Adaptive Behavioural Strategies Research Articles

Is Mating Alone Enough to Inhibit Infanticide in Male Bank Voles?

AbstractInfanticide, the killing of conspecific young, is commonly recognized as an adaptive behavioural strategy enhancing the fitness of the perpetrator. Infanticide is supposed to be inhibited in several male rodent species after mating with a time lag to the time when perpetrators own offspring would be born. This is because males with no parental care do not recognize their own offspring. It has been suggested that copulation alone is enough to inhibit infanticidal behaviour in male rodents. Infanticidal behaviour occurs in more than 50% of male bank voles (Myodes glareolus), and offspring loss because of infanticide may have a great effect on breeding success and population recruitment. In a laboratory experiment, we studied whether infanticidal male bank voles after successful mating stop the killing of pups. Infanticidal males were paired with a female until successful copulation. After the young were born, the males’ infanticidal behaviour was studied from the time of expected birth of own pups until their post‐weaning age. We predicted that mated infanticidal males are inhibited from committing infanticide especially during the time period when pups are less than 10 d old. Against our prediction, 67% of the infanticidal males continued the killing of pups in the age of 3 d. Infanticidal behaviour remained stable, and half of the males were infanticidal still at the age of weaning of pups. Our results are contradictory to previous studies, as we observed no inhibition of infanticide during early life of pups nor increase in infanticide again when their own offspring would have reached the ‘safe’ age and size after weaning. We suggest that mating alone is not sufficient to inhibit infanticide. Thus, we suggest that other cues of the female with whom the male mated with or on her territory are needed for inhibition to occur.

Stress and self-perceived parenting behaviors of parents of children with autistic spectrum conditions

The relationships between parenting stress and self-perceived parenting behaviors in 138 parents of children with autistic spectrum conditions were studied over 9–10 months. Apart from perceived communication being attenuated, there were no major areas of self-perceived parenting weakness. Parenting stress closely interacted with self-perceived involvement, communication, and limit setting over time. In parents of young children (below 4), high initial levels of parenting stress resulted in less subsequent self-perceived involvement, and poorer communication, with the child. Good self-perceived initial skills for limit setting resulted in lower levels of parenting stress. These relationships help to explain the impact of parenting stress on child behavior problems, and may be consistent with development of parental adaptive behavioral strategies to deal with extreme stress levels.

Effects of Exogenous Application of Corticotropin-Releasing Hormone to Slices of the Olfactory Cortex from Rats with an Active Strategy of Adaptive Behavior on the Water-Immersion Model of Depression

Experiments were performed on male Wistar rats. The specimens with an active strategy of behavior were exposed to unavoidable water-immersion stress. Surviving slices of the olfactory cortex were obtained 10 days after stress. The neurohormone had a strong inhibitory effect in 40% slices from active rats. The activity of glutamate receptors decreased, while the function of GABA receptors increased in 60% slices. Our results indicate that the depressive state of behaviorally active animals due to exposure to unavoidable stress is not necessarily mediated by the corticoliberinergic mechanisms in cortical structures.

Electrophysiological characteristics of depressive states in rats with passive strategies of adaptive behavior

The behavior of rats in a T-maze was used to select individuals with a passive strategy of adaptive behavior from a population of Wistar rats. These animals were subjected to water immersion and olfactory cortex slices were prepared from the brain 10 days later and used for recording of evoked focal potentials and the effects of tetanic stimulation. Postsynaptic potentials, of both the AMPA and NMDA types, were initially of decreased amplitude in passive rats. After unavoidable stress, the suppression of excitatory potentials increased and there was a simultaneous increase in the amplitude of inhibitory GABAB-ergic mechanisms. Addition of corticoliberin (10(-10) M) to the incubation medium led to reversible blockade of synaptic transmission. Tetanic stimulation of slices from stressed rats led to the development of posttetanic depression in 84% of cases and to post-tetanic potentiation in 12%; this is evidence for profound changes in synaptic transmission. Thus, activation of corticoliberinergic mechanisms in cortical structures does not promote recovery from depressive states in rats with the passive behavioral strategy induced by unavoidable stress.

Sensitivity to UV radiation in early life stages of the Mediterranean sea urchin Sphaerechinus granularis (Lamarck)

The sea urchin Sphaerechinus granularis was used to investigate the impact of relevant levels of UV-B radiation on the early life stages of a common Mediterranean free spawning benthic species. Sperm, eggs and embryos were exposed to a range of UV radiation doses. The resulting endpoints were evaluated in terms of fertilisation success, development and survival rates. Above a weighted UV radiation dose of 0.0029 kJ m − 2 , fertilisation capability of irradiated sperm decreased rapidly. The exposure of the eggs to 0.0175 kJ m − 2 and more led to delayed and inhibited development with ensuing embryonic morphological abnormalities. One-day old larvae remained strongly sensitive to UV radiation as shown by the 50% decrease of the larval survival rate for a dose of 0.025 kJ m − 2 UVR. The elevated sensitivity of embryos to experimental UVR went along with a lack of significant amount of sunscreen compounds (e.g., mycosporine-like amino acids) in the eggs. The present results demonstrated that gamete viability and embryonic development may be significantly impaired by solar UV radiation in S. granularis, compromising in this way the reproduction of the species. Unless adaptive behavioural reproductive strategies exist, the influence of ambient UV radiation appears as a selective force for population dynamics of broadcast spawners in the shallow benthic Mediterranean environment.

The organisation of the basal ganglia in the domestic chick ( Gallus domesticus): Anatomical localisation of DARPP-32 in relation to glutamate

Subpallial structures are highly conserved across the different vertebrate species. They are instrumental in the neural processing relevant to adaptive learning, decision making, motivation and behavioural strategies. Of the striatal regions, our attention has been focussed on the medial and ventral striatum (MSt), now parcellated into subregions, and also including the nucleus accumbens (Ac). Similar to mammals, the avian Ac and MSt receive glutamatergic input from the pallium and dopaminergic input from the substantia nigra and ventral tegmental area. Coincidence between glutamatergic and dopaminergic synaptic activities in the ventral/medial striatum, including the Ac, is required for memory to be formed for a given pairing of stimulus and a hedonic quality or behavioural salience. The underlying mechanism involves the activation of NMDA and dopaminergic receptors, as well as the phosphorylation of dopamine-cAMP-regulated phosphoprotein (DARPP-32). Using quantitative electron microscopy of chick specimens double-labelled against glutamate and DARPP-32 we observed direct synaptic connections between glutamate immunoreactive axon terminals and DARPP-32 labelled dendrites in the MSt and also in the posterolateral telencephalon (nidopallium caudolaterale, a prefrontal cortex equivalent region) and the hippocampus. Glutamate immunoreactive axons synapsed with both DARPP-32 immunoreactive (DARPP-32+) and DARPP-32 negative (DARPP-32−) dendrites, forming asymmetrical junctions, in all brain regions observed. The existence of direct synaptic contacts between excitatory amino acid containing axon terminals and DARPP-32 containing dopaminoceptive neurons of the chicken MSt underlines the functional homology with mammalian striatal systems.

Blockade of corticoliberin receptors prevents the development of post-stress psychopathology in rats with an active strategy of adaptive behavior

Active and passive Wistar rats were subjected to single water immersions, after which they showed signs of post-stress depression. Administration on this background of the peptide CRH-R1 receptor blocker astressin prevented the development of behavioral deficit in active individuals but had no effect on the behavior of passive rats. These results lead to the conclusion that corticoliberin receptor blockers are effective in the treatment of post-stress depression only for individuals with an initially active behavioral strategy.

Interaction of total blood calcium levels and brain catecholamines during the formation and reinforcement of memory traces in hypoparathyroidism

Interactions between the total blood calcium level and catecholamine contents in limbic brain structures during the formation and extinction of a conditioned passive avoidance reflex were studied in rats with hypoparathyroidism. Impairments of calcium support for the processes of conditioned reflex activity were seen after removal of the parathyroid glands. Animals with hypoparathyroidism not only showed changes in basal dopamine and noradrenaline levels in limbic structures, but also impairments of catecholamine dynamics during the acquisition and forced extinction of a conditioned passive avoidance reflex. These results demonstrate changes in the functional dynamics of the dopaminergic and noradrenergic systems of the brain in conditions of abnormal calcium homeostasis in the body, which underlie abnormalities of conditioned reflex activity and the acquisition of the adaptive behavioral strategies.

Are mistakes inevitable? Sex allocation specialization by workers can reduce the genetic information needed to assess queen mating frequency

Insect workers can increase their inclusive fitness by biasing colony sex allocation towards males when their mother queen is mated to multiple males and females when she is singly mated. Workers need heritable variation in odour diversity to assess queen mating frequency. Here we present a simple one-locus two-allele model, which shows that the sex ratio specialization itself will often select against rare alleles that would provide additional information for the assessment of queen mating frequency. However, under certain rather restricted conditions, such as when sex ratios are highly female biased, and when worker reproduction is rare, sex ratio specialization can select for rare alleles. This suggests that sex allocation biasing by workers will usually reduce the very information that workers need to assess queen mating frequency. Our model is an example where an explicit treatment of underlying genetics and mechanisms of behaviour, such as information use, is necessary to fully understand the evolution of an adaptive behavioural strategy.

Genetic structure in relation to movements in wild European grayling (Thymallus thymallus) in three Norwegian rivers

The relationship among genetic structure, movements, and barriers was studied in European grayling (Thymallus thymallus). Gene flow is closely related to movement patterns, and genetic differentiation may be negatively correlated with movement. Grayling movements in the Glomma River (8149 tagged) and the neighboring Trysilelva River (4070 tagged) were different among sampling sites. Most individuals were stationary (±0.5 km), but some individuals moved long distances (≤153 km). The movement data indicated potential for gene flow between the two upstream sampling sites in the Glomma River and between the two midstream sites in the Trysilelva River. Allele frequencies at seven microsatellite loci indicated pairwise differentiation across sampling sites. Genetic structuring was generally consistent with the observed movement pattern. Isolation-by-linear-distance or number of potential barriers (dams, lakes) was not significant among sites within streams or among sites within the two southern streams. They were significant, however, if two outlying northern populations in the Pasvik River were included. Our results suggest that although grayling may move long distances, they also exhibit genetic structuring within large continuous river systems. Fish movement, often the result of flexible and adaptive behavioral strategies, is the ecological mechanism for gene flow. Movements may be the adaptive link explaining how environmental conditions affect genetic structuring.

A rule-based approach to the modelling of bacterial ecosystems

This paper presents an approach to ecological/evolutionary modelling that is inspired by natural bacterial ecosystems and bacterial evolution. An individual-based artificial ecosystem model is proposed, which is designed to explore the evolvability of adaptive behavioural strategies in artificial bacteria represented by rule-based learning classifier systems. The proposed ecosystem model consists of a n-dimensional environmental grid, which can contain different types of artificial resources in arbitrary arrangements. The resources provide the energy that is necessary for the organisms to sustain life, and can trigger different types of behaviour in the organisms, such as movement towards nutrients and away from toxic substances, growth, and the controlled release of signalling resources. The balance between energy and material is modelled carefully to ensure that the ecosystem is dissipative. Those organisms that are able to efficiently exploit the available resources gradually accumulate enough energy to reproduce (by binary fission) and generate copies of themselves in the environment. Organisms are also able to produce their own resources, which can potentially be used as markers to send signals to other organisms (a behaviour known as quorum sensing). The complex relationships between stimuli and actions in the organisms are stochastically altered by means of mutations, thus enabling the organisms to adapt to their environment and maximise their lifespan and reproductive success. In this paper, the proposed bacterial ecosystem model is defined formally and its structure is discussed in detail. This is followed by results from simulation experiments that illustrate the model’s operation and how it can be used in evolutionary modelling/computing scenarios.

Risk factors for HIV infection among sex workers in Johannesburg, South Africa

Our objective was to determine the prevalence and risk factors for HIV infection among female sex workers in Johannesburg, South Africa. A cross-sectional survey of female sex workers was conducted using interviewer-administered questionnaires. Prevalent sexually transmitted infections including HIV were evaluated through standard laboratory testing. HIV infection was identified in 137 (46.4%) of 295 subjects tested. Increasing frequency of condom use was significantly negatively associated with HIV infection (odds ratio [OR] for moderate use = 0.21; 95% confidence interval [CI]: [0.09, 0.50]; OR for high use = 0.14; 95% CI: [0.06, 0.34]). Sex workers aged > or = 29 years reported significantly different patterns of behaviour than younger workers. Among women aged > or = 29, a negative association with HIV infection (OR = 0.16; 95% CI: [0.07, 0.38]) was found, but only among those not infected with Neisseria gonorrhoeae. Older women in the Johannesburg sex industry may have adaptive behavioural strategies besides condom usage which reduce their risk of acquiring HIV. However, older sex workers with gonorrhoea constitute a high-risk subgroup.

Evolvable social agents for bacterial systems modeling.

We present two approaches to the individual-based modeling (IbM) of bacterial ecologies and evolution using computational tools. The IbM approach is introduced, and its important complementary role to biosystems modeling is discussed. A fine-grained model of bacterial evolution is then presented that is based on networks of interactivity between computational objects representing genes and proteins. This is followed by a coarser grained agent-based model, which is designed to explore the evolvability of adaptive behavioral strategies in artificial bacteria represented by learning classifier systems. The structure and implementation of the two proposed individual-based bacterial models are discussed, and some results from simulation experiments are presented, illustrating their adaptive properties.

Individual‐based modelling of bacterial ecologies and evolution

This paper presents two approaches to the individual-based modelling of bacterial ecologies and evolution using computational tools. The first approach is a fine-grained model that is based on networks of interactivity between computational objects representing genes and proteins. The second approach is a coarser-grained, agent-based model, which is designed to explore the evolvability of adaptive behavioural strategies in artificial bacteria represented by learning classifier systems. The structure and implementation of these computational models is discussed, and some results from simulation experiments are presented. Finally, the potential applications of the proposed models to the solution of real-world computational problems, and their use in improving our understanding of the mechanisms of evolution, are briefly outlined.

Genetic similarity between mates and extra-pair parentage in three species of shorebirds.

Matings between close relatives often reduce the fitness of offspring, probably because homozygosity leads to the expression of recessive deleterious alleles. Studies of several animals have shown that reproductive success is lower when genetic similarity between parents is high, and that survival and other measures of fitness increase with individual levels of genetic diversity. These studies indicate that natural selection may favour the avoidance of matings with genetically similar individuals. But constraints on social mate choice, such as a lack of alternatives, can lead to pairing with genetically similar mates. In such cases, it has been suggested that females may seek extra-pair copulations with less related males, but the evidence is weak or lacking. Here we report a strong positive relationship between the genetic similarity of social pair members and the occurrence of extra-pair paternity and maternity ('quasi-parasitism') in three species of shorebirds. We propose that extra-pair parentage may represent adaptive behavioural strategies to avoid the negative effects of pairing with a genetically similar mate.

Serum protein peroxidation in rats selected by the rate of active avoidance conditioning under normal conditions and during stress.

Serum protein peroxidation was studied in rats with different strategy of adaptive behavior at rest and during short-term immobilization stress. Oxidative destruction of serum proteins was less intensive in KLA rats compared to that in KHA rats. Stress stimulated peroxidation of serum proteins in KHA rats.

Self-induced Increase of Gut Motility and the Control of Parasitic Infections in Wild Chimpanzees

When physiological adaptation is insufficient, hosts have developed behavioral responses to avoid or limit contact with parasites. One such behavior, leaf-swallowing, occurs widely among the African great apes. This behavior involves the slow and deliberate swallowing without chewing of whole bristly leaves. Folded one at a time between tongue and palate, the leaves pass through the gastro-intestinal (GI) tract visibly unchanged. Independent studies in two populations of chimpanzees (Pan troglodytes schweinfurthii) showed significant correlations between the swallowing of whole leaves and the expulsion of the nodule worm Oesophagostomum stephanostomum and a species of tapeworm (Bertiella studeri). We integrate behavioral, parasitological and physiological observations pertaining to leaf-swallowing to elucidate the behavioral mechanism responsible for the expulsion and control of nodule worm infections by the ape host. Physical irritation produced by bristly leaves swallowed on an empty stomach, increases motility and secretion resulting in diarrhea which rapidly moves leaves through the GI tract. In the proximal hindgut, the site of third-stage larvae (L3) cyst formation and adult worm attachment, motility, secretion and the scouring effect of rough leaves is enhanced by haustral contractions and peristalsis-antiperistalsis. Frequently, at the peak of reinfection, a proportion of nonencysted L3 is also predictably vulnerable. These factors should result in the disruption of the life cycle of Oesophagostomum spp. Repeated flushing during peak periods of reinfection is probably responsible for long-run reduction of worm burdens at certain times of the year. Accordingly, leaf-swallowing can be viewed as a deliberate adaptive behavioral strategy with physiological consequences for the host. The expulsion of worms based on the activation of basic physiological responses in the host is a novel hitherto undescribed form of parasitic control.

Counter-Strategies to Infanticide in Mammals: Costs and Consequences

Infanticide, the killing of nonspecific young, has been documented in numerous species of mammals and is considered an adaptive behavioral strategy to enhance the reproductive success of the perpetrator. The potential benefits of committing infanticide for males are obtaining nutritional gain and mating partners, and for females are acquiring access to resources such as food and nest sites. Some costs are associated with committing infanticide such as additional energy expenditure, risk of injury, and exposure to predation. However, the major costs associated with infanticide are borne by the victim female and the sire male in loss of fitness. In response to this selection, males and females use a variety of counter-strategies to protect their young from infanticide. We summarize the published accounts and theory associated with infanticide and the occurrence of counter-strategies in a variety of mammalian groups in order to explain how infanticide may influence individual behavior as well as the social systems of mammals. We focus on the behavioral strategies used, primarily by females, to deter major losses in reproductive success. These strategies include aggression, female choice of dominant males, and promiscuity to confuse paternity as defense against males, and territoriality, association with kin, reproductive suppression, and reproductive synchrony as defenses against females. Male counter-strategies are less well known, but intrasexual territoriality may in part function as defense against infanticide. The costs associated with the different male and female counter-strategies are likely to vary, but may include increased energy expenditure, exposure to predators and injury for both sexes, as well as increased competition for resources, limited mate choice, and postponed reproduction for females. We propose that the occurrence of infanticide does not only have the potential to affect the behavior of individuals (e.g. aggression, spacing and mate choice), but may also have consequences for the shaping of mammalian mating systems.

A physiologically-based model of a self-motivated hare in relation to its ecology

The use of individually-based, detail-rich, simulation models for the study of the behavioral ecology of wildlife is expanding for their ability to link evolutionary processes operating at the individual level (e.g. optimal foraging) to ecological and demographic processes usually described at the population level. Within this modelling framework, we tested the possibility of using artificial intelligence (AI) methods and object-oriented programming (OOP) to implement behavioral processes in a physiologically-based model of the hare ( Lepus spp.). This approach is interesting and partly innovative because the behavioral rules which ‘move’ the animals are based on the simulation of the decision-making system itself. Moreover in this model both the landscape and the behavior of a predator species (the fox) are taken into account. The model is quite complex and its dynamics exhibits interesting emergent proprieties which have not been specifically wired in. It has been internally validated and a careful calibration of the different subsystems has been attempted with respect to the actual behavior of hares. The simulated hare exhibits a quite stable ethogram under variable environmental conditions and performs both state-conditioned activities and an adaptive behavioral strategy, where the animal's behavior is modified as a function of the environmental conditions in order to maintain a constant (and positive) fitness level.

More on Juvenile Dispersal in Mammals

I attempt to explain juvenile dispersal as an adaptive behavioral strategy. I contend that the "cost" of dispersal may be over-emphasized and confused with the cost of being male. Dispersal appears to be dependent in part on which sex is raised in proximity to its opposite-sex parent. Male-biased dispersal appears to be a consequence of female philopatry, female philopatry being a consequence of daughters growing up not "knowing" their fathers. Ready access to resources and the formation of kin alliances among females may be a consequence and not a cause for female philopatry. Sexspecific dispersal distances are dependent on what is being defended, mates or resources. The fact that emigration is often delayed at the highest densities resulting in communal family groups argues against resource and/or reproductive competition as a motivation for juvenile dispersal.