Effects of Cocaine Sensitization on Drug Self-Administration, Mesocorticolimbic SAPAP Levels, and Prefrontal Ionotropic Glutamate Receptors

Towards the goal of improving the knowledge base of how drugs of abuse function to create addicts and using currently uninvestigated areas of this knowledge base, we focused our research studies the male albino rat, and strived to explain how cocaine sensitization alters particular molecular mechanisms in the mesocorticolimbic system related to glutamate receptors, SAPAPs, and affects drug self-administration. Taking all the previously discussed research studies into consideration, we hypothesized that low-dose cocaine self-administration would yield a significant elevation in drug seeking behavior for psychostimulant sensitized animals. For specific changes at the PSD, we hypothesized that acute cocaine exposure and/or cocaine sensitization would alter iGluRs levels in the mPFC, and SAPAP levels in multiple sites of the mesocorticolimbic system. To test these hypotheses, we investigated the effects of psychostimulant sensitization on various parameters of self-administration by infusing a lowdose cocaine reward proven to not induce sensitization during self-administration (reported here as 0.3 mg/kg/infusion). Although drug exposure did not significantly alter self-administration behavior, we did find that more drug exposed subjects acquired self-administration behavior when compared to drug naïve controls. We also investigated the effects of acute cocaine exposure and/or cocaine sensitization on iGluRs in the mPFC and SAPAPs in the entire mesocorticolimbic circuit thru western blotting, immunolabeling of proteins of interest, and comparing protein levels to those found in cocaine naïve controls. A limited self-administration protocol also tested if SAPAP levels were altered by self-administration of a low-dose cocaine reward. For these experiments, we found that SAPAP protein levels are altered in multiple regions of the mesocorticolimbic system in response to contingent and non-contingent cocaine exposure, and that iGluR receptor subunits are altered in the prefrontal cortex in response to noncontingent cocaine exposure

The effect of kinship on intraspecific competition in larvae of the poison frog Ameerega bassleri (Anura, Dendrobatidae)

According to inclusive fitness theory, cooperation between related individuals should ameliorate the effect of intraspecific competition. However, close relatedness is also thought to increase similarity between individuals and therefore increase the risk of exploitative competition. Studies of the effects of kinship in larval amphibians have produced mixed results concerning these two hypotheses. We examined the effect of kinship on the mean and variation of mass after 30 days of growth in groups composed of either pure siblings or a mixture of five different sibships in a species of poison frog, Ameerega bassleri. We found no significant differences between sibling and mixed treatments with respect to mass or variation in mass. Our results are consistent with other studies in larval anurans which have found no differences between sibling and mixed treatments, suggesting that the effects of kin selection and genetic similarity between competitors may in some cases cancel each other out

Mating strategies in two species of dart-poison frogs: a comparative study

Comparative field studies of species of dart-poison frogs in the genus Dendrobates were carried out to test predictions from two hypotheses that attempt to explain female-female competition for mates in species of Dendrobates with male parental care. The sex role reversal hypothesis proposes that males invest so much time and energy in parental care that receptive males are rare relative to receptive females, and females compete to find and mate with receptive males. The parental quality hypothesis proposes that females compete to monopolize the parental effort of particular males, because they potentially suffer a cost when their mates care for the offspring of other females. Comparisons between species with male parental care (Dendrobates leucomelas) and female parental care (Dendrobates histrionicus) contradicted prediction of the sex role reversal hypothesis, but were consistent with predictions of the parental quality hypothesis. Male D. histrionicus did not compete for mates more aggressively than male D. leucomelas, and male D. leucomelas were not more selective about mating than male D. histrionicus. Female D. leucomelas and D. histrionicus were both selective about mating; female D. leucomelas associated with and competed for particular males, whereas female D. histrionicus did not.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/30029/1/0000397.pd

Paternal care and the cost of polygyny in the green dart-poison frog

In species with male parental care, polygyny may reduce the parental effort provided by a male, and hence impose a cost on the fitness of his mates, because of decreased growth, survival or health of offspring. I examined a cost of polygyny in the green dart-poison frog, Dendrobates auratus , a species with male parental care in which both male polygyny and mate guarding by females occurs (Summers 1989). All D. auratus males seen carrying tadpoles in a marked area were followed and the pools where they deposited their tadpoles were recorded. Males frequently deposited more than one tadpole in the same pool (in 25% of the observed depositions a male deposited a tadpole in a pool where he had previously deposited at least one other tadpole). Experiments involving manipulation of tadpole densities in pools typically utilized by D. auratus (calabash husks and treeholes) showed that increasing tadpole number had a strong negative effect on both growth rate and survivorship, indicating that polygyny can impose a cost on the fitness of a male's offspring. Hence, females do face a potential cost, in terms of reduced offspring growth and survivorship, when their mates mate polygynously and care for the offspring of other females.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/46897/1/265_2004_Article_BF00164001.pd

Tactical reproductive parasitism via larval cannibalism in Peruvian poison frogs

We report an unusual example of reproductive parasitism in amphibians. Dendrobates variabi- lis, an Amazonian poison frog, oviposits at the surface of the water in small pools in plants and deposits tadpoles within the pools. Tadpoles are highly cannibalistic and consume young tadpoles if they are accessible. Deposition of embryos and tadpoles in the same pool is common. Genetic analyses indicate that tadpoles are fre- quently unrelated to embryos in the same pool. A pool choice experiment in the field demon- strated that males carrying tadpoles prefer to place them in pools with embryos, facilitating reproductive parasitism via cannibalism. Originally published Biology Letters, Vol. 5, No. 2, Apr 200

An Empirical Test Indicates Only Qualitatively Honest Aposematic Signaling Within a Population of Vertebrates

Signaling is an important part of intraspecific and interspecific interactions. Theoretical work examining honest signaling in aposematic species (e.g., those with conspicuous colors and secondary defenses) has focused primarily on discerning the patterns between conspicuousness and defense within populations. Most empirical work, however, has investigated these patterns across populations or species. Here, we test for honest signaling across individuals within a population of the aposematic poison frog, Ranitomeya imitator. We find no evidence that increasing levels of the aposematic signal are correlated with increasing levels of defense in this species, indicating that our study population does not signal in a quantitatively honest manner, but rather that the signal is qualitatively honest. Additionally, we found no evidence that frogs with higher levels of defense behave more boldly as a result of the presumed increased ecological release from predation, an expected outcome in a qualitatively honest system. We discuss our findings in light of the ecology and evolution of R. imitator, and suggest mechanisms that may explain the absence of a relationship between toxicity and the aposematic signal

Kin discrimination in cannibalistic tadpoles of the Green Poison Frog, Dendrobates auratus (Anura, Dendrobatidae)

O consumo de indivíduos aparentados pode reduzir a aptidão inclusiva do canibal. Assim, mecanismos que permitam que um girino reconheça seus relativos e modifique seu comportamento pode reduzir os custos do canibalismo. Alternativamente, fatores ecológicos podem tornar o tratamento preferencial dos relativos custoso demais para que seja favorecido pela seleção natural. Testamos essas duas previsões no dendrobatídeo Dendrobates auratus. O efeito do parentesco sobre o canibalismo larval foi examinado por meio de uma série de tentativas de discriminação de parentes. Observamos o comportamento de girinos de grande porte diante de dois girinos menores imobilizados, um irmão e outro não-aparentado. Nesses testes de apresentação simultânea, os girinos mostraram uma preferência significativa por atacar irmãos. Em outra série de tentativas, pares de girinos de tamanhos diferentes foram colocados juntos em aquários. A maioria dos girinos de grande porte (70%) consumiu o girino menor em menos de 24 horas. O parentesco não afetou o tempo de sobrevivência do girino pequeno. Nossos resultados são consistentes com as observações de que D. auratus é um predador indiscriminado. Como os co-específicos podem ser fortes competidores, sua eliminação rápida poderia ser vantajosa, particularmente nas pequenas poças pobres em nutrientes utilizadas por essa espécie.Cannibalizing a related individual can reduce the inclusive fitness of the cannibal. Hence, mechanisms that allow a tadpole to recognize and modify its behavior toward kin may reduce the inclusive fitness costs of cannibalism. Alternatively, ecological factors may cause preferential treatment of kin to be too costly to be favored by selection. We tested these two predictions in the Green Poison Frog, Dendrobates auratus. The effect of kinship on larval cannibalism was examined through a series of kin-discrimination trials. The behavior of large tadpoles was observed when presented with two small, tethered tadpoles, one a clutchmate and one an unrelated tadpole. In these simultaneous presentation tests, tadpoles displayed a significant preference for attacking kin. In a series of timed trials, pairs of unequally sized tadpoles were placed together in containers. The majority (70%) of large tadpoles took less than 24 hr to consume the small tadpole. Kinship did not affect the survival time of the small tadpole. Our results are consistent with observations that D. auratus is an indiscriminate predator. As conspecifics may be serious competitors, their swift elimination would be an advantage, particularly in the small, nutrient-poor pools used by this species

New Piperidine alkaloids from fire ants are not sequestered by the green and black poison frog ( Dendrobates auratus )

Neotropical poison frogs possess alkaloid-based antipredator defenses which they sequester from a diet of arthropods such as oribatid mites and myrmicine ants. Alkaloid sequestration is still poorly understood and although several studies have examined its uptake, most experiments directly feed alkaloids to the frogs. Here, we examined the alkaloid uptake system in the poison frog species Dendrobates auratus by feeding it an alkaloid-containing prey item, the red imported fire ant Solenopsis invicta (Formicidae, Myrmicinae). Captive bred frogs were either fed live ants or fruit flies dusted with powdered ants for 4 months. Using GC–MS, we confirm that S. invicta contain previously described piperidine alkaloids known as solenopsins; however, none of these piperidine alkaloids was detected in the skin of D. auratus, suggesting the frogs are incapable of sequestering solenopsins from S. invicta. It is possible that D. auratus are unable to sequester fire ant piperidines due to their long hydrocarbon side chains, a feature that makes them structurally different than most known alkaloids in poison frogs

Special issue: Kin Selection Inclusive fitness theory for the evolution of religion

Keywords: inclusive fitness kinship religious behaviour We describe and evaluate an integrative hypothesis for the origin and evolution of human religious cognition and behaviour, based on maximization of inclusive fitness. By this hypothesis, the concept of God is represented by one's circle of kin and social salience, such that serving God and serving this circle become synonymous. The theory is supported by data from anthropology, evolutionary theory, psychology, neuroscience, psychiatry, endocrinology and genetics. It is largely compatible with, yet can subsume, previous theories of religion that are also based on adaptation and natural selection. Ó 2014 The Association for the Study of Animal Behaviour. Published by Elsevier Ltd. All rights reserved. There is something sacred about kinship, as most social anthropologists who have studied its operation in the field are prepared to admit One human phenotype, religious behaviour, stands apart from all others with regard to its dominating emphasis on altruism and prosociality. This set of behaviours has yet to be analysed explicitly and comprehensively in the context of inclusive fitness theory, using the conceptual tools developed in Hamilton's wake for understanding its origins, maintenance and diversification. Like eusociality, or cooperative breeding, religion can be considered as a sociobehavioural system that has evolved in the contexts of genetic relatedness, parental manipulation (generalized here as asymmetries in control over phenotypes) and mutualism. In this article we describe and analyse an integrative theory, based on inclusive fitness maximization, for understanding the origin and evolution of religious behaviour and the concepts of God and supernatural agents. The theory is based mainly on works by Hamilton, Alexander, Trivers, Lahti, Coe, Palmer and Steadman, and it draws together evidence from anthropology, psychology, neuroscience, psychiatry, endocrinology and genetics into a unified, testable framework. The theory is novel specifically in its integrative, synthetic and reconciliatory nature, and its central emphasis on the roles of genetic relatedness and inclusive fitness in the evolution of religion. We first categorize and describe previous theories regarding the origins, bases and functions of the concept of God and other supernatural agents, and associated religious behaviour. Next, we present the theory, and discuss how it relates to, and can subsume, these earlier ideas without being strongly incompatible with any of them. We also discuss empirical evidence that bears upon the theory, and suggest opportunities for additional tests of its predictions. PREVIOUS THEORIES Previous ideas regarding the evolution of religion and concepts of God address diverse aspects of religious phenomena, at different levels of analysis, either proximate (dealing with mechanisms), or ultimate (dealing with selective pressures and other evolutionary causes). Moreover, studies of religion may focus on its supernatural components, its moralizing elements, or both in conjunction

Special issue: Kin Selection Inclusive fitness theory for the evolution of religion

Keywords: inclusive fitness kinship religious behaviour We describe and evaluate an integrative hypothesis for the origin and evolution of human religious cognition and behaviour, based on maximization of inclusive fitness. By this hypothesis, the concept of God is represented by one's circle of kin and social salience, such that serving God and serving this circle become synonymous. The theory is supported by data from anthropology, evolutionary theory, psychology, neuroscience, psychiatry, endocrinology and genetics. It is largely compatible with, yet can subsume, previous theories of religion that are also based on adaptation and natural selection. Ó 2014 The Association for the Study of Animal Behaviour. Published by Elsevier Ltd. All rights reserved. There is something sacred about kinship, as most social anthropologists who have studied its operation in the field are prepared to admit One human phenotype, religious behaviour, stands apart from all others with regard to its dominating emphasis on altruism and prosociality. This set of behaviours has yet to be analysed explicitly and comprehensively in the context of inclusive fitness theory, using the conceptual tools developed in Hamilton's wake for understanding its origins, maintenance and diversification. Like eusociality, or cooperative breeding, religion can be considered as a sociobehavioural system that has evolved in the contexts of genetic relatedness, parental manipulation (generalized here as asymmetries in control over phenotypes) and mutualism. In this article we describe and analyse an integrative theory, based on inclusive fitness maximization, for understanding the origin and evolution of religious behaviour and the concepts of God and supernatural agents. The theory is based mainly on works by Hamilton, Alexander, Trivers, Lahti, Coe, Palmer and Steadman, and it draws together evidence from anthropology, psychology, neuroscience, psychiatry, endocrinology and genetics into a unified, testable framework. The theory is novel specifically in its integrative, synthetic and reconciliatory nature, and its central emphasis on the roles of genetic relatedness and inclusive fitness in the evolution of religion. We first categorize and describe previous theories regarding the origins, bases and functions of the concept of God and other supernatural agents, and associated religious behaviour. Next, we present the theory, and discuss how it relates to, and can subsume, these earlier ideas without being strongly incompatible with any of them. We also discuss empirical evidence that bears upon the theory, and suggest opportunities for additional tests of its predictions. PREVIOUS THEORIES Previous ideas regarding the evolution of religion and concepts of God address diverse aspects of religious phenomena, at different levels of analysis, either proximate (dealing with mechanisms), or ultimate (dealing with selective pressures and other evolutionary causes). Moreover, studies of religion may focus on its supernatural components, its moralizing elements, or both in conjunction