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Senarat S, Chumee S, Kaneko G, Wandee S, Kenthao A, Kongtueng P, Uribe MC, Nganvongpanit K, Iida A, Sornying P. Histological characteristics of oocyte differentiation in the captive longnose seahorse Hippocampus trimaculatus (Leach, 1814). JOURNAL OF FISH BIOLOGY 2024. [PMID: 38894610 DOI: 10.1111/jfb.15768] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2024] [Revised: 04/04/2024] [Accepted: 04/08/2024] [Indexed: 06/21/2024]
Abstract
This study aimed to explore the reproductive histology and oocyte differentiation of the longnose seahorse Hippocampus trimaculatus (Leach, 1814) in captivity. Five mature healthy females were histologically observed. The reproductive systems of the five specimens exhibited similar morphological characteristics with a pair of saccular creamy white ovaries merging caudally into a single gonoduct. There were two germinal ridges lined with a layer of germinal epithelium (GE). The ovarian maturation of this species was considered asynchronous. The oogenic cells were classified into oogonia and oocytes at several developmental phases based on their size and characteristics. Oogonia were identified among the connective tissue in the middle area of the GE. The stromal compartment contained oocytes that were classified into four distinct phases: the primary growth (PG) phase having two steps (perinucleolar and oil droplets-cortical alveolar steps) and the secondary growth (SG) phase with three oocyte types, including early SG oocytes, late SG oocytes, and fully grown oocytes. The atretic oocytes (AO) were observed in all stages of oogenesis. Postovulatory follicles were also seen among the ovarian connective tissue. The occurrence of postovulatory follicles suggested that the specimens analysed in this study were in the spawning period. This research provides new insights into the identification of the reproductive cycles and morphological characteristics of the ovary of H. trimaculatus.
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Affiliation(s)
- Sinlapachai Senarat
- Division of Biological Science, Faculty of Science, Prince of Songkhla University, Songkhla, Thailand
- Department of Marine Science and Environment, Faculty of Science and Fisheries Technology, Rajamangala University of Technology Srivijaya, Trang, Thailand
| | - Supawadee Chumee
- Department of Marine Science and Environment, Faculty of Science and Fisheries Technology, Rajamangala University of Technology Srivijaya, Trang, Thailand
| | - Gen Kaneko
- College of Natural and Applied Science, University of Houston-Victoria, Victoria, Texas, USA
| | - Satiya Wandee
- Ranong Coastal Aquaculture Research and Development Center, Ranong, Thailand
| | - Anan Kenthao
- Department of Biology, Faculty of Science, Naresuan University, Phitsanulok, Thailand
| | - Piyamat Kongtueng
- Research Center for Veterinary Biosciences and Veterinary Public Health, Faculty of Veterinary Medicine, Chiang Mai University, Chiang Mai, Thailand
| | - Mari Carmen Uribe
- Laboratorio de Biologıa de la Reproduccion Animal, Departamento de Biologıa Comparada, Facultad de Ciencias, Universidad Nacional Autonoma de Mexico, Ciudad de México, Mexico
| | - Korakot Nganvongpanit
- Research Center for Veterinary Biosciences and Veterinary Public Health, Faculty of Veterinary Medicine, Chiang Mai University, Chiang Mai, Thailand
| | - Atsuo Iida
- Department of Animal Sciences, Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, Japan
| | - Peerapon Sornying
- Faculty of Veterinary Science, Prince of Songkla University, Songkhla, Thailand
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2
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Mason HD, Rose E, Gonzalez JE, O'Brien DA. Nocturnal surveys of lined seahorses reveal increased densities and seasonal recruitment patterns. Ecol Evol 2023; 13:e9573. [PMID: 36644702 PMCID: PMC9834011 DOI: 10.1002/ece3.9573] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2020] [Revised: 03/22/2021] [Accepted: 03/24/2021] [Indexed: 01/13/2023] Open
Abstract
Although the nighttime ecology of organisms remains understudied, nocturnal surveys play an integral part in assessing fish assemblages and the selective forces shaping them. Eleuthera (Bahamas) contains an unusual population of lined seahorses (Hippocampus erectus) in an anchialine lake, possessing morphological characteristics distinct from those found in the ocean. Population surveys for seahorses and their potential predators were conducted at midnight and midday during wet and dry seasons, with belt transects perpendicular to the shoreline that increased in depth away from shore. Nocturnal surveys uncovered seahorse densities 259% higher than daytime transects on average. Sex ratios were consistently male-biased, and the frequency of animals from different reproductive categories varied significantly by time of day, with gravid males observed around the clock but females and nongravid males observed more often at night. Spatial and seasonal recruitment was detected for the first time in this species, with an increase in juveniles detected in the shallow ends of transects during dry season surveys. Juvenile recruitment is poorly understood across syngnathid fishes, so the detection of early recruits at night has broad implications for this fish family. Seahorses from all reproductive categories were perched significantly higher in the water column during the night regardless of their depth or season. Predator densities followed a similar pattern with higher densities observed at night, indicating that elevated nocturnal perch height may be a response to predator presence. However, the selective agents driving these nocturnal behaviors have yet to be identified. Considering H. erectus is listed on the IUCN Red List as "Vulnerable," the increase in nocturnal population size and the detection of juveniles has crucial implications for understanding their ecology, recruitment, and conservation.
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Affiliation(s)
| | - Emily Rose
- The University of TampaTampaFloridaUSA
- Present address:
Department of BiologyValdosta State UniversityValdostaGeorgiaUSA
| | | | - Duncan A. O'Brien
- The Center for Ocean Research and EducationGregorytown, EleutheraThe Bahamas
- Present address:
School of Biological SciencesUniversity of BristolBristolUK
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Liu Y, Wu Y, Qin G, Chen Y, Wang X, Lin Q. Bioaccumulation and reproductive toxicity of bisphenol A in male-pregnant seahorse (Hippocampus erectus) at environmentally relevant concentrations. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 753:141805. [PMID: 32911163 DOI: 10.1016/j.scitotenv.2020.141805] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Revised: 08/07/2020] [Accepted: 08/17/2020] [Indexed: 06/11/2023]
Abstract
Seahorses, with brood pouch in adult males, are a bioindicator species that exhibit specialized reproductive strategy of "male pregnancy". Bisphenol A (BPA), one of the most pervasive endocrine-disrupting chemicals (EDCs), is hazardous for reproductive, immune, and neurological systems. However, no evidence of BPA toxicity to the male-pregnant animals is available. Herein, the reproductive toxicity of BPA was evaluated in lined seahorses (Hippocampus erectus) following exposure to environmentally relevant concentrations (10, 100, and 1000 μg/L) through physiological, histological, and transcriptional analyses. Our results indicated BPA bioaccumulation to be positively correlated with exposure doses in both sexes. Ovarian failure was only observed in the high-dose BPA treatment group, accompanied by the apoptosis of follicular cells and up-regulation of pro-apoptotic genes. However, brood pouches maintenance were surprisingly inhibited at low concentration, and transcriptomic analysis revealed disturbed profiles of genes involved in the extracellular matrix and cell-cell adhesion pathways. Interestingly, seahorse testes were less sensitive to BPA exposure than that in other teleosts. Thus, our study suggests that BPA at environmentally relevant concentrations might cause reproductive dysfunction in seahorses, potentially exerting adverse effects on the seahorse population since most of them inhabit shallow coastal areas with prevalent estrogenic contaminants.
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Affiliation(s)
- Yali Liu
- CAS Key Laboratory of Tropical Marine Bio-resources and Ecology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301, PR China; Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou 511458, PR China
| | - Yongli Wu
- CAS Key Laboratory of Tropical Marine Bio-resources and Ecology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301, PR China; University of the Chinese Academy of Sciences, Beijing 100049, PR China
| | - Geng Qin
- CAS Key Laboratory of Tropical Marine Bio-resources and Ecology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301, PR China; Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou 511458, PR China
| | - Yu Chen
- CAS Key Laboratory of Tropical Marine Bio-resources and Ecology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301, PR China; Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou 511458, PR China
| | - Xin Wang
- CAS Key Laboratory of Tropical Marine Bio-resources and Ecology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301, PR China; Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou 511458, PR China
| | - Qiang Lin
- CAS Key Laboratory of Tropical Marine Bio-resources and Ecology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301, PR China; Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou 511458, PR China; University of the Chinese Academy of Sciences, Beijing 100049, PR China.
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4
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Masonjones HD, Rose E. When more is not merrier: Using wild population dynamics to understand the effect of density on ex situ seahorse mating behaviors. PLoS One 2019; 14:e0218069. [PMID: 31265478 PMCID: PMC6605648 DOI: 10.1371/journal.pone.0218069] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2018] [Accepted: 05/25/2019] [Indexed: 11/18/2022] Open
Abstract
Seahorses are considered one of the most iconic examples of a monogamous species in the animal kingdom. This study investigates the relationship between stocking density and mating and competitive behavior from the context of the field biology of the dwarf seahorse, Hippocampus zosterae (Jordan & Gilbert). Animals were housed in 38 liter tanks at a range of densities and sex ratios (from 2-8 animals per tank), and their reproductive and other social behaviors were monitored from tank introduction through copulation. At low tank densities and even sex ratios but comparatively high field densities, frequency of both mating and competitive behaviors was low in trials. A higher level of males in tanks across all densities increased competition, activity levels, and aggression leading to egg transfer errors and brood expulsion, resulting in lower reproductive success. Across seahorse species, mean and maximum wild densities were consistently lower than those used in ex situ breeding, with adult sex ratios that were significantly female biased. However, significant variation exists in wild seahorse densities across species, with higher densities detected in focal/mark recapture studies and on artificial habitat structures than reported with belt transect sampling techniques. Interchange of knowledge gained in both aquarium and wild contexts will allow us to better understand the biology of this genus, and improve reproduction in captivity. Interpreting ex situ reproductive behaviors of seahorses within various densities reported from natural populations will help us predict the impact of conservation efforts and increase the likelihood of long-term persistence of populations for this threatened genus.
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Affiliation(s)
- Heather D. Masonjones
- Biology Department, University of Tampa, Tampa, FL, United States of America
- Department of Biology, Tufts University, Boston, MA, United States of America
- * E-mail:
| | - Emily Rose
- Biology Department, University of Tampa, Tampa, FL, United States of America
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Mobley KB, Morrongiello JR, Warr M, Bray DJ, Wong BBM. Female ornamentation and the fecundity trade-off in a sex-role reversed pipefish. Ecol Evol 2018; 8:9516-9525. [PMID: 30377519 PMCID: PMC6194251 DOI: 10.1002/ece3.4459] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2018] [Revised: 07/14/2018] [Accepted: 07/20/2018] [Indexed: 11/12/2022] Open
Abstract
Sexual ornaments found only in females are a rare occurrence in nature. One explanation for this is that female ornaments are costly to produce and maintain and, therefore, females must trade-off resources related to reproduction to promote ornament expression. Here, we investigate whether a trade-off exists between female ornamentation and fecundity in the sex-role reversed, wide-bodied pipefish, Stigmatopora nigra. We measured two components of the disk-shaped, ventral-striped female ornament, body width, and stripe thickness. After controlling for the influence of body size, we found no evidence of a cost of belly width or stripe thickness on female fecundity. Rather, females that have larger ornaments have higher fecundity and thus accurately advertise their reproductive value to males without incurring a cost to fecundity. We also investigated the relationship between female body size and egg size and found that larger females suffer a slight decrease in egg size and fecundity, although this decrease was independent of female ornamentation. More broadly, considered in light of similar findings in other taxa, lack of an apparent fecundity cost of ornamentation in female pipefish underscores the need to revisit theoretical assumptions concerning the evolution of female ornamentation.
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Affiliation(s)
- Kenyon B. Mobley
- Department of Evolutionary EcologyMax Planck Institute for Evolutionary BiologyPlönGermany
| | | | - Matthew Warr
- School of Biological SciencesMonash UniversityMelbourneVictoriaAustralia
| | - Dianne J. Bray
- Vertebrate ZoologyMuseum VictoriaMelbourneVictoriaAustralia
| | - Bob B. M. Wong
- School of Biological SciencesMonash UniversityMelbourneVictoriaAustralia
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Kvarnemo C. Why do some animals mate with one partner rather than many? A review of causes and consequences of monogamy. Biol Rev Camb Philos Soc 2018; 93:1795-1812. [PMID: 29687607 DOI: 10.1111/brv.12421] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2017] [Revised: 03/27/2018] [Accepted: 04/03/2018] [Indexed: 10/17/2022]
Abstract
Why do some animals mate with one partner rather than many? Here, I investigate factors related to (i) spatial constraints (habitat limitation, mate availability), (ii) time constraints (breeding synchrony, length of breeding season), (iii) need for parental care, and (iv) genetic compatibility, to see what support can be found in different taxa regarding the importance of these factors in explaining the occurrence of monogamy, whether shown by one sex (monogyny or monandry) or by both sexes (mutual monogamy). Focusing on reproductive rather than social monogamy whenever possible, I review the empirical literature for birds, mammals and fishes, with occasional examples from other taxa. Each of these factors can explain mating patterns in some taxa, but not in all. In general, there is mixed support for how well the factors listed above predict monogamy. The factor that shows greatest support across taxa is habitat limitation. By contrast, while a need for parental care might explain monogamy in freshwater fishes and birds, there is clear evidence that this is not the case in marine fishes and mammals. Hence, reproductive monogamy does not appear to have a single overriding explanation, but is more taxon specific. Genetic compatibility is a promising avenue for future work likely to improve our understanding of monogamy and other mating patterns. I also discuss eight important consequences of reproductive monogamy: (i) parentage, (ii) parental care, (iii) eusociality and altruism, (iv) infanticide, (v) effective population size, (vi) mate choice before mating, (vii) sexual selection, and (viii) sexual conflict. Of these, eusociality and infanticide have been subject to debate, briefly summarised herein. A common expectation is that monogamy leads to little sexual conflict and no or little sexual selection. However, as reviewed here, sexual selection can be substantial under mutual monogamy, and both sexes can be subject to such selection. Under long-term mutual monogamy, mate quality is obviously more important than mate numbers, which in turn affects the need for pre-mating mate choice. Overall, I conclude that, despite much research on genetic mating patterns, reproductive monogamy is still surprisingly poorly understood and further experimental and comparative work is needed. This review identifies several areas in need of more data and also proposes new hypotheses to test.
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Affiliation(s)
- Charlotta Kvarnemo
- Department of Biological and Environmental Sciences, University of Gothenburg, Box 463, SE-405 30 Gothenburg, Sweden
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Otero-Ferrer F, Izquierdo M, Fazeli A, Holt WV. Embryonic developmental plasticity in the long-snouted seahorse (Hippocampus reidi, Ginsburg 1933) in relation to parental preconception diet. Reprod Fertil Dev 2016; 28:1020-1028. [DOI: 10.1071/rd14169] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2014] [Accepted: 11/17/2014] [Indexed: 11/23/2022] Open
Abstract
The aim of the present study was to investigate the hypothesis that parental periconception nutrition in adult seahorses affects the development and growth of their offspring. We tested the hypothesis that because seahorse embryos develop inside the male’s brood pouch, manipulation of the male’s diet would affect offspring growth and development independently of the female’s diet. Adult males and females were fed separately with either wild-caught crustaceans or commercial aquarium diet for 1 month before conception to influence the periconception environment. Approximately 10 000 offspring were obtained from four different treatment groups (Male/Wild or Male/Commercial × Female/Wild or Female/Commercial). Weights, physical dimensions and fatty acid profiles of the newborns were determined. Offspring produced when the males receiving commercial diet were mated with wild-fed females were larger (P < 0.05) than those produced by wild-fed males. When both males and females were fed with commercial diet, their offspring were significantly smaller than those from the other treatment groups. When commercial diet-fed females were mated with wild-fed males, the offspring showed distortion of the snout : head length ratio. These results support the view that the preconception diet received by males and females differentially affects embryonic development.
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Piras F, Biagi F, Taddei AR, Fausto AM, Farina V, Zedda M, Floris A, Franzoi P, Carcupino M. Male gonads morphology, spermatogenesis and sperm ultrastructure of the seahorseHippocampus guttulatus(Syngnathidae). ACTA ZOOL-STOCKHOLM 2015. [DOI: 10.1111/azo.12126] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Francesca Piras
- Dipartimento di Scienze dalla Natura e del Territorio; Università di Sassari; Sassari Italy
| | - Francesca Biagi
- Dipartimento di Scienze dalla Natura e del Territorio; Università di Sassari; Sassari Italy
| | - Anna Rita Taddei
- Centro Grandi Attrezzature, sez. di Microscopia Elettronica (CIME); Università della Tuscia; Viterbo Italy
| | - Anna Maria Fausto
- Dipartimento per l'Innovazione nei Sistemi Biologici; Agro-alimentari e Forestali; Università della Tuscia; Viterbo Italy
| | - Vittorio Farina
- Dipartimento di Medicina Veterinaria; Università di Sassari; Sassari Italy
| | - Marco Zedda
- Dipartimento di Medicina Veterinaria; Università di Sassari; Sassari Italy
| | - Antonello Floris
- Dipartimento di Medicina Veterinaria; Università di Sassari; Sassari Italy
| | - Piero Franzoi
- Dipartimento di Scienze Ambientali; Informatica e Statistica; Università Ca’ Foscari di Venezia; Venezia Italy
| | - Marcella Carcupino
- Dipartimento di Scienze dalla Natura e del Territorio; Università di Sassari; Sassari Italy
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Sogabe A, Ahnesjö I. The ovarian structure and mode of egg production in two polygamous pipefishes: a link to mating pattern. JOURNAL OF FISH BIOLOGY 2011; 78:1833-1846. [PMID: 21651531 DOI: 10.1111/j.1095-8649.2011.02973.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
In this study, the ovarian structure and mode of egg production were examined in two pipefishes, the broad-nosed pipefish Syngnathus typhle and the straight-nosed pipefish Nerophis ophidion, which show different types of polygamous mating patterns. Syngnathus typhle showed an ovary with one germinal ridge and asynchronous egg production, corresponding to previous findings in other polygamous Syngnathus pipefishes. In contrast, the ovary of N. ophidion had two germinal ridges and eggs were produced synchronously in groups, similar to what has been observed in monogamous syngnathids. The egg production of N. ophidion, however, is clearly distinguished from that of monogamous syngnathids by the additional egg production after an ovulation. It is suggested that the differences in female mating strategies result from the difference in egg production process and that this is related to the difference in mating pattern between these two polygamous species.
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Affiliation(s)
- A Sogabe
- Graduate School of Biosphere Science, Hiroshima University, 1-4-4 Kagamiyama, Higashi-Hiroshima 739-8528, Japan.
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Abstract
Few studies have examined the underlying hormonal mechanisms that mediate reproductive cyclicity, male pregnancy and reproductive behaviour in syngnathids. Progress in these areas has been hampered by the small size of most species in the family and a lack of validated techniques for assessing endocrine function. Research on a relatively small number of species has suggested that androgens are likely regulators of spermatogenesis and the development of the male brood pouch prior to pregnancy whereas prolactin and corticosteroids synergistically promote brood pouch function during pregnancy. No evidence supports a reversal of reproductive steroid hormone function in sex-role reversed behaviour, but neuropeptides such as arginine vasotocin or isotocin should be examined for their role in regulating parturition and mating behaviour. The diversity of reproductive patterns exhibited by syngnathids suggests that they will provide a unique opportunity to assess how hormonal regulation of integumentary function, gametogenesis and reproductive behaviour have evolved within a teleost lineage. Additionally, their coastal distribution and embryo retention make them potentially important subjects for studies on the effect of endocrine disruption on fitness.
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Affiliation(s)
- S K Scobell
- Department of Biology, Texas A&M University, 3258 TAMU, College Station, TX 77843, USA.
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Scobell SK, Fudickar AM, Knapp R. Potential reproductive rate of a sex-role reversed pipefish over several bouts of mating. Anim Behav 2009. [DOI: 10.1016/j.anbehav.2009.05.036] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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