Different sperm allocation strategies in two populations of the semiterrestrial crabNeohelice granulata(Brachyura, Grapsoidea, Varunidae)

2015 ◽  
Vol 37 (4) ◽  
pp. 737-749 ◽  
Author(s):  
María P. Sal Moyano ◽  
María A. Gavio ◽  
Tomás Luppi
Keyword(s):  
Sperm Allocation ◽  
Two Populations ◽  
Allocation Strategies

scholarly journals Cryptic male choice: sperm allocation strategies when female quality varies

2002 ◽  
Vol 15 (2) ◽  
pp. 201-209 ◽  
Author(s):  
K. Reinhold ◽  
J. Kurtz ◽  
L. Engqvist
Keyword(s):  
Male Choice ◽  
Sperm Allocation ◽  
Female Quality ◽  
Allocation Strategies

scholarly journals THE EVOLUTION OF SPERM-ALLOCATION STRATEGIES AND THE DEGREE OF SPERM COMPETITION

Evolution ◽  
2005 ◽  
Vol 59 (3) ◽  
pp. 492-499 ◽  
Author(s):  
Paul D. Williams ◽  
Troy Day ◽  
Erin Cameron
Keyword(s):  
Sperm Competition ◽  
Sperm Allocation ◽  
Allocation Strategies

Sperm Allocation Strategies and Female Resistance: A Unifying Perspective

2008 ◽  
Vol 172 (1) ◽  
pp. 25-33 ◽  
Author(s):  
Lutz Fromhage ◽  
John M. McNamara ◽  
Alasdair I. Houston
Keyword(s):  
Female Resistance ◽  
Sperm Allocation ◽  
Allocation Strategies

scholarly journals Comparative performance of between-population allocation strategies for SARS-CoV-2 vaccines.

2021 ◽  
Author(s):  
Keya Joshi ◽  
Eva Rumpler ◽  
Lee Kennedy-Shaffer ◽  
Rafia Bosan ◽  
Marc Lipsitch
Keyword(s):  
Heterogeneous Population ◽  
Emerging Pathogen ◽  
Comparative Performance ◽  
Policy Makers ◽  
The Impact ◽  
Allocation Decisions ◽  
Two Populations ◽  
Epidemiologic Characteristics ◽  
Roll Out ◽  
Allocation Strategies

Vaccine allocation decisions during the ongoing COVID-19 pandemic have proven to be challenging due to competing ethical, practical, and political considerations. Complicating decision making, policy makers need to consider vaccine allocation strategies that balance needs both within and between populations. Due to limited vaccine stockpiles, vaccine doses should be allocated in locations where their impact will be maximized. Using a susceptible-exposed-infectious-recovered (SEIR) model we examine optimal SARS-CoV-2 vaccine allocation decisions across two populations considering the impact of population size, underlying immunity, continuous vaccine roll-out, and heterogeneous population risk structure. We find that in the context of an emerging pathogen, where many epidemiologic characteristics might not be known, equal vaccine allocation between populations performs optimally in most scenarios. In the specific case considering heterogeneous population risk structure, first targeting individuals at higher risk of transmission or death due to infection leads to equitable resource allocation across populations.

Sperm Allocation Strategies Depending on Female Quality in Medaka (Oryzias latipes)

2020 ◽  
Vol 37 (3) ◽  
pp. 203
Author(s):  
Yuki Kondo ◽  
Masanori Kohda ◽  
Yasunori Koya ◽  
Satoshi Awata
Keyword(s):  
Oryzias Latipes ◽  
Sperm Allocation ◽  
Female Quality ◽  
Allocation Strategies

THE EVOLUTION OF SPERM-ALLOCATION STRATEGIES AND THE DEGREE OF SPERM COMPETITION

Evolution ◽  
2005 ◽  
Vol 59 (3) ◽  
pp. 492 ◽  
Author(s):  
Paul D. Williams ◽  
Troy Day ◽  
Erin Cameron
Keyword(s):  
Sperm Competition ◽  
Sperm Allocation ◽  
Allocation Strategies

scholarly journals Strategic sperm allocation under parasitic sex-ratio distortion

2005 ◽  
Vol 2 (1) ◽  
pp. 78-80 ◽  
Author(s):  
Alison M Dunn ◽  
Tara Andrews ◽  
Hannah Ingrey ◽  
Joanna Riley ◽  
Nina Wedell
Keyword(s):  
Sex Ratio ◽  
Mating Behaviour ◽  
Selective Force ◽  
High Fecundity ◽  
Sperm Limitation ◽  
Sperm Allocation ◽  
Ratio Distortion ◽  
The Impact ◽  
Sex Ratio Distortion ◽  
Allocation Strategies

Parasitic sex-ratio distorters are a major selective force in the evolution of host mating behaviour and mate choice. Here, we investigate sperm limitation in the amphipod Gammarus duebeni and the impact of the microsporidian sex-ratio distorter Nosema granulosis on sperm allocation strategies. We show that males become sperm limited after three consecutive matings and provide uninfected, high fecundity, females with more sperm than infected females. We show that sperm limitation leads to a decrease in female productivity. The outcome of sex-ratio distortion has been shown theoretically to be sensitive to the mating limits of males. Our results indicate that strategic sperm allocation under male rarity will have a greater impact on infected females and has the potential to regulate spread of parasitic feminisers in host populations.

scholarly journals Sperm allocation strategies in a sperm heteromorphic insect

2019 ◽  
Vol 66 (3) ◽  
pp. 285-292 ◽  
Author(s):  
Kambiz Esfandi ◽  
Xiong Z He ◽  
Qiao Wang
Keyword(s):  
Reproductive Success ◽  
Empirical Evidence ◽  
Copulation Duration ◽  
Minor Role ◽  
Male Reproductive Success ◽  
Allocation Pattern ◽  
Sperm Allocation ◽  
Focal Male ◽  
Tactile Cues ◽  
Allocation Strategies

Abstract Theories predict that in polyandrous species, the focal male should increase sperm allocation per mate in the presence of rivals to gain greater share of paternity, but in the presence of additional mates, he should reduce sperm allocation per mate to save sperm for insemination of more mates. However, empirical findings are often inconsistent and reasons behind are unclear. Furthermore, many studies use copulation duration as an estimate of the number of sperm transferred. Yet, empirical evidence for such assumption is largely lacking. Here, we used a sperm heteromorphic insect Ephestia kuehniella whose males produce two types of sperm, eupyrenes (fertile) and apyrenes (nonfertile), to test these postulations. We allowed focal males to detect chemical and acoustic but no tactile cues from rivals or additional mates both before and during mating and measured copulation duration and sperm allocation in successive copulations. We demonstrate that males transfer significantly more eupyrenes per mate in the presence of rivals and that the sperm allocation pattern persists in successive copulations under this condition. However, males do not adjust apyrene allocation in response to rivals probably because apyrenes play a relatively minor role in male reproductive success. Contrary to a previous study, focal males do not respond to additional mates most likely due to the lack of tactile cues in the present study. We reveal that sperm allocation is not a function of copulation duration in this insect for spermatophore formation and delivery occupy most of copulation duration and sperm transfer is complete near the end of copulation.

Comparison of Principal Component Solutions in Two Populations

Methodology ◽  
2016 ◽  
Vol 12 (1) ◽  
pp. 11-20 ◽  
Author(s):  
Gregor Sočan
Keyword(s):  
Simulation Study ◽  
Principal Components ◽  
Common Factor ◽  
Principal Component ◽  
Component Model ◽  
Bootstrap Procedure ◽  
Factor Loadings ◽  
Component Loadings ◽  
Principal Component Model ◽  
Two Populations

Abstract. When principal component solutions are compared across two groups, a question arises whether the extracted components have the same interpretation in both populations. The problem can be approached by testing null hypotheses stating that the congruence coefficients between pairs of vectors of component loadings are equal to 1. Chan, Leung, Chan, Ho, and Yung (1999) proposed a bootstrap procedure for testing the hypothesis of perfect congruence between vectors of common factor loadings. We demonstrate that the procedure by Chan et al. is both theoretically and empirically inadequate for the application on principal components. We propose a modification of their procedure, which constructs the resampling space according to the characteristics of the principal component model. The results of a simulation study show satisfactory empirical properties of the modified procedure.

The effect of handling on the yield of two populations of Lolium perenne selected for differences in mature leaf respiration rate

1993 ◽  
Vol 89 (2) ◽  
pp. 341-346 ◽  
Author(s):  
Edwin Kraus ◽  
Hans Lambers ◽  
Chris Kolloffel
Keyword(s):  
Respiration Rate ◽  
Lolium Perenne ◽  
Mature Leaf ◽  
Leaf Respiration ◽  
Two Populations
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