1st Edition

Reproduction and Development in Platyhelminthes

By T. J. Pandian Copyright 2020
    320 Pages 61 B/W Illustrations
    by CRC Press

    320 Pages 61 B/W Illustrations
    by CRC Press

    This book is a comprehensive elucidation on aspects of reproduction and development in platyhelminthes covering from acoelids to taeniids. With the unique presence of neoblasts, turbellarians serve as a model for studies on cancer and senescence. Of ~ 27,000 species, ~ 77% are parasites; they are harmful to man and his food basket from livestock and fish. The stress hormone, cortisol level is responsible for susceptibility and resistance of the host. In digeneans, the propagatory multiplication potency is retained by all the larval forms and in either direction in sporocyst. The higher clonal diversity, mixing and selection in Second Intermediate Host (SIH) may purge inbreeding depression suffered by the fluke on propagatory multiplication in First Intermediate Host (FIH). Of 12,012 digeneans, 88% may engage 33,014 potential SIH species. They have the choice to select one among the available/awaiting 3.5 host species. The motility of vertebrate host and euryxenic flexibility/scope for selection of SIH species has increased lineage diversification in digeneans. The life cycle of cestodes is divided into aquatic and terrestrial patterns. The former includes (i) oncosphere and (ii) coracidium types and the latter (iii) hexacanth-cysticercoid, (iv) hexacanth-tetrathyridium and (v) hexacanth-cysticercus types. The share for the oncosphere, coracidium and hexacanth types is 17.0, 29.5 and 46.5%, respectively. The staggering fecundity and adoption of the intermediate host in the herbivorous/insectivorous food chain have enriched Taenioidea as the most (2,264) speciose order. Sex specific genes Smed-dmd 1 and macbol have been identified, and neuropeptides and dipeptides are involved in sexualization. Trematodes are unable to parasitize elasmobranchs, as they cannot suck body fluid/blood containing a high level of urea. Relatively higher fecundity supplemented with propagatory multiplication, incorporation of SIH in 88% species, clonal selection in SIH, and euryxenic flexibility and the widest choice for selection of SIH have led to the highest lineage diversification to render digeneans as the most speciose order in Platyhelminthes.

    General Introduction
    Introduction
    Taxonomy and Diversity
    Life Cycles
    Host-Parasite Distribution
    Fecundity
    Osmotrophism and Digestion
    Neoblasts

    Turbellaria
    Introduction
    PART A: GENERAL FEATURES
    Taxonomy and Distribution
    Reproductive System
    Transition to Parasitism
    Contrasting Strategies
    Semelparity and Iteroparity
    Sexuality
    PART B: REGENERATION
    Introduction
    Distribution and Potency
    Cell Counts and Mitosis
    Blastema and Regeneration
    Genes in Regeneration
    PART C: CLONAL REPRODUCTION
    Introduction
    Surgery and Potency
    Clonal Types
    Switching Sexuality
    Telomere and Senescence

    Monogenea
    Introduction
    Taxonomy and Distribution
    Life Cycle and Characteristics
    Host Specificity

    Digenea
    Introduction
    Taxonomy: Parasites and Hosts
    Larval Forms
    Intermediate Hosts
    Clonal Selection
    Amphiparatenic Transmission
    Polyembryony and/or Parthenogenesis
    Sequence and Potency
    The Transmission
    ‘Sweet is Shorter’
    Prevalence and Density
    Causes and Losses

    Cestoda
    Introduction
    Taxonomy and Diversity
    Reproductive System
    Life Cycles
    Neoteny- Progenesis
    Prevalence and Intensity
    Schistocephalus solidus
    Clonal Multiplications
    The Transmission
    Fishes and Losses

    Sexualization
    Introduction
    Chromosomes and Genes
    Endocrine Differentiation
    Endocrine Disruption

    Comparison and Highlights
    Introduction
    Neoblasts Types
    Clonal Selection
    Progenesis
    Habitat Distribution
    Diversification and Speciation

    References

    Biography

    Recipient of the S.S. Bhatnagar Prize, the highest Indian award for scientists, one of the ten National Professorships, T.J. Pandian has served as editor/ member of editorial boards of many international journals. His books on Animal Energetics (Academic Press) identify him as a prolific but precise writer. His five volumes on Sexuality, Sex Determination and Differentiation in Fishes, published by CRC Press, are ranked with five stars. He is presently authoring a multi-volume series on Reproduction and Development of Aquatic Invertebrates, of which the volumes on Crustacea, Mollusca, Echinodermata and Prochordata, and Annelida have already been published. The next one, Platyhelminthes, is in your hands and Minor Phyla is being prepared.