Seasonal variation in the testicular cycle of the loggerhead musk turtle, Sternotherus minor minor, from central Florida

1990 ◽  
Vol 68 (6) ◽  
pp. 1071-1074 ◽  
Author(s):  
Cory R. Etchberger ◽  
Randall H. Stovall
Keyword(s):  
Seasonal Variation ◽  
Sexual Maturity ◽  
Carapace Length ◽  
Variable Temperature ◽  
Southern Limit ◽  
Male And Female ◽  
Central Florida ◽  
Sternotherus Odoratus ◽  
Proximal Determinant ◽  
Testicular Size

Seasonal macroscopic and microscopic changes in the testicular cycle of Sternotherus minor from the southern limit of its range are described, and comparisons are made with the female reproductive cycle from the same population and other populations of Sternotherus from various latitudes. Male S. minor in central Florida reach sexual maturity at three years of age and at least 60 m carapace length. Spermatogenesis in S. minor begins in spring when spermatogonia increase and become abundant. Maximum testicular size is attained during August and September and then decreases until March when testicular mass is minimal. As in other chelonians, the male and female cycles do not peak at the same time. The timing of the testicular cycle of this population is similar to populations of Sternotherus odoratus from different latitudes (Virginia, Alabama) and from other populations of S. minor from Florida, yet differs from a population of S. odoratus from the same latitude. Because this population of S. minor inhabits water of seasonally variable temperature (whereas most S. minor are found in constant temperature situations), photoperiod, and not water temperature, may be the most important proximal determinant of the testicular cycle.

scholarly journals A comparison of the allometric growth in Uca leptodactyla (Crustacea: Brachyura: Ocypodidae) from two subtropical estuaries

2004 ◽  
Vol 84 (4) ◽  
pp. 733-735 ◽  
Author(s):  
Rosana Carina Flores Cardoso ◽  
Maria Lucia Negreiros-Fransozo
Keyword(s):  
Growth Pattern ◽  
Sexual Maturity ◽  
Carapace Length ◽  
Brazilian Coast ◽  
Allometric Growth ◽  
Size At Sexual Maturity ◽  
Subtropical Estuaries ◽  
Habitat Similarity

The allometric growth of Uca leptodactyla from two distinct subtropical estuaries on the Brazilian coast was evaluated concerning its growth pattern and size at onset of sexual maturity. Females attained maturity at similar sizes in both sites (4·1 mm of carapace length in Indaiá and 4·2 mm in Ubatumirim), while males differed slightly. They reached the size at sexual maturity of 5·3 mm of carapace length in Indaiá and 4·6 mm in Ubatumirim. Growth pattern is usually similar among crabs from distinct sites while size at sexual maturity is frequently different. However, in the case of U. leptodactyla it did not occur, probably due to the strong habitat similarity and intrinsic features of this species.

scholarly journals The population and mortality characteristics of mangrove crab (Scylla serrata) in the mangrove ecosystem of Tarakan City, Indonesia

2020 ◽  
Vol 21 (8) ◽  
Author(s):  
AGUS INDARJO ◽  
Gazali Salim ◽  
MUFRIDA ZEIN ◽  
DODDY SEPTIAN ◽  
STEPHANIE BIJA
Keyword(s):  
Carapace Length ◽  
Total Mortality ◽  
Condition Index ◽  
Mangrove Ecosystem ◽  
Scylla Serrata ◽  
Primary Data ◽  
Allometric Growth ◽  
Male And Female ◽  
Mangrove Crab ◽  
Mangrove Crabs

Abstract. Indarjo A, Salim G, Zein M, Septian D, Bija S. 2020. The population and mortality characteristics of mangrove crab (Scylla serrata) in the mangrove ecosystem of Tarakan City, Indonesia. Biodiversitas 21: 3856-3866. The mangrove crab is an iconic species of Tarakan City and is often is used as a souvenir. However, the high demand for this species can cause its population to decline. This study aimed to characterize the mangrove crab (Scylla serrata) population in the mangrove ecosystem of Tarakan City, North Kalimantan, Indonesia. This study was designed using a quantitative descriptive method with a case study model. The samples of mangrove crabs were obtained from 6 different stations using a purposive sampling method. The mangrove crab specimens were caught using 35-50 units of crab traps known as the ambau brackets. The primary data included carapace length, carapace width, carapace thickness, sex, and the total weight of each mangrove crab specimen. The results showed that male mangrove crabs have positive allometric growth when the condition index was fat. However, female crabs exhibited negative allometric growth when the condition index was thin. The Von Bertalanffy growth model analysis showed that the maximum carapace length of male mangrove crab in the mangrove ecosystem of Tarakan City was approximately 11.1118 cm for 189 days, while the female length was 9.6474 cm for 80 days. The total mortality value of male and female crabs was 120.01% and 154.94%, the mortality due to fishing was 84.69% and 135.75%, and natural mortality was 35.32% and 19.2%, respectively. The estimated rate of exploitation of both male and female crabs was 70.57% and 87.61%, respectively. The exploitation of S. serrata in the mangrove ecosystem of Tarakan City was evident, hence, conservation efforts are urgently required.

Morphological maturity and allometric growth in the squat lobster Munida rugosa

2009 ◽  
Vol 89 (6) ◽  
pp. 1189-1194 ◽  
Author(s):  
Thomas Claverie ◽  
I. Philip Smith
Keyword(s):  
Measurement Error ◽  
Sexual Maturity ◽  
Carapace Length ◽  
Size Range ◽  
Size At Maturity ◽  
Allometric Growth ◽  
Positive Allometry ◽  
Squat Lobster

Size at the onset of sexual maturity was determined in Munida rugosa based on allometric growth of chelipeds and abdomen, and on the proportion of ovigerous females. The variability of three different measurements of carapace length (CL) used previously for M. rugosa was also evaluated to minimize measurement error. Both sexes had symmetrical cheliped length and allometric cheliped growth over the size-range investigated, but males showed increased allometry beyond 22 mm CL. Females had greater positive allometry in abdomen width than males, but their size at maturity could not be precisely determined because sampled females were too large.

Sexual dimorphism and intersexuality in Upogebia stellata (Crustacea: Decapoda: Thalassinidea)

2001 ◽  
Vol 81 (6) ◽  
pp. 1061-1062 ◽  
Author(s):  
Eunice H. Pinn ◽  
R. James A. Atkinson ◽  
Andrew Rogerson
Keyword(s):  
Sexual Dimorphism ◽  
Carapace Length ◽  
Single Specimen ◽  
Male And Female ◽  
Total Length ◽  
Mud Shrimp ◽  
External Characteristics

Evidence of sexual dimorphism in the mud-shrimp Upogebia stellata was observed in the abdomen length, total length, and also in the chelae. For the same carapace length, males had a shorter abdomen and, therefore, total length, whilst their chelae were larger and more robust than the females. Of the 91 U. stellata individuals examined, a single specimen was found to be of an intersex type, i.e. it exhibited both male and female external characteristics. Sexual dimorphism and intersexuality are discussed.

scholarly journals Intraspecific Seasonal Variation of Flowering Synchronization in a Heterodichogamous Tree

Plants ◽  
2020 ◽  
Vol 9 (11) ◽  
pp. 1509
Author(s):  
Noemi Tel-Zur ◽  
Tamar Keasar
Keyword(s):  
Genetic Diversity ◽  
Seasonal Variation ◽  
Phase Duration ◽  
Male And Female ◽  
Flowering Synchrony ◽  
Flowering Season ◽  
Hand Pollination ◽  
Female Phase ◽  
Male Phase ◽  
Phase Differences

Heterodichogamous reproduction in plants involves two flowering morphs, reciprocal in their timing of male and female sexual functions. The degree of synchrony in floral sex phase, within and between individuals of each morph, determines the flowers’ potential fertilization partners. Complete within-morph synchrony enables across-morph mating alone, whereas unsynchronized floral sex phases may allow fertilization within a plant individual (geitonogamy) or within a morph. We documented the disruption of flowering synchrony in the heterodichogamous Ziziphus spina-christi towards the end of its seven-month flowering season. This desert tree has self-incompatible, protandrous, short-lived (2-day) flowers that open before dawn (‘Early’ morph) or around noon (‘Late’ morph). We counted flowers in the male and female phase on flowering branches that were sampled monthly during the 2016–2018 flowering seasons. In 2018, we also tagged flowers and followed their sex-phase distributions over two days at the start, middle, and end of the season. The switch to the female phase was delayed at the end-season (November-December), and 74% of the flowers did not develop beyond their male phase. Differences in male-phase duration resulted in asynchrony among flowers within each tree and among trees of both flowering morphs. Consequently, fertilization between trees of the same morph becomes potentially possible during the end-season. In controlled hand-pollination assays, some within-morph fertilizations set fruit. The end-season breakdown of synchronous flowering generates variability within morphs and populations. We suggest that this variability may potentially enable new mating combinations in a population and enhance its genetic diversity.

Patterns of Marine Turtle Mortality in British Waters (1992–1996) with Reference to Tissue Contaminant Levels

1998 ◽  
Vol 78 (3) ◽  
pp. 973-984 ◽  
Author(s):  
B.J. Godley ◽  
M.J. Gaywood ◽  
R.J. Law ◽  
C.J. McCarthy ◽  
C. McKenzie ◽  
...  
Keyword(s):  
Organic Contaminants ◽  
Sexual Maturity ◽  
Carapace Length ◽  
Caretta Caretta ◽  
Marine Turtle ◽  
Dermochelys Coriacea ◽  
Fishing Gear ◽  
Leatherback Turtles ◽  
Marine Turtles ◽  
Causes Of Mortality

Mortality patterns of marine turtles entangled in fishing gear, found dead at sea or stranded dead on and around the coast of Britain in the period 1992–1996 are described. Of a total of 38 dead turtles identified, 35 were leatherback turtles (Dermochelys coriacea) and three were loggerhead turtles (Caretta caretta). All D. coriacea were considered adults or subadults nearing sexual maturity. Six individuals were assessed as females, ten were classified as males and 19 were not sexed. Dermochelys coriacea (N=20 measured) ranged from 120 to 210 cm in curved carapace length (mean, 152 cm). The three C. caretta were juveniles, and ranged from 15 to 30 cm curved carapace length. Possible origins, causes of mortality and interactions with fisheries are discussed. In addition, contaminant levels were determined in the tissues of three D. coriacea. Concentrations of organic contaminants determined were found to be low.

A COMPARISON OF VARIATIONS IN PLASMA LUTEINIZING HORMONE CONCENTRATIONS IN MALE AND FEMALE DOMESTIC CHICKENS (GALLUS DOMESTICUS) FROM HATCH TO SEXUAL MATURITY

1975 ◽  
Vol 67 (2) ◽  
pp. 211-223 ◽  
Author(s):  
P. J. SHARP
Keyword(s):  
Luteinizing Hormone ◽  
Reproductive Performance ◽  
Sexual Maturity ◽  
Gallus Domesticus ◽  
Parallel Study ◽  
Stages Of Development ◽  
Male And Female ◽  
The Mean ◽  
Lh Secretion

SUMMARY Changes in plasma LH concentrations were followed in chickens of both sexes from hatch to sexual maturity using a radioimmunoassay. Mean levels of LH were lower in the females than in the males at all stages of development. These levels rose rapidly in both sexes during the first week after hatch to maxima of 6·5 ± 1·2 (s.e.m.) ng/ml (n = 6) in the males and 4·6 ± 0·6 ng/ml (n = 6) in the females. Thereafter levels of the hormone in the circulation stabilized in the males but fell over a period of 1 or 2 weeks in the females to 2·5–3 ng/ml. Plasma LH levels started to rise steeply in both sexes when they were between 16 and 19 weeks old at the same time as there was an increase in the rate of comb growth. Afterwards in six of the males studied in detail the mean plasma LH level rose significantly (P < 0·01) over a period of 5–8 weeks from 8·1 ± 1·2 to 13·2 ± 1·9 ng/ml. In a parallel study on six females the rate of LH secretion increased for approximately 3 weeks and then decreased for about the same period forming a prepubertal LH peak. The first eggs were laid between 22 and 25 weeks of age when mean plasma LH levels had fallen to about 1·8 ng/ml. The mean plasma LH level in these hens when they were laying (1·8 ± 0·3 ng/ml) was significantly lower (P < 0·01) than when they were sexually immature (2·7 ± 0·3 ng/ml). The duration of the period of rapid comb growth in each bird was closely related in the males to the time during which prepubertal LH levels were rising rapidly, and in the females to the duration of the prepubertal LH peak. Differences in mean plasma LH concentrations in individual birds of either sex before the onset of puberty appeared to be related to subsequent reproductive performance.

The Occurrence and Seasonal Variation of Accelerant-Related Burn Injuries in Central Florida

2007 ◽  
Vol 28 (5) ◽  
pp. 675-680 ◽  
Author(s):  
Susan Rainey ◽  
C Wayne Cruse ◽  
Jackie S. Smith ◽  
Kirk R. Smith ◽  
Dawn Jones ◽  
...  
Keyword(s):  
Seasonal Variation ◽  
Burn Injuries ◽  
Central Florida
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