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Gary W. Hyatt

Bio: Gary W. Hyatt is an academic researcher from University of Illinois at Chicago. The author has contributed to research in topics: Uca pugilator & Fiddler crab. The author has an hindex of 6, co-authored 7 publications receiving 743 citations.

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489 citations

Journal ArticleDOI
TL;DR: Differences between the species in the tempo and length of fights were observed, and an hypothesis, based upon habitat differences and the value of burrows as a resource, is presented to account for these differences.
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.

181 citations

Journal ArticleDOI
TL;DR: It is suggested that this role-specific relationship can be addressed by hypothesizing the optimum strategies that would tend to maximize the combatant's burrow-holding potential, while minimizing the penalties for losing a burrow.
Abstract: Statistical and information theory analyses were performed with data derived from the aggressive interactions of two temperate species of fiddler crabs (Uca pugilator and U. pugnax). Over 400 fights were observed for each species, in their natural habitats. The two species showed differences in the distributions of their aggressive acts and in the average number of acts performed during combat. Many acts were statistically linked in ways which align meaningfully with the contribution of aggressiveness to the survival of the animals. Information analysis showed quantitative differences in uncertainty measures, but the "efficiency" of their communication systems, i.e., the amount of information transmitted, remained the same between combatants of each species. An interesting finding is the relative difference (about 15%) in intraspecific normalized transmission values which occur between Resident and Wanderer. We suggest that this role-specific relationship can be addressed by hypothesizing the optimum strategies that would tend to maximize the combatant's burrow-holding potential, while minimizing the penalties for losing a burrow.

30 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: Adult female Uca pugilator were allowed to make spontaneous choices during low tide toward lights differing in intensity only, and response patterns shows that crabs consistently approached the dimmer of two white lights, but if two blue or two red-orange lights were presented, the brighter light was approached more frequently.

10 citations


Cited by
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TL;DR: Secondary sexual characters in many species function both in male-male competition and as cues for female choice, and a literature compilation of existing knowledge of traits with this dual role is compiled.
Abstract: Secondary sexual characters in many species function both in male-male competition and as cues for female choice. Based on a literature compilation of existing knowledge of traits with this dual fu ...

734 citations

Journal ArticleDOI
TL;DR: In this article, a mathematical model of fighting behavior is developed, where the contestants belong to a population with varying fighting abilities and the fights consist of the repetition of one type of interaction.

733 citations

Journal ArticleDOI
TL;DR: The twodimensionality of the human mating environment, along with phylogeny, the spatial and temporal clustering of mates and competitors, and anatomical considerations, predict that contest competition should have been the primary mechanism of sexual selection in men and a functional analysis supports this prediction.

635 citations

Journal ArticleDOI
TL;DR: In this article, the authors consider how variation in the abilities of contestants to assess resource-holding potential (RHP) influences fights and discuss support for each model, before highlighting a number of conflicting and inconclusive studies, leading them to consider alternative approaches to investigate assessment.

599 citations

01 Jan 1979
TL;DR: The drama of what G. E. Hutchinson (1965) referred to as the "evolutionary play" is heightened-or at least more obvious-among members of the same social group because of close physical proximity.
Abstract: Social behavior holds a special position among natural phenomena in relation to the Darwinian theory of organic evolution. When individuals of the same species live in close proximity they compete directly for essential resources. And intraspecific reproductive competition is the cornerstone of the theory of evolution by natural selection. Thus the drama of what G. E. Hutchinson (1965) referred to as the "evolutionary play" is heightened-or at least more obvious-among members of the same social group. If only by virtue of close physical proximity social

568 citations