A comparison of alternative methods for estimating population density of the fiddler crab Uca annulipes at Saco Mangrove, Inhaca Island (Mozambique)

In fiddler crabs both males and females defend territories that are essential for survival. Given pronounced sexual dimorphism in weaponry, how do weaponless females defend their territory from well-armed males? Using observational data and two simple experiments, we test whether male Uca annulipes protect their female neighbours from conspecific intruders. We show that males defend their female neighbours against male but not female intruders. We also show that females sometimes mate with their immediate neighbours. Male defence of female neighbours appears to represent both pre-copulatory mate-guarding and a territorial coalition. Males who ensure that their neighbour remains female could benefit through increased opportunity for future reproductive success and lower boundary maintenance costs.

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IDENTIFIKASI JENIS KEPITING BIOLA DI HUTAN MANGROVE DUSUN SETINGGA ASINDESA SEBUBUS KECAMATAN PALOH KABUPATEN SAMBAS

JURNAL HUTAN LESTARI ◽

10.26418/jhl.v8i1.39385 ◽

2020 ◽

Vol 8 (1) ◽

Author(s):

Edy Kurniawan ◽

M Sofwan Anwari ◽

M Dirhamsyah

Keyword(s):

Sampling Method ◽

Fiddler Crab ◽

Sandy Beaches ◽

Mangrove Forests ◽

Crab Species ◽

Fiddler Crabs ◽

Purposive Sampling ◽

Plot Size ◽

Uca Annulipes

The fiddler crab is also known as the kepiting biola is an animal that has broad legs that belong to the Crustacean class. Fiddler crab is a type of crab that has a habitat in intertidal areas, especially around mangrove forests and sandy beaches. This study aims to examine the identification of fiddler crab species found in the Mangrove Sebubus. The method used in this research is purposive sampling method with the use of a square plot size of 1 x 1 meter as many as 30 pieces in 3 research lines. The results showed as many as 7 species of fiddler crabs found there, that is Uca annulipes, Uca rosea, Uca forcipata, Uca bellator, Uca tetragonon, Uca paradussumieri, and Uca acuta.Keywords: Identification, Fiddler Crab, Mangrove Sebubus

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Effects of population density on female and male burrow characteristics in the fiddler crab, Uca bengali Crane, 1975

Crustaceana ◽

10.1163/15685403-00003492 ◽

2015 ◽

Vol 88 (12-14) ◽

pp. 1283-1299 ◽

Cited By ~ 4

Author(s):

Fahmida Wazed Tina ◽

Mullica Jaroensutasinee ◽

Krisanadej Jaroensutasinee

Keyword(s):

Body Size ◽

Population Density ◽

Fiddler Crab ◽

High Density ◽

The Other ◽

Low Density ◽

Density Effects ◽

Egg Incubation ◽

Other Hand ◽

Males And Females

We examined the effects of population density on body size and burrow characteristics ofUca bengaliCrane, 1975. We predicted that (1) males in high-density areas (HD) should be larger in size and build higher quality burrows than males in low-density areas (LD), and (2) HD females should be larger in size, but build lower quality burrows than LD females, as HD females can find higher numbers of good quality male burrows around them for breeding and egg incubation. Our results showed that males and females in HD were larger in size than those in LD. Since HD males were larger in size, they built higher quality burrows than males in LD. On the other hand, even though LD females were smaller in size than HD ones, they built higher quality burrows than HD females. Our results thus indicate that density effects both body size and burrow characteristics.

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Agonistic interactions in the male fiddler crab Uca leptodactyla Rathbun, 1898 at varying densities

Crustaceana ◽

10.1163/15685403-00003443 ◽

2015 ◽

Vol 88 (6) ◽

pp. 625-640 ◽

Cited By ~ 2

Author(s):

L. C. Santos ◽

C. E. R. D. Alencar ◽

F. A. M. Freire ◽

A. C. Luchiari

Keyword(s):

Population Density ◽

Mangrove Forest ◽

Fiddler Crab ◽

High Density ◽

Agonistic Behaviour ◽

Agonistic Interactions ◽

Energy Investment ◽

Low Level ◽

Crab Density ◽

Interaction Intensity

In this study we tested the effect of population density on agonistic interactions in male Uca leptodactyla Rathbun, 1898. We recorded the crab’s behaviour in pairs or in groups of five animals composed of conspecifics and heterospecifics living in the same area (sympatric) and distinct areas (allopatric) of the mangrove forest. Allopatric conspecific crabs showed higher approaching and signalling than those in other conditions. The higher the crab density, the lower the interaction intensity between animals. Low-level agonistic signals were mainly displayed in high density (groups), while claw touch mainly occurred in pairs. Allopatric conspecifics showed the more intense agonistic interactions. Therefore, Uca seems to decrease energy investment in unnecessary fights against sympatric and conspecific crabs. Population density is a major factor driving agonistic behaviour mainly when conspecific animals are kept together. This may occur due to the increased competition for the same resources.

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Genetic and morphological separation of Uca occidentalis, a new East African fiddler crab species, from Uca annulipes (H. Milne Edward, 1837) (Crustacea: Decapoda: Brachyura: Ocypodidae)

Zoologischer Anzeiger ◽

10.1016/j.jcz.2016.03.010 ◽

2016 ◽

Vol 262 ◽

pp. 10-19 ◽

Cited By ~ 10

Author(s):

Reza Naderloo ◽

Christoph D. Schubart ◽

Hsi-Te Shih

Keyword(s):

Fiddler Crab ◽

Crab Species ◽

East African ◽

Uca Annulipes

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Comparison of non-invasive methods for quantifying population density of the fiddler crab Uca tangeri

Journal of the Marine Biological Association of the United Kingdom ◽

10.1017/s002531540300818xh ◽

2003 ◽

Vol 83 (5) ◽

pp. 981-982 ◽

Cited By ~ 14

Author(s):

Joana M. Jordão ◽

Rui F. Oliveira

Keyword(s):

Population Density ◽

Fiddler Crab ◽

Activity Patterns ◽

Structure Estimation ◽

Non Invasive ◽

Absolute Density ◽

Crab Density ◽

Invasive Method ◽

Surface Active ◽

Uca Tangeri

Excavation counts (absolute density), burrow counts and surface active individuals visual counts in a Uca tangeri population were compared. Population density estimated from burrow counts was not significantly different from population density estimated by excavation, but the population density estimated with visual counts was significantly lower than the absolute density. Ovigerous females should be the main cause of these differences because they frequently remain underground, but other groups of crabs are also contributing to this difference. Burrow counting is an accurate and quick non-invasive method for the census of U. tangeri. Other population measures (e.g. sex ratio) are not obtainable by burrow counting and only further understanding of the activity patterns of this species along the tide cycle, moon phase and reproductive season will allow visual counting of surface active individuals to be used as quick, efficient and non-invasive method for crab density and population structure estimation.

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