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Showing papers on "Uca pugilator published in 1977"


Journal ArticleDOI
01 Jan 1977
TL;DR: Behavior, morphological, and physiological data suggest that 10–12 mm carapace width may represent a transitional period in male fiddler crabs, which culminates in attaining full sexual maturity.
Abstract: Field studies of 133 male Uca pugilator (4.5–20.0 mm carapace width) showed significant changes in waving and other behavior patterns as follows: (1) Wave frequency changed gradually from zero to 110–170 waves/5 min across the size continuum. (2) Wave rates stabilized at 10–12 mm carapace width. (3) Larger males spent about 50% of their above‐ground time performing actual waves. (4) Time spent feeding and time spent in the burrow decreased with age. In the case of feeding, there was a quantum drop to almost zero at the 12 mm carapace width size category. (5) The responses shown by females toward waving males of different sizes changed, so that there was a 70% increase in female attentiveness toward males in the larger size categories. Behavioral, morphological, and physiological data suggest that 10–12 mm carapace width may represent a transitional period in male fiddler crabs, which culminates in attaining full sexual maturity.

48 citations


Journal ArticleDOI
TL;DR: Dopamine produces pigment concentration in the erythrophores of intact fiddler crabs, but has no effect on the eries in isolated legs, and it is hypothesized that DA triggers release of red pigment-concentrating hormone.

46 citations


Journal ArticleDOI
01 Jan 1977
TL;DR: The sensitivity of fiddler crabs to air‐ and substrate‐borne acoustic stimuli (pure tones) was studied, using responses of interneurons in the supra‐oesophageal ganglion for the measurements to indicate that only sound carried through the substrate was important for intraspecific communication.
Abstract: The sensitivity of fiddler crabs to air‐ and substrate‐borne acoustic stimuli (pure tones) was studied, using responses of interneurons in the supra‐oesophageal ganglion for the measurements. Intact Uca pugilator could detect stimuli as both air‐borne (sound) and vibrational energies, but were much more sensitive to the latter. This finding, coupled with previous measurements of its own courtship sounds, indicated that only sound carried through the substrate was important for intraspecific communication. Destruction of Barth's Myochordotonal organ in the walking legs of both U. pugilator and U. minax decreased sensitivity to vibration by 8–20 dB. The effect was evident across the entire sensitivity spectrum, but most pronounced at the higher frequencies. The external anatomy of the receptor is described, as revealed by scanning EM study.

29 citations


Journal ArticleDOI
TL;DR: Circadian variations in the levels of red pigment-dispersing hormone and 5-hydroxytryptamine in the eyestalks of the fiddler crab, Uca pugilator, were found and the possible role of 5-HT in controlling release of RPDH is discussed.

26 citations


Journal ArticleDOI
TL;DR: A series of experiments were performed to determine the effect of the PCB, Aroclor 1242, on the rate of molting of the fiddler crab, Uc__~apugilator, and to determine whether any effects on molting were due to AroClor 1241 or to perhaps only PCDF contamination of the Aro Clor.
Abstract: Several species of aquatic crustaceans have been found to accumulate polychlorinated biphenyls (PCBs) from their environment. Specifically~ NIMMO et al. (1971b) showed that the fiddler crab, Uca pugi!ator , accumulates the PCB, Aroclor 1254~ from contaminated sediments. However, there are no published reports on the possible effects of PCBs on the physiology of the fiddler crab. We undertook a series of experiments to determine the effect of the PCB, Aroclor 1242, on the rate of molting of the fiddler crab, Uc__~apugilator. Fairly recently, however, polychlorinated dibenzofurans (PCDFs) have not only been shown to be impurities in PCBs, but also to exceed the toxicity of PCBs in chick embryo assays by approximately four to six orders of magnitude (VOS et al., 1970; BOWES et al., 1975a,b). Consequently, reported effects of PCBs, as in mortality studies such as that of NIMMO et al. (1971a) with the pink shrimp, Penaeus duorarum, may have been due in large measure to contaminating PCDFs. Therefor~ in the present investigation experiments were also performed to determine the effect of a PCDF on the rate of molting, the PCDF concentration used being that found in Aroclors by BOWES et al. (1975b). Use of such a PCDF concentration would allow us to determine whether any effects on molting were due to Aroclor 1242 or to perhaps only PCDF contamination of the Aroclor.

26 citations


Journal ArticleDOI
TL;DR: Removal of eyestalks led to initiation of vitellogenesis in immature ovaries at all times tested and also appeared to increase the rate of vitescence in already maturing ovaries.
Abstract: 1. The condition of the ovaries of intact and eyestalkless Uca pugilator from Florida was examined throughout the period from mid-September to the end of May. The frequency of molt for the animals was also observed.2. Ovarian weights for intact crabs decreased from September to December and began to increase in January. The increase did not occur uniformly throughout the population, and by March all stages of maturation were present. First oviposition occurred in April, involving about 30% of the females. No oviposition occurred as late as mid-September.3. Crabs that oviposited in April did not exhibit further vitellogenesis prior to molt which occurred in late May. A high frequency of molting again occurred in intact crabs in November and December.4. Removal of eyestalks led to initiation of vitellogenesis in immature ovaries at all times tested and also appeared to increase the rate of vitellogenesis in already maturing ovaries.5. Removal of eyestalks increased the frequency of molt maximally in Septemb...

21 citations


Journal ArticleDOI
01 Jan 1977
TL;DR: The absolute temporal and spatial addresses of half of the components, including the duration and amplitude of the display, did change significantly with increased size, but the coefficient of variation did not change significantly from one animal to the next throughout the size continuum.
Abstract: Stop action cinematography was used to analyze the wave display of the fiddler crab, Uca pugilator. Thirteen spatiotemporal wave components were quantified for twenty‐eight males, which represented a size continuum from 7.0 to 18.0 mm carapace width. Individual components of the display appeared equally variable across the waves of a particular actor and the coefficient of variation did not change significantly from one animal to the next throughout the size continuum. The absolute temporal and spatial addresses of half of the components, including the duration and amplitude of the display, did change significantly with increased size.

20 citations


01 Jan 1977
TL;DR: Observations and experiments designed to elucidate the factors involved in the determination of handedness in male fiddler crabs are presented.
Abstract: The most characteristic feature of the fiddler crab is that the adult male has an enormously developed giant cheliped, while the other remains small ; but the female has two small equal-sized chelipeds. The giant cheliped is not present in the early stages of males, but it develops enormously during the period of sexual maturation, and this has been studied by a number of authors. Yerkes ( 1901 ) collected@ numerous male specimens of Uca pugilator and U. pugnax at random and found that the numbers of right-handed and left-handed individuals were nearly equal. On the basis of this observation, he suggested that the handedness of fiddler crabs is determined priniarily by chance. Later, Morgan (1923, 1924) , experimenting with some young, sexually immature fiddler crabs, not only concluded that handed ness is not determined in the early stages but also claimed that the accidental loss of one cheliped is the sole factor determining handedness. He reported that the giant cheliped always develops on the side of the remaining cheliped. On the other hand, Vernberg and Costlow ( 1966) claimed after a series of experiments that the handedness is determined genetically. The present author (Yamaguchi, 1973 ) examined about 5,000 adult males of U. lactea and found almost equal numbers of right-handed and left-handed individuals. Gibbs (1974) studied the handedness of niale U. burgersi and found no significant difference between the numbers of left-handed and right-handed specimens. In the present paper, observations and experiments designed to elucidate the factors involved in the determination of handedness in male fiddler crabs are presented.

8 citations


Journal ArticleDOI
TL;DR: After autotomy and partial regeneration of two limb buds in Uca pugilator (16-mm carapace width), crabs were induced to autotomize two or five additional limbs when the bud of the first walking leg had reached an R value of 10 or 15, causing an acceleration of growth in the initially regenerating limb buds and hastened ecdysis.
Abstract: After autotomy and partial regeneration of two limb buds in Uca pugilator (16-mm carapace width), crabs were induced to autotomize two or five additional limbs when the bud of the first walking leg had reached an R value of 10 or 15. These procedures caused an acceleration of growth in the initially regenerating limb buds and hastened ecdysis. The two or five additional limbs were replaced very rapidly and were complete at ecdysis.After autotomy and partial regeneration of four limbs in small (12- to 13-mm) crabs, an additional one or three limbs were removed. If the limbs were autotomized when R1 was 10–16, ecdysis was delayed somewhat and the limbs were replaced rapidly. However, if the one or three additional limbs were autotomized when R1 was greater than 16, ecdysis was not delayed and the limbs were not replaced before ecdysis.These results are quite different from those obtained when some growing limb buds, rather than intact limbs, were removed after partial regeneration. The differing results are...

8 citations



01 Feb 1977
TL;DR: Data presented here suggest that the mode of action of the two metals is not the same, and the effect of mercury or cadmium on Uca pugilator depends upon a number of factors, including stage of the life cycle, sex, thermal history, and environmental conditions.
Abstract: Studies have been carried out on the synergistic effects of sublethal concentrations of mercury (Hg) and/or cadmium (Cd) in conjunction with temperature and salinity stress on larval and adult fiddler crabs, Uca pugilator. Six biological parameters of the adult organism were monitored including survival, tissue uptake, metabolism, behavior, microscopic anatomy, and enzymatic activity, using metal concentrations of 0.18 ppm Hg and 1.0 ppm Cd. Studies with larval stages (zoeal stages I, III, V and megalops) considered survival, metabolism and behavior under conditions of 1.8 ppb Hg and 1.0 ppb Cd. The effect of mercury or cadmium on Uca pugilator depends upon a number of factors, including stage of the life cycle, sex, thermal history, and environmental conditions. Data presented here suggest that the mode of action of the two metals is not the same.