BMC Evolutionary Biology Research Articles

A condition dependent link between testosterone and disease resistance in the house finch.

Testosterone has recently been proposed as a link between male quality and health and the expression of sexual traits. We investigated the relationship between testosterone and measures of the individual condition and health of males in a natural population of house finches (Carpodacus mexicanus). We also conducted a captive experiment in order to test for the effects of testosterone on resistance to coccidia, which is a common parasite of house finches. Free-living males in better condition had higher testosterone levels and lower corticosterone levels than free-living males in poor condition. In our captive experiment, increased testosterone accelerated the rate of coccidial infection as compared with sham-implanted or gonadectomized males. Although the differences were not significant, free-living males infected with coccidia had lower levels of testosterone and higher levels of corticosterone than males that were not infected. Thus, experimentally elevating testosterone levels in captive males resulted in a higher percentage of infected males, while free-living males with coccidial infection had low testosterone levels. This apparent discrepancy between captive and free-living males in the association of testosterone and disease may be explained by the condition dependence of testosterone. These results suggest that the testosterone-dependent sexual traits reliably indicate male overall condition and health and, thus, females could benefit from assessing potential mates based on these traits.

Reversible frequency-dependent switches in male mate choice.

Current sexual-selection theories predict that mating should occur preferentially with the highest-quality partner, and assume that for distinguishing among potential mates the choosy sex applies an internal representation of the characteristics of the desired mate, i.e. a template. Binary choice experiments were performed to test male mate choice between two different female colour morphs in the damselfly Ischnura elegans. Choice experiments were conducted before and after an habituation period, during which males were exposed to only one female colour morph. Given the choice between the two female morphs, males did exhibit a choice for the most recently experienced female morph. This is the first evidence for a reversible switch in mate choice in a frequency-dependent way. In contrast with previous studies on mate choice, template formation in male I. elegans seems not to be based on quality. Switching mate choice in a frequency-dependent manner, choosing the most common morph, probably allows males to minimize their search efforts and to maximize fitness.

Changes in expression and honesty of sexual signalling over the reproductive lifetime of sticklebacks.

Fitness costs of signalling are essential in order for reliable sexual signalling to prevail when the interests of the sexes conflict. This means that signalling can be subjected to a life history trade-off between present and future signalling effort. Here, I show that three-spined stickleback males (Gasterosteus aculeatus), who have a single breeding season during which they breed repeatedly, change their red nuptial coloration over the season depending on their body size at the start of breeding. Large males that completed several breeding cycles increased their red coloration over the season, whereas small males, who completed only a few cycles, did not. The increase in coloration was accompanied by an increase in parental success when males were energy constrained, but not when they had access to an unlimited food supply. Red coloration was thus an honest signal of male parental ability despite changes in signal expression when both signalling and parental care were costly and the investments in them changed simultaneously over the reproductive lifetime. However, the honesty of the signal varied over a lifetime. At the penultimate cycle, bright males cannibalized some of their eggs, probably to increase survival to the last cycle, whereas males cared for their offspring independent of coloration at the ultimate cycle.

Immunocompetence of nestling great tits in relation to rearing environment and parentage

Theoretical models of host–parasite coevolution assume a partially genetic basis to the variability in susceptibility to parasites among hosts, for instance as a result of genetic variation in immune function. However, few empirical data exist for free–living vertebrate hosts to support this presumption. In a cross–fostering experiment with nestling great tits, by comparing nestlings of the same origin we investigated (i) the variance in host resistance against an ectoparasite due to a common genetic origin, (ii) the effect of ectoparasite infestation on cell–mediated immunity and (iii) the variance in cell–mediated immunity due to a common genetic origin. Ectoparasitic hen fleas can impair the growth of nestling great tits and nestling growth was therefore taken as a measure of host susceptibility. A common origin did not account for a significant part of the variation in host susceptibility to fleas. There was no significant overall effect of fleas on nestling growth or cell–mediated immunity, as assessed by a cutaneous hypersensitivity response. A common rearing environment explained a significant part of the variation in cell–mediated immunity among nestlings, mainly through its effect on nestling body mass. The variation in cell–mediated immunity was also related to a common origin. However, the origin–related variation in body mass did not account for the origin–related differences in cell–mediated immunity. The results of the present study thus suggest heritable variation in cell–mediated immunity among nestling great tits.

Empirical evidence of a trade–off between reproductive effort and expectation of future reproduction in female three-spined sticklebacks

Optimal life-history models generally predict that the reproductive effort of iteroparous organisms may increase with age, as their expectation of future reproduction decreases. The population of three–spined sticklebacks ( Gasterosteus aculeatus ) in the Camargue (Rhone River Delta, France) is annual, all adults dying after their first breeding season. As the three–spined stickleback is a multiple spawner, we tested the hypothesis that reproductive effort may increase during the breeding season on field data. From 1987 to 1998, 653 female sticklebacks were collected in the field during the breeding seasons. The body size, body weight and weights of the liver, gonads and carcass were measured for these individuals. Only gravid females with mature eggs (176 fish) were included in the analysis. Considering the female three–spined stickleback as a capital breeder, the energetic resources available for allocation between soma and gonads were estimated by its body weight. Somatic condition decreased during the breeding season and reproductive effort (gonad weight relative to body weight) increased. These patterns did not vary significantly between years. These observed variations in reproductive effort during the breeding season can be interpreted as empirical evidence of a trade–off between reproductive effort and expectation of future reproduction.

Detecting Publication Bias in Meta-analyses: A Case Study of Fluctuating Asymmetry and Sexual Selection.

Those familiar with human nature and the publication process acknowledge that biases due to selective reporting of results are likely widespread in all fields of academic inquiry that depend on tools of statistical inference (e.g., see Begg and Berlin 1988; Iyengar and Greenhouse 1988; and the extensive discussion following each). However, although qualitative and quantitative methods exist for assessing the prevalence of selective reporting, and selective reporting has been studied in the medical and social sciences (Begg 1994, and references therein), the issue has received little attention in recent meta-analyses of ecological and evolutionary patterns. Clearly, “if publication bias is present, and if it operates in the same direction for all studies (as is likely), then [meta-analysis] is likely not only to produce biased summary estimates but also to produce estimates which are apparently precise and accurate leading to conclusions which may not only be wrong but appear convincing” (Begg and Berlin 1988, p. 437). To biologists unacquainted with the formal study of publication patterns, the terms “selective reporting” (statistical significance of an outcome influences its likelihood of being reported or published) and “publication bias” (the inflation of average effect size due to selective reporting) may imply a conscious intent to deceive, but this

Secondary Metabolites in Fleshy Fruits: Are Adaptive Explanations Needed?

1. Department of Botany, Stockholm University, S-106 91 birds, their presence has been considered to be an evoluStockholm, Sweden; tionary paradox. 2. Department of Ecological Botany, Uppsala University, Cipollini and Levey (1997) provide a list of ingenious Villavagen 14, S-752 36 Uppsala, Sweden and interesting hypotheses focusing on the potential functions of the secondary metabolites for enhancing Submitted December 8, 1997; Accepted April 9, 1998 plant seed dispersal, for example, by providing foraging cues, as regulators of seed germination, as mechanisms to force frugivores not to stay too long at the same plant, as mechanisms to manipulate seeds’ gut passage rate, and as

Male sexual ornament size but not asymmetry reflects condition in stalk–eyed flies

Models of sexual selection predict that females use ornament size to evaluate male condition. It has also been suggested that ornament asymmetry provides females with accurate information about condition. To test these ideas we experimentally manipulated condition in the stalk-eyed fly, Cyrtodiopsis dalmanni, by varying the amount of food available to developing larvae. Males of this species have greatly exaggerated eyestalk length and females prefer to mate with males with wider eyespans. Our experiments show that male ornaments (eyestalks) display a disproportionate sensitivity to condition compared with the homologous character in females, and to non-sexual traits (wing dimensions). In contrast, in neither sex did asymmetry reflect condition either in sexual ornaments or in non-sexual traits. We conclude that ornament size is likely to play a far greater role in sexual selection as an indicator of individual condition than does asymmetry.

Physical work causes suppression of ovarian function in women.

The suppression of reproductive function is known to occur in women engaging in activities that require high energetic expenses, such as sport participation and subsistence work. It is still unclear, however, if reproductive suppression is a response to high levels of energy expenditure, or only to the resulting state of negative energy balance. To our knowledge, this study provides the first evidence that work-related energy expenditure alone, without associated negative energy balance, can lead to the suppression of reproductive function in women. We document suppression of ovarian function expressed as lowered salivary progesterone levels in women from an agricultural community who work hard, but remain in neutral energy balance. We propose two alternative evolutionary explanations (the 'pre-emptive ovarian suppression' hypothesis and the 'constrained down-regulation' hypothesis) for the observed results.

Ultraviolet cues affect the foraging behaviour of blue tits

The function of avian ultraviolet (UV) vision is only just beginning to be understood. One plausible hypothesis is that UV vision enhances the foraging ability of birds. To test this, we carried out behavioural experiments using wild–caught blue tits foraging for cabbage moth and winter moth caterpillars on natural and artificial backgrounds. The light environment in our experiments was manipulated using either UV–blocking or UV–transmitting filters. We found that the blue tits tended to find the first prey item (out of four) more quickly when UV cues were present. This suggests that UV vision offers benefits to birds when searching for cryptic prey, despite the prey and backgrounds reflecting relatively little UV. Although there was no direct effect of UV on the time taken to find all four prey items in a trial, search performance in the absence of UV wavelengths tended to increase over the course of an experiment. This may reflect changes in the search tactics of the birds. To our knowledge, these are the first data to suggest that birds use UV cues to detect cryptic insect prey, and have implications for our understanding of protective coloration.

Snail sperm production characteristics vary with sperm competition risk

Sperm competition is widespread and influences both male investment in spermatogenic tissue and ejaculate characteristics. Sperm competition models assume trade-offs between sperm size and number, although such trade-offs may be difficult to detect. This study examines the effects of sperm competition risk on the sperm production characteristics of the freshwater snail Viviparus ater. In this prosobranch, females mate frequently and store sperm, generating sperm competition. Males produce two sperm morphs, fertile eupyrene sperm and non-fertilizing oligopyrene sperm. Non-fertilizing sperm may play a role in sperm competition and therefore, like fertilizing sperm, the number produced could vary relative to sperm competition risk. In addition, trade-offs between sperm number and sperm size may be expected. We manipulated the sex ratio of sexually mature snails and found the presence of rivals affected the ratio of oligopyrene/eupyrene sperm males produced. In experimental and natural populations, the number of oligopyrene sperm produced, but not the number of eupyrene sperm, was significantly higher when the sex ratio was male biased. Testis mass did not vary between experimental treatments. We also found a negative relationship between the number and size of oligopyrene sperm produced, which is consistent with evolutionary models of sperm competition, and is, to our knowledge, the first intraspecific demonstration of a trade-off between these traits.

Cloning and characterization of a virtually full-length HIV type 1 genome from a subtype B'-Thai strain representing the most prevalent B-clade isolate in China.

Cloning and characterization of a virtually full-length HIV type 1 genome from a subtype B'-Thai strain representing the most prevalent B-clade isolate in China.

Altruist Cheater Dynamics inDictyostelium:Aggregated Distribution Gives Stable Oscillations

Previous articleNext article No AccessAltruist Cheater Dynamics in Dictyostelium: Aggregated Distribution Gives Stable OscillationsAnagha K. Matapurkar and Milind G. WatveAnagha K. MatapurkarLife Research Foundation, 10 Pranav, 1000/6‐c, Navi Peth, Pune 411 030, India Search for more articles by this author and Milind G. WatveLife Research Foundation, 10 Pranav, 1000/6‐c, Navi Peth, Pune 411 030, India Search for more articles by this author Life Research Foundation, 10 Pranav, 1000/6‐c, Navi Peth, Pune 411 030, IndiaPDFPDF PLUS Add to favoritesDownload CitationTrack CitationsPermissionsReprints Share onFacebookTwitterLinkedInRedditEmail SectionsMoreDetailsFiguresReferencesCited by The American Naturalist Volume 150, Number 6December 1997 Published for The American Society of Naturalists Article DOIhttps://doi.org/10.1086/286094 Views: 44Total views on this site Citations: 16Citations are reported from Crossref HistoryReceived December 19, 1996 June 9, 1997Accepted June 9, 1997 © 1997 by The University of Chicago.PDF download Crossref reports the following articles citing this article:Leonardo Miele, Silvia De Monte, Corina E. Tarnita Aggregative cycles evolve as a solution to conflicts in social investment, PLOS Computational Biology 17, no.11 (Jan 2021): e1008617.https://doi.org/10.1371/journal.pcbi.1008617Samay Pande, Pau Pérez Escriva, Yuen-Tsu Nicco Yu, Uwe Sauer, Gregory J. Velicer Cooperation and Cheating among Germinating Spores, Current Biology 30, no.2323 (Dec 2020): 4745–4752.e4.https://doi.org/10.1016/j.cub.2020.08.091Anya E. Vostinar, Heather J. Goldsby, Charles Ofria Suicidal selection: Programmed cell death can evolve in unicellular organisms due solely to kin selection, Ecology and Evolution 9, no.1616 (Jul 2019): 9129–9136.https://doi.org/10.1002/ece3.5460H. R. Votaw, E. A. Ostrowski Stalk size and altruism investment within and among populations of the social amoeba, Journal of Evolutionary Biology 30, no.1111 (Sep 2017): 2017–2030.https://doi.org/10.1111/jeb.13172Milind Watve Why Population Density Matters, (Jul 2012): 185–202.https://doi.org/10.1007/978-1-4614-4409-1_9Joan E. Strassmann, David C. Queller How social evolution theory impacts our understanding of development in the social amoeba Dictyostelium, Development, Growth & Differentiation 53, no.44 (May 2011): 597–607.https://doi.org/10.1111/j.1440-169X.2011.01272.xMilind G Watve, Anuja Damle, Bratati Ganguly, Anagha Kale, Neelesh Dahanukar Blackmailing: the keystone in the human mating system, BMC Evolutionary Biology 11, no.11 (Jan 2011): 345.https://doi.org/10.1186/1471-2148-11-345Neil J. Buttery, Daniel E. Rozen, Jason B. Wolf, Christopher R.L. Thompson Quantification of Social Behavior in D. discoideum Reveals Complex Fixed and Facultative Strategies, Current Biology 19, no.1616 (Aug 2009): 1373–1377.https://doi.org/10.1016/j.cub.2009.06.058Tejashree Modak, Shalmali Pradhan, Milind Watve Sociobiology of biodegradation and the role of predatory protozoa in biodegrading communities, Journal of Biosciences 32, no.44 (Jul 2007): 775–780.https://doi.org/10.1007/s12038-007-0078-0Owen M. Gilbert, Kevin R. Foster, Natasha J. Mehdiabadi, Joan E. Strassmann, David C. Queller High relatedness maintains multicellular cooperation in a social amoeba by controlling cheater mutants, Proceedings of the National Academy of Sciences 104, no.2121 (May 2007): 8913–8917.https://doi.org/10.1073/pnas.0702723104Å Brännström, U Dieckmann Evolutionary dynamics of altruism and cheating among social amoebas, Proceedings of the Royal Society B: Biological Sciences 272, no.15721572 (Jul 2005): 1609–1616.https://doi.org/10.1098/rspb.2005.3116Alex C. C. Wilson, Richard K. Grosberg Ontogenetic shifts in fusion?rejection thresholds in a colonial marine hydrozoan, Hydractinia symbiolongicarpus, Behavioral Ecology and Sociobiology 57, no.11 (Aug 2004): 40–49.https://doi.org/10.1007/s00265-004-0831-4Francesca Fiegna, Gregory J. Velicer Competitive fates of bacterial social parasites: persistence and self–induced extinction of Myxococcus xanthus cheaters, Proceedings of the Royal Society of London. Series B: Biological Sciences 270, no.15231523 (Jul 2003): 1527–1534.https://doi.org/10.1098/rspb.2003.2387 Richard Ellis Hudson , Juliann Eve Aukema , Claude Rispe , and Denis Roze Altruism, Cheating, and Anticheater Adaptations in Cellular Slime Molds. R. E. Hudson et al., The American Naturalist 160, no.11 (Jul 2015): 31–43.https://doi.org/10.1086/340613Gregory J. Velicer, Lee Kroos, Richard E. Lenski Developmental cheating in the social bacterium Myxococcus xanthus, Nature 404, no.67786778 (Apr 2000): 598–601.https://doi.org/10.1038/35007066Michael W. Hart, Richard K. Grosberg KIN INTERACTIONS IN A COLONIAL HYDROZOAN ( HYDRACTINIA SYMBIOLONGICARPUS ): POPULATION STRUCTURE ON A MOBILE LANDSCAPE, Evolution 53, no.33 (May 2017): 793–805.https://doi.org/10.1111/j.1558-5646.1999.tb05373.x

Fertility and Mode of Subsistence: A Phylogenetic Analysis

Des debats recents sur la dependance de la demographie humaine vis-a-vis des modes de subsistance offrent de nouvelles pistes de reflexion pour les anthropologues et les archeologues qui travaillent sur les relations entre l'environnement naturel et les strategies de reproduction familiale, ou encore sur les origines de l'agriculture. Les AA. presentent les resultats d'une analyse synthetique prenant en compte diverses societes (a partir de sources bibliographiques) afin d'isoler les effets phylogenetiques en comparant uniquement les differences entre fertilite et mode de subsistance parmi les societes traditionnelles culturellement voisines (classification par aire geographique qui prend en compte l'ensemble du monde). L'etude quantitative mesure les degres de dependance selon la typologie des modes de subsistance representes majoritairement parmi chaque societe traditionnelle.

Female sand gobies prefer good fathers over dominant males

Female preference for males successful in male–male competition is generally assumed to result in mating with high quality males. Here I report results from an experiment disentangling the effects of intra– and intersexual selection in the sand goby, Pomatoschistus minutus , a marine fish that exhibits paternal care. I show that large males are successful in male–male competition, but contrary to what one would expect, dominants are not preferred by females and are not better at taking care of the eggs. Female preference, however, correlated with the subsequent hatching success of the eggs. Thus, female choice selects for good parenting. Hence, direct benefits in the form of superior paternal care can explain female choice in this species, supporting a good parent process of sexual selection. However, choosing on the outcome of male–male competition does not enable females to mate with the ‘best’ males.

Immune defence, extra–pair paternity, and sexual selection in birds

Secondary sexual characters have been suggested to reliably reflect the ability of individuals to resist debilitating parasites, and females may gain direct or indirect fitness benefits from preferring the most extravagantly ornamented males. Extra–pair paternity provides an estimate of an important component of sexual selection in birds. Species with a high frequency of extra–pair paternity have a variance in realized reproductive success that is greater than the variance in apparent reproductive success, and extra–pair copulations and hence extra–pair paternity by females are often directly associated with the expression of male secondary sexual characters. If sexually dichromatic species have experienced a long period of antagonistic coevolution with their parasites, such species should have evolved larger immune defence organs than sexually monochromatic species. Bird species with sexual dichromatism had larger spleens for their body size than monochromatic species in a comparative analysis. Furthermore, species with a high frequency of extra–pair paternity were sexually dichromatic and had large spleens for their body size. These results are consistent with the hypothesis that females of dichromatic bird species seek extra–pair copulations to obtain indirect fitness benefits in terms of superior resistance of their offspring to virulent parasites.

A "Good-Sperm" Model Can Explain the Evolution of Costly Multiple Mating by Females

A "Good-Sperm" Model Can Explain the Evolution of Costly Multiple Mating by Females

Alternative reproductive tactics in atlantic salmon: factors affecting mature parr success

In Atlantic salmon, as in most salmonids, males can mature early in the life cycle, as small freshwater fish, termed parr, and/or undergo a sea migration before maturing as full–size adults. The alternative life histories are contingent on environmental and social circumstances, such as growth rate, territory quality or any other factor that affects the individual9s state. In order to model the choice of life history in this group of commercially valuable species, it is necessary to understand not only the relative contribution of the different male types to subsequent generations, but also to know the factors that affect reproductive success in each type. In this paper we present the results of a study designed to investigate the factors that affect the reproductive success of mature parr. We used highly polymorphic minisatellite DNA markers to analyse paternity in a series of mating experiments where the number and body size of parr were manipulated. The fraction of eggs fertilized by mature parr ranged from 26 to 40 per cent, with individual parr fertilizing up to 26 per cent of the eggs. A strong positive correlation was found between parr size and reproductive success. The relative success of parr decreased with increasing parr number. Data from this and other studies on variation in the timing and degree of parr reproductive success are discussed in relation to the evolution of male mating strategies and life history in salmonids.

Character Definitions, Sexual Selection, and the Evolution of Swordtails

Previous articleNext article No AccessNotes and CommentsCharacter Definitions, Sexual Selection, and the Evolution of SwordtailsJohn J. Wiens, and Molly R. MorrisJohn J. Wiens Search for more articles by this author , and Molly R. Morris Search for more articles by this author PDFPDF PLUS Add to favoritesDownload CitationTrack CitationsPermissionsReprints Share onFacebookTwitterLinkedInRedditEmail SectionsMoreDetailsFiguresReferencesCited by The American Naturalist Volume 147, Number 5May, 1996 Published for The American Society of Naturalists Article DOIhttps://doi.org/10.1086/285882 Views: 6Total views on this site Citations: 13Citations are reported from Crossref Copyright 1996 The University of ChicagoPDF download Crossref reports the following articles citing this article:Melissa N Liotta, Jessica K Abbott, Oscar Rios-Cardenas, Molly R Morris Tactical dimorphism: the interplay between body shape and mating behaviour in the swordtail Xiphophorus multilineatus (Cyprinodontiformes: Poeciliidae), Biological Journal of the Linnean Society 127, no.22 (Apr 2019): 337–350.https://doi.org/10.1093/biolinnean/blz053Ji Hyoun Kang, Manfred Schartl, Ronald B Walter, Axel Meyer Comprehensive phylogenetic analysis of all species of swordtails and platies (Pisces: Genus Xiphophorus) uncovers a hybrid origin of a swordtail fish, Xiphophorus monticolus, and demonstrates that the sexually selected sword originated in the ancestral lineage of the genus, but was lost again secondarily, BMC Evolutionary Biology 13, no.11 (Jan 2013).https://doi.org/10.1186/1471-2148-13-25Julia C. Jones, Shaohua Fan, Paolo Franchini, Manfred Schartl, Axel Meyer The evolutionary history of Xiphophorus fish and their sexually selected sword: a genome-wide approach using restriction site-associated DNA sequencing, Molecular Ecology 22, no.1111 (Apr 2013): 2986–3001.https://doi.org/10.1111/mec.12269Donelle M. Robinson, M. Scarlett Tudor, Molly R. Morris Female preference and the evolution of an exaggerated male ornament: the shape of the preference function matters, Animal Behaviour 81, no.55 (May 2011): 1015–1021.https://doi.org/10.1016/j.anbehav.2011.02.005Nils Offen, Nicola Blum, Axel Meyer, Gerrit Begemann Fgfr1 signalling in the development of a sexually selected trait in vertebrates, the sword of swordtail fish, BMC Developmental Biology 8, no.11 (Oct 2008).https://doi.org/10.1186/1471-213X-8-98 Jason A. Moretz and Molly R. Morris Phylogenetic Analysis of the Evolution of a Signal of Aggressive Intent in Northern Swordtail Fishes. J. A. Moretz and M. R. Morris, The American Naturalist 168, no.33 (Jul 2015): 336–349.https://doi.org/10.1086/506920Hans Zauner, Gerrit Begemann, Manuel Mari-Beffa, Axel Meyer Differential regulation of msx genes in the development of the gonopodium, an intromittent organ, and of the "sword," a sexually selected trait of swordtail fishes (Xiphophorus), Evolution and Development 5, no.55 (Sep 2003): 466–477.https://doi.org/10.1046/j.1525-142X.2003.03053.xPATRICK R. STEPHENS, JOHN J. WIENS Ecological diversification and phylogeny of emydid turtles, Biological Journal of the Linnean Society 79, no.44 (Aug 2003): 577–610.https://doi.org/10.1046/j.1095-8312.2003.00211.xMolly R. Morris, Jason A. Elias, Jason A. Moretz Defining Vertical Bars in Relation to Female Preference in the Swordtail Fish Xiphophorus cortezi (Cyprinodontiformes, Poeciliidae), Ethology 107, no.99 (Sep 2001): 827–837.https://doi.org/10.1046/j.1439-0310.2001.00711.xJohn J. Wiens, Tod W. Reeder, Adrián Nieto Montes De Oca MOLECULAR PHYLOGENETICS AND EVOLUTION OF SEXUAL DICHROMATISM AMONG POPULATIONS OF THE YARROW'S SPINY LIZARD ( SCELOPORUS JARROVII ), Evolution 53, no.66 (May 2017): 1884–1897.https://doi.org/10.1111/j.1558-5646.1999.tb04570.xJames L. Gould, Samuel L. Elliott, Casson M. Masters, Joya Mukerji Female preferences in a fish genus without female mate choice, Current Biology 9, no.99 (May 1999): 497–500.https://doi.org/10.1016/S0960-9822(99)80217-6Dolph Schluter, Trevor Price, Arne Ø. Mooers, Donald Ludwig LIKELIHOOD OF ANCESTOR STATES IN ADAPTIVE RADIATION, Evolution 51, no.66 (May 2017): 1699–1711.https://doi.org/10.1111/j.1558-5646.1997.tb05095.xAxel Meyer The evolution of sexually selected traits in male swordtail fishes (Xiphophorus: Poeciliidae), Heredity 79, no.33 (Sep 1997): 329–337.https://doi.org/10.1038/hdy.1997.161

Serotonin-dopamine interaction and its relevance to schizophrenia.

The therapeutic success of clozapine and risperidone has focused attention on the interaction between serotonin and dopamine systems as an avenue for superior therapeutics in schizophrenia. The authors review the neurobiological basis for this interaction and its clinical relevance. The authors synthesized information from more than 100 published articles obtained through electronic and bibliography-directed searches. The serotonin system inhibits dopaminergic function at the level of the origin of the dopamine system in the midbrain as well as at the terminal dopaminergic fields in the forebrain. Serotonergic antagonists release the dopamine system from this inhibition. This disinhibition of the dopamine system in the striatum may alleviate neuroleptic-induced extrapyramidal symptoms, and a similar disinhibition in the prefrontal cortex may ameliorate negative symptoms. However, the benefits of combined serotonergic-dopaminergic blockade may be observed in only a narrow dose range and may be lost with doses that produce suprathreshold dopaminergic blockade. Serotonergic modulation of dopaminergic function provides a viable mechanism for enhancing therapeutics in schizophrenia, but much remains unclear. Future research will have to establish the existence of this interaction in humans in vivo, specify the conditions under which it leads to optimal therapeutic benefits, and explore the possibility of using specific serotonergic treatments as flexible adjuncts to typical neuroleptics, rather than the present trend toward using single drugs with combined actions.