scholarly journals Heterospecific aggression differs predominately by species, rather than sex, in Lake Malawi cichlid fish

2019 ◽  
Author(s):  
Emily C. Moore ◽  
Reade B. Roberts
Keyword(s):  
Community Structure ◽  
Rapid Evolution ◽  
Cichlid Fish ◽  
Lake Malawi ◽  
Male Aggression ◽  
Males And Females ◽  
Potential Impact ◽  
Cortisol Levels ◽  
Species Specific ◽  
Heterospecific Aggression

ABSTRACTBecause of their striking diversity, Lake Malawi cichlid fish have been well studied for male aggression, particularly among dominant males of closely related sister species within the framework of mate-choice and speciation. However, aggression in females has been largely ignored, and variation in aggressive behaviors between more distantly-related taxa is not well understood despite its potential impact in a complex community structure. To better understand variation in patterns of aggression between species, we presented males and females from five species of Lake Malawi cichlid with a non-predator intruder and recorded all movement and aggressive acts. Additionally, we measured excreted cortisol levels the day after the intruder assay to evaluate one physiological aspect of stress response. We identified species-specific patterns in both specific aggressive acts, and overall level of aggression. Additionally, we found that sexual dimorphism in aggressive acts varies by species and act, where the species with the most aggressive males also has aggressive females. Additionally, cortisol levels vary by taxa, and are associated with restless behavior in the intruder assay, but not levels of aggression. These findings have bearing on understanding sex differences in aggression and their impact on community structure in this important model of rapid evolution.

scholarly journals Variable Rates of Simple Satellite Gains across the Drosophila Phylogeny

2018 ◽  
Vol 35 (4) ◽  
pp. 925-941 ◽  
Author(s):  
Kevin H -C Wei ◽  
Sarah E Lower ◽  
Ian V Caldas ◽  
Trevor J S Sless ◽  
Daniel A Barbash ◽  
...  
Keyword(s):  
Evolutionary Dynamics ◽  
Rapid Evolution ◽  
Single Mutation ◽  
Closely Related Species ◽  
Interspecific Differences ◽  
Limited Sampling ◽  
Drosophila Phylogeny ◽  
Males And Females ◽  
Species Specific ◽  
Turn Over

Abstract Simple satellites are tandemly repeating short DNA motifs that can span megabases in eukaryotic genomes. Because they can cause genomic instability through nonallelic homologous exchange, they are primarily found in the repressive heterochromatin near centromeres and telomeres where recombination is minimal, and on the Y chromosome, where they accumulate as the chromosome degenerates. Interestingly, the types and abundances of simple satellites often vary dramatically between closely related species, suggesting that they turn over rapidly. However, limited sampling has prevented detailed understanding of their evolutionary dynamics. Here, we characterize simple satellites from whole-genome sequences generated from males and females of nine Drosophila species, spanning 40 Ma of evolution. We show that PCR-free library preparation and postsequencing GC-correction better capture satellite quantities than conventional methods. We find that over half of the 207 simple satellites identified are species-specific, consistent with previous descriptions of their rapid evolution. Based on a maximum parsimony framework, we determined that most interspecific differences are due to lineage-specific gains. Simple satellites gained within a species are typically a single mutation away from abundant existing satellites, suggesting that they likely emerge from existing satellites, especially in the genomes of satellite-rich species. Interestingly, unlike most of the other lineages which experience various degrees of gains, the lineage leading up to the satellite-poor D. pseudoobscura and D. persimilis appears to be recalcitrant to gains, providing a counterpoint to the notion that simple satellites are universally rapidly evolving.

scholarly journals Segregation of Species-Specific Male Attractiveness in F2 Hybrid Lake Malawi Cichlid Fish

2011 ◽  
Vol 2011 ◽  
pp. 1-7 ◽  
Author(s):  
Ola Svensson ◽  
Bernd Egger ◽  
Boye Gricar ◽  
Katie Woodhouse ◽  
Cock van Oosterhout ◽  
...  
Keyword(s):  
Mate Choice ◽  
Reproductive Isolation ◽  
Genetic Model ◽  
Cichlid Fish ◽  
Lake Malawi ◽  
Paternity Analysis ◽  
Colour Pattern ◽  
Male Mating ◽  
Heritable Variation ◽  
Species Specific

Among the huge radiations of haplochromine cichlid fish in Lakes Malawi and Victoria, closely related species are often reproductively isolated via female mate choice although viable fertile hybrids can be produced when females are confined only with heterospecific males. We generated F2 hybrid males from a cross between a pair of closely related sympatric cichlid fish from Lake Malawi. Laboratory mate choice experiments using microsatellite paternity analysis demonstrated that F2 hybrid males differed significantly in their attractiveness to females of the two parental species, indicating heritable variation in traits involved in mate choice that may contribute to reproductive isolation between these species. We found no significant correlation between male mating success and any measurement of male colour pattern. A simple quantitative genetic model of reproductive isolation suggests that there may be as few as two chromosomal regions controlling species-specific attractiveness. We propose that adaptive radiation of Lake Malawi cichlids could be facilitated by the presence of genes with major effects on mate choice and reproductive isolation.

scholarly journals High rates of evolution preceded shifts to sex-biased gene expression in Leucadendron, the most sexually dimorphic angiosperms

2021 ◽  
Author(s):  
Mathias Scharmann ◽  
Anthony G Rebelo ◽  
John R Pannell
Keyword(s):  
Gene Expression ◽  
Sexual Dimorphism ◽  
Rapid Evolution ◽  
Sex Bias ◽  
Sexually Dimorphic ◽  
Expression Levels ◽  
Rates Of Evolution ◽  
Expression Evolution ◽  
Males And Females ◽  
Species Specific

AbstractThe males and females of many dioecious plants differ in morphological (Dawson and Geber 1999; Barrett and Hough 2013; Tonnabel et al. 2017), physiological (Juvany and Munné-Bosch 2015), life-history (Delph 1999), and defence traits (Cornelissen and Stiling 2005). Ultimately, such sexual dimorphism must largely be due to differential gene expression between the sexes (Ellegren and Parsch 2007), but little is known about how sex-biased genes are recruited and how their expression evolves over time. We measured gene expression in leaves of males and females of ten species sampled across the South African Cape genus Leucadendron, which shows repeated changes in sexual dimorphism and includes the most extreme differences between males and females in flowering plants (Midgley 2010; Barrett and Hough 2013; Tonnabel et al. 2014). Even in the most dimorphic species in our sample, fewer than 2% of genes showed sex-biased gene expression (SBGE) in vegetative tissue, with surprisingly little correspondence between SBGE and vegetative dimorphism across species. The identity of sex-biased genes in Leucadendron was highly species-specific, with a rapid turnover among species. In animals, sex-biased genes often evolve more quickly than unbiased genes in their sequences and expression levels (Ranz et al. 2003; Khaitovich et al. 2005; Ellegren and Parsch 2007; Voolstra et al. 2007; Harrison et al. 2015; Naqvi et al. 2019), consistent with hypotheses invoking rapid evolution due to sexual selection. Our phylogenetic analysis in Leucadendron, however, clearly indicates that sex-biased genes are recruited from a class of genes with ancestrally rapid rates of expression evolution, perhaps due to low evolutionary or pleiotropic constraints. Nevertheless, we also find evidence for adaptive evolution of expression levels once sex bias evolves. Thus, although the expression of sex-biased genes is ultimately responsive to selection, high rates of expression evolution might usually predate the evolution of sex bias.

scholarly journals Rare morph Lake Malawi mbuna cichlids benefit from reduced aggression from con- and hetero-specifics

2021 ◽  
Author(s):  
Alexandra M Tyers ◽  
Gavan M Cooke ◽  
George F Turner
Keyword(s):  
Genetic Drift ◽  
Relative Frequency ◽  
Balancing Selection ◽  
Lake Malawi ◽  
Disruptive Selection ◽  
Field Observations ◽  
Two Factors ◽  
Males And Females ◽  
Heterospecific Aggression

Balancing selection is important for the maintenance of polymorphism as it can prevent either fixation of one morph through directional selection or genetic drift, or speciation by disruptive selection. Polychromatism can be maintained if the fitness of alternative morphs depends on the relative frequency in a population. In aggressive species, negative frequency-dependent antagonism can prevent an increase in the frequency of rare morphs as they would only benefit from increased fitness while they are rare. Heterospecific aggression is common in nature and has the potential to contribute to rare morph advantage. Here we carry out field observations and laboratory aggression experiments with mbuna cichlids from Lake Malawi, to investigate the role of con- and heterospecific aggression in the maintenance of polychromatism and identify benefits to rare mores which are likely to result from reduced aggression. Within species we found that males and females bias aggression towards their own morph, adding to the evidence that inherent own-morph aggression biases can contribute to balancing selection. Over-representation of rare morph territory owners may be influenced by two factors; higher tolerance of different morph individuals as neighbours, and ability of rare morphs to spend more time feeding. Reduced aggression to rare morph individuals by heterospecifics may also contribute to rare morph advantage.

Effects of choral singing on salivary cortisol levels and self-reported stress in university students

2021 ◽  
Vol 13 (4) ◽  
Author(s):  
Gunnar Glauco De Cunto Carelli Taets ◽  
Ramon Werner Heringer Gutierrez ◽  
Leila Brito Bergold ◽  
Luana Silva Monteiro
Keyword(s):  
University Students ◽  
Salivary Cortisol ◽  
Health Issues ◽  
Group Approach ◽  
Choral Singing ◽  
Before And After ◽  
Quasi Experimental ◽  
Potential Impact ◽  
Cortisol Levels

Although mental disorders are common among university students, the majority of students with mental health issues do not seek out treatment during their academic life. The aim of this study was to evaluate the effects of a novel group approach- choir singing, and its potential impact on stress, via salivary cortisol levels and self-reported stress levels in university students during 4 sessions of choir singing. It was based on a quasi-experimental research conducted with 25 Brazilian university students. Each choir singing session lasted 60 minutes. A question was asked before and after the intervention: what is the level of your stress? Salivary cortisol was collected before and after the intervention. After the choir singing intervention, there was  a statistically significant reduction in self-reported stress (p<0.0001) and salivary cortisol levels (p<0.0001). This research suggests that choir singing can reduce the self-reported stress of university students after 4 weeks of follow-up with ∆= 45.83% and salivary cortisol levels in the first week with ∆= 3.57%.

Social Status and Arginine Vasotocin Neuronal Phenotypes in a Cichlid Fish

2015 ◽  
Vol 85 (3) ◽  
pp. 203-213 ◽  
Author(s):  
Olinda Almeida ◽  
Rui F. Oliveira
Keyword(s):  
Social Status ◽  
Social Behaviour ◽  
Cichlid Fish ◽  
Brain Regions ◽  
Cell Number ◽  
Arginine Vasotocin ◽  
Cichlid Species ◽  
Neuronal Populations ◽  
Soma Size ◽  
Species Specific

The nonapeptide arginine vasotocin (AVT) and its mammalian homologue arginine vasopressin play a key role in the regulation of social behaviour across vertebrates. In teleost fishes, three AVT neuronal populations have been described in the preoptic area (POA): the parvocellular (pPOA), the magnocellular (mPOA) and the gigantocellular (gPOA). Neurons from each of these areas project both to the pituitary and to other brain regions, where AVT is supposed to regulate neural circuits underlying social behaviour. However, in the fish species studied so far, there is considerable variation in which AVT neuronal populations are involved in behavioural modulation and in the direction of the effect. In this study, the association between AVT neuronal phenotypes and social status was investigated in the Mozambique tilapia (Oreochromis mossambicus). This species is an African female mouth-brooding cichlid fish in which males form breeding aggregations in which dominant males establish territories and subordinate males to act as floaters. With respect to sex differences in AVT neuronal phenotypes, females have a larger number of AVT neurons in the pPOA and mPOA. Within males, AVT appeared associated with social subordination, as indicated by the larger cell body areas of AVT neurons in mPOA and gPOA nuclei of non-territorial males. There were also positive correlations between submissive behaviour and the soma size of AVT cells in all three nuclei and AVT cell number in the mPOA. In summary, the results provide evidence for an involvement of AVT in the modulation of social behaviour in tilapia, but it was not possible to identify specific roles for specific AVT neuronal populations. The results presented here also contrast with those previously published for another cichlid species with a similar mating system, which highlights the species-specific nature of the pattern of association between AVT and social behaviour even within the same taxonomic family.

scholarly journals Potential impact of increased temperature and CO2 on particulate dimethylsulfoniopropionate in the Southeastern Bering Sea

2011 ◽  
Vol 2 (1) ◽  
pp. 33 ◽  
Author(s):  
Peter A. Lee ◽  
Sarah F. Riseman ◽  
Clinton E. Hare ◽  
David A. Hutchins ◽  
Karine Leblanc ◽  
...  
Keyword(s):  
Community Structure ◽  
Continental Shelf ◽  
Bering Sea ◽  
Feedback Mechanism ◽  
Climate Feedback ◽  
Algal Community ◽  
Central Basin ◽  
Phytoplankton Assemblages ◽  
Potential Impact ◽  
Relative Abundances

The potential impact of elevated sea surface temperature (SST) and pCO2 on algal community structure and particulate dimethylsulfoniopropionate (DMSPp) concentrations in the southeastern Bering Sea was examined using a shipboard “Ecostat” continuous culture system. The ecostat system was used to mimic the conditions projected to exist in the world's oceans by the end of this century (i.e. elevated pCO2 (750 ppm) and elevated SST (ambient + 4°C). Two experiments were conducted using natural phytoplankton assemblages from the high-nutrient low-chlorophyll (HNLC) central basin and from the middle domain of the southeastern continental shelf. At the HNLC site, the relative abundances of haptophytes and pelagophytes were higher and the relative abundance of diatoms lower under “greenhouse” conditions (i.e. combined 750 ppm CO2 and elevated temperature) than control conditions (380 ppm CO2 and ambient temperature). This shift in algal community structure was accompanied by increases in DMSPp (2–3 fold), DMSPp:Chl a (2–3 fold) and DMSP:PON (2 fold). At the continental shelf site, the changes in the relative abundances of haptophytes, pelagophytes and diatoms under “greenhouse” conditions were similar to those observed at the HNLC site, with 2.5 fold increases in DMSPp, 50–100% increases in DMSPp:Chl a and 1.8 fold increases in DMSP:PON. At both locations, changes in community structure and the DMSPp parameters were largely driven by increasing temperature. The observed changes were also consistent with the phytoplankton-DMS-albedo climate feedback mechanism proposed in the Charlson-Lovelock-Andreae-Warren (CLAW) hypothesis.

scholarly journals Sex Differences in Substance Use Disorders: A Neurobiological Perspective

2021 ◽  
Vol 2 ◽  
Author(s):  
Jennifer L. Cornish ◽  
Asheeta A. Prasad
Keyword(s):  
Substance Use ◽  
Sex Differences ◽  
Clinical Studies ◽  
Reward Processing ◽  
Future Research ◽  
Neural Structure ◽  
Patterns Of Use ◽  
Males And Females ◽  
Potential Impact ◽  
Advance Knowledge

Clinical studies provide fundamental knowledge of substance use behaviors (substance of abuse, patterns of use, relapse rates). The combination of neuroimaging approaches reveal correlation between substance use disorder (SUD) and changes in neural structure, function, and neurotransmission. Here, we review these advances, placing special emphasis on sex specific findings from structural neuroimaging studies of those dependent on alcohol, nicotine, cannabis, psychostimulants, or opioids. Recent clinical studies in SUD analyzing sex differences reveal neurobiological changes that are differentially impacted in common reward processing regions such as the striatum, hippocampus, amygdala, insula, and corpus collosum. We reflect on the contribution of sex hormones, period of drug use and abstinence, and the potential impact of these factors on the interpretation of the reported findings. With the overall recognition that SUD impacts the brains of females and males differentially, it is of fundamental importance that future research is designed with sex as a variable of study in this field. Improved understanding of neurobiological changes in males and females in SUD will advance knowledge underlying sex-specific susceptibility and the neurobiological impact in these disorders. Together these findings will inform future treatments that are tailor designed for improved efficacy in females and males with SUD.

scholarly journals Behavioral and Endocrine Alterations to Partner Interactions and Offspring Care during Periods of Conflict

2020 ◽  
Vol 2 (1) ◽  
Author(s):  
Timothy Paciorek ◽  
Leese Joseph
Keyword(s):  
Pair Bond ◽  
Biparental Care ◽  
Resident Male ◽  
Male And Female ◽  
Pair Bonds ◽  
Convict Cichlids ◽  
Before And After ◽  
Males And Females ◽  
Cortisol Levels ◽  
Endocrine Alterations

Abstract Biparental care has evolved to ensure successful rearing of offspring. However, separation during periods of care can lead to conflicts that might negatively impact pair bonds and offspring care. In this study, pair-bonded convict cichlids (Amatitlania nigrofasciata) were observed for changes in behavior toward their partners and offspring before and after a period of separation. Males and females were designated either as a Resident (remain with offspring) or Removed (separated from partner and offspring for 5 days) individual. Behaviors between partners and toward offspring were measured before and after separation, and compared to the levels of behavior of control pairs (never separated), as well as individuals introduced to a novel partner instead. Cortisol levels of Resident male and female A. nigrofasciata were assayed using water-borne hormone collection before and after separation. Aggression between pair bond members did increase following reintroduction, but did not lead to the termination of pair bonds. Resident females showed more aggression to novel partners than Resident males. Offspring care decreased in both Resident and Removed females. Experimental pairs decreased the amount of time spent interacting with intruders. Cortisol levels were significantly higher among experimental pairs compared with control pairs that did not experience a separation. Females (both control and experimental) showed small, yet significant increases in cortisol levels, while both control and experimental males did not. These results suggest that while pair bonds appear resilient, prolonged separations influence pair bond and parental care dynamics, both behaviorally and hormonally, and require pairs to re-establish roles, resulting in less time caring for offspring.

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