Batesian mimicry

MHC molecules all-surface glycoprotien encoded by the major histocompatibility complex of genes they are involved in immunity and cell recognition mimicry, Batesian resemblance of one animal (the mimic) to another (the model) to the benefit of the mimic, as when the model is dangerous or inedible (described by Henry Walter Bates 1825-1892)... 

A non-toxic species of salamander may derive protection from predators by visually resembling a toxic form so closely that predators cannot distinguish between them Batesian mimicry). Free-ranging birds avoid both the toxic red eft Notophthalmus viridescens) and the similar-looking non-toxic red morph of the red-backed salamander Plethodon cinereus). The red-striped morph of P. cinereus, which does not resemble the red eft, is eaten (Brodie and Brodie, 1980). 

Two speculative possibilities relate to olfactory aposematism. The first is whether there are non-toxic plants that smell or taste like toxic ones. In other words, do plants practice Batesian mimicry. Such mimicry is unlikely, as mammalian herbivores constantly sample plants and thereby test for favorable and adverse effects of eating a particular species. Furthermore, given the keen sense of smell of mammals, two plant species would have to exactly smell alike for mimicry to work. Second, do two distasteful or toxic plant species smell or taste alike so that herbivores can more easily classify dangerous plants and avoid them (Mullerian mimicry) (Eisner and Grant, 1981 Lindroth, 1988 Augner and Bernays, 1998). 

Brown-headed cowbirds, Molothrus ater, and red-winged blackbirds, A. phoeniceus, removed 95-98% less rice seeds sown in flight pens if the seeds had been treated with methiocarb. The effect was the same whether 100% or only 50% of the seeds had been treated. This shows that an entire prey population can be protected even if only a portion is unpalatable. Such automimicry may permit partial treatment of crops with repellents, which would be effective, environmentally sound, and economical (Avery, 1989). Batesian mimicry offers advantages over food aversion learning (Reidinger and Mason, 1983). 

Augner, M. and Bernays, E. A. (1998). Plant defence signals and Batesian mimicry. Evolutionary Ecology 12, 667-680. 

Batesian mimicry—type of mimicry in which a palatable species has evolved to look like an unpalatable one in order to escape predation. 

Labanick, G. M., and Brandon, R. A., 1981, An experimental study of Batesian mimicry between the salamanders Plethodon jordani and Desmognathus ochrophaeus, J. Herpetol., 15 275. 

Many workers have explored various aspects of predator learning when presented with mimetic complexes (see Section 10.4.4 for list of experiments and references). Many facets of Batesian mimicry such as degree of resemblance, degree of punishment and frequency of mimics have been investigated successfully by these methods. 

Much less experimental work has been done on Mullerian mimicry than on Batesian mimicry. Thus feeding experiments have been few. Benson (1972) was able to establish natural selection operating to stabilize the mimetic pattern of Heliconius erato in Costa Rica by comparing survival times and wing damage in altered non-mimics versus controls. 

Batesian mimicry is the familiar phenomenon known simply as mimicry to most people. It is named after the English naturalist Henry W. Bates who proposed it as an explanation of certain resemblances among Amazonian butterflies (Bates, 1862). It is, unlike the situations we have examined thus far, exemplified by the deception of the predator by prey. As Rothschild (1972a) so... 

The situation differs somewhat in amphibians and reptiles where the size of the adult is not fixed but continues to increase as long as the individual lives. This results in the unusual (in insect mimicry) situation that the mimic may outgrow its model. There have been a number of discussions suggesting the idea of a super-mimic , a Batesian mimic that would give a super visual stimulus thus deterring the predator more than the model would. However, it has been concluded that a super-mimic is a poor mimic, and that several mechanisms have developed to circumvent the problem (Huheey and Brandon, 1974). As an... 

The presence of innocuous monarch butterflies flying with toxic ones raises interesting questions for mimicry. From the point of view of the predator automimics are perfect Batesian mimics if we assume that they differ in no way from their models except as a result of toxins in the diet of one and not the other. They therefore make a useful model for perfect Batesian mimicry, that is, where the predator cannot distinguish visually between model and mimic. 

Sheppard (1959) has also discussed this correlation of mimics to models, as well as the related phenomenon of pattern breakdown in Batesian mimics. If for reasons unrelated to mimicry there is a sudden increase in the number of mimics or a sudden decrease in the number of models, the selective advantage of close mimicry declines, perhaps even becomes disadvantageous and the variability of the mimics increases. 

We here touch upon a subject of difficulty and violent controversy the significance of selective advantage. Selection will favour the increasing perfection of Batesian mimicry since, other things being equal, those individuals which best resemble their model will contribute most to posterity but it will also ensure that the quality selected for will cease to be an asset. For any increase in the relative numbers of a mimic compared with its model, whether due to more perfect deception or other cause, can only be carried up to the point of equipoise, that at which the value of the resemblance is balanced by making a species conspicuous when it is in fact, relatively palatable and defenseless. ... 

There have been a few field studies testing the selective advantage of Batesian mimicry in the wild. Such experiments are fraught with difficulties Too few mimics and the statistics are poor too many and the natural system is perturbed. Nevertheless valuable data on the action of Batesian mimicry have been obtained (L. Brower et al., 1967 Cook et al., 1%9 Sternburg et al., 1977). 

Although the vast majority of the work on Batesian mimicry has been done on butterflies, it is by no means limited to this order. The following summary is meant to be representative, not exhaustive. Perhaps the best-known examples of Batesian mimicry outside of the Lepidoptera are those involving bees and wasps as models and other insects, especially flies, as mimics. The Browers (1960, 1962, 1965) have studied the reactions of toads (Bufo terrestris) to honeybees Apis mellifera) and their dronefly mimics Eristalis spp.) as well as to bumblebees Bombus americanorum) and their robberfly mimics Mallo-phora bomboides). 

In as much as bumblebee (Bombus) males are stingless, they are automimics of the stinging females. As such, like all Batesian mimics, one would expect the resemblance to be as close as possible. However, often it is not. Stiles (1979) has suggested that because male bees are subjected to diurnal temperature fluctuations, which the female bees are not, the sexual dimorphism may be a trade-off for the males between best mimicry and best thermoregulation. 

An interesting example of a mimicry complex based on ants has recently been reported (Jackson and Drummond, 1974). The ant Camponotus planatus is mimicked by (i) a clubionid spider, Myrmecotypus fuliginosus (ii) a salticid spider, Sarinda linda (iii) a mirid bug, Barberiella sp. and (iv) a mantid, Mantoida maya. This is the largest known Batesian mimicry complex based upon an ant model, and this fact may be attributed to the abundance of C. planatus. 

The Batesian and Mullerian forms of mimicry are not the only ones known (see Section 10.6), but they are the best defined and have more quantitative data... 

Table 10.1 Comparison of attributes of traditional Mullerian and Batesian mimicry...

Because of the advent of data and the desire to predict and to model mimetic systems, the past two decades have seen a number of attempts to construct mathematical models, often utilizing the simulative power of the computer. Thus Huheey (1964, 1976) has presented models for Batesian and Mullerian mimicry, respectively, based originally on the experimental data of J. Brower (1960) with respect to the feeding habits of starlings on quinine-dipped mealworms, but augmented by data on the reaction of toads and treefrogs to honeybees, Apis mellifera (Huheey, 1980b). Other workers who have made valuable... 

Traditionally, the concepts of Batesian and Mullerian mimicry have been considered completely distinct. Certainly, this seems true in many of the factors operating and in the predictions that one would make on the basis of Table 10.1. Therefore most students of mimicry have tended to view Batesian and Mullerian mimicry as discrete, isolated compartments. Some have gone so far as to say that mimicry is Batesian mimicry, that Mtillerian mimicry is merely warning coloration, and the two should not even be considered at the same time. As we shall see, this will not be the only time that semantics raises its head. Still, vexing questions continue to be posed. One is the very problem of the evolution of mimicry which, needs be, raises further questions concerning how species cross over the absolute boundaries of crypsis/aposematism or pseud-aposematism/aposematism (see Section 10.7). 

Despite the apparently discrete characters of Batesian and Mullerian mimicry, many authors (Fisher, 1958 Huheey, 1961 Linsley et al., 1961 Eisner et al., 1962 L. Brower and J. Brower, 1964 L. Brower et al., 1970 Pougheta/., 1973 Huheey, 1976 Brandon eta/., 1979 Sbordoni eta/., 1979) have discussed, from either an empirical or theoretical viewpoint, apparent intermediate cases between classical Batesian and Mullerian mimicry or the evolution of Batesian mimicry into Mullerian mimicry, or vice versa. 

An interesting example is provided by certain lycid and cerambycid beetles. The lycids are unpalatable to vertebrates, warningly colored, and mimicked by palatable cerambycids. The situation would thus seem to be simply one of Batesian mimicry, but the cerambycids are carnivorous We thus have the unusual situation of the Batesian mimic preying upon its model, thereby ingesting the model s toxin, and presumably in turn becoming toxic - a Mullerian mimic ... 

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