title: Biological associations of color variation in the Indo-Pacific swimming crab Charybdis hellerii.
abstract: A marine biological invasion is a natural process accelerated by human activities, and the crab Charybdis hellerii is an example of a globally widespread invasive species. This study evaluated color variation in C. hellerii and its relationship to the sex, size and sexual maturity of these crabs, and compared the efficiency of a freeware digital image-editing program with a commercially available program. The color of the individuals was analyzed using standardized digital images. The color pattern varied significantly with size; smaller and immature individuals were darker than larger and mature ones. The female abdomen changed in morphology and color with sexual maturity, becoming wider and orange-colored. There was no statistical difference in the color values between males and females and immature males did not show morphological or color differences in their abdomen. This study highlights the possible relationships of the color and physiological state of the reproductive system, which could help in future studies of behavior, avoiding the need to dissect and/or remove individuals from nature for assessment of sexual maturity. The freeware program showed the same efficiency in digital image analysis as a widely known commercial program.
authors.affiliation: Instituto de Ciências Exatas e Tecnologia, Universidade Federal do Amazonas, Itacoatiara, AM, Brasil.
authors.forename: Timoteo T
authors.initials: TT
authors.lastname: Watanabe
authors.affiliation: Centro de Aquicultura, Faculdade de Ciências Agrárias e Veterinárias, Universidade Estadual Paulista, Jaboticabal, SP, Brasil.
authors.forename: Fernando J
authors.initials: FJ
authors.lastname: Zara
authors.affiliation: Instituto de Ciências Exatas e Tecnologia, Universidade Federal do Amazonas, Itacoatiara, AM, Brasil.
authors.forename: Gustavo Y
authors.initials: GY
authors.lastname: Hattori
authors.affiliation: Departamento de Oceanografia Biológica, Instituto Oceanográfico, Universidade de São Paulo, São Paulo, SP, Brasil.
authors.forename: Alexander
authors.initials: A
authors.lastname: Turra
authors.affiliation: Instituto de Ciências Exatas e Tecnologia, Universidade Federal do Amazonas, Itacoatiara, AM, Brasil.
authors.forename: Bruno S
authors.initials: BS
authors.lastname: Sant'anna
mesh_terms: D000818:Animals; D003386:Brachyura / Q000033:anatomy & histology* / Q000145:classification / Q000254:growth & development*; D001938:Brazil; D003116:Color; D005260:Female; D058865:Introduced Species; D008297:Male; D010858:Pigmentation; D012727:Sex Characteristics; D012741:Sexual Maturation