scholarly journals Biological associations of color variation in the Indo-Pacific swimming crab Charybdis hellerii

2015 ◽  
Vol 87 (1) ◽  
pp. 219-232 ◽  
Author(s):  
TIMOTEO T. WATANABE ◽  
FERNANDO J. ZARA ◽  
GUSTAVO Y. HATTORI ◽  
ALEXANDER TURRA ◽  
BRUNO S. SANT'ANNA

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.

1965 ◽  
Vol 97 (1) ◽  
pp. 32-41 ◽  
Author(s):  
George H. Bick ◽  
Juanda C. Bick

AbstractVariation in thoracic color and the role of color in reproduction were studied in the field in one population of the damselfly, Argia apicalis. Mature males and females were individually marked, and observed near noon on 47 consecutive days, and hourly on three. Males occurred in two color phases: bright blue, and gray-black, neither of which could be positively associated with age or mating. Change was not a single step from blue to finally dark or vice versa but often involved intervening changes in both directions with a maximum of eight in 12 days. Dark was the more temporary condition. Females occurred in three color phases: brown, turquoise, gray-black. As with males, no one phase could be positively associated with age or mating, and multi-directional change occurred after sexual maturity.Dead pinned individuals, modified or not, were presented to living males who: (1) advanced sexually toward motionless models, (2) discriminated intact females from males, (3) reacted sexually more frequently to brown than to the other normal female colors, (4) responded sexually to a female thorax and one wing almost as frequently as to a normal female, (5) accurately discriminated a female thorax and one wing from that of a male. The blue-tipped male abdomen aided but was not indispensable for sex recognition. Dorsal and lateral thoracic color were equally important and elicited male sexual response in their entirety rather than by particular pattern. Sex discrimination broke down when the normal thoracic color was obliterated with paint regardless of its color, but a thorax painted white was an "over-optimal" attraction suggesting the importance of light intensity.


Author(s):  
Bruno Gabriel Nunes Pralon ◽  
Maria Lucia Negreiros-Fransozo

The relative growth of the fiddler crab Uca cumulanta was studied, primarily to determine the size at the onset of sexual maturity for a mangrove population in the estuary of the Patitiba River, Paraty, Rio de Janeiro state, Brazil. The evaluation of the morphological sexual maturity of U. cumulanta was performed using the allometric technique. The relationships that most precisely indicated the size at onset of sexual maturity were carapace length (CL) vs propodus length for males and CL vs abdomen width for females. Males and females are mature at 5.25 and 4.75 mm CL, respectively. The remarkable ontogenetic changes observed in the allometric growth of the male major cheliped and the female abdomen, indicate that growth of these structures is closely connected to the timing of sexual maturity. The relative size at onset maturity obtained for this species was 0.68 and this index was compared to that seen in other species in the genus.


1991 ◽  
Vol 48 (6) ◽  
pp. 1015-1021 ◽  
Author(s):  
Jan Henning L'Abée-Lund

I compared adult size and sea age at sexual maturity among nine populations of anadromous brown trout, Salmo trutta, in two Norwegian rivers to determine the extent of inter- and intrariverine variations. Variation in the mean length of spawners and in the mean sea age at sexual maturity were mainly dependent on the variations found within rather than between rivers. Mean lengths and mean age at maturity of males increased significantly with increasing altitude of the spawning area and with migration distance in freshwater. In females, positive significant correlations were found with mean lengths and altitude of the spawning area and with mean sea age at maturity and both spawning site altitude and migration distance. Mean lengths and ages of males and females were not significantly correlated with the rate of water discharge in the streams during spawning. The size of gravel substrate for spawning was of minor importance in explaining interpopulation variation in mean female size. The increase noted in mean length and in mean sea age at maturity of both males and females is probably an adaptation to greater energy expenditure to reach the uppermost natal spawning areas.


Author(s):  
Shashidhar T. M. ◽  
K. B. Ramesh

Digital Image Forensic is significantly becoming popular owing to the increasing usage of the images as a media of information propagation. However, owing to the presence of various image editing tools and softwares, there is also an increasing threats over image content security. Reviewing the existing approaches of identify the traces or artifacts states that there is a large scope of optimization to be implmentation to further enhance teh processing. Therfore, this paper presents a novel framework that performs cost effective optmization of digital forensic tehnqiue with an idea of accurately localizing teh area of tampering as well as offers a capability to mitigate the attacks of various form. The study outcome shows that propsoed system offers better outcome in contrast to existing system to a significant scale to prove that minor novelty in design attribute could induce better improvement with respect to accuracy as well as resilience toward all potential image threats.


2021 ◽  
Vol 12 (1) ◽  
pp. 48
Author(s):  
Moussa Side ◽  
Eby Yoboué Gnamma Honorine Alla ◽  
Behiri Innocent Kakou ◽  
Béatrice Abouo Adepo-Gourene

The growth and size at first sexual maturity of the species Ethmalosa fimbriata were studied in two sites in the Ebrié lagoon: Bietri, a highly anthropized environment and Vitré 2, a reference site. Growth parameters estimated from size frequencies showed that growth in both size and weight was faster in females than in males regardless of habitat. On the other hand, specimens from Biétri bay have a slower growth rate than those from Vitré 2. In Bietri bay, individuals are characterized by early sexual maturity. They reach sexual maturity at the age of 0.55 years (about 7 months), corresponding to a size of 6.13 cm for males and 8.42 cm for females; whereas in Vitré 2, they reach sexual maturity at the age of 0.82 years (about 10 months) corresponding to a size of 10.22 cm and 12.94 cm for males and females respectively. These results show that in a highly antropic environment, the growth of Ethmalosa fimbriata is affected and individuals reproduce earlier.


Zootaxa ◽  
2013 ◽  
Vol 3608 (2) ◽  
pp. 151-157 ◽  
Author(s):  
MÁRCIO FELIX ◽  
DOUGLAS FELIPE DOS SANTOS LIMA ◽  
GABRIEL MEJDALANI ◽  
RODNEY R. CAVICHIOLI

The new sharpshooter species Sonesimia nessimiani is described from Bolivia based on specimens collected on sugar cane. An identification key to males and females of all known species of the genus is given. In addition to the external morphology, color pattern, and male genitalia, female genital structures are also described and illustrated. Notes comparing the new species with the remaining six Sonesimia species are provided.


1970 ◽  
Vol 27 (12) ◽  
pp. 2155-2158 ◽  
Author(s):  
G. P. Ennis

In Newfoundland waters, shorthorn sculpins, Myoxocephalus scorpius (L.), live to age 15 and attain a maximum size of just over 50 cm. The growth rates of males and females are little different below age 4, but above age 4 the females grow faster than the males, and the difference between average length-at-age for males and females gets progressively larger with age. Males mature at a younger age and at a smaller size than females. In any age-group where there are mature and immature individuals the mature ones are larger.


1988 ◽  
Vol 15 (2) ◽  
pp. 149 ◽  
Author(s):  
PA Woolley

The ningbing antechinus is a species of small dasyurid marsupial found in the Kimberley region of Western Australia. Observations on reproduction have been made on newly captured and laboratory maintained specimens. The breeding season is short and mating occurs in June. The young are born after a long gestation, estimated to be between 45 and 52 days, in late July and early August. They are weaned in November when about 16 weeks old and they reach sexual maturity at 10-11 months, in the first breeding season after birth. Both males and females are potentially capable of breeding in a second season.


The Condor ◽  
2007 ◽  
Vol 109 (1) ◽  
pp. 187-192 ◽  
Author(s):  
Ana S. Barreira ◽  
Dario A. Lijtmaer ◽  
Stephen C. Lougheed ◽  
Pablo L. Tubaro

Abstract Abstract Ultramarine Grosbeaks (Cyanocompsa brissonii) possess a striking sexual dichromatism, with males dark blue and females brown. There are two subspecies in Argentina: the larger-bodied C. b. argentina, which is common in shrubs and semiopen areas, and the smaller C. b. sterea that inhabits forests. We measured reflectance spectra of six plumage patches from study skins to evaluate the possibility of color differences between males of each subspecies and temporal variation in plumage coloration. We found differences between subspecies in color brightness, hue, saturation, and UV chroma in the plumage patches of more conspicuous coloration, which could be related to ambient light differences between the environments that each subspecies inhabits. We also documented temporal color variation in some plumage patches, in particular a gradual decrease of UV reflectance and a gradual increase in hue after molting, possibly attributable to feather wear.


1989 ◽  
Vol 1 (3) ◽  
pp. 255 ◽  
Author(s):  
KB Karim ◽  
S Banerjee

At and near Agra, in Uttar Pradesh, India, R. h. hardwickei had a strictly defined annual reproductive cycle. Although many females were inseminated during late February to mid April, ovulation was not recorded until 11 March. Progressively more females ovulated and conceived during the following weeks until the end of April and released one ovum from either of the ovaries with nearly equal frequency. A single conceptus was carried in the ipsilateral uterine cornu during each cycle. The gestation period was 95-100 days. Births occurred between the second week of June and the end of July. Lactation lasted at least 20 days. Females attained sexual maturity at an age of 8.5-9.0 months. Males took at least 16-17 months to attain sexual maturity. Females were segregated during lactation; during the rest of the year, males and females lived together.


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