs, individuals are very trustworthy when observed in order to convince others of their trustworthiness when unobserved. It is hypothesized that this type of strong signalling might occur in other settings.
Tárgyszavak:Természettudományok Biológiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban
folyóiratcikk
behavioural consistency
signalling
trust
cost of flexibility
evolutionary game theory
personality
Megjelenés:Proceedings of The Royal Society B-Biological Sciences. - 287 : 1939 (2020), p. 1-6. -
További szerzők:Barta Zoltán (1967-) (biológus, zoológus)
Pályázati támogatás:NKFIH-1150-6/2019
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12.

001-es BibID:BIBFORM030375
Első szerző:McNamara, John M.
Cím:Cues and the optimal timing of activities under environmental changes / John M. McNamara, Zoltan Barta, Marcel Klaassen, Silke Bauer
Dátum:2011
ISSN:1461-023X
Megjegyzések:Organisms time activities by using environmental cues to forecast the future availability of important resources. Presently, there is limited understanding of the relationships between cues and optimal timing, and especially about how this relationship will be affected by environmental changes. We develop a general model to explore the relation between a cue and the optimal timing of an important life history activity. The model quantifies the fitness loss for organisms failing to time behaviours optimally. We decompose the immediate change in fitness resulting from environmental changes into a component that is due to changes in the predictive power of the cue and a component that derives from the mismatch of the old response to the cue to the new environmental conditions. Our results show that consequences may range from negative, neutral to positive and are highly dependent on how cue and optimal timing and their relation are specifically affected by environmental changes.
Tárgyszavak:Természettudományok Biológiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban
Cue-response
evolutionary trap
fitness loss
life history activity
migration
mistiming
phenology
photoperiod
reaction norm
reproduction
Egészség- és Környezettudomány
Megjelenés:Ecology Letters. - 14 : 12 (2011), p. 1183-1190. -
További szerzők:Barta Zoltán (1967-) (biológus, zoológus) Klaassen, Marcel Bauer, Silke
Pályázati támogatás:TÁMOP-4.2.1/B-09/1-KONV-2010-0007
TÁMOP
Viselkedésökológiai Kutatócsoport
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