PubMed · 11645839
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Nancy Ann Davis. 1991. Morality and biotechnology.. https://pubmed.ncbi.nlm.nih.gov/11645839/
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The prevalence of behaviour problems is reported from a questionnaire study among members of the Danish Kennel Club (DKC). In total, 4359 dog owners were included in the analyses. With logistic regression, we analysed four behaviour problems: dominance towards the owner, interdog dominance aggression, separation anxiety and shooting phobia. Compared to Labrador Retrievers, the following breeds and breed groups had higher odds of being reported to have interdog dominance aggression: Belgian Sheepdogs, Dachshunds, Dalmatians, German Shepherds, Hovawarts, Pinschers, Rottweilers, Scent dogs and Spitz dogs. Poodles, retrieving/flushing dogs, Sheepdogs, Spitz dogs and terriers had higher odds of shooting phobia. The odds of interdog dominance aggression were higher among dogs owned by younger dog owners compared to dogs owned by older dog owners. Dogs living in the capital area of Copenhagen had increased odds of interdog dominance aggression as compared to dogs living in other parts of Denmark. Dogs belonging to owners with limited knowledge of the breed before acquiring the dog had higher odds of interdog dominance aggression. Dogs attending obedience training classes had reduced odds of shooting phobia. Dogs belonging to dog breeders had reduced odds of being reported to have the investigated behaviour problems.
The effects of five trace metals, copper, cadmium, nickel, zinc and lead (presented as soluble salts) on the ability of juvenile rainbow trout to form social relationships were investigated. Comparable concentrations of the five metals in relation to their acute 96 h LC50s (concentration at which population mortality=50% at 96 h) were used (i.e. 15% of the 96 h LC50) and water quality parameters (hardness=120 mg l(-1) as CaCO(3), pH 8; DOC=3 mg l(-1)) were kept constant throughout. In the first experiment, trout exposed to sublethal concentrations of cadmium for 24 h displayed significantly lower numbers of aggressive attacks during pair-wise agonistic encounters than fish paired in the copper, nickel, zinc, lead and control water. In a second experiment, fish were exposed to the same concentration of metal for 24 h, and then returned to normal water for 24 h. When these metal pre-exposed fish were paired with non-exposed fish only cadmium pre-exposure had a significant effect on social interaction. All of the cadmium pre-exposed fish became subordinate when paired with non-exposed fish, whereas the probability of a fish pre-exposed to copper, nickel, zinc or lead becoming subordinate did not significantly differ from random. Therefore, at around 15% of the 96 h LC50, different metals exert different effects on the social behaviour of fish, suggesting potential implications for social structure and population stability.
Within a general framework of handicap signalling it was proposed that threat displays are handicaps, they can work only if they put the signaller at a disadvantage, which is only acceptable to honest signallers. The aim of the present article is to investigate this proposal with the help of a simple game-theoretical model. It was found: (1) that the use of cost-free signals is an ESS against the invasion of handicapped signals even if cheating is played as part of a mixed strategy in the population; (2) that the use of handicaps may be an ESS against cost-free signals but only if we assume that the invading cost-free signal is not accepted by weak individuals as a signal of strength; (3) that the establishment of a handicapped signal in the first place is an unresolved problem, because both cost free signals and negative-handicaps are evolutionarily stable against the invasion of handicaps; (4) that in contrast to handicaps the use of negative-handicaps can invade a population using cost-free signals (a negative-handicap is a signal which may serve other functions as well); (5) that negative-handicaps are ESS against cost-free signals as well as against handicaps; and (6) thus, the most likely evolutionary end point is that the biggest negative-handicap would be used as a threat display. This is a posture, which prepares the animal most efficiently to fight; hence, most probably it is the initial position of the fighting technique of the given species. (7) Finally, the investigation of the threat displays of well-studied taxa (great tit, cats, dogs, and hoofed mammals) confirms that threat displays are indeed negative-handicaps. They do not put the user into a disadvantaged position, instead the initial position of the species specific fighting technique is used as a threat display as predicted by the present model.