Peppered moth

[7][8] Biston betularia is found in China (Heilongjiang, Jilin, Inner Mongolia, Beijing, Hebei, Shanxi, Shandong, Henan, Shaanxi, Ningxia, Gansu, Qinghai, Xinjiang, Fujian, Sichuan, Yunnan, Tibet), Russia, Mongolia, Japan, North Korea, South Korea, Nepal, Kazakhstan, Kyrgyzstan, Turkmenistan, Georgia, Azerbaijan, Armenia, Europe and North America.

The lepidopteran life cycle consists of four stages: ova (eggs), several larval instars (caterpillars), pupae, which overwinter in the soil, and imagines (adults).

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).

Evidence for resting positions is given by data collected by the peppered moth researcher Michael Majerus, and it is given in the accompanying charts.

Majerus notes: Creationist critics of the peppered moth have often pointed to a statement made by Clarke et al. (1985): "...

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.

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.

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 12.6% were resting on or under twigs.

Either of these two circumstances might lead to the erroneous belief that speciation was involved in the observed evolution of the peppered moth.

By contrast, different subspecies of the same species can theoretically interbreed with one another and will produce fully fertile and healthy offspring, but in practice do not, as they live in different regions or reproduce in different seasons.

At the start of this period, the vast majority of peppered moths had light coloured wing patterns which effectively camouflaged them against the light-coloured trees and lichens upon which they rested.

This 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 through simulations.

[16] 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 carbonaria morph.

Biston betularia caterpillars on birch (left) and willow (right), demonstrating twig mimicry and effective countershading . [ 10 ]
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
Biston betularia betularia morpha typica , the white-bodied peppered moth.
Biston betularia betularia morpha carbonaria , the black-bodied peppered moth.