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Uca pugilator

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


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Journal ArticleDOI
TL;DR: An increase in temperature and a decrease in salinity sharply increased trimethyltin toxicity in fiddler crab zoeae.
Abstract: The toxicity of four trimethyltin concentrations to stage I zoeae of the fiddler crab,Uca pugilator, was tested at temperatures of 10°C, 20°C and 28°C and salinities of 10‰, 20‰ and 30‰. Stepwise multiple regression of the probit of mortality data produced a formula from which productive response surfaces were generated. 24 hr LC 50's in 30‰ salinity at 10°C was 12 ppm, at 20°C 3.35 ppm and 0.61 ppm at 28°C. Corresponding 48 hr LC 50's were about one-tenth of these values. An increase in temperature and a decrease in salinity sharply increased trimethyltin toxicity in fiddler crab zoeae.

10 citations

Journal ArticleDOI
TL;DR: The results show that the impact of exaggerated structures on energy expenditure may depend on exercise intensity and highlight the need to examine various locomotory intensities when attempting to assess the costs of bearing a sexually selected trait.
Abstract: Models proposed to explain sexually selected structures assume that these traits are costly. However, studies investigating the impact of such structures on locomotory costs have produced inconsistent results. Male fiddler crabs possess a large sexually selected claw and are ideal for assessing the impact of a sexually selected trait on the cost of locomotion. Here, we measured the energy expenditure of clawed, declawed and artificially loaded crabs during sustained exercise by measuring oxygen consumption and blood lactate levels. We also measured blood lactate levels of clawed and declawed crabs following a sprint and forced walk to assess energy expenditure during non-sustainable, strenuous locomotion. Clawed and declawed crabs consumed the same amount of oxygen and had the same blood lactate concentration during sustained locomotion, suggesting that the large claw does not increase energetic costs during sustainable locomotion. Following non-sustainable, strenuous locomotion, however, there was a trend for clawed crabs to have higher concentrations of lactate in their blood than declawed crabs, suggesting that bearing a large claw may increase energetic costs during strenuous locomotion and lengthen recovery time. Artificially loaded crabs produced more lactic acid than clawed and declawed crabs during sustainable locomotion, suggesting that compensatory traits help mitigate the energetic cost of carrying the large claw. Overall, our results show that the impact of exaggerated structures on energy expenditure may depend on exercise intensity and highlight the need to examine various locomotory intensities when attempting to assess the costs of bearing a sexually selected trait.

10 citations

Journal ArticleDOI
TL;DR: Two major peaks of melanophore-dispersing activity were isolated by a combination of gel filtration on Sephadex G-25 and successive ion exchange chromatography on CM- and DEAE-cellulose, and the homogeneity of MDH-1 was determined in two different paper chromatography and paper electrophoresis systems.

9 citations

Journal ArticleDOI
TL;DR: Morphological properties of hair-like sensilla, as well as their small number in relation to the large population of presumptive chemosensory axons, suggest that they have a limited role in chemosensation.
Abstract: The organization of sensory nerves and sensilla was examined in the feeding claw of two species of fiddler crabs, Uca pugnax and U. pugilator, using neuroanatomical and behavioral techniques. Surveys of the populations of axons indicate that claws of adult crabs contain 25000–40000 neurons. Approximately 85% of the population consists of axons with diameters less than 1 μm, suggesting they may represent chemosensory neurons. Females show an enhanced population of these small (putative chemosensory) axons relative to males, providing a mechanism to explain previously observed sexual differences in behavioral chemosensitivity to feeding stimulants. Surveys of the claw surface show a variety of external structures that could contain either chemo- or mechanosensory receptor neurons. There are hair-like sensilla of several types, some of which are more abundant in females than in males. In addition, claws show previously undescribed pit sensilla reminiscent of known bimodal chemo- and mechanosensory sensilla found in certain decapod crustaceans. Morphological properties of hair-like sensilla, as well as their small number in relation to the large population of presumptive chemosensory axons, suggest that they have a limited role in chemosensation. Most of the chemosensory axons probably originate in the pit sensilla.

9 citations

Journal ArticleDOI
TL;DR: Histological examination of eyestalks revealed two areas of cell bodies in the MT and medulla externa that release colloidlike substances into the intraganglionic cortical glial spaces of the fiddler crab, Uca pugilator.
Abstract: Ecdysteroids have been found in eyestalk tissues of the fiddler crab, Uca pugilator. Throughout the molt cycle, ecdysteroids are present in much higher concentrations in the eyestalk tissues than can be accounted for by equilibrium diffusion from the hemolymph. The greatest eyestalk-to-hemolymph ratio is found during anecdysis, the nonmolting period when the highest levels of the molt-inhibiting hormone are being produced and released from the eyestalks. RIA-active ecdysteroids are localized primarily (but not exclusively) in the medulla terminalis (MT) and medulla interna (MI) portions of the eyestalk ganglia. Relative levels of ecdysteroids extracted from the MT and MI fluctuate during the molt cycle. Ecdysone was the predominant ecdysteroid present in the eyestalks. Histological examination of eyestalks revealed two areas of cell bodies in the MT and medulla externa (ME) that release colloidlike substances into the intraganglionic cortical glial spaces. The location of the MT cell bodies corresponds to the pars distalis-X-organ of other crustaceans, but no organ of Bellonci (which has been proposed as a source of ecdysteroidlike compounds in shrimp) was found.

9 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
20211
20176
20162
20153
20146
20137