Showing papers on "Uca pugilator published in 1984"

Population dynamics, spatial dispersion and somatic growth of the sand fiddler crab ilea pugilator

Abstract: Echantillonnage d'une population d'Uca pugilator sur une surface de 3,9 ha, a Shackleford Banks, Caroline du Nord, tous les mois, entre mars 1979 et septembre 1980

Fiddler Crab Exercise: The Energetic Cost of Running Sideways

Abstract: The fiddler crab, Uca pugilator, used sideways octapedal locomotion during 15 min of treadmill exercise. At each velocity tested (0.06, 0.11 and 0.16 km h−1), oxygen consumption (VOO2) showed only a modest, sluggish elevation; a ‘steady-state’ was never attained. The highest VOO2 recorded, 0.22 mlO2g−1h−1, was 4.4 times the resting rate. Net whole body lactate (WBL) was found to increase at a constant rate throughout the exercise period. During recovery, VOO2 and WBL removal followed a similar time course and returned to pre-exercise rates in 30–45 min. Although the fate of lactate after exercise is unknown for crustaceans, calculations suggest that not enough oxygen is consumed by the crab during recovery to oxidize lactate completely to CO2 and H2O. A gluconeogenic fate is compatible with the data. As running velocity was increased, VOO2 increased only slightly, while the net rate of WBL production showed a substantial elevation. At low velocity aerobic metabolism accounted for 60% of the ATP produced when aerobic metabolism and anaerobic fermentation are considered. Anaerobic fermentation dominated at medium and high velocity and produced 60 and 70% of the ATP, respectively. The minimum cost of transport, the least amount of energy required to transport a given mass a distance, was determined using both aerobic and anaerobic sources. This estimation of locomotion economy for Uca pugilator was within the range predicted for a vertebrate of a similar mass.

Regulation of the release of chromatophorotropic neurohormones from the isolated eyestalk of the fiddler crab, uca pugilator

Abstract: Electrical stimulation of the isolated eyestalk of Uca pugilator induces the release of several peptides which affect epidermal chromatophores. Thresholds for release of these peptides were different, that for red pigment concentrating hormone (RPCH) being lowest, for black pigment dispersing hormone (BPDH) highest, and for black pigment concentrating hormone (BPCH) intermediate, but no red pigment dispersing hormone(RPDH) was detected at any voltage. Neurotransmitters, known to be present in crustacean central nervous systems, induced chromatophore dose dependent responses. Norepinephrine induced BPDH release, and dopamine induced both RPCH and BPCH release.

¬¬Peripheral inhibition'' of vibration-sensitive units in the leg of the fiddler crab Uca pugilator

Abstract: The activity of single vibration-sensitive neurons in the leg nerve of the fiddler crabUca pugilator was recorded extracellularly. All units recorded from fall into two groups according to basic differences in their spectral threshold curves. The first type of neuron can be excited over a broad frequency range (ca. 2–2,000 Hz) with minimal threshold at 15–30 Hz with 0.5–1.0 cm/s2 (peak). The second type of neuron, in contrast to the first one spontaneously active, is excited only in the frequency range 2–100 Hz and shows a decrease in the nerve impulse rate at vibration frequencies up to 2 kHz. The intensity necessary for complete suppression of the firing activity is 80 cm/s2 at 800 Hz, the range of frequency most sensitive for inhibition.

Fiddler crab, uca pugilator

Abstract: Electrical stimulation of the isolated eyestalk of Uca pugilator induces the release of several peptides which affect epidermal chromatophores. Thresholds for release of these peptides were different, that for red pigment concentrating hormone (RPCH) being lowest, for black pigment dispersing hormone (BPDH) highest, and for black pigment concentrating hormone (BPCH) intermediate, but no red pigment dispersing hormone (RPDH) was detected at any voltage. Neurotransmitters, known to be present in crustacean central nervous systems, induced chromatophore dose dependent responses. Norepinephrine induced BPDH release, and dopamine induced both RPCH and BPCH release.

Effect of 5-hydroxytryptamine antibodies on pigment migration in the erythrophores of the fiddler crab,Uca pugilator: Further evidence for 5-hydroxytryptamine as a neurotransmitter that stimulates release of red pigment-dispersing hormone

Abstract: 5-Hydroxytryptamine (5-HT) antibodies inhibit red pigment dispersion in the fiddler crab,Uca pugilator. This observation supports the hypothesis that 5-HT stimulates release of red pigment-dispersing hormone.