Multiple Fertilization and Consecutive Spawning in Large American Lobsters, Homarus americanus

1986 ◽  
Vol 43 (11) ◽  
pp. 2291-2294 ◽  
Author(s):  
S. L. Waddy ◽  
D. E. Aiken
Keyword(s):  
Body Size ◽  
Carapace Length ◽  
Homarus Americanus ◽  
Large Female ◽  
Bay Of Fundy ◽  
Relative Fecundity ◽  
Logarithmic Relationship

Large female American lobsters, Homarus americanus (> 120 mm carapace length), maintained at nearshore Bay of Fundy temperatures often spawn twice without an intervening molt (consecutive spawning). Consecutive spawning occurs in two forms: successive-year (spawning in two successive summers, a molt in the first and fourth years) and alternate-year (spawning in alternate summers, a molt in the first and fifth years). In both types, females often are able to fertilize the two successive broods with the sperm from a single insemination (multiple fertilization). Twenty of 21 large females that were held for up to 13 yr displayed one of these types of consecutive spawning. Consecutive spawning and multiple fertilization enable large lobsters to spawn more frequently over the long term than their smaller counterparts. This, combined with the logarithmic relationship between body size and numbers of eggs produced, means that very large lobsters have a much greater relative fecundity than previously thought.

Growth of Tagged American Lobsters, Homarus americanus, in the Bay of Fundy

1983 ◽  
Vol 40 (10) ◽  
pp. 1667-1675 ◽  
Author(s):  
Alan Campbell
Keyword(s):  
Carapace Length ◽  
Growth Curves ◽  
Homarus Americanus ◽  
Multiple Regression Model ◽  
Growth Increment ◽  
Bay Of Fundy ◽  
Von Bertalanffy ◽  
Immature Female ◽  
Size Number ◽  
Empirical Growth

Sphyrion-tagged lobsters recaptured in the Bay of Fundy during 1977–80 yielded mean annual molt increment and molt probability data for male and female lobsters of 60–171 mm carapace length from which growth curves were calculated. In addition, a multiple regression model was used to generate growth curves from premolt size, number of molt periods lobsters were exposed to, and growth increment data for 850 tagged lobsters at liberty for 1–5 yr. Von Bertalanffy parameters were calculated from these empirical growth curves, which suggest that lobsters take 20–35 yr from time of hatching to reach 200 mm carapace length in the Bay of Fundy. Analysis of pleopods indicated that the majority of lobsters molt during August–October each year. Growth per molt of immature (60–94 mm carapace length) and mature (95–170 mm carapace length) male and immature female lobsters was arithmetic (regression slope 1.04) but was regressive for mature females (slope 0.95). Mature lobsters molted less frequently than immature lobsters, but mature males grew more rapidly than mature females. Most mature females in the Bay of Fundy are on a 2-yr molt–reproductive cycle. About 20% of ovigerous females recaptured within 2 yr after release had extruded eggs a second time without molting, confirming that multiple egg extrusions between molts do occur naturally.

scholarly journals Long-Term Changes in the Diet of Gymnogobius isaza from Lake Biwa, Japan: Effects of Body Size and Environmental Prey Availability

PLoS ONE ◽  
2012 ◽  
Vol 7 (12) ◽  
pp. e53167 ◽  
Author(s):  
Jonathan Carlo Briones ◽  
Cheng-Han Tsai ◽  
Takefumi Nakazawa ◽  
Yoichiro Sakai ◽  
Rey Donne S. Papa ◽  
...  
Keyword(s):  
Body Size ◽  
Lake Biwa ◽  
Prey Availability ◽  
Long Term Changes

Size–Maturity Relationships and Related Observations in Newfoundland Populations of the Lobster (Homarus americanus)

1980 ◽  
Vol 37 (6) ◽  
pp. 945-956 ◽  
Author(s):  
G. P. Ennis
Keyword(s):  
Carapace Length ◽  
Size Range ◽  
Sex Ratios ◽  
Weight Ratio ◽  
Homarus Americanus ◽  
Spawning Season ◽  
Length Ratio ◽  
Maturity Indices

Female maturity ogives for five Newfoundland populations of the lobster (Homarus americanus) gave 50% maturities ranging from 71- to 76-mm carapace length. Sizes at which distinct inflections (indicating onset of maturity) and asymptotes (indicating 100% mature) are present in the abdomen width/carapace length ratio vs. carapace length relationships coincide with the smallest ovigerous and largest immature specimens, respectively, observed in those particular samples. Inflection in the crusher claw weight/whole weight ratio vs. carapace length relationships (used in this paper to indicate onset of maturity in males) occurred at larger sizes than inflections in the abdomen width/carapace length ratios of females.The percentage of nonovigerous females that spawn in a given year generally increases with increasing size. The highest percentage of nonovigerous females tagged with sphyrion tags prior to the spawning season that were ovigerous when recaptured 10–12 mo later was 83.8%. The percentage of ovigerous females with new shells (i.e. molted and spawned in same year) varied between areas and years and ranged from 0 to 38.5% of the total number of ovigerous females in fall samples. The percentage of ovigerous females in samples also varied between areas and years and ranged from 2.6 to 30.4% of the total number of females greater than the size at 50% maturity. In general a greater percentage of females was ovigerous at sizes between the size at 50% maturity and 80 mm (largest subcommercial size) than at commercial sizes.In a sample of nonovigerous females, the size range at which 50% were fertilized (76–80 mm) coincided closely with the size at 50% maturity (75 mm) for the area.At subcommercial sizes (< 81 mm) the sexes were approximately equally represented in fall trap-caught samples but females heavily outnumbered males in diver-caught samples taken over the same period. At commercial sizes, however, males heavily outnumbered females in the trap-caught samples while in diver-caught samples the sexes were equally represented.Key words: lobster (Homarus americanus), maturity ogives, maturity indices, percent ovigerous, sex ratios

Mass extinctions alter extinction and origination dynamics with respect to body size

2021 ◽  
Vol 288 (1960) ◽  
Author(s):  
Pedro M. Monarrez ◽  
Noel A. Heim ◽  
Jonathan L. Payne
Keyword(s):  
Body Size ◽  
Mass Extinction ◽  
Evolutionary Biology ◽  
Marine Animal ◽  
Mass Extinctions ◽  
Extinction Selectivity ◽  
Extinction Events ◽  
Mass Extinction Events ◽  
Marine Biosphere

Whether mass extinctions and their associated recoveries represent an intensification of background extinction and origination dynamics versus a separate macroevolutionary regime remains a central debate in evolutionary biology. The previous focus has been on extinction, but origination dynamics may be equally or more important for long-term evolutionary outcomes. The evolution of animal body size is an ideal process to test for differences in macroevolutionary regimes, as body size is easily determined, comparable across distantly related taxa and scales with organismal traits. Here, we test for shifts in selectivity between background intervals and the ‘Big Five’ mass extinction events using capture–mark–recapture models. Our body-size data cover 10 203 fossil marine animal genera spanning 10 Linnaean classes with occurrences ranging from Early Ordovician to Late Pleistocene (485–1 Ma). Most classes exhibit differences in both origination and extinction selectivity between background intervals and mass extinctions, with the direction of selectivity varying among classes and overall exhibiting stronger selectivity during origination after mass extinction than extinction during the mass extinction. Thus, not only do mass extinction events shift the marine biosphere into a new macroevolutionary regime, the dynamics of recovery from mass extinction also appear to play an underappreciated role in shaping the biosphere in their aftermath.

Men's and Women's Mating Preferences: Distinct Evolutionary Mechanisms?

2002 ◽  
Vol 11 (3) ◽  
pp. 88-93 ◽  
Author(s):  
Lynn Carol Miller ◽  
Anila Putcha-Bhagavatula ◽  
William C. Pedersen
Keyword(s):  
Sexual Functioning ◽  
Large Female ◽  
Detailed Knowledge ◽  
Short Term ◽  
Evolutionary Mechanisms ◽  
Men And Women ◽  
Mating Preferences ◽  
Chemical Mechanisms ◽  
Species Comparisons

Have men and women evolved sex-distinct mating preferences for short-term and long-term mating, as postulated by some evolutionary theorists? Direct tests of assumptions, consideration of confounds with gender, and examination of the same variables for both sexes suggest men and women are remarkably similar. Furthermore, cross-species comparisons indicate that humans do not evidence mating mechanisms indicative of short-term mating (e.g., large female sexual skins, large testicles). Understanding human variability in mating preferences is apt to involve more detailed knowledge of the links between these preferences and biological and chemical mechanisms associated with sexual motivation, sexual arousal, and sexual functioning.

scholarly journals Metabolic plasticity can amplify ecosystem responses to global warming

2021 ◽  
Author(s):  
Rebecca Kordas ◽  
Samraat Pawar ◽  
Guy Woodward ◽  
Eoin O'Gorman
Keyword(s):  
Global Warming ◽  
Body Size ◽  
Predictive Models ◽  
Chronic Exposure ◽  
Ecosystem Respiration ◽  
Short Term ◽  
Ecosystem Responses ◽  
Metabolic Plasticity ◽  
Ecosystem Level

Abstract Organisms have the capacity to alter their physiological response to warming through acclimation or adaptation, but empirical evidence for this metabolic plasticity across species within food webs is lacking, and a generalisable framework does not exist for modelling its ecosystem-level consequences. Here we show that the ability of organisms to raise their metabolic rate following chronic exposure to warming decreases with increasing body size. Chronic exposure to higher temperatures also increases the sensitivity of organisms to short-term warming, irrespective of their body size. A mathematical model parameterised with these findings shows that metabolic plasticity could account for an additional 60% of ecosystem energy flux with just +2 °C of warming. This could explain why ecosystem respiration continues to rise in long-term warming experiments and highlights the need to embed metabolic plasticity in predictive models of global warming impacts on ecosystems.

Long-term declines in body size and shifts in run timing of Atlantic salmon in Ireland

2006 ◽  
Vol 68 (6) ◽  
pp. 1713-1730 ◽  
Author(s):  
T. P. Quinn ◽  
P. McGinnity ◽  
T. F. Cross
Keyword(s):  
Body Size ◽  
Atlantic Salmon ◽  
And Shifts ◽  
Run Timing

Evolution of sexual dimorphism in the plateau brown frog fails to obey Rensch’s rule

2022 ◽  
pp. 27-33
Author(s):  
Tong Lei Yu
Keyword(s):  
Body Size ◽  
Large Male ◽  
Large Female ◽  
Female Size ◽  
Rensch’S Rule ◽  
Size Dimorphism ◽  
Rensch's Rule ◽  
Males And Females ◽  
Brown Frog ◽  
Using Data

Rensch’s rule describes sexual size dimorphism (SSD) that decreases with increasing body size when females are larger than males and SSD that increases when males are larger than females. The plateau brown frog Rana kukunoris, a species endemic to the eastern Tibetan Plateau, exhibits female-biased size dimorphism. Using data on body size from 26 populations and age from 21 populations, we demonstrated that SSD did not increase with increasing mean female snout-vent length (SVL) when controlling for sex-specific age structure, failing to support the Rensch’s rule. Thus, we suggest that fecundity selection (favouring large female size) balances out sexual selection (favouring large male size), which results in a similar divergence between males and females body size. In addition, sex-specific age differences explained most of the variation of SSD across populations.

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