Topic
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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TL;DR: Melatonin significantly increased activity in the photophase but not the scotophase trial, indicating that the responsiveness to melatonin continues following eyestalk removal, but the timing may not match that of intact crabs.
Abstract: The influence of melatonin on locomotor activity levels was measured in the fiddler crab Uca pugilator. First, activity in untreated, laboratory-acclimated crabs was measured over 48 hours in a 12L:12D photoperiod; this study showed a nocturnal increase in activity. In eyestalk-ablated crabs, overall activity was significantly reduced, and no significant activity pattern occurred. Next, crabs were injected with melatonin or saline (controls) at various times during the 12L:12D photoperiod (0900h, 1200h, and twice at 2100h; each trial was separated by 3-4 days) and monitored for 3 hr post-injection. Control crabs had low activity during early photophase, high at mid-photophase, increasing activity during the first scotophase trial, and decreasing activity during the second scotophase trial. Melatonin had no significant influence on activity when injected during the early-photophase activity trough or early-scotophase activity decline, but significantly increased activity when injected during the mid-photophase activity peak and early-scotophase activity incline. Next, crabs were injected during an early scotophase activity trough and monitored throughout the twelve-hour scotophase. Melatonin did not increase activity until the mid-scotophase activity increase, approximately 6 hours later, showing that the pharmacological dosage persisted in the crabs' systems and had later effects during the incline and peak of activity but not the trough. Eyestalk-ablated crabs were injected with melatonin or saline during early photo- and scotophase. Melatonin significantly increased activity in the photophase but not the scotophase trial, indicating that the responsiveness to melatonin continues following eyestalk removal, but the timing may not match that of intact crabs. Melatonin may be involved in the transmission of environmental timing information from the eyestalks to locomotor centers in U. pugilator.
18 citations
TL;DR: It is concluded that naphthalene inhibits circadian black pigment dispersion in Uca pugilator by inhibiting the release of the neurotransmitter, norepinephrine.
18 citations
TL;DR: The observations indicate that Cq-chy is differently involved in the immature and adult innate immune reactions, thus suggesting a role for CLSPs in the invertebrate innate immune system.
18 citations
TL;DR: The behavioral effect induced by diflubenzuron (DFB) exposures (>2 μg/L) was the most sensitive indicator of DFB activity and potentially may influence the ability of juvenile crabs to avoid predation, construct burrows, or feed adequately to survive in nature.
Abstract: The effects of repetitive 24-hr weekly exposures to diflubenzuron (Dimilin®) on juvenile fiddler crabs (Uca pugilator) were studied in static seawater systems for 10 weeks. Crabs surviving the 10-week exposure period were maintained in clean seawater until death. Survival, molting, and behavior were monitored daily. The no-effect concentration (NOEC) for molting (time to the first molt), survival (time until death), and behavior (ability to escape from the test container) were 20, 2, and 0.2 μg/L DFB, respectively. The behavioral effect induced by diflubenzuron (DFB) exposures (>2 μg/L) was the most sensitive indicator of DFB activity and potentially may influence the ability of juvenile crabs to avoid predation, construct burrows, or feed adequately to survive in nature.
18 citations
TL;DR: Fiddler crabs,U.
Abstract: Fiddler crabs,Uca pugilator, collected from the field showed no avoidance to burrowing in 1 μg g−1 tributyltin (TBT)-contaminated sand held in laboratory trays. Treatment ofU. pugilator with levels of tributyltin as low as 0.5 μg l−1 for 1–3 wk resulted in an acceleration of the righting reflex in females, indicative of hyperactivity. Crabs of both sexes exhibited a reduction in burrowing activity, as measured by the number of burrows dug at 15 and 60 min after release into laboratory trays containing sand, and by the number of crabs within burrows at those times. The reduction in burrowing activity was not dose-dependent at concentrations of 0.5 to 50 μg l−1, and was unchanged between one and three weeks of exposure. Since fiddler crabs are dependent on burrows for many aspects of their lives, the reduction in burrowing behavior, should it occur in nature, would have serious consequences for the species.
18 citations