Feeding / predator-prey relations / parasites and behavior

FEEDING BEHAVIOR involves doing whatever it takes to get the energy to meet physiological and developmental needs (sometimes their are different diets at different points in develop). Since some energy must be expended by the animal seeking energy, there is a distinct balance between costs and benefits of energy obtained that is particularly amenable to analysis: visit the website on OPTIMALITY. .


The HUMAN as a predator: Dan Lieberman, at Harvard, argues that "chasing animals until they collapse from exhaustion yields more meat per hunt than hunting with spears or a bow and arrow." read story.


FACTOID: Siphonophores may be earth's most abundant predators: one species, Praya dubia, can grow to a length of 160 feet.

Co-evolution. Prey (plants, animals) often co-evolves with its predator; and sometimes they become mutually dependent.
Search image Restriction of an animal's interest to a single class of object as a consequence of focused attention on particular stimuli. Drickamer states it involves a "hypothetical mental image of a prey species that a forager or hunter forms as it improves in its ability to capture that particular species." but this emphasizes developmental change that isn't always in evidence. (adapted from the Drickamer et al. 1996 Glossary; but this is not enough). see Animal Behavior (1996 4th ed, p 277). It involves an animals selective attention by which it searches for a particular object (G&B2:256-258)

EC: what is "pareidolia"; (1) provide HYPOTHETICAL example from predator/prey relationships; (2) pareidolia may lead to "mistakes" -- how can being in error ("false positives" or "false negatives") (a) contribute to an animal's fitness or (b) detract from fitness? e-mail a summary of your work; be sure to put "pareidolia" in the subject line

Social Feeding has evolved in many groups of animals: it permits the capture or collection of patchily distributed food (e.g., bird flock) large amounts of food relative to the size of an individual in the group (e.g., wolves).

Tool Using Behavior has also evolved several times in unrelated groups and allows the exploitation of otherwise inaccessible resources.
Locating Food. A wide variety of behavioral adaptations to locating food have been documented; for example: Obtaining Food
Trapping food is common (trap-door spiders, ant lions)
Luring food (angler fish & snapping turtle)

ANTI-PREDATION (G&B2: 10:275-283)

DEEP - ECOLOGY - predator-prey web version.ppt

VIEW Trials of Life video episode on "FINDING FOOD"

EPIGENETICS & DIET. "Toward the end of World War II, a German-imposed food embargo in western Holland--a densely populated area already suffering from scarce food supplies, ruined agricultural lands, and the onset of an unusually harsh winter--led to the death by starvation of some 30,000 people. Detailed birth records collected during that so-called Dutch Hunger Winter have provided scientists with useful data for analyzing the long-term health effects of prenatal exposure to famine. Not only have researchers linked such exposure to a range of developmental and adult disorders, including low birth weight, diabetes, obesity, coronary heart disease, breast and other cancers, but at least one group has also associated exposure with the birth of smaller-than-normal grandchildren.1 The finding is remarkable because it suggests that a pregnant mother's diet can affect her health in such a way that not only her children but her grandchildren (and possibly great-grandchildren, etc.) inherit the same health problems." more




Temporally Specialized Spider Web . . . . The Thermoregulatory Defense . . . . Sometimes Social Spiders . . . . Where do Poison Arrow Frogs get their Ammunition?

ALLEE EFFECT. "Perhaps the commonest [expression of the] Allee effect occurs in species that congregate to protect themselves against predators. Animals such as flamingos and penguins just won't get into breeding mood unless they are surrounded by many other mating individuals. In such species, natural selection favours animals that synchronise their breeding because their offspring are more likely to survive the vulnerable early weeks if there are plenty of other young animals around for potential predators to pick off. "This may not be a problem for a species that is usually abundant," says Bill Sutherland from the University of East Anglia, "but can become important once it becomes rare or once people are trying to breed it in captivity." In some species, a behaviour that probably evolved as a way of swamping potential predators, seems to have developed into a near-unbreakable psychological dependence." -- from Adrian Barnett's essay, "Safety in Numbers," in New Scientist 03 February 2001

PREY FIDELITY? "Ecological models suggest that biodiversity arises from the partitioning of resources among species, allowing new species with unique resource-use patterns to invade communities. However, these models have not been tested empirically because real-world species differences in resource use are often confounded with other species traits (size, rate of growth, metabolic rate, etc.). Finke and Snyder (p. 1488) overcome these obstacles by exploiting host-fidelity behavior among a group of parasitoid wasps that attack aphids. While each wasp species is a generalist consumer that attacks many aphid species, individual wasps prefer to attack the same host species from which they themselves emerged. By rearing wasps of different species on each of several aphid species, consumer wasp communities were constructed that could be independently manipulated for consumer species identity, species richness, and patterns of resource use. Exploitation of the aphid resource clearly improved with greater consumer biodiversity, but only when constituent consumers were specialists with distinct resource-niche partitioning. Thus differences in resource use among species, rather than biodiversity per se, intensify resource exploitation at higher levels of consumer biodiversity." SCIENCE, September 12 2008, 321 (5895)

See "Trials of Life" video on predator-prey relationships



In his book, Feast, Roy Strong tells us that " . . . feasting . . . . has always been hard work. Monarchs from King Belshazzar to Louis XIV have used the public consumption and distribution of food to dramatize their power, flaunting their mastery of trade routes by eating delicacies from the remote ends of the earth, reveling in the refinement of their taste, or simply indulging the jolliest of the seven deadly sins. Often, the remnants of royal feasts were distributed to the poor, culinary bribery to impress the masses and quiet their resentments, at least for the moment. . . . Sadly but inevitably, Strong ends his survey with a despairing look at our own fast food nation, where, in the words of playwright Ken LeZebnik, the feasts of old have been reduced to "sink eating": a standing fuel stop in the kitchen, poised for an instant between the faucet and the refrigerator."

[from "The Lost Art of Eating" By Ingrid D. Rowland, an essay review of Feast: A History of Grand Eatingby Roy Strong. NYRB 51(12) July 15, 2004 complete review]