Latitudinal Variation in Sexual Size Dimorphism of Sea-Run Masu Salmon, Oncorhynchus Masou

Tamate, Tsuyoshi; Maekawa, Koji

doi:10.1111/j.0014-3820.2006.tb01094.x

Cited by 39 publications

(32 citation statements)

References 30 publications

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“…Even though fecundity selection in L. a. agilis is likely stronger than in L. a. exigua , FAH cannot solely explain the more female‐biased SSD of L. a. agilis because the SSD difference is primarily due to a shift in male rather than female size. Such a pattern, which corresponds to Rensch's rule (Fairbairn, ), is usually explained via geographic differences in sexual selection (Pearson et al ., ; Tamate & Maekawa, ; Puniamoorthy et al ., ). Yet the currently available evidence for sexual selection for larger male size being weaker in L. a. agilis than in L. a. exigua is poor.…”

Section: Discussionmentioning

confidence: 99%

Geographic variation of life‐history traits in the sand lizard,Lacerta agilis: testing Darwin's fecundity‐advantage hypothesis

Roitberg

Епланова

Kotenko

et al. 2015

J of Evolutionary Biology

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The fecundity-advantage hypothesis (FAH) explains larger female size relative to male size as a correlated response to fecundity selection. We explored FAH by investigating geographic variation in female reproductive output and its relation to sexual size dimorphism (SSD) in Lacerta agilis, an oviparous lizard occupying a major part of temperate Eurasia. We analysed how sex-specific body size and SSD are associated with two putative indicators of fecundity selection intensity (clutch size and the slope of the clutch size-female size relationship) and with two climatic variables throughout the species range and across two widespread evolutionary lineages. Variation within the lineages provides no support for FAH. In contrast, the divergence between the lineages is in line with FAH: the lineage with consistently female-biased SSD (L. a. agilis) exhibits higher clutch size and steeper fecundity slope than the lineage with an inconsistent and variable SSD (L. a. exigua). L. a. agilis shows lower offspring size (egg mass, hatchling mass) and higher clutch mass relative to female mass than L. a. exigua, that is both possible ways to enhance offspring number are exerted. As the SSD difference is due to male size (smaller males in L. a. agilis), fecundity selection favouring larger females, together with viability selection for smaller size in both sexes, would explain the female-biased SSD and reproductive characteristics of L. a. agilis. The pattern of intraspecific life-history divergence in L. agilis is strikingly similar to that between oviparous and viviparous populations of a related species Zootoca vivipara. Evolutionary implications of this parallelism are discussed.

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Section: Discussionmentioning

confidence: 99%

Geographic variation of life‐history traits in the sand lizard,Lacerta agilis: testing Darwin's fecundity‐advantage hypothesis

Roitberg

Епланова

Kotenko

et al. 2015

J of Evolutionary Biology

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“…However, other studies have failed to detect sexual dimorphism in behaviour, growth, or size at early life history stages (e.g., [28,29]). Whereas different degrees and forms of SSD appears to be common at sexual maturity [4,5], it may be variable in its expression during development or simply may be too small to be easily detected at early life history stages. It seems likely that the form and degree of SSD varies across life history stages.…”

Section: Discussionmentioning

confidence: 99%

“…For example, there is interest in whether sex-specific differences during development represent a correlated response to sexual selection acting on adults or different optima for males and females [2,3]. In adult Pacific salmon in the genus Oncorhynchus , both male-biased and female-biased SSD is represented, depending on the species and population [4,5]. Among species, SSD ranges from male-biased values in which males are 4% larger than females (in chum salmon O. keta [Walbaum in Artedi, 1792]) to female-biased values in which males are 9% smaller than females (in Chinook salmon O. tshawytscha [Walbaum in Artedi, 1792])[4].…”

Section: Introductionmentioning

confidence: 99%

A Genetic Test of Sexual Size Dimorphism in Pre-Emergent Chinook Salmon

et al. 2013

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Sex differences in early development may play an important role in the expression of sexual size dimorphism at the adult stage. To test whether sexual size dimorphism is present in pre-emergent chinook salmon (Oncorhynchus tshawytscha), alevins were reared at two temperatures (10 °C and 15 °C) and sexed using the OtY1 marker on the Y-chromosome. Linear mixed models were used to test for sex differences in alevin size within families while controlling for the random effects of sire and dam nested within sire. Males and females did not differ in weight at 10 °C but males were heavier than females at 15 °C. Sex accounted for 2% of the within-family variance in weight. In addition, at 15°C, the relationship between weight and sex was greater in families with larger eggs. Whereas male-biased sexual size dimorphism was present at the juvenile stage, female-biased sexual size dimorphism was present at sexual maturity. Males were also younger than females at sexual maturity. A head start on growth by males may underlie their earlier maturation at a smaller size, thus leading to female-biased SSD at the adult stage.

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“…Young (2005) and Tamate and Maekawa (2006) reported a parallel variation in male and female size of Pacific salmon and trout Oncorhynchus spp. Young (2005) and Tamate and Maekawa (2006) reported a parallel variation in male and female size of Pacific salmon and trout Oncorhynchus spp.…”

Section: Discussionmentioning

confidence: 93%

Water level influences migratory patterns of anadromous brown trout in small streams

Jönsson

Jonsson

2018

Ecology of Freshwater Fish

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Habitats modify the population ecology of species. Here, we show how low water level influences abundance and size of adult anadromous brown trout (Salmo trutta) entering a small, South Norwegian stream for spawning. After smolting, the fish appear chiefly to feed within 10 km of the home stream. In the autumn, South Norwegian streams typically flood because of heavy rainfall, when the anadromous brown trout entered from the sea. Mean annual duration of the upstream migration period was 34 days and ended when the flooding ended and the water temperature dropped to below 4°C. During most of the migration period, on average two trout ascended the river per day. The sexes entered the spawning area concurrently, and the male:female ratio of the anadromous trout was 1.27. No fish entered when the water depth just downstream of the spawning area was below 5 cm, and mean number of fish increased with increasing water depth to ca. 30 cm, but not at higher flows when the ascent gradually decreased. Mean and maximum size of the entering spawners increased with water depth between 5 and 16 cm. Among those that had been to sea, most were recaptured in the home stream, 4% in other streams, but only two of the strays were caught close to spawning time. The present results illustrate that population traits of anadromous brown trout from a small stream differ from those in larger rivers, probably because of selection associated with water flow.

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Latitudinal Variation in Sexual Size Dimorphism of Sea-Run Masu Salmon, Oncorhynchus Masou

Cited by 39 publications

References 30 publications

Geographic variation of life‐history traits in the sand lizard,Lacerta agilis: testing Darwin's fecundity‐advantage hypothesis

Geographic variation of life‐history traits in the sand lizard,Lacerta agilis: testing Darwin's fecundity‐advantage hypothesis

A Genetic Test of Sexual Size Dimorphism in Pre-Emergent Chinook Salmon

Water level influences migratory patterns of anadromous brown trout in small streams

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