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Modelling succession to include a herbivore effect


Long-term data collected from an old-field community suggest that physical and environmental patterns alone may be insufficient to account for different patterns of succession. Using a simple Lotka–Volterra model to represent competition between early and late succession guilds, we add...

Nutritional stress and behavioural immunity of damselflies


Increased mortality in the presence of stress may result from stress-reduced availability of energy for immune function, coupled with the presence of pathogens or parasites. We tested the hypothesis that stress reduces antiparasite responses of damselflies Ischnuraverticalis (Hagen) to...

Tactic-specific success in sperm competition


Sperm competition is a major force in sexual selection, but its implications for mating–system and life–history evolution are only beginning to be understood. The well–known sneak–guard model predicts that sneaks will win in sperm competition. We now provide empirical confirmation...

Food stress, nesting growth, and fluctuating asymmetry


It has been suggested that fluctuating asymmetry (FA) is an indicator of perturbed development. Our study tests the validity of a fundamental assumption of asymmetry theory: that environmental stress imposed during development increases FA. We deprived tree swallow (Tachycineta...

Genetics of Avian Mating Systems


Traditional population genetics theory assumed that at some level in the hierarchy of genetic diversity there existed 'demes' in which males and females mate at random. Polygynous mating systems or individual variance in reproductive success were considered complications which altered...

Response of birds to broken eggs in their nests


We tested the responses of two bird species which nest on unmovable substrates (e.g., cavities and walls) to simulated and actual egg damage in their nest. Tree Swallows (Tachycineta bicolor) and Barn Swallows (Hirundo rustica) removed...

Sexual dimorphism in malodorousness of musk secretions of snakes


Sexual dimorphism is a widespread phenomenon among animals (Darwin, 1871; Andersson, 1994). Differences between the sexes come in many forms, in- cluding both morphology (e.g., size, shape, coloration) and behavior (e.g., risk-taking or defensive behavior). Sexual differences in physiology also...

Use of inhalant anesthetics in three snake species


Different snake species respond differently to various anesthetic agents. Hence, an anesthetic procedure developed for one species cannot necessarily be safely transferred to another species. The goal of this paper is to summarize our experience using inhalant anesthetics on three...