Reproduction and Development in Platyhelminthes

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 IntroductionIntroductionTaxonomy and DiversityLife CyclesHost-Parasite DistributionFecundityOsmotrophism and DigestionNeoblastsTurbellariaIntroductionPART A: GENERAL FEATURESTaxonomy and DistributionReproductive SystemTransition to ParasitismContrasting StrategiesSemelparity and IteroparitySexualityPART B: REGENERATIONIntroductionDistribution and PotencyCell Counts and MitosisBlastema and RegenerationGenes in RegenerationPART C: CLONAL REPRODUCTIONIntroductionSurgery and PotencyClonal TypesSwitching SexualityTelomere and SenescenceMonogeneaIntroductionTaxonomy and DistributionLife Cycle and CharacteristicsHost SpecificityDigeneaIntroductionTaxonomy: Parasites and HostsLarval FormsIntermediate HostsClonal SelectionAmphiparatenic TransmissionPolyembryony and/or ParthenogenesisSequence and PotencyThe Transmission‘Sweet is Shorter’Prevalence and DensityCauses and LossesCestodaIntroductionTaxonomy and DiversityReproductive SystemLife CyclesNeoteny- ProgenesisPrevalence and IntensitySchistocephalus solidusClonal MultiplicationsThe TransmissionFishes and LossesSexualizationIntroductionChromosomes and GenesEndocrine DifferentiationEndocrine DisruptionComparison and HighlightsIntroductionNeoblasts TypesClonal SelectionProgenesisHabitat DistributionDiversification and SpeciationReferences

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.