One-Trial Versus Multi-Trial Learning for a Predator Encountering a Model- Mimic System

Bobisud, L. E.; Potratz, C.

doi:10.1086/283052

Cited by 34 publications

(12 citation statements)

References 3 publications

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“…Many milkweeds contain cardenolides (cardiac glycosides) and it is well established that the caterpillar of the American monarch butterfly (Danaus plexippus (L.)) can accumulate cardenolides acquired from the foodplant in its body tissues and retain them through to the adult stage (Parsons, 1965;Brower, Brower & Corvino, 1967;Reichstein et al, 1968;Brower & Glazier, 1975). If the caterpillar has accumulated enough of certain cardenolides, then the caterpillar, pupa or adult insect will cause a bird which eats it to vomit (Brower, 1969).…”

Section: Introductionmentioning

confidence: 99%

“…As a consequence, some populations of D. plexippus may be regarded as dimorphic, with insects either emetic or non-emetic, whereas others exhibit a wide range of cardenolide concentrations and consequently a palatability spectrum amongst its members. In both cases the palatable butterflies may be regarded as mimics of the emetic members of the same population and the term automimicry" has been coined to characterise this phenomenon (Brower et al, 1967;Vane-Wright, 1976): discussions of the assumptions are present in Pough, Brower, Meck & Kessell, 1973;Huheey, 1964;Estabrook & Jesperson, 1974;Bobisud & Potratz, 1976. On the African continent the commonest butterfly of the genus Danaus is D. chrysippus (L), a species whose distribution also extends t o Asia and Australasia. In most West African populations west of Eastern Nigeria, including Ghana, D. chrysippus is monomorphic (Owen & Chanter, 1968;Owen, 1971) but in areas of East Africa, including Kenya and Tanzania, four morphs may occur (Smith, 1973;Pierre, 1974;Rothschild, von Euw, Reichstein, Smith & Pierre, 1975).…”

Section: Introductionmentioning

confidence: 99%

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Cardenolide content of Danaus chrysippus butterflies from three areas of East Africa

Brower

Gibson

Panchen

1978

Biological Journal of the Linnean Society

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The African butterfly Danaus chrysippus, like other members of the family Danaidae, feeds as a larva on species of milkweeds (Asclepiadaceae). I t has been demonstrated in a sample from a West African population that only a minority of adult D. chrysippus accumulated detectable amounts of poisonous and presumably emetic cardenolides from their larval foodplants. It has also been shown in D. chrysippus and the related monarch butterfly (D. plexippus) that the cardenolide content of adults varies with that of their respective milkweed foodplants.Three population samples of D. chrysippus from sites in East Africa are analysed for cardenolides using the spectrophotometric technique refined by Brower, Edmunds lk Moffitt (1975). which allows the assay of individual butterflies. The East African samples all have a palatability spectrum with a considerably higher percentage of cardenolide-containing individuals than the West African one. This is discussed in t e r m of its effect on potential bird predators and the 'automimicry' of emetic by palatable individuals. In East Africa D. chrysippus is polymorphic and appears to act as a model in a complex mimicry ring, whereas in West Africa it is monomorphic and may have 'shed' most of its mimics. This latter hypothesis is discussed in the light of our results.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Cardenolide content of Danaus chrysippus butterflies from three areas of East Africa

Brower

Gibson

Panchen

1978

Biological Journal of the Linnean Society

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“…An animal's selection of particular food items at a given time may reflect some important proximate factors affecting diet choice, e.g., prey discrimination, memory, monitoring internal physiological state, etc. (Bobisud and Potratz, 1976;Rozin, 1976;Zahorik, 1977;Zahorik and Haupt, 1981;Gray, 1981;Pietrewicz and Kamil, 1981). These studies, however, do not impart much information about how animals might make quantitative decisions.…”

Section: Discussionmentioning

confidence: 99%

Inheritance of optimal foraging behaviour in Columbian ground squirrels

Ritchie

1991

Evol Ecol

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in SummaryI examined the potential inheritance of the ability of Columbian ground squirrels (Spermophilus columbianus) to select an optimal diet. I calculated the diet that would maximize daily energy intake for each of 21 adult females and their litters, using a linear programming optimization model for each individual. The absolute value of the difference between an individual's predicted optimal diet and observed diet (deviation from an optimal diet) was used as a measure of an individual's foraging ability. The foraging ability of individuals was consistent over time and in different foraging environments, so I considered foraging ability to be a potentially heritable trait.Inheritance was determined from correlations of mother and offspring foraging ability. I experimentally removed some mothers just as they weaned their offspring so that offspring could not be influenced by their mother while learning to forage, while leaving the other mothers to raise their litters normally. In both cases, offspring strongly resembled their mother in foraging ability. However, offspring with mothers absent exhibited significantly larger deviations from their optimal diet. Offspring with mothers absent appeared to imitate their mother's diet during lactation, and this tendency partially explained their greater deviation. Consequently, offspring appear to inherit the ability to forage optimally from their mother, perhaps through observational learning or imitation. There may also be a genetic basis to foraging ability, but uncontrolled maternal effects in the experiment prevent a proper test for it.

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“…The forgetting rate variable (4) is 0.02 for all uscs of the algorithm. (Estabrook & Jespersen, 1974;Bobisud & Potratz, 1976) use idiosyncratic versions of HH-HH, involving the bizarre rule of subtracting from n the number of mimics previously encountered, but leaving n at its maximum if the number of mimics exceeds n.…”

Section: D Huheey Forgetting Rulementioning

confidence: 99%

Learning and memory in mimicry: II. Do we understand the mimicry spectrum?

Speed

Turner

1999

Biological Journal of the Linnean Society

100

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The evolution of mimicry is driven by the behaviour of predators. However, there has been little systematic testing of the sensitivity of evolutionary predictions to variations in assumptions about predator learning and forgetting. T o test how robust mimicry theory is to such behavioural modifications we combined sets of rules describing ways in which learning and forgetting might operate in vertebrate predators into 29 computer predator behaviour systems. These systems were applied in simulations of simplified natural mimicry situations, particularly investigating the nature of density-dependence and the benefits and losses conferred by mimicry across a spectrum of palatabilities. The classical Batesian-Muellerian spectrum was generated only by two of our 29 predator behaviour systems. Both of these 'classical predators' had extreme asymptotes of learning and fixed rate, time dependent forgetting. All edible mimics were treated by them as Batesian in that they parasitized their model's protection and had positive monotonic effects of density on model-mimic attack rates. All defended mimics were treated as Muellerian (Mullerian) in that their presence benefited their Model's protection, and showed negative monotonic density effects on attack rates. With the remaining 27 systems Batesian or Muellerian relationships extended beyond their conventional edibility boundaries. In some cases, Muellerian mimicry extended into the edible region of the 'palatability spectrum' (we term this quasi-Muellerian mimicry), and in others Batesian mimicry extended into the 'unpalatable', defended half of the spectrum (quasi-Batesian mimicry). Although most of the 29 behaviour systems included at least some regions of true Batesian and Muellerian mimicries, if forgetting was triggered by avoidance events (as suggested by J.E. Huheey) rather than by the passage of time then the mimicry spectrum excluded Mullerian mimicry altogether, and was composed of Batesian and quasiBatesian mimicries. In addition the classical prediction of monotonic density-dependent predation was shown not to be robust against variations in the forgetting algorithm. Time based forgetting which is retarded by observations of prey, or which varies its rate according to the degree of pleasantness or unpleasantness of a prey generates non-monotonic results. At low mimic densities there is a positive effect on attack rates and at higher densities a negative effect. Overall, the mode of forgetting has a more significant effect on mimetic relationships than the rate of learning. It seems to matter little whether learning and forgetting are switched or gradual functions. Predictions about mimetic evolution are therefore sensitive to assumptions about predator behaviour, though more so to variations in forgetting than learning rate. Based on findings from animal psychology and mimetic populations, we are able to rule out a number of predator behaviour systems. We suggest that the most credible of our 29 predators are those which generate results which incorporate Bates...

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One-Trial Versus Multi-Trial Learning for a Predator Encountering a Model- Mimic System

Cited by 34 publications

References 3 publications

Cardenolide content of Danaus chrysippus butterflies from three areas of East Africa

Cardenolide content of Danaus chrysippus butterflies from three areas of East Africa

Inheritance of optimal foraging behaviour in Columbian ground squirrels

Learning and memory in mimicry: II. Do we understand the mimicry spectrum?

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