scholarly journals The adaptive significance of crustacean hyperglycaemic hormone (CHH) in daily and seasonal migratory activities of the Christmas Island red crab Gecarcoidea natalis

2010 ◽  
Vol 213 (17) ◽  
pp. 3062-3073 ◽  
Author(s):  
S. Morris ◽  
U. Postel ◽  
Mrinalini ◽  
L. M. Turner ◽  
J. Palmer ◽  
...  
Keyword(s):  
Adaptive Significance ◽  
Christmas Island ◽  
Gecarcoidea Natalis

EXERCISE IN THE TERRESTRIAL CHRISTMAS ISLAND RED CRAB GECARCOIDEA NATALIS - BLOOD GAS TRANSPORT

1994 ◽  
Vol 188 (1) ◽  
pp. 235-256 ◽  
Author(s):  
A Adamczewska ◽  
S Morris
Keyword(s):  
Gas Transport ◽  
Lactate Production ◽  
Circulatory System ◽  
Indirect Evidence ◽  
Blood Gas ◽  
Christmas Island ◽  
Exercise Period ◽  
Gas Measurements ◽  
Gecarcoidea Natalis ◽  
O2 Delivery

The respiratory and circulatory physiology of the terrestrial Christmas Island red crab Gecarcoidea natalis was investigated with respect to exercise in the context of its annual breeding migration. Red crabs were allowed to walk for predetermined periods of up to 45 min. During this exercise period, blood gas measurements were made on venous, pulmonary and arterial samples to assess the function of the lungs in gas exchange and the performance of the circulatory system in gas transport and to determine the role and importance of the haemocyanin. The lungs of G. natalis were very efficient at O2 uptake, pulmonary blood being 80­90 % saturated throughout the 45 min exercise period. The maximum O2-carrying capacity was 1.1 mmol l-1, and haemocyanin (Hc) delivered 86 % of oxygen in resting crabs and 97 % during exercise. Oxygen delivery to the tissues was diffusion-limited during exercise. Indirect evidence, from the changes in haemolymph pH during transit through the lungs, suggested that the lung is the site of CO2 excretion. The Bohr shift was high at high pH (pH 7.8­7.5, phi=-1.23) but decreased at low pH (pH 7.1­6.8, phi=-0.48). The decreased Hc affinity for O2 during the exercise period facilitated O2 delivery to the tissues without impairing O2 loading at the lungs. The decrease in pH was sufficient to explain the change of affinity of Hc for O2 during the exercise period. The marked acidosis (0.8 pH unit decrease) was largely metabolic in origin, especially during sustained locomotion, but less than could be predicted from concomitant lactate production.

scholarly journals EXERCISE IN THE TERRESTRIAL CHRISTMAS ISLAND RED CRAB GECARCOIDEA NATALIS - ENERGETICS OF LOCOMOTION

1994 ◽  
Vol 188 (1) ◽  
pp. 257-274 ◽  
Author(s):  
A Adamczewska ◽  
S Morris
Keyword(s):  
Heart Rate ◽  
Energy Production ◽  
Energy Charge ◽  
Lactate Concentration ◽  
Laboratory Animals ◽  
Exercise Heart Rate ◽  
Christmas Island ◽  
Exercise Period ◽  
Gecarcoidea Natalis ◽  
Lactate Levels

The respiratory and circulatory physiology of exercising Christmas Island red crabs Gecarcoidea natalis were investigated with respect to their annual breeding migration. Red crabs were allowed to walk for up to 45 min. During this exercise period, the functioning of the circulatory system in gas transport and the energy status of the red crabs were quantified. Energy production during exercise required both aerobic and anaerobic contributions. The aerobic scope of G. natalis was low, with only a doubling of the resting rate of oxygen consumption (resting M(dot)O2=95±15 µmol kg-1 min-1). Maximal O2 consumption was attained within the first 5 min of exercise and the level remained stable thereafter. The anaerobic contribution to energy production was directly related to the speed of locomotion. l-lactate levels in blood and leg muscle were similar throughout the exercise period; blood lactate concentration was 33.39±2.29 mmol l-1 after 45 min of exercise. Heart rate in resting animals was 56±7 beats min-1. At the onset of exercise, heart rate also doubled, but without a significant increase in cardiac output. Increased O2 delivery was facilitated by increased extraction from the blood. During the 45 min of exercise, glucose levels increased rapidly in the muscle tissue (from 2.30±0.54 to 8.78±1.20 mmol l-1) and subsequently in the blood (from 1.22±0.26 to 2.12±0.17 mmol l-1), fuelling increased glycolysis during locomotion. The energy production from stored glucose/glycogen was sufficient to support the energetic needs of locomotion, since the energy charge remained stable at 0.82. Haemolymph l-lactate levels in crabs sampled in the field after migration were high compared with levels in many crustacean species but equivalent to l-lactate levels in laboratory animals exercised for less than 10 min. During their migration, therefore, the red crabs avoid exceptional l-lactate build-up in the blood by either walking very slowly or intermittently. However, G. natalis are exceptionally well adapted to cope with exhaustive locomotion and the resultant severe metabolic acidosis.

DNA evidence of whale sharks (Rhincodon typus) feeding on red crab (Gecarcoidea natalis) larvae at Christmas Island, Australia

2009 ◽  
Vol 60 (6) ◽  
pp. 607 ◽  
Author(s):  
M. G. Meekan ◽  
S. N. Jarman ◽  
C. McLean ◽  
M. B. Schultz
Keyword(s):  
Small Subunit ◽  
Whale Shark ◽  
Faecal Dna ◽  
Rhincodon Typus ◽  
Christmas Island ◽  
Crab Larvae ◽  
Pcr Products ◽  
Whale Sharks ◽  
Primer Sets ◽  
Gecarcoidea Natalis

Whale sharks (Rhincodon typus) are thought to aggregate in nearshore waters around Christmas Island (105°37′E, 10o29′S) to consume the marine larvae of the endemic red land crab (Gecarcoidea natalis). However, there have been no direct observations of sharks feeding on crab larvae. Whale shark faeces were analysed using genetic testing to confirm the presence of crab larvae in their diet. Primers were designed for amplifying two Gecarcoidea natalis mitochondrial small-subunit (mtSSU) rDNA regions. Gel electrophoresis of polymerase chain reaction (PCR) products amplified from whale shark faecal DNA produced bands of the expected size for G. natalis templates. Specificity of both primer sets for G. natalis mtSSU rDNA was expected to be high from comparisons with mtSSU rDNA regions from closely related crabs and we confirmed their specificity empirically. The amplification of fragments from faecal DNA of the same size as those produced from G. natalis DNA indicates that the whale shark had been feeding on G. natalis and that enough of the crab DNA survived digestion to be detected by these PCRs. Our study provides further evidence that aggregations of whale sharks in coastal waters occur in response to ephemeral but predictable increases in planktonic prey.

The Breeding Behaviour and Migrations of the Terrestrial Crab Gecarcoidea natalis (Decapoda: Brachyura)

1985 ◽  
Vol 33 (2) ◽  
pp. 127 ◽  
Author(s):  
JW Hicks
Keyword(s):  
Salt Water ◽  
High Tide ◽  
Wet Season ◽  
Mating Activity ◽  
Migration Activity ◽  
Christmas Island ◽  
Large Numbers ◽  
Hard Shell ◽  
Gecarcoidea Natalis ◽  
Crab Stage

The breeding migrations of the Christmas Island red crab were monitored at plateau and shoreline locations from November 1979 to May 1983. Up to three migration sequences, each resulting in egg release, occurred each year in a breeding season lasting up to 3 months. In the main sequence migration from the plateau to the shore began at the onset of the wet season and lasted 9-18 days. On arrival at the sea, crabs immersed in salt water in large numbers before retreating to the shore terrace rainforest, where males fought over possession of burrows. Crabs courted and copulated near or in the burrows; they copulated in a hard-shell condition with the male generally underneath. At the conclusion of mating activity, males again dipped in salt water before returning to the plateau. Females remained in burrows on the shore terrace for 12-13 days until eggs were nearly ripe; they then moved to shoreline rocks. They released their eggs at night on the turn of the high tide between the last quarter of the moon and the new moon, sometimes from cliff faces, then returned en masse to the plateau. Zoeae hatched immediately on contact with salt water, and baby crabs emerged at the first crab stage 27 days after egg release; successful emergence varied considerably between seasons. Baby crabs migrated inland, taking 9 days to reach the plateau. Most migration activity was diurnal, the main exceptions were egg release and dipping activities.

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