• 환경생물
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• 제35권4호
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• pp.515-520
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• 2017

Sexual dimorphism of the mouthpart, antenna and mandible of the Cyllorhynchites ursulus in South Korea was studied with linear measurements. The mouthpart and antenna measurements were conducted with a stereoscopic microscope using 122 specimens (72 males and 50 females). Microscopic observation of the mandible were conducted with a Field Emission Scanning Electron Microscope (FE-SEM) using 103 specimens (73 males and 30 females). Results showed that the size difference between males and females was significant in the size of the mouthpart and antenna. On the other hand, we could not detect sexual size dimorphism in the microstructure of the mandible. The bivariate plots made by the result of Principal Component Analysis (PCA) and Discriminant Analysis (DA) showed a size dimorphism in the size of the mouthpart and the antenna between males and females. Based on our study, sexual dimorphism in the mouthpart and antenna exists in C. ursulus from the South Korean population, and this difference seems to be related to the behavioral differences between males and females.

• 한국수산과학회지
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• 제30권6호
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• pp.992-996
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• 1997

Study on sexual dimorphism in Littorphism in Littorina brevicula should be interesting to examine that how the species prevent niche-overlap between the sexes? and how the species act differently in the reproductive roles of the sexes? Sexual dimorphism on the shell of L. brevicula was examined with 211 periwinkles larger than 5 mm shell length in Pusan, Korea. Sexual dimorphism was detected in the aperture length only. Aperture length of the female was longer than that of the male. A difference in the sexual role in the reproduction seems to be a probable explanation for the sexual dimorphism in the aperture length. The reproductive role of the male is to choose the best female and to transfer the sperm successfully by copulation, and the role of the female is to spawn their fertilised eggs into the seawater successfully. Perhaps females migrate to lower elevations on the shore than the males, so that they are submerged when they spawn. Because wave action at the lower area of the shore is stranger than that at the higher area on the shore, the females might need larger aperture size than the males to avoid dislodgement.

• 한국어류학회지
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• 제8권1호
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• pp.14-21
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• 1996

Cottus poecilopus Heckel의 성적 이형을 조사하기 위하여 치악산 계류에서 1993년 1월 부터 1994년 4월까지 조사를 실시하였다. 연령별 암수의 체장 구성비에 있어서 수컷이 암컷 보다 다소 컸으며, 뒷지느러미, 배지느러미, 가슴지느러미의 길이와 입의 크기에 있어 수컷이 암컷보다 길다. 혼인색(nuptial color)과 생식적 유두(genital papilla)는 수컷에서만 존재한다. 암컷은 산란시 큰 수컷을 선호하며, 큰 수컷은 수정란을 보호하고 수류를 일으키는데 우세하며 수정난 생존에 유리하게 작용한다. 또한 큰 입은 산란장을 형성하거나 보호하는데 이점이 있다. 이러한 성적 형태의 차이는 본종의 성적 선택의 결과에 의해 기인된 것으로 생각된다.

• Journal of Ecology and Environment
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• 제31권1호
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• pp.17-21
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• 2008

Mating behaviour of the gammarid amphipod, Hyale rubra, was observed. H. rubra displayed precopulatory mate guarding: males clasped females with their gnathopods during copulation, forming a pair. Males also participated in embryo care during the incubation period. The population was small, and the sex ratio was almost equal. Energy allocation for mating effort and parental effort in the two sexes appear to be almost equal. The mating system was sequentially polygamous (or promiscuous) and there was conspicuous sexual dimorphism in the size of the gnathopod, which was used for mate guarding. However, there appears to be relatively weak sexual competition for mating opportunities despite conspicuous sexual dimorphism. H. rubra did not display territorial competition or external fertilization. Nevertheless, the male provided paternal care. Since H. rubra inhabit tide pools and live on algae, the polygamous mating system of the species can be explained by the polygyny threshold model. The evolution of mate guarding and parental care may have been favored by the species' low population density and harsh environments, an interpretation consistent with the optimality model.

• 식물분류학회지
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• 제41권3호
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• pp.202-208
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• 2011

The present study was focused on the careful investigation of Glechoma longituba flowers collected from four populations in Korea to clarify their precise sexual systems. All floral characters of this taxon were examined by using a stereo microscopy. The nutlet size and production were compared between two distinct morphs (i.e., hermaphrodites and females), and pollen viability test of hermaphrodite and intermediate phenotype (i.e., individuals with a mixture of females and perfect flowers) was also observed by light microscopy (LM). All of the investigated floral characters of G. longituba are significantly different from one sexual morph to another. Hermaphroditic plants were larger than the female ones in corolla width and length, calyx length, filament length, anther length, and style length (all P < 0.0001, respectively). However, the nutlet width of the female plants was larger than those of the hermaphrodites (P = 0.013). Nutlet production of females was higher than hermaphrodites in Na-Ju population [H (Hermaphrodite): ca. 17.76%, F (Female): ca. 37.45%], but in Mun-San population was no significant difference between these sexual morphs (H: ca. 57.52%, F: ca. 53.16%). We have found significant differences between the fertile pollen grain of hermaphrodite and sterile pollen grain of intermediate phenotype based on pollen size and viability. The results of the present study suggest that compensation (flower size dimorphism, seed set, and pollen viability) is one of the main mechanisms in order to maintain female plants in gynodioecious G. longituba.

• Journal of Nutrition and Health
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• 제44권2호
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• pp.162-170
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• 2011

본 논문에서는 탈북 성인 남녀의 평균 신장을 남한의 것과 비교 검토함으로써 영양 환경의 질이 향상되면 남녀 간 신장의 성적이형성 (SSD, Stature Sexual Dimorphism)이 커질 것이라는 영양환경 가설을 검증하였다. 연구대상 선정은 두 단계에 걸쳐 이루어졌다. 우선, 1997년부터 2007년 4월까지 남한에 입국하여 신체를 계측한 탈북자 중에서 탈북 당시 연령이 최소 만 20세 이상이어서 성인신장을 북한에서 도달한 것으로 추정할 수 있는 사람들을 일차 표본으로 선정하였다. 이 일차 표본 중에서 1955년에서 1959년 사이에 출생한 사람들과 1980년에서 1984년 사이에 출생한 사람들을 최종 선정하여 탈북자들 사이의 세대 간 변화를 비교하였다. 남북한 비교를 위해서는 남한의 Size Korea 2004 자료를 이용하였다. Size Korea 2004 자료에서 만20세 이상 성인으로서 탈북자 표본과 같은 시기 즉, 1955년에서 1959년 사이 그리고 1980년에서 1984년 사이에 출생한 사람들의 SSD를 계산하여 탈북자 자료와 비교하였다. SSD의 크기 변화를 통계적으로 검증하기 위해서는 Greene (1989)의 검증법을 이용하였다. 조사 결과, 탈북자들 사이에서는 한국전쟁 종전 직후 출생한 세대와 1980년대에 출생한 세대 사이에 평균 신장의 증가가 관찰되지 않았고 신장 성적이형성의 크기에도 변화가 없었다. 반면에 남한에서는 두 세대 사이에 평균 신장의 확연한 증가가 있었는데 남녀 중에서도 남성 집단의 평균신장 증가가 더욱 두드러진 결과로 SSD도 증가하였다. 즉 1980년대 출생자들이 한국전쟁 종전 직후인 1955~59년 사이에 출생한 사람들보다 확연히 큰 SSD를 보여주었다. 이는 영양 환경의 질이 향상되면 남성과 여성 사이의 성적 이형성이 커지는 경향이 나타날 것이라는 영양환경 가설을 뒷받침하는 결과이다.

• Journal of Forest and Environmental Science
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• 제38권4호
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• pp.275-283
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• 2022

A study was designed to investigate the pattern of sexual dimorphism in a plantation of Garcinia kola. Twenty trees were randomly selected for the study and have been observed to flower regularly. A total of 100 inflorescence were randomly collected from the crown of each tree and 500 flowers randomly assessed within the period of four (4) flowering seasons. Floral sex assessment was done visually and with a hand magnifying lens; floral morphometric measurements (i.e. pedicel and perianth length and breadth), inflorescence length, and breadth) was taken using a veneer caliper; number of flowers per inflorescence and inflorescence per twig was counted; while, data analysis was conducted on excel using analysis of variance and pairwise t-test comparison. Four floral sexes were identified in the G. kola plantation studied which were unisexual male flowers, unisexual female flowers, cosexual unisexual male flowers, and cosexual hermaphrodite flowers. Three tree sexes were identified viz: inconstant male, invariant female, and cosexual trees. The plantation was significantly sexually dimorphic in floral sex and phenotypic traits (i.e. pedicel and perianth size), and as well as sexually dimorphic in tree sex and reproductive phenotypic traits (i.e. inflorescence size, number of inflorescences per twig, and number of flower bud per inflorescence). The sexual system of the plantation was therefore trioecious with features suggestive of evolving dioecy through the gynodioecious pathway.

• 한국동물학회지
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• 제39권4호
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• pp.437-446
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• 1996

한국산 도롱뇽(Hynobius leechii)의 암수의 신체적 특성 및 구애,싸움 행동에 대한 연구를 수행하였다. 몸의 길이, 코부터 총배설까지의 길이, 몸의 길이에 대한 코부터 총 배설강까지 길이의 비에 있어서 암컷이 수컷보다 더 길었으며, 수컷들은 몸의 길이, 코부터 총배설까지의 길이, 머리의 넓이, 꼬리부터 총배설까지의 길이, 꼬리의 넓이의 5개 요소에 있어서 모든 요소들이 서로 유의미한 상관을 보인 반면, 암컷에 있어서는 꼬리의 넓이를 제외한 모든 요소에서 의미 있는 상관을 보였다. 체외수정을 하는 한국산 도롱뇽의 성적인 행동은 암컷을 확인하는 단계,암컷을 유인하는 단계, 그리고 수정 단계로 구성되어진다. 안컷을 확인하는 단계는 암컷에게로 접근 행동 및 서로 코를 맞대는 행동으로 구성되며, 유인단계에서는 턱부비기, 꼬리치기, 냄새맡기, 파기의 네 가지의 과시 행동이 나타났다. 수정의 과정은 포집, 암컷으로부터 알주머니의 분리, 알의 수정, 수정 후 과시행동으로 구성되었다. 싸움 행동은 간단한 편으로, 공격하는 개체는 상대편의 위턱이나 뒷다리 부근을 주로 물었으며, 문 상태에서 자신의 머리를 2-3회 흔드는 행동을 보였다. 대부분의 경우에 있어서 개체의 크기에 상관없이 공격을 당한 개체는 공격한 개체로부터 재 빨리 회피를 하였으며, 승리를 한 개체는 빠른 꼬리치기 과시 행동을 보였다.

• 대한의용생체공학회:의공학회지
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• 제44권1호
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• pp.53-63
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• 2023

There have been many studies from the genetic system to physical activity and emotional expression such that there are gender differences. The purpose of this study was to determine how the structural characteristics of cortical thickness differ between males and females. This study used data from the Human Connectome Project (HCP). To analyze age-specific sexual dimorphisms of cortical thickness, selected 8-80 year old subjects were divided into five detailed age range groups according to each criterion. A total of 1,700 individual brain MRI T1 data were registered in stereotaxic space for analysis and classified into white matter (WM), gray matter (GM), and cerebro-spinal fluid (CSF). For surface-based analysis, the WM/GM surface was reconstructed from a spherical polygon model with 40962 vertices per hemisphere, and each vertex was extended to the GM/CSF boundary. Cortical thickness was then measured between each vertex using the t-link method. In the statistical analysis, intracranial volume was used as a covariate to exclude the effect of the difference in brain size of each individual, and the result of using age as a covariate was added to confirm the age effect within each group. Gender differences in cortical thickness had significant results by group. This may be an index to explain diseases with sexual dimorphism in prevalence or become a basis for explaining the characteristics of each sex that appear in behavior, personality, and aging. Therefore, the results of our study could be a criterion for age classification in future studies and for understanding 'normal' sexual dimorphism.

• Journal of Ecology and Environment
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• 제30권4호
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• pp.287-292
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• 2007

We monitored a breeding population of the Asian toad (Bufo gargarizans), in the Wonheunge pond at Sannamdong, Chungju, from 5 March to 11 April, 2006 and 14 February to 31 March, 2007 to investigate their movement patterns, breeding population sizes, and physical characteristics. Terrestrial migration to the pond started on 5 March in 2006 and 14 February in 2007. We captured a total of 266 immigrating individuals (213 males, 53 females) in 2006 and 307 (222 males, 85 females) in 2007, and found 50 adults apparently killed by motor vehicles while migrating to the pond in 2007. Emigration from the pond to terrestrial sites started on 15 March 2006 and 5 March 2007. We captured a total of 245 emigrating toads (181 males, 65 females) in 2006 and 99 (92 males, 7 females) in 2007. An additional 10 emigrating adults were found dead on the road. During both the immigration and emigration periods, two peaks in capture frequency appeared for each sex in each breeding season. The immigration peaks corresponded with higher temperatures, while the emigration peaks corresponded with high humidity. Migrating Asian toads showed sexual size dimorphism and a male-biased sex ratio. Body weights and SVL (snout-vent length) of immigrating and emigrating individuals were negatively related with migration dates.