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.

Abundance and Life History of Mysis relicta in the St. Lawrence Great Lakes

1974 ◽  
Vol 31 (3) ◽  
pp. 319-325 ◽  
Author(s):  
G. F. Carpenter ◽  
E. L. Mansey ◽  
N. H. F. Watson
Keyword(s):  
Life History ◽  
Generation Time ◽  
Lake Superior ◽  
Life Cycles ◽  
Lake Huron ◽  
Summer Period ◽  
Mysis Relicta ◽  
Frequency Distributions ◽  
History Of ◽  
Major Period

In sampling on lakes Ontario, Erie, and Superior during three cruises from spring to fall, and on Lake Huron during eight cruises, Mysis relicta was generally not taken or not abundant in waters less than 25 m in depth. Its abundance appeared to increase with depth at least up to 200 m. Populations appeared to be concentrated in waters 125–200 m deep during summer and more dispersed during spring and fall. Highest numbers were found in Lake Superior, followed by lakes Ontario and Huron. A small localized population was found in the deep eastern part of Lake Erie.Size-frequency distributions from the various cruises on lakes Superior, Huron, and Ontario indicated differences in life cycles of the mysid in the three lakes. In Lake Superior there was one major period of recruitment, from February to July, and the generation time appeared to be 2 yr. In lakes Huron and Ontario recruitment appeared to occur from February to August and to be separated into a winter and a summer period; each of the generations appeared to mature in 18 mo.

Smelling the future: subtle life-history adjustments in response to environmental conditions and perceived transmission opportunities in a trematode

Parasitology ◽  
2016 ◽  
Vol 144 (4) ◽  
pp. 464-474 ◽  
Author(s):  
C. LAGRUE ◽  
R. RINNEVALLI ◽  
R. POULIN
Keyword(s):  
Life History ◽  
Life Cycle ◽  
Intermediate Host ◽  
Definitive Host ◽  
Environmental Conditions ◽  
Life History Strategy ◽  
Host Density ◽  
Life Cycles ◽  
Life History Strategies ◽  
Priming Effects

SUMMARYA number of parasites with complex life cycles can abbreviate their life cycles to increase the likelihood of reproducing. For example, some trematodes can facultatively skip the definitive host and produce viable eggs while still inside their intermediate host. The resulting shorter life cycle is clearly advantageous when transmission probabilities to the definitive hosts are low. Coitocaecum parvum can mature precociously (progenesis), and produce eggs by selfing inside its amphipod second intermediate host. Environmental factors such as definitive host density and water temperature influence the life-history strategy adopted by C. parvum in their crustacean host. However, it is also possible that information about transmission opportunities gathered earlier in the life cycle (i.e. by cercariae-producing sporocysts in the first intermediate host) could have priming effects on the adoption of one or the other life strategy. Here we document the effects of environmental parameters (host chemical cues and temperature) on cercarial production within snail hosts and parasite life-history strategy in the amphipod host. We found that environmental cues perceived early in life have limited priming effects on life-history strategies later in life and probably account for only a small part of the variation among conspecific parasites. External cues gathered at the metacercarial stage seem to largely override potential effects of the environmental conditions experienced by early stages of the parasite.

scholarly journals The Distribution of Bacterial Doubling Times in the Wild

2017 ◽  
Author(s):  
Beth Gibson ◽  
Daniel Wilson ◽  
Edward Feil ◽  
Adam Eyre-Walker
Keyword(s):  
Life History ◽  
Mutation Rate ◽  
Generation Time ◽  
Doubling Time ◽  
Mutation Rates ◽  
Substantial Fraction ◽  
Rate Estimate ◽  
In The Wild ◽  
Doubling Times ◽  
Mutation Rate Estimate

AbstractGeneration time varies widely across organisms and is an important factor in the life cycle, life history and evolution of organisms. Although the doubling time (DT), has been estimated for many bacteria in the lab, it is nearly impossible to directly measure it in the natural environment. However, an estimate can be obtained by measuring the rate at which bacteria accumulate mutations per year in the wild and the rate at which they mutate per generation in the lab. If we assume the mutation rate per generation is the same in the wild and in the lab, and that all mutations in the wild are neutral, an assumption that we show is not very important, then an estimate of the DT can be obtained by dividing the latter by the former. We estimate the DT for four species of bacteria for which we have both an accumulation and a mutation rate estimate. We also infer the distribution of DTs across all bacteria from the distribution of the accumulation and mutation rates. Both analyses suggest that DTs for bacteria in the wild are substantially greater than those in the lab, that they vary by orders of magnitude between different species of bacteria and that a substantial fraction of bacteria double very slowly in the wild.

scholarly journals The distribution of bacterial doubling times in the wild

2018 ◽  
Vol 285 (1880) ◽  
pp. 20180789 ◽  
Author(s):  
Beth Gibson ◽  
Daniel J. Wilson ◽  
Edward Feil ◽  
Adam Eyre-Walker
Keyword(s):  
Life History ◽  
Mutation Rate ◽  
Generation Time ◽  
Doubling Time ◽  
Mutation Rates ◽  
Substantial Fraction ◽  
Rate Estimate ◽  
In The Wild ◽  
Doubling Times ◽  
Mutation Rate Estimate

Generation time varies widely across organisms and is an important factor in the life cycle, life history and evolution of organisms. Although the doubling time (DT) has been estimated for many bacteria in the laboratory, it is nearly impossible to directly measure it in the natural environment. However, an estimate can be obtained by measuring the rate at which bacteria accumulate mutations per year in the wild and the rate at which they mutate per generation in the laboratory. If we assume the mutation rate per generation is the same in the wild and in the laboratory, and that all mutations in the wild are neutral, an assumption that we show is not very important, then an estimate of the DT can be obtained by dividing the latter by the former. We estimate the DT for five species of bacteria for which we have both an accumulation and a mutation rate estimate. We also infer the distribution of DTs across all bacteria from the distribution of the accumulation and mutation rates. Both analyses suggest that DTs for bacteria in the wild are substantially greater than those in the laboratory, that they vary by orders of magnitude between different species of bacteria and that a substantial fraction of bacteria double very slowly in the wild.

scholarly journals Diapause Termination and Postdiapause in Lygus hesperus (Heteroptera: Miridae)

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Colin S Brent
Keyword(s):  
Life History ◽  
Environmental Conditions ◽  
Egg Production ◽  
Negative Impact ◽  
Early Adulthood ◽  
Lygus Hesperus ◽  
Tarnished Plant Bug ◽  
The Impact ◽  
Ovipositional Activity ◽  
Oxidative Agents

Abstract The western tarnished plant bug, Lygus hesperus Knight, overwinters as a diapausing adult in response to short day lengths. Once environmental conditions are favorable, the bugs revert to an active reproductive state. To determine the impact on life-history traits of diverting resources toward diapause rather than oogenesis during early adulthood, diapausing and nondiapausing L. hesperus females were reared from the same cohorts. Body mass, ovarian maturation, ovipositional activity, and survivorship were monitored starting either at the time of release from diapause-inducing conditions or at adult eclosion for diapausers and nondiapausers, respectively. Females that had gone through 2 wk of diapause were larger and able to mobilize the resources necessary for oogenesis faster than nondiapausers, initiating oogenesis and ovipositing sooner and at a faster initial rate. However, lifetime egg production and average daily rates were similar for both groups. Postdiapausers lived longer than nondiapausers by an average of 19 d, which is five more than the 2-wk period when they were reproductively senescent. Overall, the results indicate that short-term diapause does not have a negative impact on life history. Furthermore, the extra endogenous resources stored during diapause may be able to enhance the alacrity with which the female can take advantage of improved environmental conditions and may prolong life by shielding the females against environmental stressors such as temperature extremes, oxidative agents, or food deficits.

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 Egg production and life history of Alona guttata Sars, 1862 (Cladocera, Chydoridae): implications for colonization of temporary ponds

2022 ◽  
Vol 82 ◽  
Author(s):  
E. E. Cortez-Silva ◽  
V. F. Souza ◽  
G. S. Santos ◽  
E. M. Eskinazi-Sant’Anna
Keyword(s):  
Life History ◽  
Life Cycle ◽  
Environmental Conditions ◽  
Egg Production ◽  
Rapid Development ◽  
Temporary Ponds ◽  
Temporary Pond ◽  
Rapid Responses ◽  
History Of ◽  
Adverse Environmental Conditions

Abstract Cladocerans are a diverse group of species that show rapid responses to changes in environmental conditions. This adaptive capacity has important implications for egg production and life cycle, especially in transitory environments such as temporary waterbodies. The present study investigated the life history and egg production of Alona gutatta Sars, 1862 (Crustacea, Cladocera), an abundant and frequent species from a high-altitude temporary pond (Lagoa Seca, Minas Gerais, Brazil). Newly hatched neonates were monitored in relation to time of maturation, number of eggs produced per female and time of survival. Neonates required a mean of 8 days to mature. A. guttata survived for a mean of 30.9 ± 8.1 days and produced 2 eggs per brood, generating a mean of 10.95 ± 6.41 neonates during the entire life cycle. The rapid development, short time to produce eggs and long life cycle are important adaptations to the adverse environmental conditions of temporary aquatic environments, which can contribute to the rapid colonization of Alona guttata in transitory ecosystems.

Culture of Arterial Endothelial Cells

1975 ◽  
Vol 34 (03) ◽  
pp. 825-839 ◽  
Author(s):  
Francois M Booyse ◽  
Bonnie J Sedlak ◽  
Max E Rafelson
Keyword(s):  
Endothelial Cells ◽  
Calf Serum ◽  
Intercellular Junctions ◽  
Cell Number ◽  
Population Doubling ◽  
Homogeneous Population ◽  
Bovine Endothelial Cells ◽  
Pinocytotic Vesicles ◽  
Arterial Endothelial Cells ◽  
Doubling Times

SummaryArterial endothelial cells were obtained from bovine aortae by mild treatment with collagenase and medium perfusion. These cells were cultured in RPMI-1640 medium containing 15 mM Hepes buffer and 35% fetal calf serum at pH 7.35. Essentially ah (90–95%) the effluent cells were viable and 80% of these cells attached to the substratum within 1 hour. Small patches of attached cells coalesced to form confluent monolayers in 3–5 days. Confluent monolayers of endothelial cells consisted of a homogeneous population of tightly packed, polygonal cells. Selected cultures were serially subcultured (trypsin-EDTA) for 12–14 months (30–35 passages) without any apparent change in morphology or loss of growth characteristics. Primary and three-month old (15 passages) cultures had population doubling times of 32–34 hours and 29–31 hours, respectively. These cells (primary and subcultures) did not require a minimum cell number to become established in culture. Bovine endothelial cells (primary, first, fifth and thirteenth passages) were characterized ultrastructurally by the presence of Weibel-Palade bodies, pinocytotic vesicles and microfilaments and immunologically by the presence of thrombosthenin-like contractile proteins and Factor VIII antigen. The intercellular junctions of post-confluent cultures stained specifically with silver nitrate. From these data, we concluded that identifiable endothelial cells could be obtained from bovine aortae and cultured and maintained for prolonged periods of time.

Relationships between temperature and Pacific hake distribution vary across latitude and life-history stage

2020 ◽  
Vol 639 ◽  
pp. 185-197 ◽  
Author(s):  
MJ Malick ◽  
ME Hunsicker ◽  
MA Haltuch ◽  
SL Parker-Stetter ◽  
AM Berger ◽  
...  
Keyword(s):  
Life History ◽  
Environmental Effects ◽  
Environmental Conditions ◽  
Vancouver Island ◽  
Additive Models ◽  
Life History Stage ◽  
Fish Stocks ◽  
Merluccius Productus ◽  
Multiple Dimensions ◽  
Effects Of Temperature

Environmental conditions can have spatially complex effects on the dynamics of marine fish stocks that change across life-history stages. Yet the potential for non-stationary environmental effects across multiple dimensions, e.g. space and ontogeny, are rarely considered. In this study, we examined the evidence for spatial and ontogenetic non-stationary temperature effects on Pacific hake Merluccius productus biomass along the west coast of North America. Specifically, we used Bayesian additive models to estimate the effects of temperature on Pacific hake biomass distribution and whether the effects change across space or life-history stage. We found latitudinal differences in the effects of temperature on mature Pacific hake distribution (i.e. age 3 and older); warmer than average subsurface temperatures were associated with higher biomass north of Vancouver Island, but lower biomass offshore of Washington and southern Vancouver Island. In contrast, immature Pacific hake distribution (i.e. age 2) was better explained by a nonlinear temperature effect; cooler than average temperatures were associated with higher biomass coastwide. Together, our results suggest that Pacific hake distribution is driven by interactions between age composition and environmental conditions and highlight the importance of accounting for varying environmental effects across multiple dimensions.

scholarly journals Metabolic traits in brown trout (Salmo trutta) vary in response to food restriction and intrinsic factors

2020 ◽  
Vol 8 (1) ◽  
Author(s):  
Louise C Archer ◽  
Stephen A Hutton ◽  
Luke Harman ◽  
W Russell Poole ◽  
Patrick Gargan ◽  
...  
Keyword(s):  
Life History ◽  
Metabolic Rate ◽  
Intraspecific Variation ◽  
Brown Trout ◽  
Environmental Conditions ◽  
Food Restriction ◽  
Metabolic Rates ◽  
Intrinsic Factors ◽  
Metabolic Traits ◽  
Food Conditions

Abstract Metabolic rates vary hugely within and between populations, yet we know relatively little about factors causing intraspecific variation. Since metabolic rate determines the energetic cost of life, uncovering these sources of variation is important to understand and forecast responses to environmental change. Moreover, few studies have examined factors causing intraspecific variation in metabolic flexibility. We explore how extrinsic environmental conditions and intrinsic factors contribute to variation in metabolic traits in brown trout, an iconic and polymorphic species that is threatened across much of its native range. We measured metabolic traits in offspring from two wild populations that naturally show life-history variation in migratory tactics (one anadromous, i.e. sea-migratory, one non-anadromous) that we reared under either optimal food or experimental conditions of long-term food restriction (lasting between 7 and 17 months). Both populations showed decreased standard metabolic rates (SMR—baseline energy requirements) under low food conditions. The anadromous population had higher maximum metabolic rate (MMR) than the non-anadromous population, and marginally higher SMR. The MMR difference was greater than SMR and consequently aerobic scope (AS) was higher in the anadromous population. MMR and AS were both higher in males than females. The anadromous population also had higher AS under low food compared to optimal food conditions, consistent with population-specific effects of food restriction on AS. Our results suggest different components of metabolic rate can vary in their response to environmental conditions, and according to intrinsic (population-background/sex) effects. Populations might further differ in their flexibility of metabolic traits, potentially due to intrinsic factors related to life history (e.g. migratory tactics). More comparisons of populations/individuals with divergent life histories will help to reveal this. Overall, our study suggests that incorporating an understanding of metabolic trait variation and flexibility and linking this to life history and demography will improve our ability to conserve populations experiencing global change.

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