scholarly journals A Macroevolutionary Perspective on Multiple Sexual Traits in the Phasianidae (Galliformes)

2011 ◽  
Vol 2011 ◽  
pp. 1-16 ◽  
Author(s):  
Rebecca T. Kimball ◽  
Colette M. St. Mary ◽  
Edward L. Braun
Keyword(s):  
Sexual Dimorphism ◽  
Competitive Ability ◽  
Sexually Dimorphic ◽  
Sexual Signals ◽  
Sexual Signaling ◽  
Multiple Signals ◽  
Alternative Models ◽  
Sexual Traits ◽  
Gains And Losses ◽  
Dimorphic Species

Traits involved in sexual signaling are ubiquitous among animals. Although a single trait appears sufficient to convey information, many sexually dimorphic species exhibit multiple sexual signals, which may be costly to signalers and receivers. Given that one signal may be enough, there are many microevolutionary hypotheses to explain the evolution of multiple signals. Here we extend these hypotheses to a macroevolutionary scale and compare those predictions to the patterns of gains and losses of sexual dimorphism in pheasants and partridges. Among nine dimorphic characters, including six intersexual signals and three indicators of competitive ability, all exhibited both gains and losses of dimorphism within the group. Although theories of intersexual selection emphasize gain and elaboration, those six characters exhibited greater rates of loss than gain; in contrast, the competitive traits showed a slight bias towards gains. The available models, when examined in a macroevolutionary framework, did not yield unique predictions, making it difficult to distinguish among them. Even with this limitation, when the predictions of these alternative models were compared with the heterogeneous patterns of evolution of dimorphism in phasianids, it is clear that many different selective processes have been involved in the evolution of sexual signals in this group.

Cross-sexual Transfer

2003 ◽  
Author(s):  
Mary Jane West-Eberhard
Keyword(s):  
Sex Determination ◽  
Sexually Dimorphic ◽  
Male And Female ◽  
Alternative Phenotypes ◽  
Opposite Sex ◽  
Critical Age ◽  
Sexual Traits ◽  
Discrete Traits ◽  
Dimorphic Species ◽  
Determination Mechanism

Distinctive male and female traits are perhaps the most familiar of all divergent specializations within species. In cross-sexual transfer, discrete traits that are expressed exclusively in one sex in an ancestral species appear in the opposite sex of descendants. An example is the expression of brood care by males in a lineage where ancestral females are the exclusive caretakers of the young, as in some voles (Thomas and Birney, 1979). Despite the prominence of sexual dimorphism and sex reversals in nature, and an early explicit treatment by Darwin, discussed in the next section, cross-sexual transfer is not often recognized as a major factor in the evolution of novelty (but see, on animals, Mayr, 1963, pp. 435-439; Mayr, 1970, p. 254; on plants, Iltis, 1983). When more widely investigated, cross-sexual transfer may prove to rival heterochrony and duplication as an important source of novelties in sexually dimorphic lineages. For this reason, I devote more attention here to cross-sexual transfer than to these other, well-established general patterns of change. The male and female of a sexually dimorphic species may be so different that it is easy to forget that each individual carries most or all of the genes necessary to produce the phenotype of the opposite sex. Sex determination, like caste determination and other switches between alternative phenotypes, depends on only a few genetic loci or, in many species, environmental factors (Bull, 1983). There is considerable flexibility in sex determination and facultative reversal in some taxa. Among fish, for example, there is even a species wherein sex is determined by juvenile size at a critical age (Francis and Barlow, 1993). The sex determination mechanism, whatever its nature, leads to a series of sex-limited responses, often coordinated by hormones and not necessarily all occurring at once. A distinguishing aspect of sexually dimorphic traits in adults is that there is often a close homology between the secondary sexual traits that are differently modified in the two sexes.

Remarks on the sexual dimorphism and taxonomy of Fabia Dana, 1851 (Crustacea, Brachyura, Pinnotheridae)

Zootaxa ◽  
2013 ◽  
Vol 3616 (2) ◽  
pp. 190-200 ◽  
Author(s):  
ERNESTO CAMPOS
Keyword(s):  
Sexual Dimorphism ◽  
Sexually Dimorphic ◽  
Female Specimen ◽  
Male Specimen ◽  
Dimorphic Species

A study of the holotype of Pinnotheres hemphilli Rathbun, 1918, revealed it is an early post-hard female, not a male, of Fabia Dana, 1851. The morphology of Pinnotheres emiliai Melo, 1971 (based on a male specimen) and Fabia insularis Melo, 1971 (based on a female specimen) confirm earlier hypothesis that they belong to a sexually dimorphic species that should be known as F. emiliai (Melo, 1971). The redescription of the holotype of Fabia felderi Gore, 1986, supports its generic assignment and its relationship with F. emiliai. The implication of sexual dimorphism and intersexes in the taxon-omy of Fabia is discussed.

The first sexually dimorphic species of Oribatella (Acari, Oribatida, Oribatellidae) and a review of sexual dimorphism in the Brachypylina

Zootaxa ◽  
2010 ◽  
Vol 2332 (1) ◽  
pp. 1 ◽  
Author(s):  
VALERIE M. BEHAN-PELLETIER ◽  
BARBARA EAMER
Keyword(s):  
Sexual Dimorphism ◽  
Oribatid Mite ◽  
First Record ◽  
Western Canada ◽  
Sexually Dimorphic ◽  
Dermal Glands ◽  
Posterior Pair ◽  
Dry Soil ◽  
Dimorphic Species ◽  
A New Species

The oribatid mite genus Oribatella includes over 100 named species, none of which shows distinct sexual dimorphism in the octotaxic system of dermal glands. We propose a new species of this genus, Oribatella canadensis sp, nov., collected from dry soil habitats in western Canada, that shows distinct dimorphism in these dermal glands, the first record of this dimorphism in the Oribatelloidea. The posterior pair of glands in males, but not females, is enlarged and associated with a shallow, medial pit-tubercle complex, and is generally similar to convergent dimorphisms in some genera of Mochlozetidae (Oripodoidea), Mycobatidae (Ceratozetoidea) and Galumnidae (Galumnoidea). We describe this species based on adult and nymphal stages, and expand the diagnosis of the genus to accommodate the newly described immatures. We review the expression of sexual dimorphism in brachypyline oribatid mites and discuss its association with periodically dry habitats.

An interesting sexually dimorphic species, Neoribates isabelaensis sp. nov. (Acari, Oribatida, Parakalummidae) with remarks on sexual dimorphism in Oripodoidea 

Zootaxa ◽  
2017 ◽  
Vol 4347 (1) ◽  
pp. 94
Author(s):  
BADAMDORJ BAYARTOGTOKH ◽  
SERGEY G. ERMILOV ◽  
LEONILA CORPUZ-RAROS
Keyword(s):  
Sexual Dimorphism ◽  
Posterior Part ◽  
The Philippines ◽  
Similar Species ◽  
Sexually Dimorphic ◽  
The Family ◽  
Pheromonal Communication ◽  
Large Round ◽  
Dimorphic Species ◽  
A New Species

A new species Neoribates isabelaensis sp. nov. showing an interesting sexual dimorphism is described from bamboo litter on Luzon Island in the Philippines. This species is unique among other species of Neoribates in the structure of the posterior part of notogaster in males, which has a large round concavity bearing a pair of large sacculi S3. The specific function of this structure is not yet known, but the found sexual dimorphism is presumably involved in pheromonal communication allowing rapid sperm transfer. This is the fourth Neoribates species displaying sexually dimorphic characters. Additionally, Neoribates isabelaensis sp. nov. differs from the morphologically most similar species, Neoribates barbatus Hammer, 1968, by its smaller body size, pointed rostrum, long and setiform bothridial setae and the localization of notogastral setae h1 and h2, which insert close to each other. Further, we discussed all cases of sexual dimorphism in the family Parakalummidae as well as other related groups of Oripodoidea, and the possible function of these modifications. 

A new species of Japanese oribatid mite, Zachvatkinibates erimo sp. nov., showing sexual dimorphism (Acariformes: Oribatida: Punctoribatidae)

Zootaxa ◽  
2019 ◽  
Vol 4647 (1) ◽  
pp. 362-367
Author(s):  
SATOSHI SHIMANO ◽  
JUN-ICHI AOKI
Keyword(s):  
New Species ◽  
Sexual Dimorphism ◽  
Sandy Beach ◽  
Oribatid Mite ◽  
Sexually Dimorphic ◽  
Dimorphic Species ◽  
A New Species

A new species of oribatid mite, Zachvatkinibates erimo sp. nov., is described from a sandy beach in Hokkaido, North Japan. The new species exhibits a clear sexual dimorphism, showing enlarged areae porosae on the notogaster of the male. A key is provided to sexually dimorphic species of Zachvatkinibates. 

scholarly journals Morphology and ecology of a new sexually dimorphic species of Polydora (Polychaeta: Spionidae) associated with hermit crabs from Jamaica, West Indies

Zoosymposia ◽  
2009 ◽  
Vol 2 (1) ◽  
pp. 229-240 ◽  
Author(s):  
LARA D. ORENSKY ◽  
JASON D. WILLIAMS
Keyword(s):  
Sexual Dimorphism ◽  
West Indies ◽  
Hermit Crabs ◽  
Large Female ◽  
Sexually Dimorphic ◽  
The Third ◽  
Commensal Species ◽  
The Family ◽  
Shallow Subtidal ◽  
Dimorphic Species

A new commensal species of Polydora was found associated with hermit crabs from shallow subtidal coral reefs in Jamaica, West Indies, in 2005 and 2006. Polydora nanomon sp. nov. is the third known obligate commensal polydorid of hermit crabs. The species is found in approximately 20% of the gastropod shells, most commonly Leucozonia nassa leucozonalis (Lamarck, 1822), inhabited by Calcinus tibicen (Herbst, 1791) and other hermit crab hosts. P. nanomon sp. nov. produces a hole in the apex of the shell, enters the lumen of the uppermost whorl, and connects to the columella with a tube of mucus and detritus. One large female (up to 70 setigers) is found in the apex with up to four smaller males (generally <30 setigers). Females are distinguished from other species of Polydora by the morphology of the major spines of setiger 5. In addition to a horizontal row of major spines with two lateral teeth, companion setae, and ventral capillaries, setiger 5 contains a group of superior accessory spines, including one large falcate spine with a channel extending down the shaft, one spine with a low rounded tooth, and one companion seta. P. nanomon sp. nov. exhibits sexual dimorphism with the males being much smaller than females, having a reduced first segment, and lacking accessory spines on setiger 4 (= setiger 5 on females). The occurrence of sexual dimorphism within the family Spionidae is reviewed.

New insights to the taxonomy of Rhagodes eylandti (Walter, 1889): A remarkable sexually dimorphic species (Solifugae: Rhagodidae)

Zootaxa ◽  
2019 ◽  
Vol 4648 (3) ◽  
pp. 494-510 ◽  
Author(s):  
HASSAN MADDAHI ◽  
MANSOUR ALIABADIAN ◽  
MAJID MORADMAND ◽  
OMID MIRSHAMSI
Keyword(s):  
Sexual Dimorphism ◽  
Type Material ◽  
Sexually Dimorphic ◽  
Distribution Map ◽  
Diagnostic Characters ◽  
Intraspecific Variations ◽  
First Time ◽  
Dimorphic Species

The taxonomy of the widespread camel spider, Rhagodes eylandti (Walter, 1889), is herein updated and revised by proposing three nominal taxa as its junior synonyms. These are based on data from males of two taxa, Rhagodes melanopygus nigricans Birula, 1905 and R. plumbescens (Walter, 1889), and a female of R. melanochaetus Heymons, 1902. Consequently, both sexes of R. eylandti are re-described and the validity of their morphological diagnostic characters is evaluated. Detailed morphological and morphometrical characters, as well as data on sexual dimorphism and intraspecific variations, are provided. The illustrations of type material are given for the first time. Moreover, a distribution map and ecological notes are presented. 

Description of the female of Ceromya glaucescens Tachi & Shima (Diptera: Tachinidae) and discovery of unusual sexual dimorphism in this species

Zootaxa ◽  
2017 ◽  
Vol 4237 (3) ◽  
pp. 583
Author(s):  
TAKUJI TACHI
Keyword(s):  
Sexual Dimorphism ◽  
Sequence Data ◽  
Morphological Characters ◽  
Morphological Data ◽  
Compound Eyes ◽  
Sexually Dimorphic ◽  
Separate Species ◽  
Wing Patterns ◽  
Males And Females ◽  
Dimorphic Species

Sexual dimorphism is a phenomenon in which the male and female of a species differ in features of the external morphology such as size, shape, colour, or the development of appendages. In the Diptera, stalked compound eyes, leg modifications and wing patterns are well-known examples of sexual dimorphism (McAlpine 1979; Zeil 1983; Adler & Adler 1991; Meyerrochow & Reid 1994; Wilkinson & Dodson 1996; Sivinski 1997; Baker & Wilkinson 2001; Eberhard 2002; Puniamoorthy et al. 2008). Males and females of sexually dimorphic species are often described as separate species due to the dissimilarity in external characters, thus leading to problems in identification and proper association of the sexes. In contrast to characters that are usually involved in sexual dimorphism, leg chaetotaxy is considered one of the invariable character systems, irrespective of sex, in the tribe Siphonini of the Tachinidae, and is thus widely used in keys to genera and species (O’Hara 1989; Andersen 1996). Species’ identification by DNA barcoding has been used in various groups of organisms (Hebert et al. 2003; Ratnasingham & Hebert 2013). In insects, males, usually more easily identified by morphological characters (e.g., postabdominal features) than females, are often used for barcoding. The identification of females will improve as sequence data accumulate, such as data from pairs collected in copula. In this paper, I describe sexual dimorphism in the Japanese endemic species of tachinid fly Ceromya glaucescens Tachi & Shima, 2000 of the tribe Siphonini, and use molecular and morphological data for the identification of this species. Sequence data of C. silacea (Meigen, 1824) are also included for comparison. 

scholarly journals Bearded ladies: females suffer fitness consequences when bearing male traits

2013 ◽  
Vol 9 (6) ◽  
pp. 20130644 ◽  
Author(s):  
Lindsey Swierk ◽  
Tracy Langkilde
Keyword(s):  
Evolutionary Biology ◽  
Reproductive Output ◽  
Sexually Dimorphic ◽  
Sceloporus Undulatus ◽  
Secondary Sexual Traits ◽  
Intralocus Sexual Conflict ◽  
Fitness Consequences ◽  
Sexual Traits ◽  
Male Ornaments ◽  
Dimorphic Species

A central assumption in evolutionary biology is that females of sexually dimorphic species suffer costs when bearing male secondary sexual traits, such as ornamentation. Nevertheless, it is common in nature to observe females bearing rudimentary versions of male ornaments (e.g. ‘bearded ladies’), as ornaments can be under similar genetic control in both sexes. Here, we provide evidence that masculinized females incur both social and reproductive costs in nature. Male fence lizards ( Sceloporus undulatus ) discriminated against ornamented females during mate choice. Ornamented females had lower reproductive output, and produced eggs that were laid and hatched later than those of non-ornamented females. These findings support established theories of the evolution of sexual dimorphism and intralocus sexual conflict, and raise questions regarding the persistence of masculinizing ornamentation in females.

scholarly journals Heterospecific interactions and the proliferation of sexually dimorphic traits

2012 ◽  
Vol 58 (3) ◽  
pp. 453-462 ◽  
Author(s):  
Karin S. Pfennig ◽  
Allen H. Hurlbert
Keyword(s):  
Sexual Selection ◽  
Species Richness ◽  
Sexual Dimorphism ◽  
Reproductive Isolation ◽  
Strong Evidence ◽  
North American ◽  
New World ◽  
Sexually Dimorphic ◽  
Incipient Species ◽  
Sexual Traits

Abstract Sexual selection is expected to promote speciation by fostering the evolution of sexual traits that minimize reproductive interactions among existing or incipient species. In species that compete for access to, or attention of, females, sexual selection fosters more elaborate traits in males compared to females. If these traits also minimize reproductive interactions with het-erospecifics, then species with enhanced risk of interactions between species might display greater numbers of these sexually dimorphic characters. We tested this prediction in eight families of North American birds. In particular, we evaluated whether the number of sexually dimorphic traits was positively associated with species richness at a given site or with degree of sympatry with congeners. We found no strong evidence of enhanced sexual dimorphism with increasing confamilial species richness at a given site. We also found no overall relationship between the number of sexually dimorphic traits and overlap with congeners across these eight families. However, we found patterns consistent with our prediction within Anatidae (ducks, geese and swans) and, to a lesser degree, Parulidae (New World warblers). Our results suggest that sexually selected plumage traits in these groups potentially play a role in reproductive isolation.

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