Uca pugilator

About: Uca pugilator is a research topic. Over the lifetime, 376 publications have been published within this topic receiving 12303 citations.

Adaptive Significance of Reproductive Cycles in the Fiddler Crab Uca pugilator: A Hypothesis

Abstract: Semimonthly peaks in courtship behavior of male crabs coincide with peaks in the temporal distribution of receptive females. Females mate once each month, 4 to 5 days before one of the semimonthly spring tides. The relation of the time of reproduction to tide cycles may be an adaptation to increase to a maximum the probability that the final stage of the planktonic larvae will be transported by tidal currents to substrates suitable for adults.

Combat in the Fiddler Crabs Uca Pugilator and U. Pugnax: a Quantitative Analysis

Abstract: The aggressive behavior of two temperate species of fiddler crabs (Uca pugilator and U. pugnax) was studied in the field. Most of the fights wer between Residents (crabs owning burrows) and Wanderers seeking to displace them, though less commonly, fighting occurred between Residents occupying adjacent burrows. Over 400 fights were observed in each species. The two species showed differences in the sequences of acts performed during fights. Uca pugnax also performed two acts never observed in U. pugilator. Wanderers were rarely successful in displacing Residents of the same size or larger, but they won a small percentage of fights when they were larger than the Resident. Uca pugilator Wanderers select Residents that are slightly smaller, but we found no evidence for size selection in U. pugnax. Strongly motivated Wanderers repeatedly performed a key act (Downpush), which was also strongly correlated with successfully displacing Residents. Combat duration and number of acts were not related to temperature, the time of day, or the time in relation to low tide. However, the incidence of fighting increases in the early afternoon. Most of the fights occur within 1-3 hours after low tide. Differences between the species in the tempo and length of fights were observed. An hypothesis, based upon habitat differences and the value of burrows as a resource, is presented to account for these differences. We compared our data to CRANE'S (1967) for U. rapax, a tropical species. There are some important differences between her findings and ours, even though U. pugnax is closely related to U. rapax. We suggest that at least one of her opinions on the significance of aggression in tropical fiddlers is in conflict with evolutionary theory. Some of her other ideas do not apply to temperate species, where climatic factors may be responsible for behavioral convergence. Our data also indicate that the differences and similarities between species are sufficiently provocative to warrant further comparative studies.

Roles of neurotransmitters in regulating reproductive hormone release and gonadal maturation in decapod crustaceans

Abstract: Summary Experiments done in this laboratory showed 5-hydroxytryptamine (5-HT) stimulates gonadal maturation in male and female sand fiddler crabs, Uca pugilator, and red swamp crayfish, Procambarus clarkii. This action of 5-HT is indirect, 5-HT apparently stimulating release of the gonad-stimulating hormone (GSH) that is present in the brain and thoracic ganglia. For example, studies with ovarian explants showed 5-HT has no direct effect on the ovary. But, when ovarian explants were incubated with 5-HT and brain or thoracic ganglia, the incubation medium produced greater ovarian maturation than did the medium when ovarian explants were incubated with brain or thoracic ganglia alone, 5-HT presumably enhancing GSH release. In males 5-HT not only induces testicular maturation but also development of the androgenic glands. 5-HT in males, as in females, apparently triggers GSH release; but in males GSH in turn stimulates the androgenic glands which release the androgenic gland hormone, resulting in testicular ...

The ultrastructure of nerve endings containing pigment-dispersing hormone (PDH) in crustacean sinus glands: Identification by an antiserum against a synthetic PDH

Abstract: A high-liter antiserum has been obtained from two rabbits immunized with a glutaraldehyde conjugate of synthetic pigment-dispersing hormone (PDH) from Uca pugilator and bovine thyroglobulin. The antiserum blocked melanophore-dispersing activity of the peptide in vivo. In sinus glands (SG) of Carcinus maenas, Cancer pagurus, Uca pugilator and Orconectes limosus, electron-microscopic immunocytochemistry revealed sparsely distributed axon endings containing a distinct PDH-immunoreactive type of neurosecretory granules (diameter 90–130 nm). Exocytotic figures indicating release of the content of these granules into hemolymph lacunae were occasionally observed. Preservation of fine structure and antigenicity of the PDH granules were markedly dependent on the fixation procedure used. A preliminary experiment with C. maenas showed that preterminal axon dilatations near the basal lamina seemed to accumulate PDH-granules when animals were kept in complete darkness for three days. Immunodot blotting of fractions after high pressure liquid chromatography (HPLC) of extracts from SGs of C. maenas and O. limosus revealed a strongly immunoreactive substance at a retention time very similar to those of synthetic PDHs of Uca pugilator and Pandalus borealis. It is also coincident with a zone of biological activity. Thus, the antigen demonstrated by immunocytochemistry is identical or very similar to one of the known PDHs.