scholarly journals No early gender effects on energetic status and life history in a salmonid

2015 ◽  
Vol 2 (12) ◽  
pp. 150441 ◽  
Author(s):  
Thomas Régnier ◽  
Jacques Labonne ◽  
Joëlle Chat ◽  
Ayaka Yano ◽  
Yann Guiguen ◽  
...  
Keyword(s):  
Life History ◽  
Life Histories ◽  
Salmo Trutta ◽  
Significant Proportion ◽  
Early Life History ◽  
Gender Effects ◽  
Sexually Dimorphic ◽  
Males And Females ◽  
First Time ◽  
Gender Specific

Throughout an organism's early development, variations in physiology and behaviours may have long lasting consequences on individual life histories. While a large part of variation in critical life-history transitions remains unexplained, a significant proportion may be caused by early gender effects as part of gender-specific life histories shaped by sexual selection. In this study, we investigated the presence of early gender effects on the timing of emergence from gravel and the energetic status of brown trout ( Salmo trutta ) early stages. To investigate this question, individual measures of emergence timing, metabolic rate and energetic content were coupled for the first time with the use of a recent genetic marker for sdY (sexually dimorphic on the Y-chromosome), a master sex-determining gene. Our results show that gender does not influence the energetic content of emerging juveniles or their emergence timing. These findings suggest that gender differences may appear later throughout salmonid life history and that selective pressures associated with the critical period of emergence from gravel may shape early life-history traits similarly in both males and females.

Sex differences in melanotic encapsulation responses (immunocompetence) in the damselfly Lestes forcipatus Rambur

2002 ◽  
Vol 80 (9) ◽  
pp. 1578-1583 ◽  
Author(s):  
Christopher P Yourth ◽  
Mark R Forbes ◽  
Robert L Baker
Keyword(s):  
Sex Differences ◽  
Immune Responses ◽  
Life Histories ◽  
Mass Gain ◽  
Sexually Dimorphic ◽  
Foreign Objects ◽  
Males And Females ◽  
And Gender ◽  
Parasitic Mites ◽  
Melanotic Encapsulation

A few studies have shown that male and female invertebrates differ in immunity and that these differences appear related to differences in sexual dimorphism and gender differences in life histories. Melanotic encapsulation of foreign objects in insects is one form of immunity. The damselfly Lestes forcipatus Rambur is moderately sexually dimorphic, and much is known about patterns of mass gain in congeners relating to differences in life history between males and females. In this study, females were more immunoresponsive than males under controlled temperatures, following emergence, and at a time when parasitic mites were challenging these hosts. However, males and females that overlapped in mass at emergence did not differ in their immune responses. Males in better condition at emergence were more immunoresponsive than lighter males, but this relation was not found in females. Sex differences in immune expression may have implications for how females versus males are able to deal with challenges from parasites, under varying environmental conditions.

Spatially dynamic maternal control of migratory fish recruitment pulses triggered by shifting seasonal cues

2018 ◽  
Vol 69 (6) ◽  
pp. 942 ◽  
Author(s):  
Daisuke Goto ◽  
Martin J. Hamel ◽  
Mark A. Pegg ◽  
Jeremy J. Hammen ◽  
Matthew L. Rugg ◽  
...  
Keyword(s):  
Life History ◽  
Early Life ◽  
Life Histories ◽  
Egg Production ◽  
Local Density ◽  
Early Life History ◽  
Biophysical Model ◽  
Larval Stages ◽  
Predation Mortality ◽  
Stability And Resilience

Environmental regimes set the timing and location of early life-history events of migratory species with synchronised reproduction. However, modified habitats in human-dominated landscapes may amplify uncertainty in predicting recruitment pulses, impeding efforts to restore habitats invaluable to endemic species. The present study assessed how environmental and spawner influences modulate recruitment variability and persistence of the Missouri River shovelnose sturgeon (Scaphirhynchus platorynchus) under modified seasonal spawning and nursery habitat conditions. Using a spatially explicit individual-based biophysical model, spawning cycle, early life-history processes (dispersal, energetics and survival) and prey production were simulated under incrementally perturbed flow (from –10 to –30%) and temperature (+1 and +2°C) regimes over 50 years. Simulated flow reduction and warming synergistically contracted spring spawning habitats (by up to 51%) and periods (by 19%). Under these conditions, fewer mature females entered a reproductive cycle, and more females skipped spawning, reducing spawning biomass by 20–50%. Many spawners migrated further to avoid increasingly unfavourable habitats, intensifying local density dependence in larval stages and, in turn, increasing size-dependent predation mortality. Diminished egg production (by 20–97%) and weakened recruitment pulses (by 46–95%) ultimately reduced population size by 21–74%. These simulations illustrate that environmentally amplified maternal influences on early life histories can lower sturgeon population stability and resilience to ever-increasing perturbations.

The life histories of north-temperate populations of the crayfish Cambarus robustus and Cambarus bartoni

1985 ◽  
Vol 63 (10) ◽  
pp. 2313-2322 ◽  
Author(s):  
Premysl Hamr ◽  
Michael Berrill
Keyword(s):  
Life History ◽  
Life Histories ◽  
Carapace Length ◽  
Late Summer ◽  
Temperate Climate ◽  
Free Living ◽  
Southern Ontario ◽  
The Third ◽  
Early Fall ◽  
First Time

The life histories of the crayfish Cambarus robustus and Cambarus bartoni were studied in the Kawartha Lakes region of southern Ontario. There were marked differences in their breeding and molting cycles compared with the familiar pattern of the Orconectes species of this region. Egg extrusion occurred later (July in C. robustus, June in C. bartoni), and juveniles therefore did not become free living until late summer or early fall. With little growing time in their first summer, they measured only 5–10 mm in carapace length (CPL) before growth ceased for the winter. At the end of their second summer the still immature crayfish measured 17–26 mm CPL in C. robustus and 13–20 mm CPL in C. bartoni. Maturity was therefore not attained until the end of the third summer, when most C. robustus matured at 34–45 mm CPL and C. bartoni at 25–30 mm CPL. The majority of individuals apparently reproduced for the first time during their fourth summer; a few apparently survived into another summer, reaching carapace lengths greater than 50 mm in C. robustus and 30 mm in C. bartoni. In males of both species, form 1 and form 2 occur throughout the summer. Although lacking the synchrony of Orconectes species, breeding and molting activities are still confined to the period between April and October. The timing of the life-history events observed in these two Cambarus species may be adaptations to seasonal stresses of the swift water environments that these species inhabit as well as to the relative harshness of the northern temperate climate.

Maturation, reproduction and early life history of anglerfish Lophius piscatorius in Faroese waters

2015 ◽  
Vol 60 ◽  
pp. 114 ◽  
Author(s):  
Lise H. Ofstad ◽  
Torstein Petersen ◽  
Petur Steingrund
Keyword(s):  
Life History ◽  
Early Life ◽  
Early Life History ◽  
Nursery Ground ◽  
Life Stages ◽  
Morphological Transformation ◽  
Spawning Areas ◽  
History Of ◽  
Males And Females ◽  
First Maturity

<p>Maturation, reproduction and early life history of <em>Lophius piscatorius </em>was investigated in Faroese waters. Length at first maturity (L50) was 58 cm for males and 84 cm for females, corresponding to an age of about four years for males and seven years for females. The proportions of females and males were similar in fish less than 55 cm long, and were skewed towards more males in medium sized fish (55–75  cm).  Females  were  predominant  in the larger fish (&gt; 85 cm). Observations of spawning males and females, egg ribbons and pelagic anglerfish larvae, suggest that the main spawning season is from February to April and the spawning area seems to be southwest of the Faroe Plateau and in the Faroe Bank area. The Faroe Plateau probably serves as a nursery ground for juvenile anglerfish. Morphological transformation from larvae to juveniles occurred when the fish were about 7–9 cm long and they settled to the bottom when they were about 11 cm long. Thus, all life stages, as well as nursery areas, spawning areas and feeding areas of anglerfish are found in Faroese waters, indicating a separate stock in the area.</p>

Immature stages of Calycopis bellera (Hewitson) and C. janeirica (Felder) (Lepidoptera, Lycaenidae, Theclinae, Eumaeini): Taxonomic significance and new evidence for detritivory

Zootaxa ◽  
2009 ◽  
Vol 2325 (1) ◽  
pp. 39-61 ◽  
Author(s):  
MARCELO DUARTE ◽  
ROBERT K. ROBBINS
Keyword(s):  
Morphological Characters ◽  
Sexually Dimorphic ◽  
Immature Stages ◽  
Taxonomic Significance ◽  
Larval Instars ◽  
Species Groups ◽  
Males And Females ◽  
First Time ◽  
New Evidence

Details of egg, larval, and pupal morphology are described and illustrated for Calycopis bellera (Hewitson) and C. janeirica (Felder), with a special emphasis on larval chaetotaxy. Wild-caught Calycopis females laid eggs on dead leaves in the laboratory, and the caterpillars successfully completed development on an artificial agar diet to which no leaves were added. Males and females of the sexually dimorphic C. bellera had been previously placed in different genera or different species groups. Calycopis janeirica had been chronically misidentified (and misspelled C. jeneirica). Males and females of this species appear to be correctly associated for the first time. Whereas C. bellera has five larval instars—as reported previously for C. caulonia—C. janeirica has four. Morphological characters of the immatures of C. bellera and C. janeirica are summarized in a table and compared with those of other reared Calycopis species.

Taxonomic revision of Perdita subgenus Heteroperdita Timberlake (Hymenoptera: Andrenidae), with descriptions of two ant-like males

Zootaxa ◽  
2016 ◽  
Vol 4214 (1) ◽  
pp. 1 ◽  
Author(s):  
ZACHARY M. PORTMAN ◽  
JOHN L. NEFF ◽  
TERRY GRISWOLD
Keyword(s):  
United States ◽  
New Species ◽  
Geographic Distribution ◽  
Taxonomic Revision ◽  
Junior Synonym ◽  
Sexually Dimorphic ◽  
Southwestern United States ◽  
Identification Keys ◽  
Males And Females ◽  
First Time

Perdita subgenus Heteroperdita Timberlake, a distinctive subgenus of 22 species from the southwestern United States and adjacent Mexico, all specialists on Tiquilia (Boraginaceae), is revised. Nine new species are described: Perdita (Heteroperdita) desdemona Portman, sp. n., P. (H.) exusta Portman & Griswold, sp. n., P. (H.) hippolyta Portman & Griswold, sp. n. (male previously incorrectly described as P. pilonotata Timberlake), P. (H.) hooki Portman & Neff, sp. n., P. (H.) nuttalliae Portman, sp. n., P. (H.) prodigiosa Portman & Griswold, sp. n., P. (H.) sycorax Portman, sp. n., P. (H.) titania Portman & Griswold, sp. n., and P. (H.) yanegai Portman, sp. n. The following sexes are associated and described for the first time: the male of P. (H.) frontalis Timberlake, 1968, the female of P. (H.) optiva Timberlake, 1954, and the true male of P. (H.) pilonotata Timberlake, 1980. Perdita (H.) fasciatella Timberlake, 1980 is proposed as a junior synonym of P. (H.) sexfasciata Timberlake, 1954. A neotype is designated for P. (H.) pilonotata Timberlake, 1980. Two species in particular, P. prodigiosa and P. pilonotata, are sexually dimorphic with distinctive ant-like males. Information is presented on floral relationships, phenology, and geographic distribution. Identification keys for males and females are provided. 

STUDIES OF WESTERN TREE RUSTS: IV. UREDINOPSIS HASHIOKAI AND U. PTERIDIS CAUSING PERENNIAL NEEDLE RUST OF FIR

1959 ◽  
Vol 37 (1) ◽  
pp. 93-107 ◽  
Author(s):  
W. G. Ziller
Keyword(s):  
Life History ◽  
Geographical Distribution ◽  
Life Histories ◽  
Life Cycles ◽  
Pteridium Aquilinum ◽  
Abies Lasiocarpa ◽  
Perfect State ◽  
Bracken Fern ◽  
First Time

Observations in the field and the results of inoculation experiments show that perennial needle rust of fir (Abies spp.), known as Peridermium pseudo-balsameum (Diet. & Holw.) Arth. & Kern, is caused by Uredinopsis hashiokai Hirats. f. and U. pteridis Diet. & Holw. (U. macrosperma Magn.), which complete their life cycles on bracken fern (Pteridium aquilinum (L.) Kühn var. lanuginosum (Bong.) Fern.). The pycnial and aecial states of Uredinopsis hashiokai are described, and for the first time the life histories of U. hashiokai and U. pteridis are presented. The two species are indistinguishable from each other in life history, host relationship, and morphology of most of the spore states; they differ from each other in their geographical distribution and in the morphology of their urediniospores. It remains unknown which of the two species of Uredinopsis represents the perfect state of Peridermium pseudo-balsameum. Uredinopsis aspera Faull proved to be a later synonym of U. hashiokai. U. hashiokai is noteworthy because of its similarity to U. pteridis, and both species are unusual in development of their spore states on fir, particularly in the long periods required for maturation of the aecia, which are produced from localized, perennial mycelium 4 to 11 months after infection in Abies lasiocarpa (Hook.) Nutt. and A. grandis (Dougl.) Lindl. respectively.

Estimates of the Theoretical Biomass of Juvenile Winter Flounder, Pseudopleuronectes americanus (Walbaum) Required for a Fishery in Rhode Island

1965 ◽  
Vol 22 (4) ◽  
pp. 945-954 ◽  
Author(s):  
Saul B. Saila ◽  
Donald B. Horton ◽  
Richard J. Berry
Keyword(s):  
Life History ◽  
Rhode Island ◽  
Significant Proportion ◽  
Early Life History ◽  
Vital Statistics ◽  
Winter Flounder ◽  
Pseudopleuronectes Americanus ◽  
Empirical Estimates ◽  
Equilibrium Yield ◽  
History Of

A model of the life history of the winter flounder was constructed using empirical estimates of vital statistics. The initial stock weight of juveniles was determined by substituting trial initial stock weight values into equations which contained average values of growth and mortality coefficients until the observed value of the equilibrium yield was approximated. Model data indicated that the stock weight of juvenile winter flounder at an age of 5 months constituted a significant proportion of the equilibrium yield even with conservative estimates of model coefficients. Growth appeared to be sufficiently rapid during early life-history stages to provide for a large increase in biomass in spite of considerable natural mortality.

scholarly journals Towards cancer-aware life-history modelling

2015 ◽  
Vol 370 (1673) ◽  
pp. 20140234 ◽  
Author(s):  
Hanna Kokko ◽  
Michael E. Hochberg
Keyword(s):  
Life History ◽  
Life Histories ◽  
Life History Theory ◽  
Cancer Susceptibility ◽  
Natural Populations ◽  
Sexually Dimorphic ◽  
Adaptive Responses ◽  
Extrinsic Mortality ◽  
Size Evolution ◽  
In The Wild

Studies of body size evolution, and life-history theory in general, are conducted without taking into account cancer as a factor that can end an organism's reproductive lifespan. This reflects a tacit assumption that predation, parasitism and starvation are of overriding importance in the wild. We argue here that even if deaths directly attributable to cancer are a rarity in studies of natural populations, it remains incorrect to infer that cancer has not been of importance in shaping observed life histories. We present first steps towards a cancer-aware life-history theory, by quantifying the decrease in the length of the expected reproductively active lifespan that follows from an attempt to grow larger than conspecific competitors. If all else is equal, a larger organism is more likely to develop cancer, but, importantly, many factors are unlikely to be equal. Variations in extrinsic mortality as well as in the pace of life—larger organisms are often near the slow end of the fast–slow life-history continuum—can make realized cancer incidences more equal across species than what would be observed in the absence of adaptive responses to cancer risk (alleviating the so-called Peto's paradox). We also discuss reasons why patterns across species can differ from within-species predictions. Even if natural selection diminishes cancer susceptibility differences between species, within-species differences can remain. In many sexually dimorphic cases, we predict males to be more cancer-prone than females, forming an understudied component of sexual conflict.

Beaver impact on stream fish life histories: the role of landscape and local attributes

2014 ◽  
Vol 71 (11) ◽  
pp. 1603-1615 ◽  
Author(s):  
Aneta Bylak ◽  
Krzysztof Kukuła ◽  
Józef Mitka
Keyword(s):  
Life History ◽  
Life Histories ◽  
Salmo Trutta ◽  
Fish Assemblages ◽  
Stream Fish ◽  
Beaver Ponds ◽  
Eurasian Beaver ◽  
Brown Trout Salmo Trutta ◽  
Cottus Poecilopus ◽  
Stream Fish Assemblages

The Eurasian beaver (Castor fiber) has been reintroduced into the Carpathian Mountains and has once again become an important factor for modifying streams. Forty-three sampling sites were compared with 10 reference sites in streams not settled by beavers. Models related to the impacts of beavers on various fish life history stages and a model presenting attributes influencing the ichthyofauna structure in streams with and without beavers were generated. Significant differences in the fish species composition were found between beaver ponds versus the running sections of streams. The changes associated with pond aging caused decrease of Siberian bullhead (Cottus poecilopus) density. For brown trout (Salmo trutta), beaver ponds were the only location where large individuals were found, while the upstream parts of the beaver complexes provided spawning habitat and an area for fry growth. Common minnow (Phoxinus phoxinus) and stone loach (Barbatula barbatula) had higher density in ponds than in streams. The decisive factors for the ichthyofauna in the mountain streams settled by beavers were local attributes related to beaver activity. Our results illustrate interactions among beaver, landscape context, and fish life history in influencing the response of the stream fish assemblages to beaver recolonization. It also helps answer the question of how Eurasian beaver influence stream fish assemblages, at a much larger scale than previous studies.

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