Foraging activity

Human labor dominated all subsistence foraging activities, as the food acquired by gathering and hunting sufficed merely to maintain the essential metabolic functions and to support veiy slow population growth. Societies not very different from this ancestral archetype survived in some parts of the world (South Africa, Australia) well into the twentieth century Because they commanded veiy little energy beyond their subsistence food needs, they had very few material possessions and no permanent abodes. 

At a more subtle level, behavioral disturbances may make it more difficult for animals to find food. Pyrethroids, carbamates, OPs, and neonicotinoids can disturb the foraging activity of bees (Thompson 2003). Interestingly, effects have been shown upon the wagtail dance of bees, and this disrupts communication between individuals as to the location of nectar-bearing plants. Also, the neonicotinoid imidacloprid has been shown to adversely affect conditioned responses such as proboscis extension of honeybees (Guez et al. 2001). Nicotinoids can disturb the functioning of cholinergic synapses, which are involved in the operation of the proboscis reflex as... 

Compound Dose rate (g a.i./ha) Crop Mortality Effects Foraging activity Colony development... 

Figure 12.1 Harvester ant foragers are stimulated to leave the nest in search of seeds in response to cues present in the task-specific cuticular hydrocarbon profile of patrollers. After inhibition of foragers at harvester ant colonies by removal of patrollers, colony foraging behavior was rescued by the addition of ant mimics, glass beads coated with task-specific cuticular hydrocarbons from patrollers, to the nest entrance at a rate of 1 bead every 10 seconds. Data were normalized to account for differences in the absolute number of foragers active each day. The same letters above bars denote statistical significance using a Tukey s post-hoc test. From Greene and Gordon, 2003.

Figure 12.2 Foraging activity at harvester ant colonies was affected by the simulated return rate of patrollers back to the colony. Letters above bars denote differences in statistical significance among treatments (LSD, p < 0.05). Error bars denote standard error of the mean. From Greene and Gordon, 2007a.

Fernandez, P. C., Gil, M. and Farina, W. M. (2003). Reward rate and forager activation in honeybees recruiting mechanisms and temporal distribution of arrivals. Behav. Ecol. Sociobiol., 54, 80-87. 

To investigate the toxicity of field-applied MMP, USDA and Texas A M researchers in 1981 near Lubbock, Texas, treated 10-acre plots of sunflowers in late full bloom with MPEG and MMP, respectively.( ) Six colonies of bees were placed near each of these fields as well as near a third untreated field which was retained as a control. Dally collections of dead bees and pollen were made to monitor the toxic effects of the insecticide and to estimate levels of foraging activity. The results are shown in Table II. 

While an effect on the gut, possibly paralysis, was considered, the foraging activity of the insect on a treated leaf, and the immediate return of normal feeding when offered an untreated leaf, seem to rule this out. 

Honey bees are beneficial arthropods playing a key role in pollinating wild and crop plants. Unfortunately, during their foraging activity they can be exposed to pesticides. The members of the colony can also be poisoned indirectly by contaminated food brought back to the hive by the foragers. The aim of this chapter is to discuss some aspects of the acute toxicity of pesticides to Apis mellifera. 

Few data are available to evaluate long-term exposure of bee colonies to transgene products. Colonies fed sucrose solutions supplemented with BBI (6 jig/ml) over a 2-month period were compared with a control colony fed with standard sucrose solution. There were no differences between the two, either in the amount of stored food and brood or in the foraging activity and learning abilities of the treated bees. Additionally, the proteolytic activities measured in adult bees and larvae sampled at the end of the exposure period were similar for control and BBI-treated hives (M.H. Pham-Delegue, unpublished data). 

Hirvonen H, Holopainen S, Lempiainen N, Selin M, Tulonen J (2007) Sniffing the trade-off effects of eel odours on nocturnal foraging activity of native and introduced crayfish juveniles. Mar Freshw Behav Physiol 40 213-218... 

Maerz, J. C., Panebianco, N. L., and Madison, D. M., 2001, Effects of predator chemical cues and behavioral biorhythms on foraging activity of terrestrial salamanders, / Chem. Ecol. 27 1333-1344. 

As pointed out by Charnov et al. (1976), foraging animals tend to depress the availability of resources through their foraging activities. Thus, effective resource distribution may depend upon the manner in which foragers search for, exploit, and depress resource units. We separate resource depression states into four major classes (i) the resource unit is removed from the foraging site coincident with its exploitation, (ii) resource remains within the sensory field but has no resource value (e.g., an already mated female), (iii) resource remains within sensory field and replenishes itself (e.g., flower produces new nectar after original supply has been extracted), and (iv) resource becomes less vulnerable to attack and/or exploitation as a result of previous use (e.g., previously damaged birch leaves Haukioja, 1980). 

Let us turn now from the realm of chemical mediation against overcrowding per se to the realm of chemical partitioning of food foraging activities. 

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