scholarly journals Sperm allocation in relation to female size in a semelparous salmonid

2016 ◽  
Vol 3 (12) ◽  
pp. 160497 ◽  
Author(s):  
Yuya Makiguchi ◽  
Masaki Ichimura ◽  
Takenori Kitayama ◽  
Yuuki Kawabata ◽  
Takashi Kitagawa ◽  
...  

To maximize reproductive success, males have to adaptively tailor their sperm expenditure in relation to the quality of potential mates because they require time to replenish their sperm supply for subsequent mating opportunities. Therefore, in mating contexts where males must choose among females in a short period of time, as is the case with semelparous species (which die after one intensely competitive short duration breeding season), selection on sperm allocation can be expected to be a powerful selective agent that shapes the male reproductive success. We quantitatively investigated sperm allocation patterns in chum salmon in relation to perceived female quality by developing a novel method for determining the amount of sperm allocated per ejaculate during spawning bouts. We examined the relationship between sperm expenditure and the body size of paired females (a proxy of egg number and egg quality) in the absence of male–male competition in an experimental channel. The estimated amount of sperm released per spawning event was positively correlated with the size of paired females. However, the number of spawning events a female participated in, which reduces the number of eggs she spawns in each subsequent bout, did not affect this relationship. These results provide support for predictions arising from the sperm allocation hypothesis, male salmon do economize their sperm expenditure in accordance with paired female body size as predicted for their first spawning event, but males overestimate or are unable to assess the quality of females beyond size and provide more sperm than they should in theory when paired with a female that spawned previously. Overall, the observed sperm allocation pattern in chum salmon appears to be adapted to maximize reproductive success assuming female size is an honest indicator of quality, although temporal changes in a female's quality during a reproductive season should be considered when examining sperm allocation strategies.

2008 ◽  
Vol 65 (7) ◽  
pp. 1191-1197 ◽  
Author(s):  
A. Bang ◽  
P. Grønkjær ◽  
B. Lorenzen

Abstract Bang, A., Grønkjær, P., and Lorenzen, B. 2008. The relation between concentrations of ovarian trace elements and the body size of Atlantic cod Gadus morhua. – ICES Journal of Marine Science, 65: 1191–1197. Trace metals in the ovaries of fish are transferred from the female via the yolk to the offspring, which makes the early life stages susceptible to deleterious effects of potentially toxic elements contained in the ovaries. Here, the concentrations of 13 elements from the ovaries of 133 ripe female North Sea cod Gadus morhua weighing 0.2–18 kg were correlated with female size, accounting for differences in maturity and condition. Most elements were negatively correlated with the size variables weight, length and, especially, ovarian dry weight. Further, they were negatively correlated with maturity and condition. Many of the trace elements showed true size-dependence, but the correlations were generally weak. A linear discriminant analysis separated “small” and “large” fish at a length of 85 cm based on concentrations of Co, Mn, Se, and Zn, and correctly assigned 78 of 102 small fish and 23 of 31 large fish to their respective size category. This corresponds to an overall classification success of 75.9%. The results suggest that embryos and early larvae from small females are exposed to higher levels of potentially harmful metals. If the differences in trace element concentration influence survival success, this will add to the negative effects of size distribution truncation and declines in size-at-maturity experienced by many populations of cod.


2017 ◽  
Author(s):  
Wolf U. Blanckenhorn

AbstractA Preprint reviewed and recommended by Peer Community Evolutionary Biology: http://dx.doi.org/10.24072/pci.evolbiol.100027Evidence for selective disadvantages of large body size remains scarce in general. Previous phenomenological studies of the yellow dung fly Scathophaga stercoraria have demonstrated strong positive sexual and fecundity selection on male and female size. Nevertheless, the body size of flies from a Swiss study population has declined by almost 10% from 1993 to 2009. Given substantial heritability of body size, this negative evolutionary response of an evidently positively selected trait suggests important selective factors being missed (e.g. size-selective predation or parasitism). A periodic epidemic outbreak of the fungus Entomophthora scatophagae allowedassessment of selection exerted by this parasite fatal to adult flies. Fungal infection varied over the season from ca. 50% in the cooler and more humid spring and autumn to almost 0% in summer. The probability of dying from fungal infection increased with adult body size. All infected females died before laying eggs, so there was no fungus impact on female fecundity beyond its impact on mortality. Large males showed the typical mating advantage in the field, but this pattern of positive sexual selection was nullified by fungal infection. Mean fluctuating asymmetry of paired appendages (legs, wings) did not affect the viability, fecundity or mating success of yellow dung flies in the field. This study demonstrates rare parasite-mediated disadvantages of large adult body size in the field. Reduced ability to combat parasites such as Entomophthora may be an immunity cost of large size in dung flies, although the hypothesized trade-off between fluctuating asymmetry, a presumed indicator of developmental instability and environmental stress, and immunocompetence was not found here.


2012 ◽  
Vol 81 (4) ◽  
pp. 311-320 ◽  
Author(s):  
Jakub Michalcewicz ◽  
Michał Ciach

ABSTRACT.The body size of xylophagous beetles is determined by the host plant species, as well as by the amount and quality of breeding material. Consequently, the biometric traits of adults can be used as an indicator of the attractiveness of the breeding material and the quality of a habitat. The paper presents selected biometric traits of rosalia longicornRosalia alpina(L.) imagines in three populations from the Beskid Niski Mts (Carpathian Mts, south-eastern Poland). Two populations of this beetle from managed forests and one from a protected area in the Magura National Park were compared. The former developed on two different host plants (European beechFagus sylvaticaand wych elmUlmus glabra), the latter on European beech. No significant differences were found between the biometric traits of imagines from the three populations. No intersexual differences were found for the width of the pronotum in any of the populations, but females had longer elytra than males in all the populations. The lack of body size differences in these populations potentially indicates that this species occurs only in favourable habitat conditions. The limited species range and the patchy distribution of the rosalia longicorn are indications of its stringent habitat requirements and its dependence on forest management. Habitats supplying a sufficient amount and quality of suitable breeding material for the development of the rosalia longicorn should be protected.


1986 ◽  
Vol 56 (3) ◽  
pp. 615-623 ◽  
Author(s):  
D. V. Muralidhara ◽  
P. S. Shetty

1. Nutritional deprivation was induced preweaning in Wistar rats by increasing the litter size to sixteen, while paired litters with only five pups served as controls. The nutritionally deprived pups were rehabilitated after weaning by ad lib. access to an adequate diet.2. The body-weights and body lengths were significantly lower in the nutritionally deprived group and significant differences persisted even after 9 weeks of rehabilitation.3. The body temperature of the nutritionally deprived animals was significantly lower than that of their paired controls, both before and following nutritional rehabilitation, except for a short period after weaning when the nutritionally deprived animals were initially given the diet ad lib.4. The resting oxygen consumption of the nutritionally deprived animals was comparable to that of the controls when corrected for metabolic body size, both before and after weaning. Noradrenaline-stimulated increase in 02 consumption (non-shivering thermogenesis; NST) was reduced by 50% at weaning in the nutritionally deprived animals and returned to levels comparable to those of controls within a short period of rehabilitation.5. The decrease in NST capacity seen in the nutritionally deprived animals was associated with an inability to thermoregulate when exposed to cold (5°), resulting in death. Cold-induced thermogenesis (CIT) also reappeared soon after nutritional rehabilitation.6. Reduction in metabolic rate, NST and CIT seen in the animals nutritionally deprived preweaning was short-lived and disappeared soon after nutritional rehabilitation. Rapid reversal of these physiological changes indicates that they do not confer any long-term benefit or change in metabolic efficiency and are unlike the changes in body size and growth which do not completely recover following nutritional rehabilitation.


1998 ◽  
Vol 76 (10) ◽  
pp. 1815-1821 ◽  
Author(s):  
W J Loughry ◽  
Paulo A Prodöhl ◽  
Colleen M McDonough ◽  
W S Nelson ◽  
John C Avise

We used microsatellite DNA markers to identify the putative parents of 69 litters of nine-banded armadillos (Dasypus novemcinctus) over 4 years. Male and female parents did not differ in any measure of body size in comparisons with nonparents. However, males observed paired with a female were significantly larger than unpaired males, although paired females were the same size as unpaired females. Females categorized as possibly lactating were significantly larger than females that were either definitely lactating or definitely not lactating. There was no evidence of assortative mating: body-size measurements of mothers were not significantly correlated with those of fathers. Nine-banded armadillos give birth to litters of genetically identical quadruplets. Mothers (but not fathers) of female litters were significantly larger than mothers of male litters, and maternal (but not paternal) body size was positively correlated with the number of surviving young within years, but not cumulatively. There were no differences in dates of birth between male and female litters, nor were there any significant relationships between birth date and maternal body size. Body size of either parent was not correlated with the body sizes of their offspring. Cumulative and yearly reproductive success did not differ between reproductively successful males and females. Average reproductive success (which included apparently unsuccessful individuals) also did not differ between males and females. The majority of adults in the population apparently failed to produce any surviving offspring, and even those that did usually did so in only 1 of the 4 years. This low reproductive success is unexpected, given the rapid and successful range extension of this species throughout the southeastern United States in this century.


1984 ◽  
Vol 62 (3) ◽  
pp. 381-385 ◽  
Author(s):  
W. Bruce McGillivray

Much of the variance in feeding rates of nestlings by adult House Sparrows (Passer domesticus) at Calgary, Alberta appears to be due to individual variation in the quality of the parents. Males contribute less to nestling feeding than do males at other localities. The body size and sexual size dimorphism of House Sparrows has been shown to increase with increasing latitude in North America. Hence, sparrows at Calgary are larger than average and there is a suggestion that the relative contribution by the sexes is related to male size and concomitant energetic limitations. The relationship between weight and body size is strong in the fall for both male and female House Sparrows but is poor during the breeding season. Adult females, but not males, increase their nestling feeding rate in inclement weather.


2021 ◽  
Vol 32 ◽  
pp. 04003
Author(s):  
Ludmila Samusenko ◽  
Andrey Mamaev ◽  
Natalya Rodina ◽  
Ekaterina Sergeeva

For modern cattle industry, it is very important to evaluate bull-sires of different breeds by semen quality. The relevance of this problem arises in the context of development of artificial insemination technologies and biotechnology, the increasing role of sire-bulls in the genetic improvement of the herd, which makes it possible to significantly change the breed composition of herds in large regions in a short period of time. In cattle breeding, sires of Black-and-white and Holstein black-and-white breeds, which are imported into the Russian Federation, are used almost throughout the country. The purpose of the study is to assess the practical possibility of using the measured data of the bioelectric potential of superficially localized biologically active centres of sire-bulls to evaluate the quality of their semen production. The subject of the study was the semen production of the bulls of Black-and-white and Holstein blackand-white breeds. The groups were formed according to the principle of analogues; the bulls were from 2 to 4 years old; the body weight was from 700 to 800 kg. As a result of evaluating the sperm quality in sire-bulls with a high level of biopotential of the superficially localized biologically active centres, in the field of vision of the preparation, spermatozoa with an intact acrosome were found, which amounted to 96.5% of the total number of spermatozoa of the preparation and had a significant difference with the experimental group. The use of bioenergetic data of the superficially localized biologically active centres makes it possible to evaluate the sperm quality before semen collection and thereby, reduce the time and labour costs for low-quality ejaculates culling.


The Auk ◽  
2007 ◽  
Vol 124 (3) ◽  
pp. 1010-1022 ◽  
Author(s):  
Michael T. Murphy

AbstractI report on the lifetime reproductive success (LRS) of female Eastern Kingbirds (Tyrannus tyrannus) in central New York. I investigated the major correlates of LRS and specifically tested the hypothesis that small body size yields reproductive benefits. Lifetime reproductive success varied widely: 15–20% of females failed to fledge young over their life, whereas 50% of young were fledged by 20% of females. Female lifespan varied between one and eight years, and females that died after one breeding season tended to be smaller-bodied than long-lived females (≥2 seasons). I therefore conducted analyses of LRS for the entire sample and for longer-lived females separately. As in other species, lifespan was the strongest predictor of LRS, followed by the proportion of eggs laid that resulted in fledged young (P). Lifetime reproductive success varied positively with clutch size and, as predicted, inversely with body size (i.e., tarsus length) of females. However, variance partitioning indicated that most variation in LRS was attributable to the effects of lifespan and P, but that a substantial negative covariance existed between lifespan and P. The latter result was consistent with experimental evidence of a cost of reproduction in Eastern Kingbirds. Analysis of the correlates of lifespan, P, and clutch size showed that over a female's lifetime, (1) the longest-lived birds fledged an intermediate proportion of the eggs that they laid, (2) the most productive birds were of intermediate wing length, and (3) females with small tarsi produced the largest clutches and lost the fewest nests to predators. Hence, although lifespan was the dominant influence on LRS, negative effects of large female size appeared to be expressed through the influence of body size on other demographic parameters that contribute to LRS.Éxito Reproductivo Completo de Vida de Hembras de Tyrannus tyrannus: Influencia de la Duración de la Vida, la Depredación de Nidos y el Tamaño Corporal


Crustaceana ◽  
2017 ◽  
Vol 90 (7-10) ◽  
pp. 1061-1078 ◽  
Author(s):  
Mariana Negri ◽  
Tatiana Magalhães ◽  
Natália Rossi ◽  
Darryl L. Felder ◽  
Fernando L. Mantelatto

The shrimpCuapetes americanusis widely distributed in shallow waters of the western Atlantic Ocean, inhabiting sandy and rocky bottoms, macroalgae, seagrass beds, and mangrove roots. As the life cycle and ecology of this species remain poorly known, we investigated some reproductive traits of this species at Bocas del Toro, Panama. We collected and examined 167 individuals (63 males, 58 non-ovigerous females and 46 ovigerous females). Although males numerically dominated the larger size classes, ovigerous females were significantly larger than males and non-ovigerous females. All 46 ovigerous females were used to calculate embryo loss and embryo volume increase. Only females with eggs at an initial developmental stage () were used to estimate fecundity and reproductive output. A mean of 75.84 ± 40.16 embryos () occurred per female, a value near those reported for other species of Pontoniinae. A positive correlation between fecundity and female body size was observed, but it lacked significance. Likewise, a significant correlation between female body size and embryo volume was not detected. Embryo volume increased 35%, and females lost 26% of embryos on average during the incubation period, though significant changes were measurable only during early embryonic development. Mean reproductive output in the analysed reproductive event (0.22 ± 0.11, ) suggested a rate of energy investment in reproduction higher than average, as compared to females of most other decapods. A decrease in relative reproductive output was observed with the increase of female size, indicating that larger females were investing proportionally less energy in reproduction than smaller ones, when measured in relation to the body size, but this correlation also lacked significance. We review how these initial insights on reproduction ofC. americanusat Bocas del Toro compare to those of other populations in various localities.


2019 ◽  
Vol 66 (3) ◽  
pp. 285-292 ◽  
Author(s):  
Kambiz Esfandi ◽  
Xiong Z He ◽  
Qiao Wang

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.


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