Peppered moth
Biston betularia betularia morpha typica
Conservation status
Least Concern
Scientific classification
Kingdom: Animalia Phylum: Arthropoda Class: Insecta Order: Lepidoptera Family: Geometridae Genus: Biston Species: B. The conservation status of a Species is an indicator of the likelihood of that species remaining extant either in the present day or the near future Least Concern ( LC) is an IUCN category assigned to extant species or lower taxa which have been evaluated but do not qualify for any other category Arthropods are Animals belonging to the Phylum Arthropoda (from Greek ἄρθρον arthron, " Joint " Insects ( Class Insecta) are a major group of Arthropods and the most diverse group of Animals on the Earth with over a million described Lepidoptera is an order of Insect that includes Moths and butterflies. The geometer moths or Geometridae are a family of the order Lepidoptera. Biston is a genus of large long-winged Moths belonging to the family Geometridae. betularia
Binomial name
Biston betularia Linnaeus, 1758
Subspecies
B. Carl Linnaeus (Latinized as Carolus Linnaeus, also known after his ennoblement as, May 23 new style (13 May old style 1707 who laid the foundations for The book Systema Naturae was one of the major works of the Swedish doctor of medicine Carolus Linnaeus. b. betularia B. b. cognataria B. b. parva

The peppered moth (Biston betularia) is a temperate species of night-flying moth. As an Animal behavior, nocturnality describes sleeping during the Daytime and being active at Night - the opposite of the diurnal A moth is an Insect closely related to the Butterfly, both being of the order Lepidoptera. Peppered moth evolution is often used by educators as an example of natural selection. The evolution of the Peppered moth over the last two hundred years has been studied in detail Natural selection is the process by which favorable Heritable traits become more common in successive Generations of a Population of

Ecology and life cycle

In Britain, the peppered moth is univoltine (i. Voltinism is a term used in biology to indicate the number of broods or generations of an organisms in a year e. it has one generation per year), whilst in south-eastern North America it is bivoltine (two generations per year). The lepidopteran life cycle consists of four stages: ova (eggs), several larval instars (caterpillars), pupae, which overwinter live in the soil, and imagines (adults). Lepidoptera is an order of Insect that includes Moths and butterflies. A life cycle is a period involving 1 Generation of an Organism through means of Reproduction, whether through Asexual reproduction or Sexual A larva ( Latin; plural larvae) is a juvenile form of Animal with indirect development, undergoing Metamorphosis (for example An instar is a developmental stage of Arthropods, such as Insects, between each moult ( ecdysis) until sexual maturity is reached Caterpillars are the Larval form of a member of the order Lepidoptera (the Insect order comprising butterflies and Moths A pupa ( Latin pupa for doll pl pupae or pupas) is the life stage of some Insects undergoing transformation In Biology, the imago is the last stage of development of an Insect, after the last Ecdysis of an incomplete metamorphosis, or after emergence During the day, the moths typically rest on trees, where they are preyed on by birds.

The caterpillar is a twig mimic, varying in colour between green and brown. Biological mimicry occurs when a group of organisms the mimics, have It goes into the soil late in the season, where it pupates in order to spend the winter. The imagines emerge from the pupae between late May and August, the males slightly before the females (this is common and expected from sexual selection). Sexual selection is the Theory proposed by Charles Darwin that states that certain evolutionary traits can be explained by Intraspecific competition They emerge late in the day and dry their wings before flying that night.

The males fly every night of their lives in search of females, whereas the females release pheromones to attract males, only flying on the first night. A pheromone (from Greek φέρω phero "to bear" + ‘ορμόνη " Hormone " is a Chemical that triggers a natural Since the pheromone is carried by the wind, males tend to travel up the concentration gradient, i. Diffusion is the net movement of particles (typically molecules from an area of high concentration to an area of low concentration by uncoordinated random movement e. , towards the source. During flight, they are subject to predation by bats. The males guard the female from other males until she lays the eggs. The female lays about 2,000 pale-green ovoid eggs about 1 mm in length into crevices in bark with her ovipositor. The ovipositor is an organ used by some of the Animals for Oviposition, i

Resting behaviour

Figure 2a. Total number of observed moths = 59: Exposed trunk = 7; unexposed trunk = 7; trunk-branch joint = 23; branches = 22

Figure 2b. Total number of observed moths = 23: Exposed trunk =1; unexposed trunk =1; trunk branch join = 3; branches thicker than 5 centimetres diameter = 10; branches and twigs less thick than 5 centimetres = 8

A mating pair or a lone individual will spend the day hiding from predators, particularly birds. In the case of the former, the male stays with the female to ensure paternity. The best evidence for resting positions is given by data collected by the peppered moth researcher Michael Majerus, and it is given in the accompanying charts. Dr Michael E N Majerus (born 1954 is a Geneticist at the University of Cambridge, and the author of several books These data were originally published in Howlett and Majerus (1987), and an updated version published in Majerus (1998), who concluded that the moths rest in the upper part of the trees. Majerus notes:

Creationist critics of the peppered moth have often pointed to a statement made by Clarke et al. "Creationism" can also refer to Creation myths in general or to a concept about the origin of the soul. (1985): ". . . In 25 years we have only found two betularia on the tree trunks or walls adjacent to our traps, and none elsewhere". The reason now seems obvious. Few people spend their time looking for moths up in the trees. That is where peppered moths rest by day.

From their original data, Howlett and Majerus (1987) concluded that peppered moths generally rest in unexposed positions, using three main types of site. Firstly, a few inches below a branch-trunk joint on a tree trunk where the moth is in shadow; secondly, on the underside of branches and thirdly on foliate twigs. The above data would appear to support this.

Further support for these resting positions are given from experiments watching captive moths taking up resting positions in both males (Mikkola, 1979; 1984) and females (Liebert and Brakefield, 1987).

Majerus et al (2000) have shown that peppered moths are cryptically camouflaged against their backgrounds when they rest in the boughs of trees. It is clear that in human visible wavelengths, typica are camouflaged against lichens and carbonaria against plain bark. In Physics wavelength is the distance between repeating units of a propagating Wave of a given Frequency. Lichens (ˈlaɪkən or /lɪtʃən/ are symbiotic associations of a Fungus (the mycobiont with a photosynthetic partner (the photobiont also known as Bark, also known as periderm is the outermost layer of stems and Roots of Woody plants such as Trees It overlays the Wood and consists However, birds are capable of seeing ultraviolet light that humans cannot see. Ultraviolet ( UV) light is Electromagnetic radiation with a Wavelength shorter than that of Visible light, but longer than X-rays Using an ultraviolet-sensitive video camera, Majerus et al showed that typica reflect ultraviolet light in a speckled fashion and are camouflaged against crustose lichens common on branches, both in ultraviolet and human-visible wavelengths. However, typica are not as well camouflaged against foliose lichens common on tree trunks; though they are camouflaged in human wavelengths, in ultraviolet wavelengths, foliose lichens do not reflect ultraviolet light.

During an experiment in Cambridge over the seven years 2001-2007 Majerus noted the natural resting positions of peppered moths, and of the 135 moths examined over half were on tree branches, mostly on the lower half of the branch, 37% were on tree trunks, mostly on the north side, and only 12. The city of Cambridge (ˈkeɪmbrɪdʒ is a university town and the administrative centre of the county of Cambridgeshire, England 6% were resting on or under twigs. ^[1][2]

Morphs

Further information: Polymorphism (biology)

There are several melanic and non-melanic morphs of the peppered moth. Polymorphism in biology occurs when two or more clearly different Phenotypes exist in the same population of a species — in other words the occurrence of more than one Melanism μέλας is an increased amount of black or nearly black Pigmentation (as of Skin, Feathers or Hair) of an organism resulting from Polymorphism in biology occurs when two or more clearly different Phenotypes exist in the same population of a species — in other words the occurrence of more than one A particular morph can be indicated in a standard way by following the species name in the form "morpha morph name". In Britain, the typical white speckled morph is known as morpha typica, the melanic morph is morpha carbonaria, and the intermediate phenotype is morpha insularia. A phenotype is any observable characteristic of an Organism, such as its morphology, Development, biochemical or physiological properties These are controlled genetically.

At present, the molecular genetics and biochemistry of the melanism in this species remains unknown. Molecular genetics is the field of Biology which studies the structure and function of Genes at a molecular level Biochemistry is the study of the chemical processes in living Organisms It deals with the Structure and function of cellular components such as True (2003) has reviewed this and suggests work based on candidate genes from other insects such as the fruit fly, Drosophila melanogaster. A candidate gene is a Gene, located in a Chromosome region suspected of being involved in the expression of a trait such as a disease whose Protein product Drosophila melanogaster (from the Greek for black-bellied dew-lover) is a two-winged insect that belongs to the Diptera, the order

It is a common mistake to confuse the name of the morph with that of the species or subspecies, hence mistakes such as "Biston carbonaria" and "Biston betularia carbonaria". In Biology, a species is one of the basic units of Biological classification and a Taxonomic rank. In Zoology, as in other branches of Biology, subspecies is the Taxonomic rank immediately subordinate to a Species. This might lead to the erroneous belief that speciation was involved in the observed evolution of the peppered moth. Speciation is the Evolutionary process by which new biological Species arise This is not the case; individuals of each morph can breed and produce fertile offspring with individuals of all other morphs; hence there is only one peppered moth species.

In Europe, there are three morphs: morpha typica, the typical white morph (also known as "morpha betularia"), morpha carbonaria, the melanic black morph (also previously known as "morpha doubledayaria"), and morpha medionigra, an intermediate semi-melanic morph. European breeding experiments have shown that in Biston betularia betularia, the allele for melanism producing morpha carbonaria is controlled by a single locus. An allele (ˈæliːl (UK /əˈliːl/ (US (from the Greek αλληλος allelos, meaning each other) is one member of a pair or series of different forms In the fields of Genetics and Evolutionary computation, a locus (plural loci) is a fixed position on a Chromosome such as the position of a The melanic allele is dominant to the non-melanic allele. This situation is, however, somewhat complicated by the presence of three other alleles that produce indistinguishable morphs of morpha medionigra. These are of intermediate dominance, but this is not complete (Majerus, 1998).

In North America, the melanic black morph is morpha swettaria. In Biston betularia cognataria, the melanic allele (producing morpha swettaria) is similarly dominant to the non-melanic allele. There are also some intermediate morphs. In Japan, no melanic morphs have been recorded; they are all morpha typica. For a topic outline on this subject see List of basic Japan topics.

Evolution

Main article: Peppered moth evolution

Biston betularia betularia morpha typica, the white-bodied peppered moth. The evolution of the Peppered moth over the last two hundred years has been studied in detail

Biston betularia betularia morpha carbonaria, the black-bodied peppered moth.

The evolution of the peppered moth over the last two hundred years has been studied in detail. Originally, the vast majority of peppered moths had light coloration, which effectively camouflaged them against the light-colored trees and lichens which they rested upon. Camouflage is a method of cryptic or concealing coloration that allows an otherwise visible Organism However, due to widespread pollution during the Industrial Revolution in England, many of the lichens died out, and the trees which peppered moths rested on became blackened by soot, causing most of the light-colored moths, or typica, to die off due to predation. The Industrial Revolution was a period in the late 18th and early 19th centuries when major changes in agriculture manufacturing and transportation had a profound effect on the Soot (ˈsʊt is a general term that refers to the black impure carbon particles resulting from the incomplete combustion of a hydrocarbon At the same time, the dark-colored, or melanic, moths, carbonaria, flourished because of their ability to hide on the darkened trees. ^[3]

Since then, with improved environmental standards, light-colored peppered moths have again become common, but the dramatic change in the peppered moth's population has remained a subject of much interest and study, and has led to the coining of the term "industrial melanism" to refer to the genetic darkening of species in response to pollutants. As a result of the relatively simple and easy-to-understand circumstances of the adaptation, the peppered moth has become a common example used in explaining or demonstrating natural selection to laypeople and classroom students. Natural selection is the process by which favorable Heritable traits become more common in successive Generations of a Population of ^[4]

The first carbonaria morph was recorded by Edleston in Manchester in 1848, and over the subsequent years it increased in frequency. Predation experiments, particularly by Bernard Kettlewell, established that the agent of selection was birds who preyed on the morpha carbonaria morph. Henry Bernard Davis Kettlewell ( 24 February 1907 - 1979 was a British Geneticist, Lepidopterist and Medical doctor, who

Jonathan Wells is one of a number of creationists who have criticized the use of peppered moth melanism as an example of evolution in action. John Corrigan "Jonathan" Wells (born c 1946) is an American author and a prominent advocate of Intelligent design who has devoted his life "Creationism" can also refer to Creation myths in general or to a concept about the origin of the soul. In his book Icons of Evolution, Wells alleges that peppered moth studies, and in particular Kettlewell's experiments, were erroneous and fraudulent. Icons of Evolution is a Controversial book by the Intelligent design advocate and fellow of the Discovery Institute, Jonathan Wells Similarly, in 2002 Judith Hooper claimed outright fraud in Kettlewell's experients in her book titled Of moths and men. Judith Hooper (born April 15, 1949, in San Francisco California) is an American journalist Of Moths and Men is a Controversial book by the Journalist Judith Hooper about the Oxford University Ecological genetics Despite some valid criticisms of the early experiments, there has been no evidence of fraud and subsequent experiments and observations have clearly shown the phenomenon and supported its initial explanation. ^[5][6][7] The problem, according to the Young Earth creationist Dr. Young Earth creationism (YEC is the religious belief that Heaven, Earth, and Life on Earth were created by a direct act of God dating Tommy Mitchell of "Answers in Genesis", is that it only shows a case of natural selection, and not of evolution, as a population of a kind of moth turned into simply a population of another kind of moth. Answers in Genesis ( AiG) is a Non-profit Christian Apologetics ministry with a particular focus on Young Earth creationism and ^[8] While it is true that this example shows natural selection causing microevolution within a species, it demonstrates rapid and obvious adaptiveness with such change,^[9] and despite the claims of creationists, there are no barriers preventing such changes from accumulating to form new species. Microevolution is the occurrence of small-scale changes in Allele frequencies in a population over a few generations also known as change at or below the Species ^[10]

Further reading

• Melanism: Evolution in Action (1998) by Michael Majerus is the definitive reference on this work, which provides an introduction to evolutionary theory as well as describing the peppered moth case study. Melanism Evolution in Action (ISBN 0-19-854982-2 is a book by Dr Mike Majerus, published in 1998 Dr Michael E N Majerus (born 1954 is a Geneticist at the University of Cambridge, and the author of several books

References

External links

• More on the peppered moth as an example of evolution
• Bruce Grant has written several papers on melanism in the peppered moth which are listed on his home page. Professor Bruce S Grant is emeritus professor of Biology at the College of William and Mary.
• Online lecture: "The rise and fall of the melanic Peppered Moth" presented by Laurence Cook.
• Matt Young. Talk Reason: arguments against creationism, intelligent design, and religious apologetics. Moonshine: Why the Peppered Moth remains an Icon of Evolution. Department of Physics, Colorado School of Mines. Retrieved on 2007-09-10. Year 2007 ( MMVII) was a Common year starting on Monday of the Gregorian calendar in the 21st century. Events 506 - The Bishops of Visigothic Gaul meet in the Council of Agde.
• Michael Majerus (2004). Dr Michael E N Majerus (born 1954 is a Geneticist at the University of Cambridge, and the author of several books The Peppered moth: decline of a Darwinian disciple (. doc). Retrieved on 2007-09-10. Year 2007 ( MMVII) was a Common year starting on Monday of the Gregorian calendar in the 21st century. Events 506 - The Bishops of Visigothic Gaul meet in the Council of Agde.
• Dr. Tommy Mitchell (2008). Much Ado About Moths. Retrieved on 2008-04-30. 2008 ( MMVIII) is the current year in accordance with the Gregorian calendar, a Leap year that started on Tuesday of the Common Events 313 - Roman emperor Licinius unifies the entire Eastern Roman Empire under his rule