scholarly journals Life history and production of pelagic mysids and decapods in the Oyashio region, Japan

Crustaceana ◽  
2013 ◽  
Vol 86 (4) ◽  
pp. 449-474
Author(s):  
Kana Chikugo ◽  
Atsushi Yamaguchi ◽  
Kohei Matsuno ◽  
Rui Saito ◽  
Ichiro Imai
Keyword(s):  
Life History ◽  
Life Histories ◽  
Dominant Species ◽  
Life Cycles ◽  
Annual Production ◽  
Juvenile Growth ◽  
High Biomass ◽  
Oyashio Region ◽  
Generation Times ◽  
High Production

Pelagic Mysidacea and Decapoda have important roles in marine ecosystems. However, information on their life histories is extremely limited. This study aimed to evaluate the life cycles of pelagic Mysidacea and Decapoda in the Oyashio region, Japan. Production of the four dominant species was estimated by combining body mass (DM) data and abundance data. Mysidacea belonging to 5 species from 5 genera occurred in the study area. Their abundance and biomass ranged between 11.7-50.1 ind. m−2 and 1.2-7.9 g wet mass (WM) m−2, respectively. Six species from 6 genera belonged to Decapoda, and their abundance and biomass ranged between 9.0-17.3 ind. m−2 and 3.0-17.3 g WM m−2, respectively. Based on body length histograms, there were two to four cohorts for the three dominant mysids and one dominant decapod on each sampling date. Life histories of the two numerically dominant mysids (Eucopia australis and Boreomysis californica) followed similar patterns: recruitment of young in May, strong growth from April to June, and a longevity of three years. Life cycles of the two minor species (the mysid Meterythrops microphthalma and the decapod Hymenodora frontalis) were not clear because of their low abundance. The timing of recruitment of the young and the strong juvenile growth for the two dominant mysids corresponds with the season when their prey is abundant. The annual production of the dominant mysid species was 14.0 mg DM m−2 (B. californica) and 191.8 mg DM m−2 (E. australis). Annual production/biomass () ratios ranged between 0.242 (H. frontalis) and 0.643 (M. microphthalma). Compared with other regions, the Oyashio region showed high production and low ratios. The high production in the Oyashio region may be related to the high biomass of these species. Because of the low temperature conditions (3°C), pelagic mysids and decapods in the Oyashio region may have slower growth, longer generation times and lower ratios than in other oceans.

scholarly journals A review of the life cycles and life-history adaptations of pelagic tunicates to environmental conditions

2011 ◽  
Vol 69 (3) ◽  
pp. 358-369 ◽  
Author(s):  
Don Deibel ◽  
Ben Lowen
Keyword(s):  
Life History ◽  
Environmental Conditions ◽  
Generation Time ◽  
Egg Production ◽  
Food Concentration ◽  
Life Cycles ◽  
Population Doubling ◽  
Event Scale ◽  
Generation Times ◽  
Doubling Times

Abstract Deibel, D., and Lowen, B. 2012. A review of the life cycles and life-history adaptations of pelagic tunicates to environmental conditions. – ICES Journal of Marine Science, 69: 358–369. Phylogeny, life cycles, and life-history adaptations of pelagic tunicates to temperature and food concentration are reviewed. Using literature data on lifetime egg production and generation time of appendicularians, salps, and doliolids, rmax, the maximum rate of lifetime reproductive fitness, is calculated as a common metric of adaptation to environmental conditions. The rmax values are high for all three groups, ranging from ∼0.1 to 1.9 d−1, so population doubling times range from ∼8 h to 1 week. These high values of rmax are attributable primarily to short generation times, ranging from 2 to 50 d. Clearly, pelagic tunicates are adapted to event-scale (i.e. days to weeks) rather than seasonal-scale changes in environmental conditions. Although they are not closely related phylogenetically, all three groups have a unique life-history adaptation promoting high lifetime fitness. Appendicularians have late oocyte selection, salps are viviparous, and doliolids possess a polymorphic asexual phase. There has been little research on hermaphroditic appendicularians, on large oceanic salps, and on doliolids generally. Research is needed on factors regulating generation time, on the heritability of life-history traits, and on age- and size-specific rates of mortality.

scholarly journals The influence of juvenile and adult environments on life-history trajectories

2005 ◽  
Vol 273 (1587) ◽  
pp. 741-750 ◽  
Author(s):  
Barbara Taborsky
Keyword(s):  
Life History ◽  
Life Histories ◽  
Adult Life ◽  
Growth Conditions ◽  
Offspring Size ◽  
Juvenile Growth ◽  
Life History Variation ◽  
Major Life ◽  
Adult Growth ◽  
Trade Offs

There is increasing evidence that the environment experienced early in life can strongly influence adult life histories. It is largely unknown, however, how past and present conditions influence suites of life-history traits regarding major life-history trade-offs. Especially in animals with indeterminate growth, we may expect that environmental conditions of juveniles and adults independently or interactively influence the life-history trade-off between growth and reproduction after maturation. Juvenile growth conditions may initiate a feedback loop determining adult allocation patterns, triggered by size-dependent mortality risk. I tested this possibility in a long-term growth experiment with mouthbrooding cichlids. Females were raised either on a high-food or low-food diet. After maturation half of them were switched to the opposite treatment, while the other half remained unchanged. Adult growth was determined by current resource availability, but key reproductive traits like reproductive rate and offspring size were only influenced by juvenile growth conditions, irrespective of the ration received as adults. Moreover, the allocation of resources to growth versus reproduction and to offspring number versus size were shaped by juvenile rather than adult ecology. These results indicate that early individual history must be considered when analysing causes of life-history variation in natural populations.

Life history variation in plants: an exploration of the fast-slow continuum hypothesis

1996 ◽  
Vol 351 (1345) ◽  
pp. 1341-1348 ◽  
Keyword(s):  
Life History ◽  
Life Histories ◽  
Sexual Maturity ◽  
Life History Traits ◽  
Continuum Hypothesis ◽  
Adult Mortality ◽  
Life Cycles ◽  
Differential Mortality ◽  
Life History Variation ◽  
Net Reproductive Rate

Several empirical models have attempted to account for the covariation among life history traits observed in a variety of organisms. One of these models, the fast-slow continuum hypothesis, emphasizes the role played by mortality at different stages of the life cycle in shaping the large array of life history variation. Under this scheme, species can be arranged from those suffering high adult mortality levels to those undergoing relatively low adult mortality. This differential mortality is responsible for the evolution of contrasting life histories on either end of the continuum. Species undergoing high adult mortality are expected to have shorter life cycles, faster development rates and higher fecundity than those experiencing lower adult mortality. The theory has proved accurate in describing the evolution of life histories in several animal groups but has previously not been tested in plants. Here we test this theory using demographic information for 83 species of perennial plants. In accordance with the fast-slow continuum, plants undergoing high adult mortality have shorter lifespans and reach sexual maturity at an earlier age. However, demographic traits related to reproduction (the intrinsic rate of natural increase, the net reproductive rate and the average rate of decrease in the intensity of natural selection on fecundity) do not show the covariation expected with longevity, age at first reproducion and life expectancy at sexual maturity. Contrary to the situation in animals, plants with multiple meristems continuously increase their size and, consequently, their fecundity and reproductive value. This may balance the negative effect of mortality on fitness, thus having no apparent effect in the sign of the covariation between these two goups of life history traits.

Coevolutionary interactions between host life histories and parasite life cycles

Parasitology ◽  
1998 ◽  
Vol 116 (S1) ◽  
pp. S47-S55 ◽  
Author(s):  
J. C. Koella ◽  
P. Agnew ◽  
Y. Michalakis
Keyword(s):  
Life History ◽  
Life Cycle ◽  
Life Histories ◽  
Life History Traits ◽  
Evolutionary Ecology ◽  
Life Cycles ◽  
Microsporidian Parasite ◽  
History Of ◽  
Host Life ◽  
Host Parasite

SummarySeveral recent studies have discussed the interaction of host life-history traits and parasite life cycles. It has been observed that the life-history of a host often changes after infection by a parasite. In some cases, changes of host life-history traits reduce the costs of parasitism and can be interpreted as a form of resistance against the parasite. In other cases, changes of host life-history traits increase the parasite's transmission and can be interpreted as manipulation by the parasite. Alternatively, changes of host's life-history traits can also induce responses in the parasite's life cycle traits. After a brief review of recent studies, we treat in more detail the interaction between the microsporidian parasite Edhazardia aedis and its host, the mosquito Aedes aegypti. We consider the interactions between the host's life-history and parasite's life cycle that help shape the evolutionary ecology of their relationship. In particular, these interactions determine whether the parasite is benign and transmits vertically or is virulent and transmits horizontally.Key words: host-parasite interaction, life-history, life cycle, coevolution.

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.

Life History Studies on Trematodes of the Subfamily Reniferinae

Parasitology ◽  
1933 ◽  
Vol 25 (4) ◽  
pp. 518-545 ◽  
Author(s):  
S. Benton Talbot
Keyword(s):  
Life History ◽  
Life Cycle ◽  
Life Histories ◽  
Life Cycles ◽  
Small Fish ◽  
Intermediate Hosts ◽  
Natural Group ◽  
Remarkable Similarity ◽  
Physella Gyrina ◽  
Mother Sporocyst

1. The life histories of Lechriorchis primus Stafford, L. tygarti n.sp. and Caudorchis eurinus n.gen. et sp. have been experimentally completed in three hosts, the first complete life histories to be worked out for species of the subfamily Reniferinae.2. The definitive hosts of the three forms were found to be two species of garter snakes, Thamnophis sauritus and T. sirtalis.3. Three species of snails, Physella gyrina, P. parkeri, and P. ancillaria, have been found to serve as the first intermediate host in the life cycles of Lechriorchis primus and Caudorchis eurinus n.gen. et sp., and two species of snails, Physella gyrina and P. heterostropha, in the life cycle of Lechriorchis tygarti n.sp.4. The tadpoles of two species of frogs, Rana clamitans and R. pipiens, were found to serve as the second intermediate hosts in the life cycles of all three trematodes. The cercariae penetrate larvae of Triturus and small fish, but live only a short time in these animals.5. Every stage in the life history of Lechriorchis primus, including egg, miracidium, mother sporocyst, daughter sporocyst, cercaria, metacercaria, and developmental stages in the definitive host, has been described in detail.6. The mother sporocyst of forms having a stylet cercaria is described for the first time.7. The flame cell pattern of the cercariae of L. primus, L. tygarti n.sp., and Caudorchis eurinus n.gen. et sp. has been determined to be of the “2 × 6 × 3’ type. Also the adult stage of C. eurinus was determined to have the same type.8. It has been pointed out that the life histories of the members of the subfamily are uniform in that their life history stages display a remarkable similarity.9. It has been suggested that this uniform type of life cycle and remarkable similarity of larval stages offer the most logical basis for establishing the subfamily Reniferinae as a natural group.

scholarly journals Life History Effects on Neutral Diversity Levels of Autosomes and Sex Chromosomes

Genetics ◽  
2020 ◽  
Vol 215 (4) ◽  
pp. 1133-1142 ◽  
Author(s):  
Guy Amster ◽  
Guy Sella
Keyword(s):  
Life History ◽  
Sex Chromosomes ◽  
Life Histories ◽  
Genetic Data ◽  
Mutation Rates ◽  
Female Ratio ◽  
Diversity Patterns ◽  
History Effects ◽  
Generation Times ◽  
Male To Female

Understanding the determinants of neutral diversity patterns on autosomes and sex chromosomes provides a bedrock for the interpretation of population genetic data; in particular, differences between the two informs our understanding of sex-specific demographic and mutation processes. While sex-specific age-structure and variation in reproductive success have long been known to affect neutral diversity, theoretical descriptions of these effects were complicated and lacking in generality, stymying attempts to relate diversity patterns of species with their life history. Here, we derive general yet simple expressions for these effects. In particular, we show that life history effects on X-to-autosome ratios of pairwise diversity levels (X:A diversity ratios) depend only on the male-to-female ratios of mutation rates, generation times, and reproductive variances. Our results reveal that changing the male-to-female ratio of generation times has opposite effects on X:A ratios of diversity and divergence. They also explain how sex-specific life histories modulate the response of X:A diversity ratios to changes in population size. More generally, they clarify that sex-specific life history—generation times in particular—should have marked effects on X:A diversity ratios in many taxa and enable further investigation of these effects.

scholarly journals Life history effects on neutral diversity levels of autosomes and sex chromosomes

2017 ◽  
Author(s):  
Guy Amster ◽  
Guy Sella
Keyword(s):  
Life History ◽  
Sex Chromosomes ◽  
Life Histories ◽  
Marked Effect ◽  
Genetic Data ◽  
Mutation Rates ◽  
X Chromosomes ◽  
Diversity Patterns ◽  
History Effects ◽  
Generation Times

AbstractAll else being equal, the ratio of genetic diversity levels on X and autosomes at selectively neutral sites should mirror the ratio of their numbers in the population and thus equal ¾. Because X chromosomes spend twice as many generations in females as in males, however, the ratio of diversity levels is also affected by sex differences in life history. The effects of life history on diversity levels, notably those of sex-specific age structures and reproductive variances, have been studied for decades, yet existing theory relies on many parameters that are difficult to measure and lacks generality in ways that limit their applicability. We derive general yet simple expressions for these effects and show that life history effects on X-to-autosome (X:A) ratios of diversity levels depend only on sex-ratios of mutation rates, generation times, and reproductive variances. These results reveal that changing the sex-ratio of generation times has opposite effects on X:A ratios of polymorphism and divergence. They also explain how sex-specific life histories modulate the response of X:A polymorphism ratios to changes in population size. More generally, they clarify that sex-specific life history—generation times in particular—should have a marked effect on X:A polymorphism ratios in many taxa and enable the investigation of these effects.Significance StatementUnderstanding the determinants of neutral diversity patterns on autosomes and sex chromosomes provides a bedrock for our interpretation of population genetic data. Sex-specific age-structure and variation in reproductive success have long been thought to affect neutral diversity, but theoretical descriptions of these effects were complicated and/or lacked in generality, stymying attempts to relate diversity patterns of species with their life history. We derive general yet simple expressions for these effects, which clarify how they impact neutral diversity and should enable studies of relative diversity levels on the autosomes and sex chromosomes in many taxa.

Life histories of some Benthic invetebrates form streams of the Northern Jarrah Forest, Western Australia

1988 ◽  
Vol 39 (6) ◽  
pp. 785 ◽  
Author(s):  
SE Bunn
Keyword(s):  
Life History ◽  
Life Histories ◽  
Adult Emergence ◽  
Adaptive Strategy ◽  
Life Cycles ◽  
Jarrah Forest ◽  
Stream Insects ◽  
Long Period ◽  
Life History Pattern ◽  
High Degree

Life history patterns of thirteen species of invertebrates from streams of the northern jarrah forest were examined over a 1-year period. Five species had univoltine cycles with a single cohort and demonstrated a high degree of synchrony of larval development and a restricted period of adult emergence. Two species of Leptophlebiidae also had univoltine cycles but showed the more typical pattern of Australian mayflies, with extended recruitment, multiple overlapping cohorts and a long period of adult emergence. Uroctena sp., a small gammarid, had a generation time of 1 year but showed considerable spatial variation in the degree of synchrony of development. This appeared to be a result of differences in the constancy of stream discharge and was not attributable to differences in the temperature regime of the streams. At least three species demonstrated cohort splitting which resulted in an apparently bivoltine cycle. A life-history pattern of alternating long and short development times is described which, on average, would produce two generations every 3 years. This is considered to be a highly adaptive strategy for Australian stream insects with slow life cycles and can explain the extended periods of recruitment and adult emergence so often observed. Streams of the northern jarrah forest are depauperate compared with other Australian streams, despite predictable temperature and discharge regimes. The insular nature of the south-west Bassian region and its long period of isolation may be the principle cause of this reduced diversity. The invertebrate community of these streams is simple in structure and has a high degree of seasonality that is atypical of the temperate streams of Australia and New Zealand.

Fast and slow life histories of carnivores

2011 ◽  
Vol 89 (8) ◽  
pp. 692-704 ◽  
Author(s):  
Evi Paemelaere ◽  
F. Stephen Dobson
Keyword(s):  
Life History ◽  
Body Size ◽  
Litter Size ◽  
Life Histories ◽  
Life History Traits ◽  
Life Cycles ◽  
Age At Maturity ◽  
Negatively Associated ◽  
Trade Offs ◽  
Body Sizes

The fast–slow continuum hypothesis explains life-history traits as reflecting the causal influence of mortality patterns in interaction with trade-offs among traits, particularly more reproductive effort at a cost of shorter lives. Variation among species of different body sizes produce more or less rapid life cycles (respectively, from small to large species), but the fast–slow continuum remains for birds and mammals when body-size effects are statistically removed. We tested for a fast–slow continuum in mammalian carnivores. We found the above trade-offs initially supported in a sample of 85 species. Body size, however, was strongly associated with phylogeny (ρ = 0.79), and thus we used regression techniques and independent contrasts to make statistical adjustments for both. After adjustments, the life-history trade-offs were not apparent, and few associations of life-history traits were significant. Litter size was negatively associated with age at maturity, but slightly positively associated with offspring mass. Litter size and mass were negatively associated with the length of the developmental period. Gestation length showed weak but significant negative associations with age at maturity and longevity. We conclude that carnivores, despite their wide range of body sizes and variable life histories, at best poorly exhibited a fast–slow continuum.

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