scholarly journals SHIFT IN EGG-LAYING STRATEGY TO AVOID PLANT DEFENSE LEADS TO REPRODUCTIVE ISOLATION IN MUTUALISTIC AND CHEATING YUCCA MOTHS

Evolution ◽  
2013 ◽  
Vol 68 (1) ◽  
pp. 301-307 ◽  
Author(s):  
David M. Althoff
Keyword(s):  
Reproductive Isolation ◽  
Plant Defense ◽  
Egg Laying

scholarly journals Male-Female Interactions and the Evolution of Postmating Prezygotic Reproductive Isolation among Species of the Virilis Subgroup

2011 ◽  
Vol 2011 ◽  
pp. 1-11 ◽  
Author(s):  
Nada Sagga ◽  
Alberto Civetta
Keyword(s):  
Reproductive Isolation ◽  
Egg Laying ◽  
Sperm Transfer ◽  
Geographic Locations ◽  
Future Studies ◽  
Egg Hatchability ◽  
Fertilization Rates ◽  
Postzygotic Barriers ◽  
Storage Organs

Reproductive isolation reduces breeding between species. Traditionally, prezygotic and postzygotic barriers to reproduction have been broadly studied, but in recent years, attention has been brought to the existence of barriers that act after copulation but before fertilization. Here, we show that when D. virilis females from different geographic locations mate with D. novamexicana males, egg laying is normal, but fertilization rates are severely reduced, despite normal rates of sperm transfer. This reduction in fertilization is probably due to lower retention of heterospecific sperm in female storage organs one-to-two days after copulation. An inspection of egg hatchability in crosses between females and males from other virilis subgroup species reveals that isolation due to poor egg hatchability likely evolved during the diversification of D. virilis/D. lummei from species of the novamexicana-americana clade. Interestingly, the number of eggs laid by D. virilis females in heterospecific crosses was not different from the numbers of eggs laid in conspecific crosses, suggesting that females exert some form of cryptic control over the heterospecific ejaculate and that future studies should focus on how female and female-sperm interactions contribute to the loss or active exclusion of heterospecific sperm from storage.

scholarly journals The evolution of strong reproductive isolation between sympatric intertidal snails

2020 ◽  
Vol 375 (1806) ◽  
pp. 20190545 ◽  
Author(s):  
Sean Stankowski ◽  
Anja M. Westram ◽  
Zuzanna B. Zagrodzka ◽  
Isobel Eyres ◽  
Thomas Broquet ◽  
...  
Keyword(s):  
Reproductive Isolation ◽  
Biological Diversity ◽  
Demographic History ◽  
Egg Laying ◽  
Female Reproduction ◽  
Open Questions ◽  
Geographical Separation ◽  
Short Period ◽  
Littorina Arcana ◽  
Subsequent Effect

The evolution of strong reproductive isolation (RI) is fundamental to the origins and maintenance of biological diversity, especially in situations where geographical distributions of taxa broadly overlap. But what is the history behind strong barriers currently acting in sympatry? Using whole-genome sequencing and single nucleotide polymorphism genotyping, we inferred (i) the evolutionary relationships, (ii) the strength of RI, and (iii) the demographic history of divergence between two broadly sympatric taxa of intertidal snail. Despite being cryptic, based on external morphology, Littorina arcana and Littorina saxatilis differ in their mode of female reproduction (egg-laying versus brooding), which may generate a strong post-zygotic barrier. We show that egg-laying and brooding snails are closely related, but genetically distinct. Genotyping of 3092 snails from three locations failed to recover any recent hybrid or backcrossed individuals, confirming that RI is strong. There was, however, evidence for a very low level of asymmetrical introgression, suggesting that isolation remains incomplete. The presence of strong, asymmetrical RI was further supported by demographic analysis of these populations. Although the taxa are currently broadly sympatric, demographic modelling suggests that they initially diverged during a short period of geographical separation involving very low gene flow. Our study suggests that some geographical separation may kick-start the evolution of strong RI, facilitating subsequent coexistence of taxa in sympatry. The strength of RI needed to achieve sympatry and the subsequent effect of sympatry on RI remain open questions. This article is part of the theme issue ‘Towards the completion of speciation: the evolution of reproductive isolation beyond the first barriers'.

scholarly journals Noncompetitive Gametic Isolation between Sibling Species of Cricket: A Hypothesized Link between Within-Population Incompatibility and Reproductive Isolation between Species

2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
Jeremy L. Marshall ◽  
Nicholas DiRienzo
Keyword(s):  
Reproductive Isolation ◽  
Sibling Species ◽  
Reproductive Tract ◽  
Egg Laying ◽  
Female Reproductive Tract ◽  
Common Mechanism ◽  
Species Divergence ◽  
Genetic Pathway ◽  
Genetic Tests

Postmating, prezygotic phenotypes are a common mechanism of reproductive isolation. Here, we describe the dynamics of a noncompetitive gametic isolation phenotype (namely, the ability of a male to induce a female to lay eggs) in a group of recently diverged crickets that are primarily isolated from each other by this phenotype. We not only show that heterospecific males are less able to induce females to lay eggs but that there are male by female incompatibilities in this phenotype that occur within populations. We also identify a protein in the female reproductive tract that correlates with the number of eggs that she was induced to lay. Functional genetic tests using RNAi confirm that the function of this protein is linked to egg-laying induction. Moreover, the dysfunction of this protein appears to underlie both within-population incompatibilities and between-species divergence—thus suggesting a common genetic pathway underlies both. However, this is only correlative evidence and further research is needed to assess whether or not the same mutations in the same genes underlie variation at both levels.

scholarly journals Beneficial worm allies warn plants of parasite attack belowground and reduce aboveground herbivore preference and performance

2021 ◽  
Author(s):  
Shokoofeh Kamali ◽  
Ali Javadmanesh ◽  
Lukasz Stelinski ◽  
Tina Kyndt ◽  
Alireza seifi ◽  
...  
Keyword(s):  
Gene Expression ◽  
Plant Defense ◽  
Host Preference ◽  
Root Zone ◽  
Defense Responses ◽  
Egg Laying ◽  
Steinernema Feltiae ◽  
Systemic Resistance ◽  
Guaiacol Peroxidase ◽  
And Performance

We investigated responses of tomato to two functional guilds of nematodes - plant parasite (Meloidogyne javanica) and entomopathogens (Heterorhabditis bacteriophora, Steinernema feltiae belowground, and S. carpocapsae) - as well as a leaf mining insect (Tuta absoluta) aboveground. Our results indicate that entomopathogenic nematodes (EPNs): 1) induced plant defense responses, 2) reduced root knot nematode (RKN) infestation belowground and 3) reduced herbivore (T. absoluta) host preference and performance aboveground. Concurrently, we investigated the plant signaling mechanisms underlying these interactions using biochemical and transcriptome analyses. We found that both entomopathogen and parasite triggered immune responses in plant roots with shared gene expression. Tomato plants responded similarly to presence of RKN or EPN in the root zone, by rapidly activating polyphenol oxidase (PPO) and guaiacol peroxidase (GP) activity in roots, but simultaneously suppressed this activity in aboveground tissues. We quantified changes in gene expression in tomato that may play essential roles in defense response to RKN, which were also coincidentally triggered by EPN. Overall, EPN inoculation directly mediated enhanced plant defense and reduced subsequent RKN infection. Likewise, we show that EPNs modulate plant defense against RKN invasion. Inoculation of tomato roots with EPNs belowground reduced both host preference and performance of the aboveground herbivore, T. absoluta. Inoculations of roots with EPN also triggered an immune response in tomato which could explain an observed decrease in egg laying and developmental performance exhibited by herbivores on EPN-inoculated plants. Our results support the hypothesis that subterranean EPNs activate a battery of plant defenses associated with systemic acquired resistance (SAR) and/or induced systemic resistance (ISR) with antagonistic effects on temporally co-occurring subterranean plant pathogenic nematodes a

Experimental increase in female mass during the fertile phase leads to enhanced extra-pair paternity in pied flycatchers Ficedula hypoleuca

2019 ◽  
Author(s):  
Mireia Plaza ◽  
Alejandro Cantarero ◽  
Juan Moreno
Keyword(s):  
Negative Relationship ◽  
Ficedula Hypoleuca ◽  
Egg Laying ◽  
Female Dominance ◽  
Laying Date ◽  
Control Group ◽  
Wing Loading ◽  
Potential Fecundity ◽  
Fertile Phase ◽  
Extra Pair Paternity

Female mass in most altricial birds reaches its maximum during breeding at egg-laying, which coincides temporally with the fertile phase when extra-pair paternity (EPP) is determined. Higher mass at laying may have two different effects on EPP intensity. On the one hand, it would lead to increased wing loading (body mass/wing area), which may impair flight efficiency and thereby reduce female’s capacity to resist unwanted extra-pair male approaches (sexual conflict hypothesis). On the other hand, it would enhance female condition, favouring her capacity to evade mate-guarding and to search for extra-pair mates (female choice hypothesis). In both cases, higher female mass at laying may lead to enhanced EPP. To test this prediction, we reduced nest building effort by adding a completely constructed nest in an experimental group of female pied flycatchers (Ficedula hypoleuca). Our treatment caused an increase in mass and thereby wing loading and this was translated into a significantly higher EPP in the manipulated group compared with the control group as expected. There was also a significant negative relationship between EPP and laying date and the extent of the white wing patch, an index of female dominance. More body reserves at laying mean not only a higher potential fecundity but a higher level of EPP as well. This interaction had not previously received due attention but should be considered in future studies of avian breeding strategies.

Elevated nest predation risk promotes offspring size variation in birds with prolonged parental care.

2019 ◽  
Author(s):  
Gretchen F. Wagner ◽  
Emeline Mourocq ◽  
Michael Griesser
Keyword(s):  
Predation Risk ◽  
Reproductive Cycle ◽  
Perceived Risk ◽  
Nest Predation ◽  
Bird Species ◽  
Size Variation ◽  
Egg Laying ◽  
Offspring Size ◽  
Natural Predation ◽  
Risk Spreading

Predation of offspring is the main cause of reproductive failure in many species, and the mere fear of offspring predation shapes reproductive strategies. Yet, natural predation risk is ubiquitously variable and can be unpredictable. Consequently, the perceived prospect of predation early in a reproductive cycle may not reflect the actual risk to ensuing offspring. An increased variance in investment across offspring has been linked to breeding in unpredictable environments in several taxa, but has so far been overlooked as a maternal response to temporal variation in predation risk. Here, we experimentally increased the perceived risk of nest predation prior to egg-laying in seven bird species. Species with prolonged parent-offspring associations increased their intra-brood variation in egg, and subsequently offspring, size. High risk to offspring early in a reproductive cycle can favour a risk-spreading strategy particularly in species with the greatest opportunity to even out offspring quality after fledging.

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