Fluctuating Asymmetry in the Saddle Patch Shape of the Pacific Ocean Killer Whale (Orcinus orca) Populations

Mäkeläinen, Pirjo; Ginneken, Astrid M. van; Pietiäinen, Hannu

doi:10.5735/086.050.0607

Cited by 5 publications

(5 citation statements)

References 21 publications

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“…Previous studies of killer whale pigmentation patterns have combined both sexes when looking for ecotype differences (Baird and Stacey , Mäkeläinen et al . ), and Mäkeläinen et al . () found no effect of sex on eye patch size.…”

Section: Methodsmentioning

confidence: 91%

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Quantifying variation in killer whale (Orcinus orca) morphology using elliptical Fourier analysis

Emmons

Hard

Dahlheim

et al. 2018

Marine Mammal Science

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In the northeastern Pacific Ocean, there are three “ecotypes” of killer whales that differ in diet, ecology, behavior, acoustics, genetics, and morphology. Previous attempts to describe the morphological differences among populations of killer whales (Orcinus orca) have been limited to descriptive accounts or categorical studies. We used elliptical Fourier analysis (EFA) to quantify shape differences of dorsal fins and pigmentation patterns among the ecotypes from photo‐identification data of more than 500 individuals. Variation in shapes of the dorsal fin, saddle patch, and eye patch were successfully quantified using EFA, and there were highly significant (P < 0.01) differences among the ecotypes in all three morphological traits. The ability of EFA to discriminate ecotypes based on dorsal fin and eye patch shapes was substantial, while it did not perform as well for saddle patches. Visualization of the shape variation along principal component axes mirrored previous descriptions of the differences among ecotypes. Although the degree of inheritance of morphology in killer whales has not been determined, these results are consistent with previous inference of reduced gene flow between the ecotypes, and introduces elliptical Fourier analysis to the study of cetacean morphometrics.

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Section: Methodsmentioning

confidence: 91%

“…Mäkeläinen et al . () demonstrated that the saddle patches of resident killer whales are the most asymmetric, followed by offshores then Bigg's killer whales, and suggested that genetic factors like small population size and reproductive isolation were most likely responsible.…”

Section: Discussionmentioning

confidence: 99%

Quantifying variation in killer whale (Orcinus orca) morphology using elliptical Fourier analysis

Emmons

Hard

Dahlheim

et al. 2018

Marine Mammal Science

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“…Killer whales are known to be polymorphic and exhibit variation in body size and pigmentation patterns (Evans et al ., 1982; Baird & Stacey, 1988; Visser & Mäkeläinen, 2000; Pitman & Ensor, 2003; Pitman et al ., 2007, 2011; Foote et al ., 2009; Mäkeläinen et al ., 2013). The pigmentation patterns of the grey ‘saddle patch’ behind the dorsal fin and the white ‘eye patch’ have been shown to vary among locations, populations and morphotypes (Evans et al ., 1982; Baird & Stacey, 1988; Visser & Mäkeläinen, 2000; Pitman & Ensor, 2003; Pitman et al ., 2011; Mäkeläinen et al ., 2013). Individual variation in the saddle patch pigmentation pattern can be sufficient to identify individuals, but normally acquired marks such as scars and nicks are needed for individual identification (Bigg, 1982).…”

Section: Introductionmentioning

confidence: 99%

“…A previous study found the saddle patches of 471 North Pacific individuals from different populations could be categorized into five variants (Baird & Stacey, 1988) and the proportions of these variants can vary among populations (Ford et al ., 2000). These patterns can also be asymmetrical between the sides of the same individual (Mäkeläinen et al ., 2013). Eye patch shapes can be more variable in small details, and there is often asymmetry between sides (Evans et al ., 1982; Visser & Mäkeläinen, 2000).…”

Section: Introductionmentioning

confidence: 99%

A comparison of pigmentation features among North Atlantic killer whale (Orcinus orca) populations

et al. 2014

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Here we present a comparison of saddle and eye patch patterns of killer whales from Norwegian, Icelandic, British, Spanish and Greenlandic waters. We found only a small amount of variation in saddle patch shapes, which may reflect a recent phylogenetic divergence from the most recent common ancestor. Eye patch shapes were more variable than saddle patches in small details. Most individuals had eye patches with parallel orientation, with the exception of a small group of killer whales from the Hebrides, which, as previously reported, had sloping eye patches that sloped downward at the posterior end. This differentiation in pigmentation patterns of the Hebridean killer whales from neighbouring populations could reflect one or more of several evolutionary processes, including a deeper phylogenetic divergence, low gene flow with other local populations and drift.

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“…Studies have also found that more symmetrical women report fewer medical conditions (Milne et al, 2003), give birth to their first child at an earlier age (Manning et al, 1997), have more offspring (Møller et al, 1995), and have higher mid-menstrual cycle estradiol levels, indicating greater conception probability (Jasienska et al, 2006). Such findings, coupled with evidence that symmetry is partially heritable (Dongen, 2000), have led researchers to hypothesize that symmetry is an honest signal of genotypic and phenotypic quality (e.g., Sugiyama, 2005, 2015). Thus, from a hypergyny hypothesis perspective, the female relatives of androphilic males would be expected to signal their elevated fertility via greater facial symmetry.…”

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confidence: 99%

Facial symmetry of the sisters of Thai and Istmo Zapotec androphilic males.

Jiménez¹,

Skorska²,

Zahran³

et al. 2024

Evolutionary Behavioral Sciences

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Male androphilia (i.e., sexual attraction to adult males) is considered an evolutionary paradox because it reduces direct reproduction but is influenced by genetic factors, reliably occurs across cultures, and has persisted over evolutionary time. The hypergyny hypothesis rests on the premise that the female relatives of androphilic males possess physical traits that signal fertility, such as elevated symmetry. If this premise were true, such traits could help attract reproductive partners with higher socioeconomic status, thereby furnishing resources to produce and sustain multiple offspring. This, in turn, would help females to offset their androphilic male siblings' lack of reproduction. The present study examined whether the sisters of male androphiles have elevated facial symmetry compared with women without androphilic male siblings. Sixty-six women with androphilic male siblings and 271 women without androphilic male siblings were recruited from Thailand and the Istmo region of Oaxaca, Mexico. Results demonstrated no significant differences in facial asymmetry between women with and without androphilic male siblings. In the absence of such a difference, this study, like previous ones, does not support the hypergyny hypothesis as a viable explanation for the evolutionary paradox of male androphilia. Public Significance StatementMales' sexual attraction to females and females' sexual attraction to males is perhaps the largest and most phylogenetically widespread of any psychological sex difference. The occurrence of exclusive male same-sex sexual attraction in most human cultures deviates from this common pattern. The present study is significant because it attempts to elucidate the evolutionary basis of male same-sex sexual attraction-a trait that has long perplexed evolutionists.

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Fluctuating Asymmetry in the Saddle Patch Shape of the Pacific Ocean Killer Whale (Orcinus orca) Populations

Cited by 5 publications

References 21 publications

Quantifying variation in killer whale (Orcinus orca) morphology using elliptical Fourier analysis

Quantifying variation in killer whale (Orcinus orca) morphology using elliptical Fourier analysis

A comparison of pigmentation features among North Atlantic killer whale (Orcinus orca) populations

Facial symmetry of the sisters of Thai and Istmo Zapotec androphilic males.

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