scholarly journals Can cryptic female choice prevent invasive hybridization in external fertilizing fish?

2021 ◽  
Author(s):  
Tyler H. Lantiegne ◽  
Craig F. Purchase
Keyword(s):  
Sperm Competition ◽  
Female Choice ◽  
North American ◽  
Native Species ◽  
Salmo Trutta ◽  
Swimming Performance ◽  
Cryptic Female Choice ◽  
Swimming Velocity ◽  
Reproductive Tactics ◽  
The North

Polyandrous mating systems result in females mating with multiple males. This includes the potential for unintended matings and subsequent sperm competition with hybridizing species, especially in the presence of alternative reproductive tactics (sneaker males). Cryptic female choice allows females to bias paternity towards preferred males under sperm competition and may include conspecific sperm preference when under hybridization threat. The potential becomes particularly important in context of invasive species that can novelly hybridize with natives. We provide the first examination of conspecific sperm preference in a system of three species with potential to hybridize: North American native Atlantic salmon (Salmo salar) and brook char (Salvelinus fontinalis), and invasive brown trout (Salmo trutta) from Europe. Using naturalized populations on the island of Newfoundland, we measured changes in sperm swimming performance, a known predictor of paternity, to determine the degree of upregulation to female cues related to conspecific sperm preference. Compared to water alone, female ovarian fluid in general had a pronounced effect and upregulated sperm motility (mean 53%) and swimming velocity (mean 30%). However, patterns in the degree of upregulation suggest there is no conspecific sperm preference in the North American populations. Furthermore, female cues from both native species tended to boost the sperm of invasive males more than their own. We conclude that cryptic female choice is too weak in this system to prevent invasive hybridization and is likely insufficient to promote or maintain reproductive isolation between the native species.

Post-Copulatory Sexual Selection

2021 ◽  
Author(s):  
Patricia L.R. Brennan ◽  
Dara N. Orbach
Keyword(s):  
Sexual Selection ◽  
Sperm Competition ◽  
Female Choice ◽  
Reproductive Tract ◽  
Seminal Fluid ◽  
Fertilization Success ◽  
Female Reproductive Tract ◽  
Cryptic Female Choice ◽  
Trade Offs ◽  
Morphological Criteria

The field of post-copulatory sexual selection investigates how female and male adaptations have evolved to influence the fertilization of eggs while optimizing fitness during and after copulation, when females mate with multiple males. When females are polyandrous (one female mates with multiple males), they may optimize their mating rate and control the outcome of mating interactions to acquire direct and indirect benefits. Polyandry may also favor the evolution of male traits that offer an advantage in post-copulatory male-male sperm competition. Sperm competition occurs when the sperm, seminal fluid, and/or genitalia of one male directly impacts the outcome of fertilization success of a rival male. When a female mates with multiple males, she may use information from a number of traits to choose who will sire her offspring. This cryptic female choice (CFC) to bias paternity can be based on behavioral, physiological, and morphological criteria (e.g., copulatory courtship, volume and/or composition of seminal fluid, shape of grasping appendages). Because male fitness interests are rarely perfectly aligned with female fitness interests, sexual conflict over mating and fertilization commonly occur during copulatory and post-copulatory interactions. Post-copulatory interactions inherently involve close associations between female and male reproductive characteristics, which in many species potentially include sperm storage and sperm movement inside the female reproductive tract, and highlight the intricate coevolution between the sexes. This coevolution is also common in genital morphology. The great diversity of genitalia among species is attributed to sexual selection. The evolution of genital attributes that allow females to maintain reproductive autonomy over paternity via cryptic female choice or that prevent male manipulation and sexual control via sexually antagonistic coevolution have been well documented. Additionally, cases where genitalia evolve through intrasexual competition are well known. Another important area of study in post-copulatory sexual selection is the examination of trade-offs between investments in pre-copulatory and post-copulatory traits, since organisms have limited energetic resources to allocate to reproduction, and securing both mating and fertilization is essential for reproductive success.

scholarly journals Crayfish plague affects juvenile survival and adult behaviour of invasive signal crayfish

Parasitology ◽  
2020 ◽  
Vol 147 (6) ◽  
pp. 706-714 ◽  
Author(s):  
John Rhidian Thomas ◽  
Chloe V. Robinson ◽  
Agata Mrugała ◽  
Amy R. Ellison ◽  
Emily Matthews ◽  
...  
Keyword(s):  
North American ◽  
Native Species ◽  
North American Species ◽  
Juvenile Survival ◽  
Signal Crayfish ◽  
Aphanomyces Astaci ◽  
The North ◽  
High Infection ◽  
Oomycete Pathogen ◽  
The Impact

AbstractThe spread of invasive, non-native species is a key threat to biodiversity. Parasites can play a significant role by influencing their invasive host's survival or behaviour, which can subsequently alter invasion dynamics. The North American signal crayfish (Pacifastacus leniusculus) is a known carrier of Aphanomyces astaci, an oomycete pathogen that is the causative agent of crayfish plague and fatal to European crayfish species, whereas North American species are considered to be largely resistant. There is some evidence, however, that North American species, can also succumb to crayfish plague, though how A. astaci affects such ‘reservoir hosts’ is rarely considered. Here, we tested the impact of A. astaci infection on signal crayfish, by assessing juvenile survival and adult behaviour following exposure to A. astaci zoospores. Juvenile signal crayfish suffered high mortality 4-weeks post-hatching, but not as older juveniles. Furthermore, adult signal crayfish with high-infection levels displayed altered behaviours, being less likely to leave the water, explore terrestrial areas and exhibit escape responses. Overall, we reveal that A. astaci infection affects signal crayfish to a much greater extent than previously considered, which may not only have direct consequences for invasions, but could substantially affect commercially harvested signal crayfish stocks worldwide.

5. Sexual selection after mating

2018 ◽  
pp. 69-87
Author(s):  
Leigh W. Simmons
Keyword(s):  
Sexual Selection ◽  
Sperm Competition ◽  
Female Choice ◽  
Reproductive Tract ◽  
Multiple Mating ◽  
Reproductive Traits ◽  
Cryptic Female Choice ◽  
Mate Acquisition ◽  
Evolutionary Consequences

Darwin viewed sexual selection as a process that ended with mate acquisition, assuming that females are fundamentally monogamous, mating with just one male. ‘Sexual selection after mating’, however, shows this assumption to be false. Sexual selection continues long after the physical act of mating is over, as sperm compete inside a female’s reproductive tract and females bias the paternity of their young by selectively using sperm from particular males. Multiple mating by females has turned out to be ubiquitous across animal taxa. The far-reaching evolutionary consequences of sperm competition and cryptic female choice for the evolution of reproductive traits are examined, from the gametes themselves to the adult organisms producing them.

scholarly journals Post-copulatory opportunities for sperm competition and cryptic female choice provide no offspring fitness benefits in externally fertilizing salmon

2016 ◽  
Vol 3 (3) ◽  
pp. 150709 ◽  
Author(s):  
Alyson J. Lumley ◽  
Sian E. Diamond ◽  
Sigurd Einum ◽  
Sarah E. Yeates ◽  
Danielle Peruffo ◽  
...  
Keyword(s):  
Sperm Competition ◽  
Female Choice ◽  
Life Stage ◽  
Cryptic Female Choice ◽  
Growth And Survival ◽  
Offspring Fitness ◽  
Natural Streams ◽  
Fitness Benefits ◽  
Similar Survival

There is increasing evidence that females can somehow improve their offspring fitness by mating with multiple males, but we understand little about the exact stage(s) at which such benefits are gained. Here, we measure whether offspring fitness is influenced by mechanisms operating solely between sperm and egg. Using externally fertilizing and polyandrous Atlantic salmon ( Salmo salar ), we employed split-clutch and split-ejaculate in vitro fertilization experiments to generate offspring using designs that either denied or applied opportunities for sperm competition and cryptic female choice. Following fertilizations, we measured 140 days of offspring fitness after hatch, through growth and survival in hatchery and near-natural conditions. Despite an average composite mortality of 61%, offspring fitness at every life stage was near-identical between groups fertilized under the absence versus presence of opportunities for sperm competition and cryptic female choice. Of the 21 551 and 21 771 eggs from 24 females fertilized under monandrous versus polyandrous conditions, 68% versus 67.8% survived to the 100-day juvenile stage; sub-samples showed similar hatching success (73.1% versus 74.3%), had similar survival over 40 days in near-natural streams (57.3% versus 56.2%) and grew at similar rates throughout. We therefore found no evidence that gamete-specific interactions allow offspring fitness benefits when polyandrous fertilization conditions provide opportunities for sperm competition and cryptic female choice.

Sperm competition: evolutionary causes and consequences

1995 ◽  
Vol 7 (4) ◽  
pp. 755 ◽  
Author(s):  
TR Birkhead
Keyword(s):  
Sperm Competition ◽  
Zebra Finch ◽  
Female Choice ◽  
Temporal Pattern ◽  
Cryptic Female Choice ◽  
Optimal Time ◽  
Optimal Timing ◽  
Sperm Precedence ◽  
Male And Female ◽  
Ejaculate Size

The interaction between functional and mechanistic approaches to sperm competition and between male and female perspectives are described and illustrated by a study of the zebra finch, Taeniopygia guttata. Sperm competition experiments in the laboratory show that last male sperm precedence occurs (as it does in many other taxa) although the mechanism is unknown (as in most other taxa). Empirically-derived values were used to construct a mathematical model of sperm competition in the zebra finch. The model indicates that precedence occurs as a consequence of: (i) the temporal pattern of pair copulations; (ii) the rate at which sperm are lost from the female tract; and (iii) more sperm being transferred during extra-pair copulations than during pair copulations. The latter effect is a consequence of males seeking extra-pair copulations after their own pair copulation period has ended. The effect of sperm numbers on the pattern of sperm precedence may be further increased by: (i) extra-pair males increasing ejaculate size (sperm numbers) (for which there is no evidence); (ii) extra-pair males being of a better quality and transferring more sperm or better quality sperm (for which there is some evidence); and (iii) cryptic female choice. Females eject over 99% of sperm following insemination; if they eject fewer sperm from males chosen as extra-pair copulation partners, the potential for cryptic female choice is considerable. However, this is still being investigated. The model also predicts the optimal time for an extra-pair copulation to occur (from either a male or female perspective). A comparison between the predicted and observed pattern suggests that the optimal timing of extra-pair copulations is constrained in both sexes.

scholarly journals Effects of ovarian fluid on sperm traits and its implications for cryptic female choice in zebrafish

2019 ◽  
Vol 30 (5) ◽  
pp. 1298-1305 ◽  
Author(s):  
Federica Poli ◽  
Simone Immler ◽  
Clelia Gasparini
Keyword(s):  
Sperm Motility ◽  
Female Choice ◽  
Swimming Performance ◽  
Fertilization Success ◽  
Cryptic Female Choice ◽  
Ovarian Fluid ◽  
Opposite Pattern ◽  
Key Factor ◽  
Substantial Control

AbstractIn polyandrous mating systems, females maintain the opportunity to bias male fertilization success after mating in a process known as cryptic female choice. Mechanisms of cryptic female choice have been described both in internal and external fertilizers, and may affect fertilization processes at different stages before, during, and after fertilization. In internal fertilizers, females have substantial control over sperm storage and fertilization, whereas in external fertilizers, female control is limited. A key factor proposed to mediate cryptic female choice is the fluid surrounding the eggs, the ovarian fluid, as it may directly affect sperm performance. Here, we studied the role of ovarian fluid in post-mating sexual selection using the zebrafish, Danio rerio. Firstly, we assessed how ovarian fluid affects sperm swimming performance compared with freshwater. We focused on sperm motility, velocity, swimming trajectory, and longevity, all traits associated with competitive fertilization success in externally fertilizing fish. In a second step, we used a North Carolina II design to explore female, male, and female x male effects by testing sperm motility of 2 males in the ovarian fluid of 2 females in a total of 11 blocks. Our results indicate that the ovarian fluid affects sperm performance differently from freshwater. Specifically, sperm velocity, motility, and longevity were higher in the ovarian fluid than in freshwater, whereas sperm linearity and beat cross frequency showed the opposite pattern. Moreover, these effects varied according to male, female, and male x female identities, supporting the potential for cryptic female choice mediated by ovarian fluid in this species.

The separation of Betulapopulifolia and Betulapendula and their status in Ontario

1988 ◽  
Vol 18 (8) ◽  
pp. 1017-1026 ◽  
Author(s):  
P. M. Catling ◽  
K. W. Spicer
Keyword(s):  
North American ◽  
Native Species ◽  
Hybrid Population ◽  
Width Ratio ◽  
The North ◽  
Quantitative Characters ◽  
Length Width ◽  
Qualitative Characters ◽  
Discriminant Analyses ◽  
Resin Glands

The North American Betulapopulifolia differs from the European Betulapendula in having a larger number of peltate resin glands on greyish twigs, leaves with long–caudate tips, and a dense pubescence on the adaxial surface of the pistillate scales. Furthermore, B. populifolia is a plant of acid, peaty, or sandy substrates, whereas B. pendula grows in acid to neutral or occasionally slightly alkaline substrates. The bark of B. pendula exfoliates in long thin strands, whereas in B. populifolia it exfoliates as small, very thin rectangular flakes or appears not to exfoliate at all. The basal parts of older trunks of B. pendula often develop vertical fissures, which never develop in B. populifolia. Analysis of variance suggests that the most useful quantitative characters for distinguishing the two species are scale width and the length/width ratio of the terminal one-quarter of the leaf. Several other quantitative characters are useful discriminators but are not entirely reliable by themselves. Discriminant analyses with and without qualitative characters separated a sample of North American B. populifolia from a sample of European B. pendula. The derived discriminant formula placed many members of a variable natural population from near Ottawa in an intermediate position, suggesting hybridization. The use of heavily weighted qualitative characters in the discriminant formula placed much of the hybrid population in the B. populifolia group, whereas the use of quantitative characters alone placed much of the hybrid population in the B. pendula group. As putative hybrids are being widely distributed by nurseries, the identification of the two species is likely to become increasingly problematic. Betulapendula is a widespread and naturally spreading escape from cultivation in southern Ontario, while B. populifolia is a native species confined in Ontario to the eastern portion of the province between the Ottawa and St. Lawrence rivers, with a possible outlier in Elgin County in southwestern Ontario.

Sign in / Sign up

Export Citation Format

Share Document