scholarly journals Carex secalina (Cyperaceae), a species critically endangered in Europe: from propagule germination to propagule production

2011 ◽  
Vol 74 (2) ◽  
pp. 141-147 ◽  
Author(s):  
Waldemar Żukowski ◽  
Marlena Lembicz ◽  
Paweł Olejniczak ◽  
Agnieszka Bogdanowicz ◽  
Julian Chmiel
Keyword(s):  
Life History ◽  
Small Area ◽  
Critically Endangered ◽  
Age At First Reproduction ◽  
The Third ◽  
Germination Ability ◽  
First Reproduction ◽  
History Of ◽  
Selected Traits ◽  
And Bisexual

The size and reproduction ability of the three field populations of <em>Carex secalina</em> Willd. ex Wahlenb. have been assessed. In the parallel garden study selected traits from the life history of the species have been studied, such as age at first reproduction, fertility, the size of seeds, their germination ability and size of seedlings. The populations of <em>C. secalina</em> discovered in Poland in 2000 are characterised by small abundance and small area. All individuals from the three populations in the garden produced generative shoots in the third year of life. Statistically significant differences between the populations were found in the production of shoots with unisexual spikes and bisexual ones, the latter had not been reported in the hitherto literature on the species. The seeds started germinating after a 6-months rest. The first seedlings were observed in the first decade of May. The largest seedlings were noted in the population producing the smallest seeds. The results contribute to explaining the renewal of the populations of this species in the field.

scholarly journals Palaeohistology reveals a slow pace of life for the dwarfed Sicilian elephant

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Meike Köhler ◽  
Victoria Herridge ◽  
Carmen Nacarino-Meneses ◽  
Josep Fortuny ◽  
Blanca Moncunill-Solé ◽  
...  
Keyword(s):  
Life History ◽  
Body Mass ◽  
Growth Period ◽  
Extended Period ◽  
Island Rule ◽  
Rule Based ◽  
Age At First Reproduction ◽  
Slow Pace ◽  
First Reproduction ◽  
Adaptive Shifts

AbstractThe 1-m-tall dwarf elephant Palaeoloxodon falconeri from the Pleistocene of Sicily (Italy) is an extreme example of insular dwarfism and epitomizes the Island Rule. Based on scaling of life-history (LH) traits with body mass, P. falconeri is widely considered to be ‘r-selected’ by truncation of the growth period, associated with an early onset of reproduction and an abbreviated lifespan. These conjectures are, however, at odds with predictions from LH models for adaptive shifts in body size on islands. To settle the LH strategy of P. falconeri, we used bone, molar, and tusk histology to infer growth rates, age at first reproduction, and longevity. Our results from all approaches are congruent and provide evidence that the insular dwarf elephant grew at very slow rates over an extended period; attained maturity at the age of 15 years; and had a minimum lifespan of 68 years. This surpasses not only the values predicted from body mass but even those of both its giant sister taxon (P. antiquus) and its large mainland cousin (L. africana). The suite of LH traits of P. falconeri is consistent with the LH data hitherto inferred for other dwarfed insular mammals. P. falconeri, thus, not only epitomizes the Island Rule but it can also be viewed as a paradigm of evolutionary change towards a slow LH that accompanies the process of dwarfing in insular mammals.

The life history of Cooperia Pectinata Ransom

1967 ◽  
Vol 15 (4) ◽  
pp. 739 ◽  
Author(s):  
RK Keith
Keyword(s):  
Life History ◽  
Infective Larva ◽  
Patent Period ◽  
The Third ◽  
History Of

Observations are reported on the morphology of the egg and infective larva, and on the development in calves of the parasitic stages of Cooperia pectinata Ransom. The third and fourth moults occurred 2 and 8 days, respectively, after infection. The pre-patent period was 13-14 days.

The Evolution of Life History Parameters in Teleosts

1984 ◽  
Vol 41 (6) ◽  
pp. 989-1000 ◽  
Author(s):  
Derek A. Roff
Keyword(s):  
Growth Rate ◽  
Life History ◽  
Life History Theory ◽  
Larval Survival ◽  
Reasonable Assumption ◽  
Natural Mortality ◽  
Age At First Reproduction ◽  
Life History Parameters ◽  
First Case ◽  
First Reproduction

Empirical studies have shown that in teleosts there is a significant correlation between the life history parameters, age at first reproduction, natural mortality, and growth rate. In this paper 1 hypothesize that these correlations are the result of evolutionary adjustments due to the trade-off between reproduction, growth, and survival. A simple and reasonable assumption is that the costs of reproduction are sufficient to cause the ltmt function to decrease. A simple expression relating the age at first reproduction is derived from this assumption. This formula accounts for a statistically significant portion (60.6%) of the variation in age at first reproduction in 30 stocks of fish. To extend the model to predict the distribution of life history parameters across all teleosts, an explicit cost function is incorporated. The model is analyzed with respect to two fitness measures, the expected lifetime fecundity and malthusian parameter, r. In the first case it is shown that the optimal age at maturity, T, depends only on the natural mortality rate (M) and the growth rate (k). In the second case, T is a function of k and the logarithm of a parameter, In C; the latter is a product of egg and larval survival, maximum body length (Lx), and the proportionality coefficient of the fecundity/length function. Difficulties of measuring egg and larval survival make the testing of the latter case difficult for particular species. However, this method provides a simple formula for the computation of r; this is shown generally to be approximately zero, thereby adding strength to the assumptions of the first analysis. The distribution patterns of T on k and M on k are predicted and compared with the observed pattern. In general, the predictions are validated: however, certain combinations of k and ln C are shown to occur very infrequently. The prediction of such "empty" regions of the parameter space remains a challenge for future development of life history theory.

Presence of the cerambycid beetles Psacothea hilaris and Monochamus alternatus affecting the life cycle strategy of Bursaphelenchus xylophilus

Nematology ◽  
2001 ◽  
Vol 3 (5) ◽  
pp. 455-461 ◽  
Author(s):  
Noritoshi Maehara ◽  
Kazuyoshi Futai
Keyword(s):  
Life History ◽  
Bursaphelenchus Xylophilus ◽  
Pinewood Nematode ◽  
Fourth Stage ◽  
Monochamus Alternatus ◽  
The Third ◽  
Life Cycle Strategy ◽  
Pine Trees ◽  
History Of ◽  
Cerambycid Beetles

AbstractAlthough fourth-stage dispersal juveniles (JIV) of Bursaphelenchus xylophilus, the pinewood nematode (PWN), developed in the presence of both Monochamus alternatus and Psacothea hilaris, the numbers and the percentage of JIV were far higher in the presence of the former than of the latter. JIV first appeared 7 days after pupation of M. alternatus and the number increased from the day of beetle eclosion to the third day thereafter, then remained stable. We conclude that the presence of specific vectors affects both the life history of the PWN and the numbers of nematodes carried by vectors emerging from killed pine trees.

scholarly journals Effects of non-toxic filamentous cyanobacteria isolated from tri an reservoir on Daphnia

2020 ◽  
Vol 42 (3) ◽  
Author(s):  
Pham Thanh Luu ◽  
Tran Thi Hoang Yen ◽  
Tran Thanh Thai ◽  
Ngo Xuan Quang ◽  
Hoang Nghia Son
Keyword(s):  
High Performance Liquid Chromatography ◽  
Life History ◽  
Liquid Chromatography ◽  
Secondary Metabolites ◽  
High Performance ◽  
Toxic Effects ◽  
Filamentous Cyanobacteria ◽  
Age At First Reproduction ◽  
Bioactive Secondary Metabolites ◽  
First Reproduction

This study is aimed to examine whether the presence of non-toxic filamentous cyanobacteria can cause toxic effects on Daphnia magna. Six strains of Oscillatoria perornata were isolated from the Tri An Reservoir and cultured in our laboratory for investigation. The results revealed that all strains were negative with the mcyA moleculer marker. The high performance liquid chromatography (HPLC) results showed that toxin was not detected in their culture products, indicating that these strains corresponded to non-toxin producing strains. However, the results of chronic assay indicated that these non-toxin producing O. perornata conferred toxic effects on the tested animals. The age at first reproduction of D. magna was delayed and the survival of D. manga decreased in proportional with the increase of the density of cells of O. perornata exposed. Significant differences in the life history responses were observed for D. mangna exposed to O. perornata. These results suggested that bioactive secondary metabolites other than microcystins produced by the filamentous cyanobacteria O. perornata may contribute to the toxic effects on Daphnia. Besides cyanotoxins, other secondary metabolites must be taken into account when investigating the toxic effects of cyanobacteria.   

Larvae of Ceratophyllus wickhami and other Species of Fleas

Parasitology ◽  
1930 ◽  
Vol 22 (2) ◽  
pp. 242-259 ◽  
Author(s):  
Enid K. Sikes
Keyword(s):  
Life History ◽  
Seventeenth Century ◽  
Instar Larva ◽  
Grey Squirrel ◽  
Experimental Conditions ◽  
Tracheal System ◽  
Xenopsylla Cheopis ◽  
The Third ◽  
History Of ◽  
Third Instar Larva

A short historical account is given of the writings on flea larvae since the seventeenth century. The larvae have been known since Leeuwenhoek tried to breed them in 1683.The life-history of Ceratophyllus wickhami is described. The fleas were bred in the laboratory on a grey squirrel. Three larval instars occur, and the life-history occupies, on an average, 6 weeks under experimental conditions.The external anatomy of the third instar larva of C. wickhami is described. The mouth parts are generalised and suggest the condition of a primitive insect. The tracheal system is composed of a double longitudinal trunk on each side, with spiracles on the prothorax, metathorax and first eight abdominal segments.The first and second instar of C. wickhami are similar to the third instar larvae, except in size and the presence of a hatching spine in the first stage.The larva of Ceratophyllus fasciatus is mentioned. The importance of the species lies in the presence of completely separated galea and lacinia.Larvae of Xenopsylla cheopis and X. astia are briefly described. The larvae of the two species are practically identical except for the shape of the mandibles.

Observations on the life history of the cat Lungworm. Aelurostrongylus abstrusus (Railliet, 1898) (Nematoda: Metastrongylidae)

1957 ◽  
Vol 5 (2) ◽  
pp. 188 ◽  
Author(s):  
MJ Mackerras
Keyword(s):  
Life History ◽  
Lung Tissue ◽  
Prepatent Period ◽  
The Body ◽  
Characteristic Pattern ◽  
Aelurostrongylus Abstrusus ◽  
The Third ◽  
Third Stage ◽  
History Of

First-stage larvae of Aelurostrongylus abstrusus (Railliet) developed readily in the garden slug, Agriolimax laevis (Muller), two moults occurring in this host. When infected slugs were eaten by a cat, the third-stage larvae migrated at once to the lungs, where they underwent the third and fourth moults. The prepatent period in the cat was about 39 days. When infected slugs were fed to laboratory-bred mice, the third-stage larvae were not digested, but congregated in great numbers in the gastro-splenic ligament, forming minute yellowish cysts. They were also recovered in small numbers from other parts of the body. Third-stage larvae survived unchanged in mice for 12 weeks, and probably would survive for longer periods. Mice were regarded as important auxillary hosts. The minute adult worms were found in the bronchioles of the cat. They were always very difficult to locate. The eggs were laid in the alveoli, forming a characteristic pattern of small, solid nodules scattered throughout the lung tissue.

The Life History of Onesia accepta Malloch (Diptera, Calliphoridae)

Parasitology ◽  
1933 ◽  
Vol 25 (3) ◽  
pp. 342-352 ◽  
Author(s):  
Mary E. Fuller
Keyword(s):  
Life History ◽  
Pupal Stage ◽  
Body Cavity ◽  
The Body ◽  
External Morphology ◽  
Feeding Period ◽  
Larval Instars ◽  
The Third ◽  
History Of

The life history of Onesia accepta Mall. is described. This species is parasitic on the earthworm Microscolex dubius Fletcher. The first and second larval instars are passed under the skin and the third instar in the body cavity of the host. The feeding period of the maggot is approximately 20 days, and the pupal stage about 12 days.The external morphology of the three larval instars and of the puparium is described in detail.

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