Studies of bumble bee behaviour have given support to the view that they maximize net rate of energetic gain while foraging [5], [6], [8].
This winter switch in ecological strategy, from one which capitalizes on energy gain through foraging to another which curtails the energetic cost of metabolism, is a common theme for hibernating organisms [19].
The potential intake rate at a stopover site, i.e. the intake per day a goose can gain if foraging at maximum intensity, limits the rate at which geese can replenish their energy reserves [17].
The regression of mass gain on foraging duration was statistically significant (F = 22.3, df = 1, 10, P = 0.0008).
Energy expenditure may increase as a result of the mass-dependent cost of locomotion (both terrestrial and aerial), thereby reducing net gain during foraging (Taylor et al., 1980; Witter and Cuthill, 1993).
Mass gain during foraging trips was inversely related to trip duration (Fig. 4a), decreasing from approximately 1 kg/day at sea during the late 1980s to approximately 0.7 kg/day in 1993 1996, to a low of 0.29 ±.36 kg/day in 1998, and returning to 1 kg/day in 1999.
Groups also gain benefits for resource acquisition [2] via information about environmental quality gained through social foraging [3], [4].
The New Forest is being stripped of mushrooms as wild food foraging gains popularity, in part because of TV foodies and celebrity chefs, an expert warned on Friday.
From this, he deduces a fundamental rule or evolutionary ecological mechanism for explaining context dependency: individuals within a species trade off foraging gains against the risk of being consumed by predators.
This ultimately affects the decisions an individual fish makes with regard to habitat choice in order to maximize lifetime fitness and suggests that the large-scale migration pattern shown here has evolved in response to seasonally fluctuating trade-offs between predator avoidance and foraging gains.
