title: Spermatophore affects the egg-spawning and egg-carrying behavior in the female giant freshwater prawn, Macrobrachium rosenbergii.
abstract: In crustaceans, mating occurs during the ecdysis after female molting. During this period, a male transfers its spermatophore into a female which, in some species, stores the spermatophore for a long period prior to spawning and fertilization. However, in some species including the giant freshwater prawn, Macrobrachium rosenbergii, the male deposits its spermataphore onto the external surface of the thoracic segment of the female which affects the spawning time and maternal behavior. This study investigated the spawning behavior of the M. rosenbergii females, which was divided into pre-spawning, spawning, and post-spawning phases. It was revealed that mated female prawns with attached spermatophore exhibited an earlier spawning than unmated individuals, leading to assessment of the factors that may elicit this phenomenon. Four groups of female prawns were allocated to groups including mating females with spermatophore still attached, mating females with the spermatophore removed, artificially inseminated females with spermatophores, and an unmated control. There was a significant reduction in the time of egg-spawning in the presence of spermatophores, and the mating activity was also a contributing factor. Furthermore, over 90% of the mated and artificially inseminated females in which spermatophores were deposited carried the eggs in the abdominal brood chamber until completion of embryonic development while others discarded the eggs within 2 days post-spawning. This study implies that the spermatophore may contain ovulation-inducing factors which stimulate an earlier spawning and fostering of brooding behavior.
authors.affiliation: Department of Anatomy, Faculty of Science, Mahidol University, Rama VI Road, Bangkok 10400, Thailand.
authors.forename: Thanapong
authors.initials: T
authors.lastname: Kruangkum
authors.affiliation: Department of Anatomy, Faculty of Science, Mahidol University, Rama VI Road, Bangkok 10400, Thailand; Center of Excellence for Shrimp Molecular Biology and Biotechnology (Centex Shrimp), Faculty of Science, Mahidol University, Rama VI Road, Bangkok 10400, Thailand.
authors.forename: Rapeepun
authors.initials: R
authors.lastname: Vanichviriyakit
authors.affiliation: Mahidol University, Nakhonsawan Campus, Nakhonsawan 60130, Thailand.
authors.forename: Charoonroj
authors.initials: C
authors.lastname: Chotwiwatthanakun
authors.affiliation: Department of Anatomy, Faculty of Science, Mahidol University, Rama VI Road, Bangkok 10400, Thailand; Department of Anatomy, Faculty of Science, Prince of Songkla University, Hatyai, Songkhla 90112, Thailand.
authors.forename: Jirawat
authors.initials: J
authors.lastname: Saetan
authors.affiliation: Department of Anatomy, Faculty of Science, Mahidol University, Rama VI Road, Bangkok 10400, Thailand; Mahidol University, Nakhonsawan Campus, Nakhonsawan 60130, Thailand.
authors.forename: Yotsawan
authors.initials: Y
authors.lastname: Tinikul
authors.affiliation: Department of Anatomy, Faculty of Science, Mahidol University, Rama VI Road, Bangkok 10400, Thailand.
authors.forename: Chaitip
authors.initials: C
authors.lastname: Wanichanon
authors.affiliation: Faculty of Science, Health, Education and Engineering, University of the Sunshine Coast, Locked Bag 4, Maroochydore DC, QLD 4558, Australia.
authors.forename: Scott F
authors.initials: SF
authors.lastname: Cummins
authors.affiliation: Department of Anatomy, Faculty of Science, Mahidol University, Rama VI Road, Bangkok 10400, Thailand; Pro Vice-Chancellor's Office, Faculty of Science and Technology, Deakin University, Locked Bag 20000, Geelong, VIC 3220, Australia.
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Hanna
authors.affiliation: Department of Anatomy, Faculty of Science, Mahidol University, Rama VI Road, Bangkok 10400, Thailand. Electronic address: prasert.sob@mahidol.ac.th.
authors.forename: Prasert
authors.initials: P
authors.lastname: Sobhon
mesh_terms: D000818:Animals; D005260:Female; D005306:Fertilization / Q000502:physiology; D008297:Male; D010063:Ovum / Q000502:physiology*; D033541:Palaemonidae / Q000502:physiology*; D012098:Reproduction / Q000502:physiology*; D012726:Sexual Behavior, Animal / Q000502:physiology*; D013093:Spermatogonia / Q000502:physiology*
keywords: Artificial insemination; Brooding behavior; Spawning behavior; Spawning time; Spermatophore deposition