scholarly journals Sexual dimorphism and associated population characteristics in the benthopelagic shrimp Pasiphaea sivado (Crustacea: Caridea: Pasiphaeidae)

2017 ◽  
Vol 81 (1) ◽  
pp. 57
Author(s):  
Daniela Silveira Simão ◽  
José Luís Pérez Gil ◽  
Pere Abelló
Keyword(s):  
Sexual Dimorphism ◽  
Sex Ratio ◽  
Population Biology ◽  
Critical Size ◽  
Gender Segregation ◽  
Western Mediterranean ◽  
Population Characteristics ◽  
Male Dominance ◽  
Mediterranean Populations ◽  
First Time

Morphological and size dimorphism between genders of the benthopelagic shrimp Pasiphaea sivado are reported for the first time in the present work. All five pleopod protopods of females are thinner and more elongated than the male pleopod protopods, which in turn are anteriorly rounded and have robust shapes. The shape variability of the second pleopod protopods was also analysed using geometric morphometrics techniques which clearly differentiated between the thinner, elongated shape of the females and the robust shape of males. An important application of the observations of sexual dimorphism in pleopod shape in adult P. sivado is, from now on, the ability to quickly assess the gender of individuals when fisheries and population biology studies are carried out in the field unaided by a magnifying. A critical size from which the population sex ratio biases changed from female to male dominance was found in all studied western Mediterranean populations of P. sivado. This critical size different and became progressively smaller from populations in the Alboran Sea to populations in the Catalan Sea. Concerning sex ratio, no significant tendency of gender segregation was found across the bathymetric distribution range of the species, suggesting that this species does not perform differential depth distribution by gender.

scholarly journals Population biology of the crab Armases angustipes (Crustacea, Decapoda, Sesarmidae) at Brazilian tropical coast

2014 ◽  
Vol 104 (2) ◽  
pp. 150-161 ◽  
Author(s):  
Marina de Sá Leitão C. de Araújo ◽  
Deusinete de O. Tenório ◽  
Daniela da S. Castiglioni
Keyword(s):  
Population Structure ◽  
Sexual Dimorphism ◽  
Sex Ratio ◽  
Population Biology ◽  
Carapace Width ◽  
Reproductive Activity ◽  
Coastal Regions ◽  
Phytoplankton Productivity ◽  
Number Of Individuals ◽  
Tropical Coast

The semi terrestrial crabs are important elements of the fauna of coastal regions. The aim of this study was to analyze the population structure of Armases angustipes (Dana, 1852) at estuaries of the Ariquindá River, considered a non impacted area, and Mamucabas River, considered a few impacted area, on the south coast of state of Pernambuco, Brazil. The species occurred in all months of the year. The number of individuals per month varied, being higher in the months of transition between the seasons. This is probably due to significant seasonal variations of air and burrow temperature and burrow salinity. There was no sexual dimorphism in size of A. angustipes in the mangrove of Ariquindá River, but males were larger than females in the mangrove of Mamucabas River. In both estuaries, the sex ratio did not differ from Mendelian proportion, but showed a deviation for females. The analysis of temporal variation in sex ratio showed significant differences in some months of the year. These variations are due to cyclical events that act distinctly on each sex. In both estuaries, size classes of carapace width were equally represented by both sexes. The ovigerous females of A. angustipes occurred only in some months of the year, especially in summer, in both estuaries. Probably the high phytoplankton productivity observed in summer favors the reproductive activity, since these algae serve as food for the larvae. Specimens of the population of Rio Ariquindá are largest and wider than those of Mamucabas River. This fact, associated with the low abundance of crabs and the lower frequency of ovigerous females observed in Mamucabas River, is an indication that this population may be influenced by the environmental impacts that this estuary has received.

scholarly journals Reproduction and population structure of the sea cucumber Holothuria tubulosa in the Dardanelles Strait, Turkey

2015 ◽  
Vol 17 (1) ◽  
pp. 47 ◽  
Author(s):  
H. DERELİ ◽  
S. TÜRK ÇULHA ◽  
M. ÇULHA ◽  
B. H. ÖZALP ◽  
A. A. TEKİNAY
Keyword(s):  
Population Density ◽  
Gonadosomatic Index ◽  
Morphological Characteristics ◽  
Environmental Parameters ◽  
Population Characteristics ◽  
High Positive Correlation ◽  
Mediterranean Populations ◽  
Reproductive Patterns ◽  
First Time ◽  
The Relationship

In this study, Holothuria tubulosa Gmelin 1791 was investigated from April 2013 to March 2014 in the Dardanelles Strait, to outline the morphological characteristics, reproductive patterns and the relationship between population characteristics and environmental parameters. Between 15 and 30 individuals of this species were sampled monthly from three stations. There was a negative allometry between length and weight, being gutted weight the most reliable measurement for this species. Reproductive patterns of the species were identified the first time for Turkish coasts. By macroscopic examination of the gonads, smallest sizes (gutted length) were measured as 8.4 and 8.1 cm for female and male, respectively. Sex ratio was calculated as 1: 1.1 with differences between seasons. The reproduction of sea cucumbers occurred between August and September after Gonadosomatic Index (GSI) values reached their maximum in July. The species was found down to 10 m depth with a population density of 0.21 / m2, which was rather low compared to previously reported values for Mediterranean populations of this species. There was a high positive correlation between population density and GSI of the species. The highest population density was observed where the largest sea grass meadows are found.

scholarly journals Population characteristics of the house rat (Rattus rattus) in rural areas of Pothwar, Pakistan

2021 ◽  
pp. 110-115
Author(s):  
Surrya Khanam ◽  
Muhammad Mushtaq
Keyword(s):  
Sex Ratio ◽  
Rural Areas ◽  
Population Biology ◽  
Control Strategies ◽  
Rattus Rattus ◽  
Age Groups ◽  
Reproductive Activity ◽  
Population Characteristics ◽  
Four Seasons ◽  
Suitable Environment

The house rat (Rattus rattus) is the major commensal rodent species present in rural habitats of Pakistan. Little is known about the biology of this species in the country. Hence, proper control plans for its management could not be developed. The objective of the present study was to determine the population biology of the house rat in rural commensal habitats of Pothwar, Pakistan. A two-year study was conducted in four villages during four seasons. A total of 217 house rats were captured with snap traps. The species had an unbiased sex ratio. Individuals from different age groups were present in the population, and the adults outnumbered sub-adults and juveniles. Reproductive activity was observed throughout the year, and reproductively active individuals outnumbered the inactive ones. These results show that rural commensal habitats were providing suitable environment for the house rats throughout the year. The findings of the present study will be useful for the planning of control strategies in the commensal habitats of rural Pothwar.

Population biology and fecundity of the Indo-Pacific hermit crab Clibanarius longitarsus (Anomura: Diogenidae)

2005 ◽  
Vol 85 (1) ◽  
pp. 121-125 ◽  
Author(s):  
Carlos Litulo
Keyword(s):  
Sexual Dimorphism ◽  
Sex Ratio ◽  
Hermit Crab ◽  
Population Biology ◽  
Size Structure ◽  
Reproductive Activity ◽  
Female Size ◽  
Frequency Distributions ◽  
One Year ◽  
Average Size

The population biology and reproduction of the hermit crab Clibanarius longitarsus were studied with emphasis on size structure, sex ratio, breeding season and fecundity. Specimens were sampled monthly over a period of one year (January–December 2003) at Costa do Sol mangrove, Maputo Bay, southern Mozambique. A total of 597 individuals was obtained of which 202 were males, 192 non-ovigerous females and 203 ovigerous females. Annual size–frequency distributions were polymodal for males and bimodal for non-ovigerous and ovigerous females, respectively. Sexual dimorphism was recorded by the larger average size attained by males in relation to females. Sex ratio was female-biased during most months of the study. Clibanarius longitarsus showed a higher reproductive activity with two major peaks (March and October). Juvenile recruitment was continuous throughout the study period. Clutch size was positively associated with female size. The high number of ovigerous females as obtained in the present population may evidence a higher reproductive activity displayed by C. longitarsus at Costa do Sol mangrove.

Do secondary sexual dimorphism and female intolerance to drought influence the sex ratio and extinction risk of Taxus baccata?

Plant Ecology ◽  
2008 ◽  
Vol 200 (2) ◽  
pp. 229-240 ◽  
Author(s):  
Grzegorz Iszkuło ◽  
Anna K. Jasińska ◽  
Marian J. Giertych ◽  
Adam Boratyński
Keyword(s):  
Sexual Dimorphism ◽  
Sex Ratio ◽  
Extinction Risk ◽  
Taxus Baccata ◽  
Secondary Sexual Dimorphism ◽  
Secondary Sexual

Institutions of Ancient Roman Law

2018 ◽  
Author(s):  
Luigi Capogrossi Colognesi
Keyword(s):  
Western Mediterranean ◽  
Roman Law ◽  
Private Institutions ◽  
Public And Private ◽  
Family Wealth ◽  
Medieval Europe ◽  
History Of ◽  
The Republic ◽  
Unique Source ◽  
First Time

This chapter gives a rapid overview of the history of Roman public and private institutions, from their early beginning in the semi-legendary age of the kings to the later developments of the Imperial age. A turning point has been the passage from the kingdom to the republic and the new foundation of citizenship on family wealth, instead of the exclusiveness of clan and lineages. But still more important has been the approval of the written legislation of the XII Tables giving to all citizens a sufficient knowledge of the Roman legal body of consuetudinary laws. From that moment, Roman citizenship was identified with personal freedom and the rule of law. Following political and military success, between the end of IV and the first half of III century bce Rome was capable of imposing herself as the central power in Italy and the western Mediterranean. From that moment Roman hegemony was exercised on a growing number of cities and local populations, organized in the form of Roman of Latin colonies or as Roman municipia. Only in the last century bce were these different statutes unified with the grant of Roman citizenship to all Italians. In this same period the Roman civil law, which was applied to private litigants by the Roman praetors, had become a very complex and sophisticated system of rules. With the empire the system did not change abruptly, although the Princeps did concentrate in his hands the last power of the judiciary and became the unique source of new legislation. In that way, for the first time, the Roman legal system was founded on rational and coherent schemes, becoming a model, which Antiquity transmitted to the late medieval Europe.

THE SPEAR LOBSTER, LINUPARUS SOMNIOSUS BERRY & GEORGE, 1972 (DECAPODA, PALINURIDAE) IN INDONESIA

Crustaceana ◽  
1999 ◽  
Vol 72 (7) ◽  
pp. 673-684 ◽  
Author(s):  
Daisy Wowor
Keyword(s):  
Sexual Dimorphism ◽  
Southeast Asia ◽  
Shallow Waters ◽  
Dimorphisme Sexuel ◽  
First Time

AbstractABSTRACT The spear lobster, Linuparus somniosus Berry & George, 1972 (Palinuridae), is here reported for the first time from relatively shallow waters off southern Java, Indonesia. This is only the second time that the species is recorded from Southeast Asia. Sexual dimorphism in the pereiopods is reported: those of males being more robust than those of females. Several other taxonomic characters are also discussed. Notes on the local fisheries for this species are provided. Linuparus somniosus Berry & George, 1972 (Palinuridae) est signale pour la premiere fois d'eaux relativement peu profondes au sud de Java (Indonesie); c'est la seconde fois seulement que l'espece est signalee du Sud-est de l'Asie. Le dimorphisme sexuel des pereiopodes est mentionne, ceux du male etant plus robustes que ceux de la femelle. D'autres caracteres taxonomiques sont aussi discutes. Des notes sur les pecheries locales de cette espece sont fournies.

scholarly journals Sexual dimorphism in a top predator ( Notophthalmus viridescens ) drives aquatic prey community assembly

2018 ◽  
Vol 285 (1890) ◽  
pp. 20181717 ◽  
Author(s):  
Denon Start ◽  
Stephen De Lisle
Keyword(s):  
Sexual Dimorphism ◽  
Sex Ratio ◽  
Intraspecific Variation ◽  
Structure And Function ◽  
Sexually Dimorphic ◽  
Ecological Communities ◽  
Top Predator ◽  
Aquatic Mesocosms ◽  
And Function ◽  
The Impact

Intraspecific variation can have important consequences for the structure and function of ecological communities, and serves to link community ecology to evolutionary processes. Differences between the sexes are an overwhelmingly common form of intraspecific variation, but its community-level consequences have never been experimentally investigated. Here, we manipulate the sex ratio of a sexually dimorphic predacious newt in aquatic mesocosms, then track their impact on prey communities. Female and male newts preferentially forage in the benthic and pelagic zones, respectively, causing corresponding reductions in prey abundances in those habitats. Sex ratio differences also explained a large proportion (33%) of differences in the composition of entire pond communities. Ultimately, we demonstrate the impact of known patterns of sexual dimorphism in a predator on its prey, uncovering overlooked links between evolutionary adaptation and the structure of contemporary communities. Given the extreme prevalence of sexual dimorphism, we argue that the independent evolution of the sexes will often have important consequences for ecological communities.

scholarly journals Distribution of the rare species of clingfishes — small-headed clingfish Apletodon dentatus (Actinopterygii, Gobiesocidae) — near Crimean coasts

2017 ◽  
Vol 2 (2) ◽  
pp. 41-48
Author(s):  
E. P. Karpova ◽  
A. R. Boltachev ◽  
O. N. Danylyuk
Keyword(s):  
New Species ◽  
Species Composition ◽  
Coastal Waters ◽  
Taxonomic Status ◽  
Population Characteristics ◽  
The Black Sea ◽  
Mediterranean Populations ◽  
Morphological Studies ◽  
Significant Difference ◽  
A New Species

Cryptobenthic fauna investigations are highly relevant at studying biodiversity of regions. Studies of the species composition of Gobiesocidae family were carried out in order to clarify ichthyofauna of different regions, and a new species for the Black Sea coastal zone of Crimea was found. Information about its morphology, biology, behavior and other characteristics is very important because of weak study and indeterminate taxonomic status of this species. As a result of morphological studies of the Crimean specimens no significant difference with the type of the Atlantic-Mediterranean populations has been proven. Naturalization of small-headed clingfish in coastal waters of Crimea has been confirmed and some population characteristics, such as a length-weight relationship, have been described. Peculiarities of habitat which which small-headed clingfish prefers and features of localization, enabling competitiveness have been identified. Identification keys were compiled and are given in the paper.

scholarly journals First record of the sipunculan worm Phascolion (Phascolion) caupo Hendrix, 1975 in the Mediterranean Sea

2012 ◽  
Vol 13 (1) ◽  
pp. 89 ◽  
Author(s):  
L.M. FERRERO-VICENTE ◽  
A. LOYA-FERNANDEZ ◽  
C. MARCO-MENDEZ ◽  
E. MARTINEZ-GARCIA ◽  
J.I. SAIZ-SALINAS ◽  
...  
Keyword(s):  
Mediterranean Sea ◽  
First Record ◽  
Western Mediterranean ◽  
High Load ◽  
San Pedro ◽  
Soft Bottoms ◽  
The Mediterranean ◽  
First Time

Specimens of the sipunculan worm Phascolion (Phascolion) caupo Hendrix, 1975 have been collected for the first time in the Mediterranean Sea, thus increasing the number of known sipunculan species of up to 36 in this area. They were encountered on soft bottoms from the coast of San Pedro del Pinatar (Western Mediterranean). Thirty specimens were collected at a depth ranging from 32.6 to 37.2 m, mainly in sandy substrata with high load of silt and clays. 80% of the individuals were found inhabiting empty shells of gastropods or empty tubes of serpulid polychaetes.

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