scholarly journals Selected life history traits of Leptaxis simia (Gastropoda: Hygromiidae) established in the laboratory

2021 ◽  
Vol 67 (4) ◽  
pp. 367-376
Author(s):  
Elżbieta Kuźnik-Kowalska ◽  
Robert A. D. Cameron ◽  
Małgorzata Proćków
Keyword(s):  
Sexual Maturity ◽  
Life History Traits ◽  
Shell Growth ◽  
Land Snail ◽  
Reproductive Capacity ◽  
Juvenile Growth ◽  
Full Size ◽  
Mode Of Reproduction ◽  
Long Period ◽  
In Captivity

Among ten adult specimens of the Madeiran endemic land snail Leptaxis simia kept in the laboratory, a single clutch of 110 eggs was reared, and the mortality, growth and reproductive capacity of hatchlings over a 1240- day period were monitored. Of 70 hatchlings, 34 survived to complete shell growth at around 640 days. Growth was rapid, and mortality high in the early stages; growth slowed and mortality was very low as full size was approached. Snails kept singly failed to lay any eggs. Among those with potential mates, only three clutches were produced, one of which yielded no hatchlings. Clutches were produced at least five months after shell growth was complete. Mortality increased sharply after the onset of sexual maturity, and the oldest snail survived for three and a half years. The apparently very strictly semelparous mode of reproduction, delayed sexual maturity and relatively long period of juvenile growth are discussed in relation to other species, and to the practical problems of rearing potentially endangered species in captivity.

scholarly journals Cost of autotomy drives ontogenetic switching of anti-predator mechanisms under developmental constraints in a land snail

2012 ◽  
Vol 279 (1748) ◽  
pp. 4811-4816 ◽  
Author(s):  
Masaki Hoso
Keyword(s):  
High Efficiency ◽  
Shell Growth ◽  
Land Snail ◽  
Life History Strategies ◽  
Body Parts ◽  
Developmental Constraint ◽  
Developmental Constraints ◽  
Evolution Of Life ◽  
Snake Range ◽  
In The Wild

Autotomy of body parts offers various prey animals immediate benefits of survival in compensation for considerable costs. I found that a land snail Satsuma caliginosa of populations coexisting with a snail-eating snake Pareas iwasakii survived the snake predation by autotomizing its foot, whereas those out of the snake range rarely survived. Regeneration of a lost foot completed in a few weeks but imposed a delay of shell growth. Imprints of autotomy were found in greater than 10 per cent of S. caliginosa in the snake range but in only less than 1 per cent out of it, simultaneously demonstrating intense predation by the snakes and high efficiency of autotomy for surviving snake predation in the wild. However, in experiments, mature S. caliginosa performed autotomy less frequently. Instead of the costly autotomy, they can use defensive denticles on the inside of their shell apertures. Owing to the constraints from the additive growth of shells, most pulmonate snails can produce these denticles only when they have fully grown up. Thus, this developmental constraint limits the availability of the modified aperture, resulting in ontogenetic switching of the alternative defences. This study illustrates how costs of adaptation operate in the evolution of life-history strategies under developmental constraints

scholarly journals Sexual Maturity in Adolescents Suffering from Sickle Cell Disease: A Cross-sectional Study

2021 ◽  
Author(s):  
Vijay Shah ◽  
Akash Patel ◽  
Praful Bambharoliya ◽  
Jigisha Patadia
Keyword(s):  
Sickle Cell Disease ◽  
Sickle Cell ◽  
Sexual Maturity ◽  
Tanner Stage ◽  
Cross Sectional Study ◽  
Reproductive Capacity ◽  
Sectional Study ◽  
Cell Disease ◽  
Cross Sectional ◽  
The Mean

Introduction: Sickle Cell Disease (SCD) is an inherited chronic haemolytic anaemia. The diseased person suffers from various complications such as anaemia, frequent infection, fever, hand-foot syndrome, stroke, etc. Puberty changes includes the appearance of the secondary sexual characteristics, increase in height, change in body composition and development of reproductive capacity. Aim: To study the sexual maturity and effect of multiple blood transfusions in adolescents suffering from SCD. Materials and Methods: It was a cross-sectional study conducted on 35 adolescents of age group 11 to 15 years, suffering from SCD. Study was conducted over a period of six months from March 2018 to September 2018 at Department of Paediatrics. SCD was diagnosed by Haemoglobin (Hb) electrophoresis. Weight and height were measured of all the participants. For assessing the sexual maturity, Tanners staging was used. Unpaired t-test was done for data analysis. Results: The mean age of the patients was 13.03±1.7 years. There were 25 males and 10 females. The mean age of male patients between Tanner stage 2(14.63±0.52 years) and Tanner stage 3 (14.75±0.5 years) was significantly higher than the Indian data for males (11.3 and 12.8 years, respectively). The mean age of female patients between Tanner stages 2 (13.5±2.12 years) and Tanner stage 3 (14.33±1.16 years) was higher than the Indian reference data for girls (10.2 and 11.6 years respectively). Conclusion: This study concluded that adolescents with SCD were significantly shorter in height and weight than the standard reference population. Sexual maturity is delayed in adolescents with sickle cell anaemia.

Chamelea gallina reproductive biology and Minimum Conservation Reference Size: implications for fishery management in the Adriatic Sea

BMC Zoology ◽  
2021 ◽  
Vol 6 (1) ◽  
Author(s):  
Giada Bargione ◽  
Fortunata Donato ◽  
Giulio Barone ◽  
Massimo Virgili ◽  
Pierluigi Penna ◽  
...  
Keyword(s):  
Sexual Maturity ◽  
Adriatic Sea ◽  
Seawater Temperature ◽  
Reproductive Capacity ◽  
Great Effort ◽  
Important Species ◽  
Spawning Period ◽  
The Past ◽  
Chamelea Gallina ◽  
Size At Sexual Maturity

Abstract Background The striped venus clam Chamelea gallina is an economically important species in Adriatic Sea fisheries. The use of hydraulic dredging for its catch has a long history in Italy and its management faced several stages of development in the last 40 years. A great effort has been made in the past two decades to move from poorly or weakly managed fisheries to a well-structured co-management system to improve the sustainability of this fishery. However, a prerequisite for appropriate resource management is a sound knowledge of the biology and reproductive strategy of the species. Results We investigated three major biological features– the gametogenic cycle, size at sexual maturity and partial fecundity – by microscopic, histological and video analysis techniques. We demonstrated that its breeding season is driven by rises in seawater temperature and chlorophyll-a concentration and that its spawning period lasted from March to September. Size at sexual maturity was reached very early in the life cycle. As regards partial fecundity – the number of mature oocytes potentially released by females with ripe gonads in a single release event – varied in relation to size. Nevertheless, the reduction on the Minimum Conservation Reference Size (MCRS) from 25 to 22 mm (Delegated Regulation (EU) 2020/2237) lead to a 40% reduction in the number of emitted eggs. Conclusions We suggest that the ability of Adriatic clam stocks to withstand the strong fishing pressure of the past 40 years and the present one is due to their high reproductive potential and multiple spawning events combined with the effect of management measures (closed areas/seasons, quota, MCRS) and technical constraints on the gear and the sieve on board. Moreover, since the reduced MCRS for Venus shells is still larger than the size at maturity, it will probably not be detrimental to the reproductive capacity of the stock.

scholarly journals Life history traits of the temperate mini-maximalist Idiosepius notoides, (Cephalopoda: Sepioidea)

2003 ◽  
Vol 83 (6) ◽  
pp. 1297-1300 ◽  
Author(s):  
Sean R. Tracey ◽  
Mike A. Steer ◽  
Gretta T. Pecl
Keyword(s):  
Life History ◽  
Growth Rates ◽  
Sexual Maturity ◽  
Life History Traits ◽  
Mantle Length ◽  
Power Curve ◽  
Short Life ◽  
Gender Dimorphism ◽  
Cephalopod Species

Age, growth and maturation of the temperate ‘mini-maximalist’ Idiosepius notoides from Tasmania is described and compared with those of its tropical congener Idiosepius pygmaeus. Using statolith increment analysis, growth of I. notoides was best described by a power curve with a maximum age of 115 days recorded. Males have a shorter lifespan than females, however growth rates were similar between the sexes. Idiosepius notoides grows to a larger size than its tropical counterpart. Onset of maturity in I. notoides occurred at an age of approximately 68 days for males and 88 days for females compared to 45–60 days for I. pygmaeus. Size at onset of sexual maturity was analogous between the two species, with males mature at approximately 6·5 mm mantle length (ML) and females at 14·0 mm ML. Idiosepius notoides, like I. pygmaeus, is a small short-lived sepioid with significant gender dimorphism and the capacity to spawn multiple times throughout its short life. This research supports the concept of similar cephalopod species living longer and growing larger in cooler environments.

Late-glacial to Holocene transition in northern Spain deduced from land-snail shelly accumulations

2012 ◽  
Vol 78 (2) ◽  
pp. 373-385 ◽  
Author(s):  
Yurena Yanes ◽  
Igor Gutiérrez-Zugasti ◽  
Antonio Delgado
Keyword(s):  
Shell Growth ◽  
Late Glacial ◽  
Land Snail ◽  
Balance Model ◽  
Adult Size ◽  
Northern Spain ◽  
Shell Size ◽  
Juvenile Stages ◽  
Climate Fluctuation ◽  
Extreme Seasonality

AbstractShells of the helicid Cepaea nemoralis were studied using taphonomic, isotopic and morphometric measurements to estimate late glacial–Holocene (~ 12.1–6.3 cal ka BP) environmental conditions in northern Spain. Higher taphonomic alteration among Holocene shells suggests lower sedimentation rates or higher shell-destruction rates than during glacial conditions. Shells preserved the aragonitic composition despite differing degree of skeleton damage. Shell δ13C values were − 10.3 ± 1.1‰, − 8.2 ± 2.3‰, and − 7.3 ± 1.6‰ for modern, Holocene and late-glacial individuals, respectively. Higher δ13C values during the late-glacial and some Holocene periods imply higher water stress of C3 plants and/or higher limestone contribution than today. Intrashell δ13C values were higher during juvenile stages suggesting higher limestone ingestion to promote shell growth. Shell δ18O values were − 1.1 ± 0.7‰, − 0.9 ± 0.8‰ and − 0.1 ± 0.7‰ for modern, Holocene and late-glacial specimens, respectively. A snail flux-balance model suggests that during ~ 12.1 − 10.9 cal ka BP conditions were drier and became wetter at ~ 8.4 − 6.3 cal ka BP and today. Intrashell δ18O profiles reveal that glacial individuals experienced more extreme seasonality than interglacial shells, despite possible larger hibernation periods. Shell size correlated positively with δ18O values, suggesting that growth rates and ultimate adult size of C. nemoralis may respond to climate fluctuation in northern Spain.

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.

Reproductive hormone monitoring of dugongs in captivity: Detecting the onset of sexual maturity in a cryptic marine mammal

2013 ◽  
Vol 140 (3-4) ◽  
pp. 255-267 ◽  
Author(s):  
Elizabeth A. Burgess ◽  
Wendy H. Blanshard ◽  
Andrew D. Barnes ◽  
Sam Gilchrist ◽  
Tamara Keeley ◽  
...  
Keyword(s):  
Marine Mammal ◽  
Sexual Maturity ◽  
Reproductive Hormone ◽  
In Captivity

Larval intraspecific competition for food in the European grapevine moth Lobesia botrana

2014 ◽  
Vol 104 (4) ◽  
pp. 517-524 ◽  
Author(s):  
D. Thiéry ◽  
K. Monceau ◽  
J. Moreau
Keyword(s):  
Life History ◽  
Intraspecific Competition ◽  
Life History Traits ◽  
Larval Mortality ◽  
Lobesia Botrana ◽  
Reproductive Capacity ◽  
Strong Increase ◽  
European Grapevine Moth ◽  
Grapevine Moth ◽  
Larval Crowding

AbstractEffective pest management with lower amounts of pesticides relies on accurate prediction of insect pest growth rates. Knowledge of the factors governing this trait and the resulting fitness of individuals is thus necessary to refine predictions and make suitable decisions in crop protection. The European grapevine moth, Lobesia botrana, the major pest of grapes in Europe, is responsible for huge economic losses. Larvae very rarely leave the grape bunch on which they were oviposited and thus cannot avoid intraspecific competition. In this study, we determined the impact of intraspecific competition during the larval stage on development and adult fitness in this species. This was tested by rearing different numbers of larvae on an artificial diet and measuring developmental and reproductive life history traits. We found that intraspecific competition during larval development has a slight impact on the fitness of L. botrana. The principal finding of this work is that larval density has little effect on the life history traits of survivors. Thus, the timing of eclosion, duration of subsequent oviposition, fecundity appears to be more uniform in L. botrana than in other species. The main effect of larval crowding was a strong increase of larval mortality at high densities whereas the probability of emergence, sex ratio, pupal mass, fecundity and longevity of mated females were not affected by larval crowding. Owing to increased larval mortality at high larval densities, we hypothesized that mortality of larvae at high densities provided better access to food for the survivors with the result that more food was available per capita and there were no effect on fitness of survivors. From our results, larval crowding alters the reproductive capacity of this pest less than expected but this single factor should now be tested in interaction with limited resources in the wild.

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