Life history adaptations of the fingernail clams Sphaerium occidentale and Musculium securis to ephemeral habitats

1981 ◽  
Vol 59 (12) ◽  
pp. 2219-2229 ◽  
Author(s):  
P. M. McKee ◽  
G. L. Mackie
Keyword(s):  
Life History ◽  
Life Cycle ◽  
Life Histories ◽  
Stochastic Theory ◽  
Environmental Stresses ◽  
Temporary Pond ◽  
Continue Development ◽  
Large Numbers ◽  
Fingernail Clams ◽  
Ephemeral Habitats

Life histories of the fingernail clams Sphaerium occidentale and Musculium securis from a temporary pond are examined to show adaptations to ephemeral habitats. Musculium securis ceases growth upon birth and only newborn occur in the dry pond, whereas all length classes of S. occidentale are omnipresent. Aestivation is not obligatory in the life cycle of either species. Both grow and reproduce regardless of aestivation experience.Life history strategies of both clams counteract environmentally imposed, density-independent mortality pressures. Sphaerium occidentale has slower growth and greater longevity than M. securis which must complete its life cycle before the pond dries. During aestivation, broods continue development in S. occidentale but not in M. securis. If water is present in fall, both opportunistically use this period for development. Both produce large numbers of small newborn and exhibit multivoltine and iteroparous strategies, although M. securis releases consecutive broods only during a single spring birth period and only if the aquatic season is extended, whereas S. occidentale releases consecutive broods during a spring birth period, in autumn if water is present, and during a 2nd year. A mixed tactic, according to the stochastic theory, has been adopted by both for survival under highly variable environmental stresses.

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.

A contribution to the morphology and life history of Proteocephalus niloticus (Beddard, 1913) from Varanus niloticus (L.) in Ghana

Parasitology ◽  
1963 ◽  
Vol 53 (1-2) ◽  
pp. 201-215 ◽  
Author(s):  
Gwendolen Rees
Keyword(s):  
Life History ◽  
Life Cycle ◽  
Technical Staff ◽  
Large Numbers ◽  
History Of ◽  
The University ◽  
University Of Ghana ◽  
Zoology Department

1. A plerocercoid of ‘Acanthotaenia’ has been found in large numbers in ‘cysts’ in the pancreas of Rana occipitalis (Günther) in Ghana.2. ‘Cysts’ containing plerocercoids were fed to Varanus niloticus (L.). Adults of Proteocephalus niloticus (Beddard) were recovered from the intestine 3 weeks later.3. It is suggested that the life cycle involves three hosts, the first being a copepod.4. The morphology of the larva and adult is described.I wish to express my sincere gratitude to the authorities of the University of Ghana for inviting me to spend some time in the Zoology Department there. I am most grateful, also, to Professor R. D. Purchon for his kindly interest and for the facilities which he placed at my disposal. It is a pleasure to thank Dr J. D. Thomas and the technical staff for their assistance in the collection of material.

Respiratory Adaptations of the Fingernail Clams Sphaerium occidentale and Musculium securis to Ephemeral Habitats

1983 ◽  
Vol 40 (6) ◽  
pp. 783-791 ◽  
Author(s):  
Paul M. McKee ◽  
Gerald L. Mackie
Keyword(s):  
Oxygen Uptake ◽  
Life Histories ◽  
Natural Habitat ◽  
Pond Water ◽  
Temperature Acclimation ◽  
Early Summer ◽  
Temporary Pond ◽  
Obligate Aerobe ◽  
Fingernail Clams ◽  
Growth And Reproduction

Experiments performed on seasonal collections of the pisidiids Sphaerium occidentale and Musculium securis from a temporary pond suggest that respiratory adaptations are related to the specific life histories of the two species. Sphaerium occidentale lives up to 3 yr and all age classes aestivate during dry periods, while M. securis lives for about 1 yr and only newborn aestivate. Both species are iteroparous and reproduce primarily in late spring and early summer. Oxygen uptake rates at field temperature and Q10 values are low in both species during hibernation and aestivation, indicating respiratory stability and energy conservation. These rates and respiratory coefficients peak in spring during maximal growth and reproduction. Respiration in M. securis is more independent of temperature than in S. occidentale, reflecting the requirement of the former to complete growth and reproduction more quickly. Both animals show temperature acclimation patterns permitting early activity in spring and, thus, a more efficient exploitation of the short aquatic season. This pattern is more pronounced in the shorter lived M. securis. During aestivation, M. securis is a facultative anaerobe, while S. occidentale is an obligate aerobe. Neither species displays an oxygen debt following aestivation when immersed in water. Arousal from aestivation, as indicated by oxygen uptake, is delayed when clams are introduced to pond water. This apparently inhibits a premature resumption of activity and decreases the likelihood of desiccation in the natural habitat.

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 The chromosome cycle in Coccidia and Gregarines

1915 ◽  
Vol 89 (610) ◽  
pp. 83-94 ◽  
Keyword(s):  
Life History ◽  
Life Cycle ◽  
Chromosome Numbers ◽  
Life Histories ◽  
The Other ◽  
Chromosome Cycle ◽  
History Of ◽  
Careful Investigation

Despite the large amount of work which has already been devoted to the study of the Coccidia and Gregarines, very little indeed is known definitely about the behaviour of the chromosomes in these Protozoa. Not only has the chromosome cycle been left uninvestigated and undescribed in the majority of these organisms which have hitherto been studied, but the very existence of chromosomes in the nuclear divisions at many stages in the life-history of certain forms has even been denied; and the most contradictory and unsatis­factory accounts have been given of that most important phase in the life-cycle of the chromosomes—the phase of meiosis, or reduction. In order to fill up this gap in our knowledge of the Sporozoa, we have made —during the last few years—a very detailed study of the chromosomes of a coccidian and a gregarine. One of us (C. D.) has investigated the coccidian Aggregate eberthi Labbé, whilst the other (A. P. J.) has studied the gregarine Diplocystis schneideri Kunstler. Careful investigation of these two organisms has shown that the nuclear divisions at all stages in the life-histories are mitotic, and that the chromosome numbers are remarkably constant.

Life Histories of Charophytes from Permanent and Temporary Wetlands in Eastern Australia

1999 ◽  
Vol 47 (3) ◽  
pp. 383 ◽  
Author(s):  
Michelle T. Casanova ◽  
Margaret A. Brock
Keyword(s):  
Life History ◽  
Sexual Reproduction ◽  
Vegetative Growth ◽  
Life Histories ◽  
Distribution Patterns ◽  
Reproductive Organs ◽  
Annual Species ◽  
Large Numbers ◽  
Eastern Australia ◽  
Life History Patterns

The results of an experiment on the demography of charophytes in permanent and temporary sites in two wetlands are outlined and the charophytes that germinated and established are described in relation to their life histories. Three life-history patterns are represented. First, Monoecious annual species germinate easily and rapidly after inundation, they grow quickly and initiate sexual reproduction at the expense of vegetative expansion, produce relatively few, large oospores and die in winter. Second, Dioecious annual species are slower to germinate than Monoecious annuals, they grow more slowly, but also initiate sexual reproduction early in life. They usually produce large numbers of small oospores and die in unfavourable seasons. Both winter-growing and summer-growing Dioecious annuals were represented in experiments. Third, Dioecious perennials germinate after a lag time and establishment; vegetative growth and expansion takes place early in spring. Reproduction in Dioecious perennials is stimulated by increasing water temperatures and other environmental cues. Vegetative reproductive organs are produced in autumn and individual shoots can be very long-lived. Life-history parameters such as germination requirements, establishment requirements and timing of vegetative growth and reproduction can be important in determining the distribution patterns in charophytes.

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.

Trichoptera of a Victorian forest stream: Species composition and life histories

1987 ◽  
Vol 38 (6) ◽  
pp. 845 ◽  
Author(s):  
JC Dean ◽  
DI Cartwright
Keyword(s):  
Life History ◽  
Species Richness ◽  
Life Cycle ◽  
Species Composition ◽  
Life Histories ◽  
Abundant Species ◽  
Early Summer ◽  
The Other ◽  
Leaf Pack ◽  
Forest Stream

The species composition and life histories of the Trichoptera of a Victorian forest stream were investigated for 21 months. Monthly samples were collected from zones of fast current in midstream over the whole study period, and also from side riffles and leaf-pack accumulations for periods of 7 and 8 months, respectively. In all, 40 species were recorded as larvae, and it is suggested that species richness is similar to comparable streams in the Northern Hemisphere. The communities of all three biotopes were dominated by Tamasia acuta (Calocidae). Information is presented on life histories of the nine most abundant species. Ethochorema turbidum (Hydrobiosidae) exhibited a non-seasonal life history, while the remaining eight species were seasonal and displayed varying degrees of synchrony. Tamasia acuta required 2-3 years to complete the life cycle, Alloerella grisea (Helicophidae) required 1-2 years, and the other six species were univoltine. Agapetus monticolus and A. kimminsi (Glossosomatidae) were temporally segregated, with the former emerging in spring and early summer and the latter in summer and autumn.

Hormones and Behavior

2019 ◽  
pp. 11-26
Author(s):  
Maren N. Vitousek ◽  
Laura A. Schoenle
Keyword(s):  
Life History ◽  
Life Histories ◽  
Life History Traits ◽  
Developmental Plasticity ◽  
Endocrine System ◽  
Phenotypic Traits ◽  
Social Environments ◽  
Trade Offs ◽  
And Behavior

Hormones mediate the expression of life history traits—phenotypic traits that contribute to lifetime fitness (i.e., reproductive timing, growth rate, number and size of offspring). The endocrine system shapes phenotype by organizing tissues during developmental periods and by activating changes in behavior, physiology, and morphology in response to varying physical and social environments. Because hormones can simultaneously regulate many traits (hormonal pleiotropy), they are important mediators of life history trade-offs among growth, reproduction, and survival. This chapter reviews the role of hormones in shaping life histories with an emphasis on developmental plasticity and reversible flexibility in endocrine and life history traits. It also discusses the advantages of studying hormone–behavior interactions from an evolutionary perspective. Recent research in evolutionary endocrinology has provided insight into the heritability of endocrine traits, how selection on hormone systems may influence the evolution of life histories, and the role of hormonal pleiotropy in driving or constraining evolution.

scholarly journals Classical soloists’ life histories and the music conservatoire

2021 ◽  
pp. 025576142199115
Author(s):  
Tim Palmer ◽  
David Baker
Keyword(s):  
Higher Education ◽  
Life History ◽  
Life Histories ◽  
Qualitative Data ◽  
Classical Music ◽  
Loss Of Autonomy ◽  
Cultural Interest ◽  
Concert Pianist ◽  
Analytic Induction ◽  
Musical Excellence

This article explores the life histories of virtuoso classical music soloists with particular reference to conservatoire provision. Detailed life-history interviews were conducted with six virtuosi between May 2018 and January 2019. These participants were three singers, two cellists and a concert pianist. Resultant qualitative data were stored in an NVivo software database and understood through a process of analytic induction. Key findings spotlight the significance of Higher Education, a connection between broad creative and cultural interest and musical excellence, and a significant role for conservatoires in diversifying their training and easing transition into the career. The soloists also warned of dangers relating to controlling teachers, loss of autonomy and a need to convey their career realities to students.

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