Testing the differential cost assumption of the handicap hypothesis with a tropical jumping spider

Behaviour ◽  
2020 ◽  
Vol 157 (5) ◽  
pp. 433-449 ◽  
Author(s):  
Leonardo Braga Castilho ◽  
Maydianne C.B. Andrade ◽  
Regina H. Macedo
Keyword(s):  
Sexual Selection ◽  
Lower Cost ◽  
Courtship Display ◽  
High Quality ◽  
Jumping Spider ◽  
Selection Processes ◽  
Unit Increase ◽  
Predatory Attack ◽  
Handicap Hypothesis ◽  
Experimental Trials

Abstract The handicap hypothesis predicts that more elaborate males attract more predators, but are also better able to escape attacks. Thus, a unit increase in trait elaboration has a lower cost for a high-quality male (i.e., differential cost). Although widely accepted, the handicap hypothesis has seldom been appropriately tested, especially concerning the differential cost assumption. Here, we tested this assumption using the jumping spider Hasarius adansoni. The courtship display of male H. adansoni involves bright white patches that contrast with their dark-coloured body. In experimental trials, we measured male escape capacity following a simulated predatory attack. Measurements of escape capacity were correlated to the size of white patches. Contrary to expectations, spiders with larger white patches did not exhibit better escape capacity. We conclude that this trait does not function as a handicap. It is possible that other sexual selection processes are at work.

scholarly journals The physical environment mediates male harm and its effect on selection in females

2017 ◽  
Vol 284 (1858) ◽  
pp. 20170424 ◽  
Author(s):  
Li Yun ◽  
Patrick J. Chen ◽  
Amardeep Singh ◽  
Aneil F. Agrawal ◽  
Howard D. Rundle
Keyword(s):  
Drosophila Melanogaster ◽  
Sexual Selection ◽  
Physical Environment ◽  
Selective Advantage ◽  
Laboratory Studies ◽  
Male Choice ◽  
Female Fitness ◽  
High Quality ◽  
Evolutionary Consequences ◽  
Natural And Sexual Selection

Recent experiments indicate that male preferential harassment of high-quality females reduces the variance in female fitness, thereby weakening natural selection through females and hampering adaptation and purging. We propose that this phenomenon, which results from a combination of male choice and male-induced harm, should be mediated by the physical environment in which intersexual interactions occur. Using Drosophila melanogaster , we examined intersexual interactions in small and simple (standard fly vials) versus slightly more realistic (small cages with spatial structure) environments. We show that in these more realistic environments, sexual interactions are less frequent, are no longer biased towards high-quality females, and that overall male harm is reduced. Next, we examine the selective advantage of high- over low-quality females while manipulating the opportunity for male choice. Male choice weakens the viability advantage of high-quality females in the simple environment, consistent with previous work, but strengthens selection on females in the more realistic environment. Laboratory studies in simple environments have strongly shaped our understanding of sexual conflict but may provide biased insight. Our results suggest that the physical environment plays a key role in the evolutionary consequences of sexual interactions and ultimately the alignment of natural and sexual selection.

scholarly journals Twenty-five tonnes of high quality forages annually in Canterbury

2004 ◽  
pp. 85-91
Author(s):  
T.J. Fraser ◽  
T.L. Knight ◽  
I.M. Knowles ◽  
M.G. Hyslop
Keyword(s):  
Lower Cost ◽  
Forage Yield ◽  
Dairy Calves ◽  
Forage Production ◽  
High Quality ◽  
Cereal Breeding ◽  
Significant Difference ◽  
Recent Developments ◽  
High Yields ◽  
Final Harvest

Recent developments in cereal breeding for forage production have given the potential to greatly increase annual forage dry matter (DM) production. This paper reports on the findings from two cereal forage production trials on irrigated Canterbury land. Trial 1 studied the potential of a range of single and multi-grazed cereal forages over a 9 month period to produce high yields and quality from both grazing and whole-crop silage forage. Trial 2 studied the suitability of different cereal/ legume combinations for green-chop silage grown over a three month summer period. These two cereal forage systems, when combined in a 12 month period, produced in excess of 25 tonnes of high quality forage per hectare, almost double the DM production achieved using current perennial pasture based systems. Trial 1 showed no significant difference in the total DM produced by either single or multi-graze treatments. In Trial 2 pea/cereal combinations produced over 6 t DM/ha. Due to an earlier final harvest the multi-graze system is more easily combined with the summer crop and more likely to produce a lower cost and more sustainable forage system. Animal performance on forage produced in Trial 1 showed that dairy calves can grow well on cereal forages during winter. Keywords: cereal, feed supplements, forage, forage yield, legume, silage

scholarly journals Offspring viability benefits but no apparent costs of mating with high quality males

2010 ◽  
Vol 7 (3) ◽  
pp. 419-421 ◽  
Author(s):  
Leigh W. Simmons ◽  
Rebecca Holley
Keyword(s):  
Sexual Selection ◽  
Sexual Conflict ◽  
Alternative Hypothesis ◽  
Dung Beetle ◽  
Male Courtship ◽  
High Quality ◽  
Female Resistance ◽  
Genetic Quality ◽  
Onthophagus Taurus ◽  
Courtship Signals

Traditional models of sexual selection posit that male courtship signals evolve as indicators of underlying male genetic quality. An alternative hypothesis is that sexual conflict over mating generates antagonistic coevolution between male courtship persistence and female resistance. In the scarabaeine dung beetle Onthophagus taurus , females are more likely to mate with males that have high courtship rates. Here, we examine the effects of exposing females to males with either high or low courtship rates on female lifetime productivity and offspring viability. Females exposed to males with high courtship rates mated more often and produced offspring with greater egg–adult viability. Female productivity and lifespan were unaffected by exposure to males with high courtship rates. The data are consistent with models of sexual selection based on indirect genetic benefits, and provide little evidence for sexual conflict in this system.

scholarly journals The Promises and Pitfalls of 311 Data

2016 ◽  
Vol 54 (4) ◽  
pp. 794-823 ◽  
Author(s):  
Ariel White ◽  
Kris-Stella Trump
Keyword(s):  
Voter Turnout ◽  
Local Governments ◽  
Lower Cost ◽  
Political Engagement ◽  
The United States ◽  
High Quality ◽  
City Governments ◽  
Return Rates ◽  
Fine Grained ◽  
Neighborhood Condition

Local governments operate 311 service request lines across the United States, and the publicly available data from these lines provide a continuously measured, geographically fine-grained, and non-self-reported measure of citizens’ interactions with government. It seems a promising measure of neighborhood political participation. However, these data are empirically and theoretically different from many common citizen-level participation measures. We compare geographically aggregated 311 call data with three other measures of political and civic participation: voter turnout, political donations, and census return rates. We show that rates of 311 calls are negatively related to lower cost activities (voter turnout and census return rates), but positively related to the high-cost activity of campaign donation. We caution against interpreting 311 data as a generic measure of political engagement or participation, at least in the absence of high-quality controls for neighborhood condition. However, we argue that these data are still potentially useful for researchers, because they are by definition a measure of the service demands that neighborhoods place on city governments.

scholarly journals Sexual selection drives the evolution of wing interference patterns

2018 ◽  
Author(s):  
MF Hawkes ◽  
E Duffy ◽  
R Joag ◽  
A Skeats ◽  
J Radwan ◽  
...  
Keyword(s):  
Sexual Selection ◽  
Digital Imaging ◽  
Colour Vision ◽  
Species Recognition ◽  
Sexual Attractiveness ◽  
Courtship Display ◽  
Structural Coloration ◽  
Male And Female ◽  
Selection For ◽  
First Time

AbstractThe seemingly transparent wings of many insects have recently been found to display dramatic structural coloration. These structural colours (wing interference patterns: WIPs) may be involved in species recognition and mate choice, yet little is known about the evolutionary processes that shape them. Additionally, existing research has been restricted by analysing WIPs without due consideration of how they are actually perceived by the viewers’ colour vision. Here, we use multispectral digital imaging and a model ofDrosophilavision to compare WIPs of male and femaleDrosophila simulansfrom replicate populations forced to evolve with or without sexual selection for 68 generations. We show for the first time that WIPs modelled inDrosophilavision evolve in response to sexual selection, and confirm that WIPs correlate with male sexual attractiveness. These findings add a new element to the otherwise well describedDrosophilacourtship display and confirm that wing colours evolve through sexual selection.

scholarly journals SARS-CoV-2 variants in Paraguay: Detection and surveillance with a readily modifiable, multiplex real-time RT-PCR

2021 ◽  
Author(s):  
Magaly Martinez ◽  
Phuong-Vi Nguyen ◽  
Maxwell Su ◽  
Fatima Cardozo ◽  
Adriana Valenzuela ◽  
...  
Keyword(s):  
Real Time ◽  
Sanger Sequencing ◽  
Lower Cost ◽  
Population Level ◽  
Nanopore Sequencing ◽  
Receptor Binding Domain ◽  
Rt Pcr ◽  
High Quality ◽  
Rna Detection ◽  
Detection Of Mutations

Objectives The objective of the current study was to develop a lower-cost and scalable protocol to identify and monitor SARS-CoV-2 variants in Paraguay by pairing real-time RT-PCR detection of spike mutations with amplicon Sanger sequencing and whole-genome Nanopore sequencing. Methods 201 acute-phase nasopharyngeal samples from SARS-CoV-2-positive individuals were tested with two rRT-PCRs: 1) N2RP assay to confirm SARS-CoV-2 RNA detection (CDC N2 target), and 2) the Spike SNP assay to detect mutations in the spike receptor binding domain. The assay was performed with probes to identify mutations associated with the following variants: alpha (501Y), beta/gamma (417variant/484K/501Y), delta (452R/478K), and lambda (452Q/490S). Results All samples were positive for SARS-CoV-2 in the N2RP assay (mean Ct, 20.8; SD 5.6); 198/201 (98.5%) tested positive in the Spike SNP assay. The most common genotype was 417variant/484K/501Y, detected in 102/198 samples (51.5%) and most consistent with P.1 lineage (gamma variant) in Paraguay. No mutations (K417 only) were found in 64/198 (32.3%); and K417/484K was identified in 22/198 (11.1%), consistent with P.2 (zeta). Seven samples (3.5%) tested positive for 452R without 478K, and one sample with genotype K417/501Y was confirmed as B.1.1.7 (alpha). Results were confirmed by Sanger sequencing in 181/181 samples (100%) with high-quality amplicon sequences, and variant calls were consistent with Nanopore sequencing in 29/29 samples. Conclusions The Spike SNP assay provides accurate detection of mutations associated with SARS-CoV-2 variants. This can be implemented in laboratories performing rRT-PCR to improve population-level surveillance for these mutations and inform the judicious use of scarce sequencing resources.

scholarly journals The effects of male harm vary with female quality and environmental complexity in Drosophila melanogaster

2018 ◽  
Vol 14 (8) ◽  
pp. 20180443 ◽  
Author(s):  
Alison MacPherson ◽  
Li Yun ◽  
Tania S. Barrera ◽  
Aneil F. Agrawal ◽  
Howard D. Rundle
Keyword(s):  
Drosophila Melanogaster ◽  
Sexual Selection ◽  
Natural Selection ◽  
Sexual Conflict ◽  
Mate Competition ◽  
Environmental Complexity ◽  
High Quality ◽  
Female Quality ◽  
Behavioural Interactions ◽  
Recent Attention

Mate competition provides the opportunity for sexual selection which often acts strongly on males, but also the opportunity for sexual conflict that can alter natural selection on females. Recent attention has focused on the potential of sexual conflict to weaken selection on females if male sexual attention, and hence harm, is disproportionately directed towards high- over low-quality females, thereby reducing the fitness difference between these females. However, sexual conflict could instead strengthen selection on females if low-quality females are more sensitive to male harm than high-quality females, thereby magnifying fitness differences between them. We quantify the effects of male exposure on low- versus high-quality females in Drosophila melanogaster in each of two environments (‘simple’ and ‘complex’) that are known to alter behavioural interactions. We show that the effects of male harm are greater for low- compared to high-quality females in the complex but not the simple environment, consistent with mate competition strengthening selection on females in the former but not in the latter environment.

scholarly journals Sexual selection drives the evolution of male wing interference patterns

2019 ◽  
Vol 286 (1903) ◽  
pp. 20182850 ◽  
Author(s):  
M. F. Hawkes ◽  
E. Duffy ◽  
R. Joag ◽  
A. Skeats ◽  
J. Radwan ◽  
...  
Keyword(s):  
Sexual Selection ◽  
Digital Imaging ◽  
Colour Vision ◽  
Species Recognition ◽  
Sexual Attractiveness ◽  
Courtship Display ◽  
Structural Coloration ◽  
Male And Female ◽  
Male Wing ◽  
Selection For

The seemingly transparent wings of many insects have recently been found to display unexpected structural coloration. These structural colours (wing interference patterns: WIPs) may be involved in species recognition and mate choice, yet little is known about the evolutionary processes that shape them. Furthermore, to date investigations of WIPs have not fully considered how they are actually perceived by the viewers' colour vision. Here, we use multispectral digital imaging and a model of Drosophila vision to compare WIPs of male and female Drosophila simulans from replicate populations forced to evolve with or without sexual selection for 68 generations. We show that WIPs modelled in Drosophila vision evolve in response to sexual selection and provide evidence that WIPs correlate with male sexual attractiveness. These findings add a new element to the otherwise well-described Drosophila courtship display and confirm that wing colours evolve through sexual selection.

scholarly journals Sexual selection and organs of sense: Darwin’s neglected insight

2019 ◽  
Vol 69 (1) ◽  
pp. 63-82 ◽  
Author(s):  
Mark A. Elgar ◽  
Tamara L. Johnson ◽  
Matthew R.E. Symonds
Keyword(s):  
Sexual Selection ◽  
Sex Pheromones ◽  
High Quality

Abstract Studies of sexual selection that occurs prior to mating have focussed on either the role of armaments in intra-sexual selection, or extravagant signals for inter-sexual selection. However, Darwin suggested that sexual selection may also act on ‘organs of sense’, an idea that seems to have been largely overlooked. Here, we refine this idea in the context of the release of sex pheromones by female insects: females that lower the release of sex pheromones may benefit by mating with high-quality males, if their signalling investment results in sexual selection favouring males with larger or more sensitive antennae that are costly to develop and maintain.

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