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Chiba S, Iwamoto A, Shimabukuro S, Matsumoto H, Inoue K. Mechanisms that can cause population decline under heavily skewed male-biased adult sex ratios. J Anim Ecol 2023; 92:1893-1903. [PMID: 37434418 DOI: 10.1111/1365-2656.13980] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Accepted: 06/02/2023] [Indexed: 07/13/2023]
Abstract
While adult sex ratio (ASR) is a crucial component for population management, there is still a limited understanding of how its fluctuation affects population dynamics. To demonstrate mechanisms that hinder population growth under a biased ASR, we examined changes in reproductive success with ASR using a decapod crustacean exposed to female-selective harvesting. We examined the effect of ASR on the spawning success of females. A laboratory experiment showed that the number of eggs carried by females decreased as the proportion of males in the mating groups increased. Although the same result was not observed in data collected over 25 years in the wild, the negative effect of ASR was suggested when success in carrying eggs was considered as a spawning success. These results indicate that a surplus of males results in females failing to carry eggs, probably due to sexual coercion, and the negative effect of ASR can be detected at the population level only when the bias increases because failure in spawning success occurs in part of population. We experimentally examined how male-biased sex ratios affected the maintenance of genetic diversity in a population. The diversity of paternity in a clutch increased with the number of candidate fathers. However, over 50% of a clutch was fertilised by a single male regardless of the sex ratio, and the degree of diversity was less than half of the highest diversity expected in each mating group. We also experimentally examined the mating ability of males during the breeding season. The experiment showed that multiple mating by males could not compensate for the risk that their genotypes would be lost when multiple males competed for one female. These results suggest that a male-biased ASR could trigger a decline of genetic diversity in a population. We show that ASR skewed by female-selective harvesting decreases reproductive success not only of males that have few mating opportunities but also of females. We discuss that we may still underestimate the significance of ASR on population persistence due to the difficulty of revealing the effect of ASR.
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Affiliation(s)
- Susumu Chiba
- Graduate School of Ocean and Fisheries Sciences, Tokyo University of Agriculture, Abashiri, Japan
- Department of Ocean and Fisheries Sciences, Tokyo University of Agriculture, Abashiri, Japan
| | - Aya Iwamoto
- Department of Ocean and Fisheries Sciences, Tokyo University of Agriculture, Abashiri, Japan
| | - Seina Shimabukuro
- Department of Ocean and Fisheries Sciences, Tokyo University of Agriculture, Abashiri, Japan
| | - Hiroyuki Matsumoto
- Graduate School of Ocean and Fisheries Sciences, Tokyo University of Agriculture, Abashiri, Japan
| | - Karin Inoue
- Graduate School of Ocean and Fisheries Sciences, Tokyo University of Agriculture, Abashiri, Japan
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Encounter with heavier females changes courtship and fighting efforts of male field crickets Gryllus bimaculatus (Orthoptera: Gryllidae). J ETHOL 2022. [DOI: 10.1007/s10164-021-00742-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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3
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Mating rock shrimp hedge their bets: old males take greater risk, but only after careful assessment of the investment scenario. Behav Ecol Sociobiol 2015. [DOI: 10.1007/s00265-015-2009-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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4
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Yasuda CI, Matsuo K, Wada S. Previous mating experience increases fighting success during male-male contests in the hermit crab Pagurus nigrofascia. Behav Ecol Sociobiol 2015. [DOI: 10.1007/s00265-015-1941-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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5
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Baeza JA, Bauer RT, Okuno J, Thiel M. Molecular phylogeny of hinge-beak shrimps (Decapoda: Caridea:RhynchocinetesandCinetorhynchus) and allies: a formal test of familiar and generic monophyly using a multilocus phylogeny. Zool J Linn Soc 2014. [DOI: 10.1111/zoj.12173] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- J. Antonio Baeza
- Department of Biological Sciences; Clemson University; 132 Long Hall Clemson South Carolina 29634 USA
- Smithsonian Marine Station at Fort Pierce; 701 Seaway Drive Fort Pierce Florida 34949 USA
- Departamento de Biología Marina; Facultad de Ciencias del Mar; Universidad Católica del Norte; Larrondo 1281 Coquimbo Chile
| | - Raymond T. Bauer
- Department of Biology; University of Louisiana at Lafayette; P.O. Box 42451 Lafayette Louisiana USA
| | - Junji Okuno
- Coastal Branch of Natural History Museum and Institute; Chiba, 123 Yoshio, Katsuura Chiba 299-5242 Japan
| | - Martin Thiel
- Departamento de Biología Marina; Facultad de Ciencias del Mar; Universidad Católica del Norte; Larrondo 1281 Coquimbo Chile
- Centro de Estudios Avanzados en Zonas Aridas CEAZA; Coquimbo Chile
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La GH, Choi JY, Chang KH, Jang MH, Joo GJ, Kim HW. Mating behavior of Daphnia: impacts of predation risk, food quantity, and reproductive phase of females. PLoS One 2014; 9:e104545. [PMID: 25111600 PMCID: PMC4128813 DOI: 10.1371/journal.pone.0104545] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2014] [Accepted: 07/10/2014] [Indexed: 11/23/2022] Open
Abstract
High predation risk and food depletion lead to sexual reproduction in cyclically parthenogenetic Daphnia. Mating, the core of sexual reproduction, also occurs under these conditions. Assessment of the environmental conditions and alteration of mating efforts may aid in determining the success of sexual reproduction. Here, we evaluated the impacts of predation risk, food quantity, and reproductive phase of females on the mating behavior of Daphnia obtusa males including contact frequency and duration using video analysis. Mating-related behavior involved male-female contact (mating) as well as male-male contact (fighting). Mating frequency increased while unnecessary fighting decreased in the presence of predation risk. In addition, low food concentration reduced fighting between males. Males attempted to attach to sexual females more than asexual females, and fighting occurred more frequently in the presence of sexual females. Duration of mating was relatively long; however, males separated shortly after contact in terms of fighting behavior. Thus, assessment of environmental factors and primary sexing of mates were performed before actual contact, possibly mechanically, and precise sex discrimination was conducted after contact. These results suggest that mating in Daphnia is not a random process but rather a balance between predation risk and energetic cost that results in changes in mating and fighting strategies.
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Affiliation(s)
- Geung-Hwan La
- Department of Environmental Education, Sunchon National University, Suncheon, Korea
| | - Jong-Yun Choi
- Department of Life Sciences, Pusan National University, Busan, Korea
| | - Kwang-Hyeon Chang
- Department of Environmental Sciences and Engineering, Kyung Hee University, Gyeonggi, Korea
| | - Min-Ho Jang
- Department of Biology Education, Kongju National University, Gongju, Korea
| | - Gea-Jae Joo
- Department of Life Sciences, Pusan National University, Busan, Korea
| | - Hyun-Woo Kim
- Department of Environmental Education, Sunchon National University, Suncheon, Korea
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Anthes N, Werminghausen J, Lange R. Large donors transfer more sperm, but depletion is faster in a promiscuous hermaphrodite. Behav Ecol Sociobiol 2013. [DOI: 10.1007/s00265-013-1662-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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8
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Sekii K, Vizoso DB, Kuales G, De Mulder K, Ladurner P, Schärer L. Phenotypic engineering of sperm-production rate confirms evolutionary predictions of sperm competition theory. Proc Biol Sci 2013; 280:20122711. [PMID: 23446521 DOI: 10.1098/rspb.2012.2711] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Sperm production is a key male reproductive trait and an important parameter in sperm competition theory. Under sperm competition, paternity success is predicted to depend strongly on male allocation to sperm production. Furthermore, because sperm production is inherently costly, individuals should economize in sperm expenditure, and conditional adjustment of the copulation frequency according to their sperm availability may be expected. However, experimental studies showing effects of sperm production on mating behaviour and paternity success have so far been scarce, mainly because sperm production is difficult to manipulate directly in animals. Here, we used phenotypic engineering to manipulate sperm-production rate, by employing dose-dependent RNA interference (RNAi) of a spermatogenesis-specific gene, macbol1, in the free-living flatworm Macrostomum lignano. We demonstrate (i) that our novel dose-dependent RNAi approach allows us to induce high variability in sperm-production rate; (ii) that a reduced sperm-production rate is associated with a decreased copulation frequency, suggesting conditional adjustment of mating behaviour; and (iii) that both sperm production and copulation frequency are important determinants of paternity success in a competitive situation, as predicted by sperm competition theory. Our study clearly documents the potential of phenotypic engineering via dose-dependent RNAi to test quantitative predictions of evolutionary theory.
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Affiliation(s)
- Kiyono Sekii
- Evolutionary Biology, Zoological Institute, University of Basel, , Basel, Switzerland, Department of Zoology, University of Oxford, Oxford, UK.
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Ory NC, Dudgeon D, Dumont CP, Miranda L, Thiel M. Effects of predation and habitat structure on the abundance and population structure of the rock shrimp Rhynchocinetes typus (Caridea) on temperate rocky reefs. MARINE BIOLOGY 2012; 159:2075-2089. [PMID: 24391278 PMCID: PMC3873050 DOI: 10.1007/s00227-012-1994-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/25/2012] [Accepted: 06/21/2012] [Indexed: 06/03/2023]
Abstract
Human disturbances, such as overfishing, may disrupt predator-prey interactions and modify food webs. Underwater surveys were carried out at six shallow-water reef barrens in temperate waters of northern-central Chile from October to December 2010 to describe the effects of predation, habitat complexity (low, medium and high) and refuge availability on the abundance and population structure of the rock shrimp Rhynchocinetes typus (Rhynchocinetidae), an important mesoconsumer on subtidal hard substrata. Three sites were within managed (restricted access) areas for fishermen, and three were unmanaged (open-access). Field observations and tethering experiments were conducted to examine the relationship between fish and shrimp abundances, and the relative predation rates on shrimps. Direct effects of predation on R. typus body-size distribution were examined from shrimps collected in the field and fish stomachs. The presence and the abundance of R. typus increased with habitat reef complexity and refuge availability. Shrimp abundance was negatively related to fish abundance in managed areas, but not in open-access areas, where shrimp densities were the highest. Also, predation rates and body-size distribution of shrimps were unrelated, although fish consumed more large shrimps than should be expected from their distribution in the field. R. typus occurred most often in shelters with wide openings, offering limited protection against predators, but providing potential aggregation sites for shrimps. Overall, direct effects of predation on shrimp densities and population structure were weak, but indirect effects on shrimp distribution within reefs appear to have been mediated through behavioural responses. Our study highlights the need to assess both numerical and behavioural responses of prey to determine the effects of predator loss on mesoconsumer populations.
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Affiliation(s)
- Nicolas C. Ory
- The Swire Institute of Marine Science, The University of Hong Kong, Pokfulam Rd, Hong Kong, People’s Republic of China
- School of Biological Sciences, The University of Hong Kong, Pokfulam Rd, Hong Kong, People’s Republic of China
| | - D. Dudgeon
- School of Biological Sciences, The University of Hong Kong, Pokfulam Rd, Hong Kong, People’s Republic of China
| | - C. P. Dumont
- The Swire Institute of Marine Science, The University of Hong Kong, Pokfulam Rd, Hong Kong, People’s Republic of China
- School of Biological Sciences, The University of Hong Kong, Pokfulam Rd, Hong Kong, People’s Republic of China
| | - L. Miranda
- Facultad Ciencias del Mar, Universidad Católica del Norte, Larrondo 1281, Coquimbo, Chile
| | - M. Thiel
- Facultad Ciencias del Mar, Universidad Católica del Norte, Larrondo 1281, Coquimbo, Chile
- Centro de Estudios Avanzados en Zonas Áridas (CEAZA), Coquimbo, Chile
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Pairing success and sperm reserve of male Gammarus pulex infected by Cyathocephalus truncatus (Cestoda: Spathebothriidea). Parasitology 2011; 138:1429-35. [DOI: 10.1017/s0031182011001247] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
SUMMARYManipulative parasites with complex life cycles are known to induce behavioural and physiological changes in their intermediate hosts. Cyathocephalus truncatus is a manipulative parasite which infects Gammarus pulex as intermediate host. G. pulex males display pre-copulatory mate guarding as a response to male-male competition for access to receptive females. In this paper, we tested the influence that C. truncatus-infection might have on male G. pulex sperm number and pairing success. We considered 3 classes of G. pulex males in our experiments: (i) uninfected males found paired in the field, (ii) uninfected males found unpaired in the field, or (iii) infected males found unpaired in the field. Both infected males and uninfected unpaired males paired less with a new female than uninfected paired males did. Furthermore, infected males appear to be at a strong disadvantage when directly competing for females with a healthy rival male, and had fewer sperm in their testes. We discuss the potential effect of male and female mating strategies on such male host mating alteration.
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Weir LK, Grant JWA. Courtship rate signals fertility in an externally fertilizing fish. Biol Lett 2010; 6:727-31. [PMID: 20410031 DOI: 10.1098/rsbl.2010.0139] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Sperm limitation is widespread across many animal species. Several mechanisms of sperm allocation have been proposed, including optimal allocation according to clutch size and equal allocation across females. However, considerably less effort has been directed at investigating the behavioural signals associated with sperm limitation in males, which may include mating rate and the intensity of courtship. We investigated whether multiple successive spawnings affect individual male fertilization success, mating rates and courtship rates in Japanese medaka (Oryzias latipes). Across an average of 17 spawning events per male, fertilization success decreased from 83.7 per cent for the first spawning to 40 per cent for the last spawning while courtship rate decreased from 3.4 to 1.5 min⁻¹. Females appeared to respond to male sperm depletion by reducing clutch size. Our results suggest that male Japanese medaka are sperm-limited, and that courtship rate may be an honest indication of fertilization ability.
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Affiliation(s)
- Laura K Weir
- Simon Fraser University, Burnaby, British Columbia, Canada.
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Kuriwada T, Kumano N, Shiromoto K, Haraguchi D. Copulation reduces the duration of death-feigning behaviour in the sweetpotato weevil, Cylas formicarius. Anim Behav 2009. [DOI: 10.1016/j.anbehav.2009.07.031] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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13
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Lemaître JF, Rigaud T, Cornet S, Bollache L. Sperm depletion, male mating behaviour and reproductive ‘time-out’ in Gammarus pulex (Crustacea, Amphipoda). Anim Behav 2009. [DOI: 10.1016/j.anbehav.2008.08.028] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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14
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Dennenmoser S, Thiel M. Effects of Social Structure on the Behaviour and Performance of Alternative Reproductive Phenotypes in Male Rock Shrimp, Rhynchocinetes typus. Ethology 2008. [DOI: 10.1111/j.1439-0310.2007.01464.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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