The life history, nymphal growth rates, and feeding habits of Siphlonisca aerodromia Needham (Ephemeroptera: Siphlonuridae) in Maine

1986 ◽  
Vol 64 (2) ◽  
pp. 427-430 ◽  
Author(s):  
K. Elizabeth Gibbs ◽  
Terry M. Mingo
Keyword(s):  
Growth Rate ◽  
Life History ◽  
Sex Ratio ◽  
Growth Rates ◽  
Feeding Habits ◽  
Main Channel ◽  
Head Width ◽  
Snow Melt ◽  
Animal Material ◽  
Nymphal Growth

Siphlonisca aerodromia Needham has a univoltine life history in Maine. Adults emerge in late May or early June. Each female contains about 394 large (0.46 mm long) eggs covered with coiled fibers that anchor the eggs to the substrate. Eggs are deposited in the main channel of the stream and small nymphs appear in January. Nymphal growth rate (GHW) was expressed as a percent per day increase in head width. Initially nymphs feed on detritus and grow slowly (GHW = 0.28–0.79) at water temperatures near 0 °C. Following snow melt, the nymphs move into the adjacent Carex floodplain. Here, water temperature increases, animal material, in the form of mayfly nymphs, becomes increasingly common in the diet, and growth rate increases (GHW = 2.13–2.89). The sex ratio of nymphs collected in May and June was 1:1.8 (male:female).

Seaweed-associated animal communities in the Firth of Clyde, with special reference to the population biology of the amphipod Hyale nilssoni (Rathke)

1986 ◽  
Vol 90 ◽  
pp. 271-286
Author(s):  
P. G. Moore
Keyword(s):  
Growth Rate ◽  
Life History ◽  
Sex Ratio ◽  
Seasonal Changes ◽  
Population Biology ◽  
Dynamic Equilibrium ◽  
Present Knowledge ◽  
New Work ◽  
Animal Communities ◽  
Breeding Status

SynopisPresent knowledge of animal communities associated with the algae of the Firth of Clyde is briefly reviewed. New work is presented on Hyale nilssoni (Rathke), the commonest amphipod inhabiting high littoral seaweeds, which describes the life-history characteristics over three years of a population associated with Pelvetia. Seasonal changes in growth rate, sex ratio and breeding status are described. Fecundity is investigated and data on brood and egg sizes compared with populations from other latitudes. The dynamic equilibrium between the grazer (Hyale) and the grazed (Pelvetia) is described.

Growth ecology of the tree lizard Urosaurus bicarinatus (Squamata: Phrynosomatidae), in a tropical dry forest of the Chamela Region, Mexico

2016 ◽  
Vol 66 (2) ◽  
pp. 189-199 ◽  
Author(s):  
Aurelio Ramírez-Bautista ◽  
Uriel Hernández-Salinas ◽  
J. Gastón Zamora-Abrego
Keyword(s):  
Growth Rate ◽  
Life History ◽  
Growth Rates ◽  
Average Rate ◽  
Growth Patterns ◽  
Dry Forest ◽  
Von Bertalanffy ◽  
Mexican Pacific ◽  
Males And Females ◽  
Tree Lizard

Determination of growth rate provides an important component of an organism’s life history, making estimations of size at maturity, survival rate, and longevity possible. Here, we report on growth rate of males and females of the tropical tree lizard Urosaurus bicarinatus, in a seasonal environment in the state of Jalisco on the Mexican Pacific Coast. We calculated body growth rates and fitted these to the Von Bertalanffy, the logistic-by-length, and the logistic-by-weight growth models. The Von Bertalanffy model provided the best fit, and we used it to analyze the growth pattern. Males and females did not differ in estimated asymptotic size and other characteristic growth parameters. Estimated growth curve predicted an age at maturity of 38 mm SVL on 120 days for males, and 40 mm SVL on 170 days for females. On the basis of the similarities in the growth rates between the sexes, comparisons were made between seasons, and we found that the average rate of growth was slightly, albeit insignificantly, higher in the rainy season than in the dry season. The similarities in the growth patterns for the sexes of this species might be indicative of variance in its life history traits (e.g., fecundity, egg size) compared to those of other populations of this species and other species of this genus; therefore, it is important to document interpopulation differences to understand the evolutionary changes that have led to optimal adaptation in a particular environment more accurately.

scholarly journals Life history characteristics of a cave isopod (Mesoniscus graniger Friv.)

ZooKeys ◽  
2018 ◽  
Vol 801 ◽  
pp. 359-370 ◽  
Author(s):  
Dávid Derbák ◽  
László Dányi ◽  
Elisabeth Hornung
Keyword(s):  
Life History ◽  
Sex Ratio ◽  
Size Distribution ◽  
Body Length ◽  
Reproductive Strategy ◽  
Population Characteristics ◽  
Female Dominance ◽  
Head Width ◽  
Data Set ◽  
Offspring Number

The special environmental conditions of caves provide habitat for several endemic and relict species, among them terrestrial isopods. The Baradla Cave system (north-eastern Hungary) hosts Mesoniscusgraniger (Frivaldszky, 1865) (Oniscidea, Microcheta, Mesoniscidae), a pygmy, blind, fragile troglophile woodlice species. Its stable environment can be characterised by the lack of light, high relative humidity (96%), low and constant temperature (about 10 °C). We explored the population characteristics (sex ratio, size distribution) and life history traits of the species (e.g. longevity, reproductive strategy, offspring number, and size). Sex ratio and size distribution of the individuals (head-width measurements) were estimated based on a yearly pooled pitfall-trap data set (N = 677). We studied the species’ reproductive strategy under natural conditions (Baradla Cave, Aggtelek National Park). Model populations were set up in the cave and checked monthly between March and October, 2016 (15 replicates, each with 12 randomly chosen adult individuals; ΣN = 180). Digital photos were taken of the live animals and their length was estimated based on the photos by using ImageJ software (average body length: 6.56 ± 0.79 mm). The results showed female dominance in the population [(male:female = 0.43:0.57); p < 0.001 (GLM)]. Female head width (0.87 ± 0.18 mm) was significantly greater than that of males [0.79 ± 0.08 mm; p < 0.001 (t-test)]. Based on our present data we assume that the offspring number per single female is low (3–5), and new-borns have a relatively large size (body length: 4.22 ± 0.53 mm) compared to the adults. The probability of reproduction was continuous by monthly intervals (binomial test) and longevity exceeds one year. Our results suggest that the species follows a stenodynamic life history.

Life history variation in Celleporella hyalina (Bryozoa)

1986 ◽  
Vol 228 (1251) ◽  
pp. 127-132 ◽  
Keyword(s):  
Growth Rate ◽  
Life History ◽  
Sex Ratio ◽  
Water Flow ◽  
Reproductive Output ◽  
Life History Strategy ◽  
Colony Growth ◽  
Allocation Of Resources ◽  
Life History Variation ◽  
Male And Female

In colonies of the cheilostome bryozoan Celleporella hyalina (L.), water flow regime has a significant effect on colony growth rate and, indirectly, on the number of reproductive zooids produced. Higher growth rates occur under conditions of higher water flow. Sex ratio and reproductive output are not, however, significantly affected. Colonies of different genotypes show significant differences in their reproductive versus somatic investment, and in their allocation of resources to male and female functions. There is therefore genetically based variation in life history strategy within the population of colonies. This variation may reflect limitation of normalizing selection imposed by microenvironmental variability.

Population structure, growth rates and spatial distribution of two dioecious tree species in a wet forest in Puerto Rico

2010 ◽  
Vol 26 (4) ◽  
pp. 433-443 ◽  
Author(s):  
Jimena Forero-Montaña ◽  
Jess K. Zimmerman ◽  
Jill Thompson
Keyword(s):  
Growth Rate ◽  
Puerto Rico ◽  
Life History ◽  
Growth Rates ◽  
Cost Of Reproduction ◽  
Sexual Differences ◽  
Reproductive Costs ◽  
Dioecious Species ◽  
Male And Female ◽  
Males And Females

Abstract:Dioecious plants often exhibit male-biased sex ratios and sexual differences in life history traits such as plant size, growth rate and frequency of flowering, which arise from the different costs of reproduction for male and female plants. In tropical dioecious species sexual differences in reproductive costs have been demonstrated for several subcanopy species, but few canopy dioecious trees have been studied. We recorded the sexual expression of c. 2600 trees of Cecropia schreberiana and Dacryodes excelsa, two canopy dioecious species, during several censuses over 2 y in a 16-ha plot located in ‘subtropical wet forest’ in the Luquillo Mountains, Puerto Rico. There were similar numbers of male and female trees of C. schreberiana but D. excelsa had a female-biased population. Cecropia schreberiana showed no differences in male and female diameter distributions or growth rates, suggesting that reproductive maturation and longevity are similar for both sexes. This lack of differences in size and growth rate in C. schreberiana may result from mechanisms to compensate for the higher cost of reproduction in females, no resource limitation related to its pioneer life-history, or similar male and female reproductive costs. In contrast, D. excelsa males were larger than females, probably because males grow slightly faster than females. This sexual difference in D. excelsa may reflect a higher cost of reproduction in females than in males. Spatial segregation of males and females into different habitats is not common in tropical forest and neither C. schreberiana nor D. excelsa males and females exhibited significant spatial segregation. The contrasting results for these two canopy species reflect their different life history strategies in this hurricane-affected forest.

Relationship between body size and population growth rate in two opportunistic polychaetes

2002 ◽  
Vol 82 (3) ◽  
pp. 403-408 ◽  
Author(s):  
D. Prevedelli ◽  
R. Simonini
Keyword(s):  
Growth Rate ◽  
Body Size ◽  
Sex Ratio ◽  
Population Growth ◽  
Growth Rates ◽  
Life Histories ◽  
Population Growth Rate ◽  
Population Growth Rates ◽  
The Relationship ◽  
Dinophilus Gyrociliatus

The relationship between body size and population growth rate λ has been studied in two species of opportunistic polychaetes, Dinophilus gyrociliatus and Ophryotrocha labronica, which colonize harbour environments. These species exhibit a semi-continuous iteroparous reproductive strategy, are phylogenetically closely-related but differ in body size and in some aspects of their sexuality. Ophryotrocha labronica is about 4 mm in body length, displays only slight sexual dimorphism and its sex ratio is biased towards the female sex in the ratio 2:1. Dinophilus gyrociliatus is about 1 mm in length, the males are extremely small and the sex ratio is strongly biased (3:1) in favour of the females. In spite of the considerable differences in all traits of their life histories and in many demographic parameters, the growth rates of the two populations are very similar. The analyses carried out have shown that the rapid attainment of sexual maturity of D. gyrociliatus gives it an advantage that offsets the greater fecundity of O. labronica. It is very likely that the reproductive peculiarities of D. gyrociliatus help to raise the population growth rates. The ‘saving’ on the male sex achieved both by the shift of the sex ratio in favour of the females and by the reduction in the males' body size would appear to enable D. gyrociliatus to grow at the same rate as O. labronica, a larger and more fecund species.

scholarly journals Ontogenetic changes in the elemental composition and stoichiometry of marine copepods with different life history strategies

2020 ◽  
Vol 42 (3) ◽  
pp. 320-333 ◽  
Author(s):  
Enric Saiz ◽  
Kaiene Griffell ◽  
Albert Calbet
Keyword(s):  
Growth Rate ◽  
Life History ◽  
Elemental Composition ◽  
Growth Rates ◽  
Stoichiometric Composition ◽  
Maximum Growth ◽  
Life History Strategies ◽  
Ontogenetic Variation ◽  
Ontogenetic Changes ◽  
P Content

Abstract We describe the ontogenetic variation in elemental and stoichiometric composition of two copepod species with very contrasted life history patterns, the calanoid Paracartia grani and the cyclopoid Oithona davisae. The first species is a broadcasting, highly productive copepod, whereas the latter is an egg-carrying copepod, much less productive. We reared cultures of both species under conditions of excess food and analyzed their C, N and P composition, and their molar ratios, along development. Both species differed on their specific P content, whereas the specific C and N content were similar. As expected, the specific P content of P. grani was higher, resulting in lower C:P and N:P ratios. Furthermore, we compared our elemental composition data with previously reported stage-specific (nauplii and adult female) maximum growth rates of these two species. We found that for O. davisae, the ontogenetic variation in specific P content agreed with the reported differences in growth rate along development; however, in the case of P. grani, in which juvenile and adult maximum growth rates are similar, the variations in specific P content along development did not reflect the growth rate pattern.

Variation in life-history traits of Plasmodium mexicanum, a malaria parasite infecting western fence lizards: a longitudinal study

2000 ◽  
Vol 78 (7) ◽  
pp. 1230-1237 ◽  
Author(s):  
Rebecca J Eisen
Keyword(s):  
Growth Rate ◽  
Life History ◽  
Growth Rates ◽  
Life History Traits ◽  
Warm Season ◽  
Host Population ◽  
Sand Fly ◽  
Infected Host ◽  
Average Growth ◽  
History Of

The life history of malaria parasites (Plasmodium spp.) is directly related to their transmission, virulence, and population dynamics. I followed the life history of Plasmodium mexicanum in naturally infected western fence lizards (Sceloporus occidentalis) over a 4-year period, using a mark-recapture technique. The life-history traits measured included peak parasitemias and population growth rates of asexual forms, gametocytes, and total parasites. Among malaria infections, variation was high for all measured traits. Growth rates varied up to 11-fold, and among stable infections, average asexual parasitemias ranged from 0.2 to 13.2 and gametocytemias from 0.5 to 66.2 parasites per 1000 erythrocytes. This variation was not related to infection prevalences, which were similar among years and between male and female hosts. Host age and gender were not related to peak parasitemia or average growth rate of asexual forms. However, the growth rate of gametoctyes was higher in older lizards. Gametocytemia and parasitemia were significantly higher late in the warm season, when sand-fly vectors are active. These data reveal that life-history traits of P. mexicanum are highly variable within an infected host population, and that the variation is partially related to the age of the infected host or the time of year the host was examined.

Do phosphorus requirements for RNA limit genome size in crustacean zooplankton?

Genome ◽  
2008 ◽  
Vol 51 (9) ◽  
pp. 685-691 ◽  
Author(s):  
Dag O. Hessen ◽  
Marc Ventura ◽  
James J. Elser
Keyword(s):  
Growth Rate ◽  
Life History ◽  
Body Size ◽  
Genome Size ◽  
Growth Rates ◽  
Life History Strategies ◽  
Crustacean Zooplankton ◽  
Limited Growth ◽  
P Deficiency ◽  
Small Genome

As for most other organisms, genome size in zooplankton differs widely. This may have a range of consequences for growth rate, development, and life history strategies, yet the causes of this pronounced variability are not settled. Here we propose that small genome size may be an evolutionary consequence of phosphorus (P) allocation from DNA to RNA under P deficiency. To test this hypothesis we have compared the two major groups of zooplankton, copepods and cladocerans, that have overlapping niches and body size. Relative to the cladocerans, copepods have a more complex life history and a lower mass-specific P content, while cladocerans tend to have higher P and RNA contents and higher specific growth rates and frequently experience P-limited growth, likely due to a shortage of P for ribosome synthesis. Cladocerans also generally have smaller genomes than copepods (1C = 0.17–0.63 pg DNA·cell–1 vs. 1C = 0.10–10 pg DNA·cell–1). Furthermore, cladocerans have a higher slope of the relationship of body size with DNA content (1.5 vs. 0.28 in copepods) and present almost 15-fold higher RNA:DNA ratios (24.8 in cladocerans vs. 1.6 in copepods). Hence, small genome size in cladocerans could reflect an evolutionary pressure towards “efficient” genomes to conserve a key element needed to maximize growth rate. We do not claim that this is a universal cause of genome size variability, but propose that streamlining of genomes could be related to P conservation rather than energy conservation. This could be relevant for a range of organisms that may suffer P-limited growth rates.

scholarly journals Influence of trematode infections on in situ growth rates of Littorina littorea

1999 ◽  
Vol 79 (3) ◽  
pp. 425-430 ◽  
Author(s):  
Kim N. Mouritsen ◽  
A. Gorbushin ◽  
K. Thomas Jensen
Keyword(s):  
Growth Rate ◽  
Life History ◽  
Growth Rates ◽  
Environmental Conditions ◽  
Differential Effect ◽  
Littorina Littorea ◽  
In Situ Growth ◽  
Trematode Infections ◽  
Effect On Growth

The influence of various species of digenean trematodes on the in situ growth rate of Littorina littorea (Gastropoda: Prosobranchia) from different habitats was investigated. The main results showed: (1) that infections either reduced or had no significant effect on growth in comparison with uninfected snails; (2) that the same type of infection could have a differential effect on growth depending on the habitat/population from which the snails originated. These findings are consistent with the life history hypothesis expecting no or a stunting effect of trematode infections on the growth of longer-lived snails, but do also emphasize that growth rates following trematode invasion can be significantly modified by environmental conditions, such as, food availability.

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