Sex Ratio as a Function of Size in Marine Crustacea

Wenner, Adrian M.

doi:10.1086/282774

Cited by 383 publications

(293 citation statements)

References 28 publications

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“…Crustacean populations, in almost all cases, have sex ratios differing from 1:1 (WENNER, 1972). In the present study the proportion obtained (1:1.3) differed statistically from the expected value (1:1), which is not in agreement with the Fisher Theory (FISHER, 1930).…”

Section: Discussioncontrasting

confidence: 82%

“…Probably, the deviation of proportion males/females found in the present study (females more abundant in the middle-size classes) may be attributed to a faster growth of males, to sexual selection and to smaller longevity of females (BERTNESS, 1981;ABRAMS, 1988;BENVENUTO & GHERARDI, 2001). This pattern has been the most common one reported in the literature (WENNER, 1972;MANJÓN-CABEZA & GARCÍA RASO, 1995;GHERARDI & NARDONE, 1997;FRANSOZO & MANTELATTO, 1998;GARCIA & MANTELATTO, 2001) for hermit crab populations inhabiting both the intertidal and infralittoral areas. Unfortunately, we are not able to compare the present results with those of NEGREIROS-FRANSOZO et al (1991) which were obtained from one punctual collection.…”

Section: Discussionmentioning

confidence: 57%

“…Both presented non-normal distribution with a peak of occurrence in intermediate classes whereas the distribution of males skewed toward larger size classes. This and the unequal sex-ratio probably can be attributed to factors such as differential mortality and growth rates between sexes and migrations (WENNER, 1972;HARTNOLL, 1982), with males reaching larger sizes in less time than females but being influenced by shell limitation. On the other hand, natural selection may favour large males if they have an advantage over small males either in competition for receptive females and/or more frequent successful copulation (ABRAMS, 1988).…”

Section: Discussionmentioning

confidence: 99%

“…According to that author, natural selection favours an equal proportion between the sexes. However, differences in the sex ratio can be related to differences in life cycle, growth rate and behavior of males and females (WENNER, 1972).…”

Section: Discussionmentioning

confidence: 99%

“…The sex-ratio analysis by size classes revealed an anomalous pattern (see WENNER, 1972 for review) which is characterized by a decrease in the males/females ratio in the intermediary classes and subsequent increase in the largest size classes. Probably, the deviation of proportion males/females found in the present study (females more abundant in the middle-size classes) may be attributed to a faster growth of males, to sexual selection and to smaller longevity of females (BERTNESS, 1981;ABRAMS, 1988;BENVENUTO & GHERARDI, 2001).…”

Section: Discussionmentioning

confidence: 99%

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Population and reproductive features of the western Atlantic hermit crab Pagurus criniticornis (Anomura, Paguridae) from Anchieta Island, southeastern Brazil

Mantelatto

Faria

Iossi

et al. 2007

Iheringia, Sér. Zool.

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ABSTRACT. The population of the hermit crab Pagurus criniticornis (Dana, 1852) was studied based on seasonal abundance, size frequency distribution, sex ratio, reproductive period, fecundity and shell relationship. Specimens were collected monthly by SCUBA diving in the infralittoral area of Anchieta Island, Ubatuba. A total of 1,017 individuals was analyzed. Animal size (minimum and maximum shield length, respectively) was 0.7 and 2.9 mm for males, 0.6 and 2.8 mm for non-ovigerous females, and 1.0 and 2.5 mm for ovigerous females. The sex ratio was 1:1.29. Sexual dimorphism was recorded by the presence of males in the largest size classes. Ovigerous females were captured during all months along the year, with percentages varying from 8% (July) to 84.3% (February) in relation to the total females collected. Mean ± SD fecundity was 168 ± 125 eggs and tended to increase with increasing hermit size. Shells of four gastropod species [Cerithium atratum (Born, 1778), Morula nodulosa (Adams, 1845), Anachis lyrata (Sowerby, 1832) and Modulus modulus (Linnaeus, 1758)] were occupied by ovigerous females of P. criniticornis but fecundity was not significantly different in relation to the different shell types. The profile showed continuous and intense reproduction of P. criniticornis probably related to strategies developed to compensate for interspecific competition in the studied insular area. KEYWORDS.Crustacea, hermit crab, populational biology, fecundity. RESUMO. Caracterização populacional e reprodutiva do ermitão do Atlântico OcidentalPagurus criniticornis (Anomura, Paguridae) da Ilha Anchieta, sudeste do Brasil. A população do ermitão Pagurus criniticornis (Dana, 1872) foi avaliada com base na abundância sazonal, distribuição da freqüência de tamanho, razão sexual, período reprodutivo, fecundidade e relação com a concha ocupada. Os espécimes foram coletados mensalmente por meio de mergulho autônomo no infralitoral da Ilha Anchieta, Ubatuba. Um total de 1.017 indivíduos foi analisado. O tamanho dos animais (comprimento mínimo e máximo do escudo cefalotorácico, respectivamente) foi de 0,7 e 2,9 mm para os machos, 0,6 e 2,8 mm para as fêmeas não ovígeras e 1,0 e 2,5 mm para as fêmeas ovígeras. A razão sexual foi de 1:1,29. Foi observado dimorfismo sexual em função da presença de machos nas maiores classes de tamanho. Fêmeas ovígeras foram capturadas em todos os meses do ano, com a porcentagem variando de 8% (Julho) a 84,3% (Fevereiro) em relação ao total de fêmeas coletadas. A fecundidade média foi de 168 ± 125 ovos e tendeu a ser maior com o aumento do tamanho do ermitão. Fêmeas ovígeras de P. criniticornis foram encontradas ocupando quatro espécies de conchas de gastrópodes [Cerithium atratum (Born, 1778), Morula nodulosa (Adams, 1845), Anachis lyrata (Sowerby, 1832) e Modulus modulus (Linnaeus, 1758)] no entanto, a fecundidade não foi significativamente diferente em relação aos diferentes tipos de conchas. A população de P. criniticornis apresentou um perfil reprodutivo contínuo e intenso, possivelmente relacionad...

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Section: Discussioncontrasting

confidence: 82%

Section: Discussionmentioning

confidence: 57%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

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Population and reproductive features of the western Atlantic hermit crab Pagurus criniticornis (Anomura, Paguridae) from Anchieta Island, southeastern Brazil

Mantelatto

Faria

Iossi

et al. 2007

Iheringia, Sér. Zool.

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Insights of the Population Structure and Breeding Biology of a Xanthid Crab Etisus laevimanus Randall, 1840, on the Rocky Intertidal Region of the Gujarat Coast

Shrimali,

Patel,

Patel

et al. 2024

Ecology and Evolution

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The population structure and breeding biology of a Xanthid crab, Etisus laevimanus Randall, 1840, a commonly occurring species on the rocky intertidal region of Saurashtra coast of Gujarat State, India, were investigated. Samples were collected from the intertidal region for 12 consecutive months during low tide using catch per unit effort in a 500 m2 area. The individuals were categorized into male, non‐ovigerous female, or ovigerous female. For fecundity estimation, the total number of eggs, size of eggs, and weight of egg mass were measured along with the carapace width and body weight of the respective ovigerous females. Sexual dimorphism was evident in the collected samples, with males being significantly larger than females. The overall as well as monthly sex ratio was female‐biased. Size frequency distribution showed a bimodal frequency distribution in males while being unimodal in females. The occurrence of ovigerous females throughout the year suggests that the species has a continuous breeding pattern with peaks from December to April. The total number of eggs, size of eggs, and weight of the egg mass showed a significantly positive correlation with the carapace width of the ovigerous females.

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Toxicological effects of fungicide mixtures on the amphipod Austrochiltonia subtenuis

Keough

Long

et al. 2017

Enviro Toxic and Chemistry

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Approaches to assess the toxicity of mixtures often use predictive models with acute mortality as an endpoint at relatively high concentrations. However, these approaches do not reflect realistic situations where organisms could be exposed to chemical mixtures over long periods at low concentrations at which no significant mortalities occur. The present study investigated chronic effects of 2 common fungicides, Filan® (active ingredient [a.i]) boscalid) and Systhane™ (a.i. myclobutanil), on the amphipod Austrochiltonia subtenuis at environmentally relevant concentrations under laboratory conditions. Sexually mature amphipods were exposed singly and in combination to Filan (1, 10, and 40 μg a.i./L) and Systhane (3 μg a.i./L) over 28 d. Survival, growth, a wide range of reproduction endpoints, and glutathione-S-transferase (GST) activity were measured at the end of the experiment. Both fungicides had significant independent effects on male growth, sex ratio, and juvenile size. Filan mainly affected female growth and the number of embryos per gravid female, whereas Systhane mainly affected the time for females to become gravid. The combined effects of these fungicides on numbers of gravid females and juveniles were antagonistic, causing a 61% reduction in the number of gravid females and a 77% reduction in the number of juveniles produced at the highest concentrations (40 μg a.i./L of boscalid and 3 μg a.i./L of myclobutanil) compared with the controls. There were no significant effects on survival or GST activity. The present study demonstrated that the effects of mixtures were endpoint dependent and that using a variety of endpoints should be considered for a comprehensive understanding of mixture effects. Also, chronic studies are more informative than acute studies for environmentally relevant fungicide concentrations. Environ Toxicol Chem 2017;36:2651-2659. © 2017 SETAC.

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Sex Ratio as a Function of Size in Marine Crustacea

Cited by 383 publications

References 28 publications

Population and reproductive features of the western Atlantic hermit crab Pagurus criniticornis (Anomura, Paguridae) from Anchieta Island, southeastern Brazil

Population and reproductive features of the western Atlantic hermit crab Pagurus criniticornis (Anomura, Paguridae) from Anchieta Island, southeastern Brazil

Insights of the Population Structure and Breeding Biology of a Xanthid Crab Etisus laevimanus Randall, 1840, on the Rocky Intertidal Region of the Gujarat Coast

Toxicological effects of fungicide mixtures on the amphipod Austrochiltonia subtenuis

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