scholarly journals Female mate preference explains countergradient variation in the sexual coloration of guppies ( Poecilia reticulata )

2011 ◽  
Vol 279 (1734) ◽  
pp. 1684-1690 ◽  
Author(s):  
Kerry A. Deere ◽  
Gregory F. Grether ◽  
Aida Sun ◽  
Janet S. Sinsheimer
Keyword(s):  
Geographical Variation ◽  
Poecilia Reticulata ◽  
Direct Evidence ◽  
Carotenoid Content ◽  
Pigment Ratio ◽  
Male Attractiveness ◽  
Countergradient Variation ◽  
Sexual Coloration ◽  
Two Populations ◽  
Orange Spot

We tested the hypothesis that mate choice is responsible for countergradient variation in the sexual coloration of Trinidadian guppies ( Poecilia reticulata ). The nature of the countergradient pattern is that geographical variation in the carotenoid content of the orange spots of males is counterbalanced by genetic variation in drosopterin production, resulting in a relatively uniform pigment ratio. A female hue preference could produce this pattern, because hue is the axis of colour variation most directly affected by the pigment ratio. To test this hypothesis, we crossed two populations differing in drosopterin production and produced an F 2 generation with variable drosopterin levels. When the carotenoid content of the orange spots was held constant, female guppies preferred males with intermediate drosopterin levels. This shows that females do not simply prefer males with greater orange spot pigment content; instead, the ratio of the pigments also affects male attractiveness. To our knowledge, this is the first direct evidence for a hypothesized agent of countergradient sexual selection.

scholarly journals Guppies prefer to follow large (robot) leaders irrespective of own size

2018 ◽  
Author(s):  
David Bierbach ◽  
Hauke J. Mönck ◽  
Juliane Lukas ◽  
Marie Habedank ◽  
Pawel Romanczuk ◽  
...  
Keyword(s):  
Body Size ◽  
Risk Taking ◽  
Poecilia Reticulata ◽  
Direct Evidence ◽  
Behavioral Patterns ◽  
Behavioral Differences ◽  
Leaders And Followers ◽  
Biomimetic Robotic Fish ◽  
Risk Taking Behavior ◽  
Swimming Capacity

AbstractBody size is often assumed to determine how successful an individual can lead others with larger individuals being more likely to lead than smaller ones. However, direct evidence for such a relation is scarce. Furthermore, even if larger individuals are more likely to lead, body size correlates often with specific behavioral patterns (e.g., swimming capacity) and it is thus unclear whether larger individuals are more often followed than smaller ones because they are larger or because they behave in a certain way. To control for behavioral differences among differentially-sized leaders, we used biomimetic robotic fish – Robofish – of different sizes. Robofish is accepted as a conspecific by live guppies (Poecilia reticulata) and provides standardized behaviors irrespective of its size. We specifically asked whether larger leaders are preferentially followed when behavior is controlled for and whether the preferences of followers depend on their own body size or their risk taking behavior (‘boldness’). We found that live guppies followed larger Robofish leaders closer than smaller ones and this pattern was independent of the followers’ own body size as well as risk-taking behavior. This is the first study that shows a ‘bigger is better’ pattern in leadership in shoaling fish that is fully independent of behavioral differences between differentially-sized leaders and followers’ own size and personality.

scholarly journals Geographic variation in the morphology of the sand-dwelling lizard Nothobachia ablephara (Squamata: Gymnophthalmidae)

2019 ◽  
Vol 18 (2) ◽  
pp. 195-207
Author(s):  
Carolina Nisa Ramiro ◽  
Renato Sousa Recoder ◽  
Miguel Trefaut Rodrigues
Keyword(s):  
Geographic Variation ◽  
Morphological Traits ◽  
Geographical Variation ◽  
Multivariate Analyses ◽  
Molecular Study ◽  
Northeastern Brazil ◽  
Sexually Dimorphic ◽  
Morphometric Variation ◽  
The One ◽  
Two Populations

Geographic variation in the morphology of the sand-dwelling lizard Nothobachia ablephara (Squamata: Gymnophthalmidae). Nothobachia ablephara is a small microteiid lizard with an elongated body and reduced limbs; it occurs in isolated dune felds in the state of Bahia (Xique-Xique and Alagoado) and small sandy patches in northeastern Brazil. A previous molecular study found a marked mtDNA divergence between populations of N. ablephara from Alagoado and Xique-Xique dunes, suggesting that the two populations diverged from one another between 3 and 4 million years ago. Given this isolation, it is interesting to explore whether morphological traits of the lizards refect the reported genetic divergence of the populations. Scale counts of the sexes and the populations differ signifcantly, but there is considerable overlap of values. Univariate and multivariate analyses revealed signifcant morphometric variation between sexes and populations; however, this is mostly explained by size differences. Females are larger than males in all characters that are sexually dimorphic, and individuals from Xique-Xique are larger than those from Alagoado in all characters that vary geographically. The sample from Alagoado has more sexually dimorphic characters than the one from Xique-Xique. Although N. ablephara displays some geographical variation, the two populations could not be unequivocally distinguished by scale counts and morphometric data.

scholarly journals Intra-Specific Venom Variation in the Australian Coastal Taipan Oxyuranus scutellatus

Toxins ◽  
2020 ◽  
Vol 12 (8) ◽  
pp. 485 ◽  
Author(s):  
Theo Tasoulis ◽  
Anjana Silva ◽  
Punnam Chander Veerati ◽  
Mark Baker ◽  
Wayne C. Hodgson ◽  
...  
Keyword(s):  
Sexual Dimorphism ◽  
Snake Venom ◽  
Geographical Variation ◽  
East Coast ◽  
Population Variation ◽  
The Other ◽  
North East ◽  
The North ◽  
Specific Variation ◽  
Two Populations

Intra-specific venom variation has the potential to provide important insights into the evolution of snake venom, but remains a relatively neglected aspect of snake venom studies. We investigated the venom from 13 individual coastal taipans Oxyuranus scutellatus from four localities on the north-east coast of Australia, spanning a distance of 2000 km. The intra-specific variation in taipan venom was considerably less than the inter-specific variation between it and the other Australian elapids to which it was compared. The electrophoretic venom profile of O. scutellatus was visually different to six other genera of Australian elapids, but not to its congener inland taipan O. microlepidotus. There was minimal geographical variation in taipan venom, as the intra-population variation exceeded the inter-population variation for enzymatic activity, procoagulant activity, and the abundance of neurotoxins. The pre-synaptic neurotoxin (taipoxin) was more abundant than the post-synaptic neurotoxins (3FTx), with a median of 11.0% (interquartile range (IQR): 9.7% to 18.3%; range: 6.7% to 23.6%) vs. a median of 3.4% (IQR: 0.4% to 6.7%; range: 0% to 8.1%). Three taipan individuals almost completely lacked post-synaptic neurotoxins, which was not associated with geography and occurred within two populations. We found no evidence of sexual dimorphism in taipan venom. Our study provides a basis for evaluating the significance of intra-specific venom variation within a phylogenetic context by comparing it to the inter-specific and inter-generic variation. The considerable intra-population variation we observed supports the use of several unpooled individuals from each population when making inter-specific comparisons.

scholarly journals A STUDY OF LINKAGE DISEQUILIBRIUM IN BRITISH POPULATIONS OF DROSOPHILA SUBOBSCURA

Genetics ◽  
1979 ◽  
Vol 92 (3) ◽  
pp. 983-994 ◽  
Author(s):  
B Charlesworth ◽  
D Charlesworth ◽  
M Loukas
Keyword(s):  
Linkage Disequilibrium ◽  
Geographical Variation ◽  
Direct Evidence ◽  
Drosophila Subobscura ◽  
Broad Agreement ◽  
Enzyme Loci ◽  
Linkage Disequilibrium Measure ◽  
High Degree ◽  
Individual Enzyme ◽  
Very High

ABSTRACT Data have been obtained concerning the genetic content of samples of O chromosomes from three British populations, and J chromosomes from one population, of Drosophila subobscura. Some improvements to the genetic map of the O and J chromosomes have been made. Allele frequencies at the loci studied do not show much geographical variation, except where associations with geographically varying gene arrangements distort the picture. Striking nonrandom associations between alleles at three enzyme loci and closely linked O chromosome gene arrangements are present. Some historical explanation for these associations cannot at present be ruled out, but it is clear that a very high degree of genetic differentiation must exist between different gene arrangements in this species. There is no convincing direct evidence for linkage disequilibrium between pairs of enzyme loci, although there is a significant association between close linkage and a high value of the linkage disequilibrium measure. This suggests that there may be disequilibria between closely linked enzyme loci that are too small to be individually detectable. These results are in broad agreement with those reported by workers on other Drosophila species. At present there appears to be no evidence to support the concept that selection is sufficiently strong at individual enzyme loci to produce a high degree of nonrandom associations. (FRANKLIN and LEWONTIN 1970).

scholarly journals Bolder guppies do not have more mating partners, yet sire more offspring

2019 ◽  
Vol 19 (1) ◽  
Author(s):  
Magdalena Herdegen-Radwan
Keyword(s):  
Reproductive Success ◽  
Personality Traits ◽  
Personality Trait ◽  
Poecilia Reticulata ◽  
Direct Evidence ◽  
Animal Groups ◽  
Fitness Consequences

Abstract Background Intra-individual stable but inter-individually variable behaviours, i.e. personalities, are commonly reported across diverse animal groups, yet the reasons for their maintenance remain controversial. Therefore, studying fitness consequences of personality traits is necessary to discriminate between alternative explanations. Results Here, I measured boldness, a highly repeatable personality trait, and reproductive success in male guppies, Poecilia reticulata. I found that bolder males had higher reproductive success than their shyer conspecifics and they sired offspring with females who had larger clutches. Conclusions This result provides direct evidence for fitness consequences of boldness in the guppy. It suggests that the effect may be driven by bolder males mating with more fecund females.

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