The Role of Jelly Coats in Sperm-Egg Encounters, Fertilization Success, and Selection on Egg Size in Broadcast Spawners

2001 ◽  
Vol 157 (6) ◽  
pp. 626
Author(s):  
Farley ◽  
Levitan
Keyword(s):  
Egg Size ◽  
Fertilization Success

Influence of density and major histocompatibility genotype on sexual selection in a salmonid alternative mating strategy

2012 ◽  
Vol 69 (4) ◽  
pp. 670-680 ◽  
Author(s):  
Laura K. Weir ◽  
Jeffrey A. Hutchings ◽  
Daniel D. Heath
Keyword(s):  
Sexual Selection ◽  
Salmo Salar ◽  
Fertilization Success ◽  
Mating Strategy ◽  
Male Mating ◽  
Salmonid Fishes ◽  
Major Histocompatibility ◽  
Main Determinant ◽  
Alternative Mating Strategy

Various mechanisms of sexual selection can occur at both the whole organism and gamete levels. Fertilization success in salmonid fishes is largely determined by behavioural competition within and between “fighter” and “sneaker” male strategies, but is also influenced by interactions among gametes. We investigated the influence of density, fighter male presence, and major histocompatibility (MH) genotype on patterns of fertilization success in sneaker Atlantic salmon ( Salmo salar ). At low density and in the absence of fighter males, monopolization by single sneaker males occurred, suggesting that male–male competition was the main determinant of fertilization success. By contrast, at high density and (or) in the presence of fighter males, several sneakers succeeded in fertilizing eggs. Our study, the first to investigate the role of MH-mediated fertilization for a genetically based alternative male mating strategy, suggests that a larger proportion of eggs were fertilized by sneakers whose MH genotypes were more similar to those of the female than expected by chance. These findings highlight the importance of examining sexual selection under different competitive conditions.

scholarly journals Fertilization ecology of egg coats: physicalversuschemical contributions to fertilization success of free-spawned eggs

2002 ◽  
Vol 205 (11) ◽  
pp. 1657-1668 ◽  
Author(s):  
Robert D. Podolsky
Keyword(s):  
Alternative Hypothesis ◽  
Chemical Constituents ◽  
Sperm Concentration ◽  
Fertilization Success ◽  
Target Size ◽  
Jelly Coat ◽  
Physical Attributes ◽  
Sperm Swimming Speed ◽  
Dendraster Excentricus

SUMMARYFree-spawned eggs are typically enclosed within accessory structures that are shed early in development. Most research on the role of these structures in fertilization has focused on chemical constituents and their influence on sperm—egg interaction. Here I test an alternative hypothesis that accessory structures play an important physical role in fertilization by increasing the size and buoyancy of the egg, making it a better target for sperm. In the sand dollar Dendraster excentricus, the jelly coat increases egg target size sixfold. At nonsaturating sperm concentrations,fertilization declined consistently following jelly coat removal by two independent methods. Regression analysis using a standard fertilization kinetics model found that 54-73% of this decline on average was predicted by changes in the rate of sperm—egg collision, resulting from changes in egg target size and density. Sperm swimming speed, a key parameter in the model, did not vary as a function of sperm concentration or exposure to egg-water. The organic cost of jelly is a fraction of that of the ovum,providing an efficient means of extending target size beyond the ovum size that is optimal for larval or juvenile development. These results support the hypothesis that physical attributes of jelly coats can account for a significant portion of their contribution to fertilization, and may help to explain why coats and other accessory structures are often substantially larger than expected from the nature of chemical interactions between egg and sperm.

scholarly journals Male size does not correlate with fertilization success in two bufonid toads that show size-assortative mating

2013 ◽  
Vol 59 (6) ◽  
pp. 740-746 ◽  
Author(s):  
Xiao-Li Fan ◽  
Zhi-Hua Lin ◽  
Xiang Ji
Keyword(s):  
Body Size ◽  
Assortative Mating ◽  
Clutch Size ◽  
Egg Size ◽  
Dry Mass ◽  
Fertilization Success ◽  
Male Body ◽  
Mating Pattern ◽  
Male Size ◽  
Male Preference

Abstract We examined sexual size dimorphism (SSD), mating pattern, fertilization efficiency and female reproductive traits in two bufonid toads (Bufo gargarizans and Duttaphrynus melanostictus) to test the idea that importance of male body size for egg fertilization success depends on the mating pattern. Female-biased SSD was evident only in D. melanostictus. Female B. gar-garizans laid fewer larger eggs nearly three months earlier than did female D. melanostictus. Fertilization efficiencies on average were higher in B. gargarizans (95%) than in D. melanostictus (91%). Though differing in the degree of SSD, body size, breeding season, clutch size, egg size and fertilization efficiency, the two toads were similar in four aspects: (1) both showed size-assortative mating; (2) females did not tradeoff egg size against egg number; (3) male size, clutch size and clutch dry mass were greater in male-larger than in female-larger pairs after accounting for female snout-vent length (SVL); and (4) the ratio of male to female SVL did not affect fertilization efficiency. Our data show that: (1) a female preference for large males is likely not important in terms of egg fertilization success; (2) a male preference for large females is likely important because larger females are more fecund; and (3) size-assortative mating arises from a male preference for large females. Our study demonstrates that male size is not always important for egg fertilization success in anurans that show size-assortative mating.

The role of calcium in constraining egg synthesis in the Audouin’s Gull (Ichthyaetus audouinii)

2013 ◽  
Vol 91 (9) ◽  
pp. 640-645 ◽  
Author(s):  
F. Ramirez ◽  
M. Garcia-Tarrasón ◽  
L. Rami ◽  
M. Genovart ◽  
L. Jover ◽  
...  
Keyword(s):  
Physiological Response ◽  
Reproductive Strategies ◽  
Egg Size ◽  
Potential Role ◽  
Size Variation ◽  
Eggshell Thickness ◽  
Egg Volume ◽  
Causal Inferences ◽  
The Relationship

Understanding how resources are allocated to form eggs is crucial to our better understanding of avian reproductive strategies. However, little is currently known about how egg synthesis in wild birds might be constrained by the availability of specific micronutrients. Here, we investigated the potential role of calcium (Ca) in constraining egg synthesis in the Audouin’s Gull (Ichthyaetus audouinii (Payraudeau, 1826)). In particular, we evaluated the relationship between plasma Ca levels (mg/dL) in incubating females (as an indicator of the physiological response of females to increased Ca demand associated with clutch production) and several fitness-related egg traits such as egg size (i.e., egg volume), egg shape, and eggshell thickness from three-egg clutches. Egg size was positively related with incubating female plasma Ca levels, with the slope of this relationship being significantly higher for later-laid eggs. The observational nature of this study and reversed timing precludes causal inferences, but observed relationships supported the constraining role of Ca in egg synthesis and suggested that Ca may also have a role in modulating the intraclutch pattern of egg-size variation typical of this gull species.

The proximate effects of food supply on intraclutch egg-size variation in American kestrels

1996 ◽  
Vol 74 (1) ◽  
pp. 118-124 ◽  
Author(s):  
Karen L. Wiebe ◽  
Gary R. Bortolotti
Keyword(s):  
Food Supply ◽  
Egg Size ◽  
Size Variation ◽  
Food Supplementation ◽  
Laying Order ◽  
American Kestrels ◽  
Good Body Condition ◽  
Adaptive Explanation ◽  
Food Shortages

Egg size can be an important determinant of offspring survival in birds. We measured eggs from 275 clutches of wild American kestrels (Falco sparverius) to study the degree of intraclutch variability in egg size. We also performed two food-supplementation experiments to investigate the proximate role of food supply during laying in determining egg size. Females with relatively abundant food and those in good body condition did not lay eggs that were more uniform in size than those laid by control females. This result is contrary to hypotheses that propose an adaptive explanation for intraclutch egg-size variation and also to ideas of energy depletion during laying. Patterns of egg size versus laying order were different between years, suggesting that females did not adaptively manipulate laying order and egg size within a clutch. The food-supplementation experiments showed that laying female kestrels probably depend on both stored energy reserves and on daily energy surpluses to form eggs. It appears that slight intraclutch variations in egg size occur in response to short-term food shortages during laying, but that these variations are probably nonadaptive. This is in marked contrast to interclutch (among females) variation in egg size, which we have shown varies significantly with food supply.

Significance of Intraclutch Egg-Size Variation in Common Eider: The Role of Egg Size and Quality of Ducklings

1998 ◽  
Vol 29 (1) ◽  
pp. 3 ◽  
Author(s):  
Kjell Einar Erikstad ◽  
Torkild Tveraa ◽  
Jan Ove Bustnes
Keyword(s):  
Egg Size ◽  
Size Variation ◽  
Common Eider
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