Showing papers on "Uca pugilator published in 2000"
TL;DR: Evidence is provided that from the perspective of the signaling male, the claw-waving display of U. pugilator is not a dual-function signal but rather is primarily directed to receptive females.
Abstract: Many territorial advertisement signals are thought to be dual-function signals, directed to both rival male and receptive female conspecifics. However, few studies have tested this assumption by examining whether in fact both sexes are likely to elicit signaling behavior from territorial males. In this study, I experimentally manipulated the social context of male sand fiddler crabs (Uca pugilator) to investigate the effect of different audiences on the performance of the claw-waving display, a territorial signal that is often presumed to be directed to both males and females. To test whether males perform this signal to both audiences, I measured the frequency of waving behavior by focal males when housed in field enclosures alone, with only males, with only females, or with both males and females. Focal males waved at a low frequency when alone, and the presence of males had no effect on their level of waving. However, in the presence of females, focal males showed a significantly higher level of waving, whether or not males were also present. In addition, there was no association between fighting and waving behavior. This experiment provides evidence that from the perspective of the signaling male, the claw-waving display of U. pugilator is not a dual-function signal but rather is primarily directed to receptive females.
95 citations
TL;DR: Results strongly suggest that cadmium acts at least in part to increase the secretion of GIH from the sinus gland, which could then act by inhibiting secretion of GSH by the thoracic ganglion, directly inhibit the oocytes.
41 citations
TL;DR: The external features of an intersex fiddler crab, Uca pugilator, are described and both male- and female-type sexual characteristics occur on the specimen, which exhibits reduced bilateral asymmetry in its chelipeds.
Abstract: The external features of an intersex fiddler crab, Uca pugilator , are described. Both male- and female-type sexual characteristics occur on the specimen. This sexually abnormal individual exhibits reduced bilateral asymmetry in its chelipeds. Its abdomen is intermediate between those of a typical male and a typical female. The first and second pairs of pleopods closely resemble those found in a typical male. One female-type pleopod occurs on the right side of the third abdominal segment, while on the fifth segment of the abdomen there exist two female-type pleopods, one on each side. No male genital apertures were found, but two female gonopores occur, one on each side of the midline of the thoracic segment that bears the third pair of walking legs. Possible causes for the sexual aberrations found in this specimen are discussed. Les caracteres externes d’un crabe violoniste, Uca pugilator , intersexue sont decrits. Les caracteres sexuels mâles et femelles sont presents a la fois sur le specimen. Cet individu sexuellement anormal montre une asymetrie bilaterale reduite des chelipedes. L’abdomen est intermediaire entre ceux d’un mâle et d’une femelle typiques. Les premieres et secondes paires de pleopodes sont celles d’un mâle typique. Un pleopode de type femelle est present sur le cote droit du troisieme segment abdominal, alors que, sur le cinquieme segment il en existe deux de type femelle, un sur chaque cote. Aucun orifice genital mâle n’a ete observe, mais il y avait deux gonopores femelles, de part et d’autre de la ligne mediane du segment thoracique portant la troisieme paire de pattes ambulatoires. Les causes possibles de ces aberrations sexuelles sont discutees.
31 citations
TL;DR: It is found that male sand fiddler crabs (U. pugilator) wave significantly more in the presence of females than males, suggesting that their waves are primarily directed to females.
Abstract: Like many territory advertisement signals, the claw waving display of fiddler crabs (genus Uca) is commonly thought to have the dual function of simultaneously repelling males and attracting females. I have found, however, that male sand fiddler crabs (U. pugilator) wave significantly more in the presence of females than males, suggesting that their waves are primarily directed to females. Here I use laboratory video playback experiments to ask whether male and female U. pugilator are both responsive to the display. Males and females were presented with video of an example of either a waving or a feeding male conspecific, or no video, and their behavior was measured in seven behavioral categories that were then collapsed into three principal components. Analysis of variance of females' principal component scores revealed significant differences in their behavior in the presence of waving male video compared with feeding male video or no video, demonstrating that females attend to the display. Male behavior, however, was not significantly different between the three treatments, which is inconsistent with the hypothesis that claw waving serves to repel or threaten other males. These results, together with my recent work on male signaling behavior, suggests that the claw waving display of U. pugilator is a signal primarily directed to females and attended to by females, and thus is not an example of a dual function signal.
20 citations