The peppered moth and industrial melanism: evolution of a natural selection case study

Abstract

From the outset multiple causes have been suggested for changes in melanic gene frequency in the peppered moth Biston betularia and other industrial melanic moths. These have included higher intrinsic fitness of melanic forms and selective predation for camouflage. The possible existence and origin of heterozygote advantage has been debated. From the 1950s, as a result of experimental evidence, selective predation became the favoured explanation and is undoubtedly the major factor driving the frequency change. However, modelling and monitoring of declining melanic frequencies since the 1970s indicate either that migration rates are much higher than existing direct estimates suggested or else, or in addition, non-visual selection has a role. Recent molecular work on genetics has revealed that the melanic (carbonaria) allele had a single origin in Britain, and that the locus is orthologous to a major wing patterning locus in Heliconius butterflies. New methods of analysis should supply further information on the melanic system and on migration that will complete our understanding of this important example of rapid evolution.

Urbanization Is Associated with Divergence in Pace-of-Life in Great Tits

“…It is commonly assumed that the novelty of the urban environmental features induces new and strong selection pressures providing the potential for rapid trait change (Markó et al, 2013;Alberti, 2015;Hendry et al, 2017). However, direct empirical measures of urban natural selection remain scarce (but see e.g., the emblematic peppered moth case, Cook and Saccheri, 2013). New genomic resources offer a powerful way to bypass the data consuming classical selection analyses by testing for genomewide signatures of selection associated with urbanization, even in non-model species (Harris et al, 2015).…”

Mimicry inHeliconiusand Ithomiini butterflies: The profound consequences of an adaptation

“…For instance, the sole fish has a colour pattern matching the sand floor of the ocean, which renders the fish difficult to detect [2]. Similarly, the wings of the peppered moth Biston betularia display a black-peppered pattern that matches light-coloured bark and associated lichen, on which the moth rests during the day [3]. A more subtle type of camouflage involves mimicking objects of no nutritious value for predators.…”

“…Male ithomiines are thought to acquire their chemical defences, pyrrolizidine alkaloids, at the adult stage, from decaying flowers or stems of Apocynaceae, Boraginaceae and Asteraceae [17]. Pyrrolizidine 00008-p. 3 alkaloids are then transferred to females during copulation, as a nuptial gift. Ithomiines numerically dominate forest butterfly communities, and probably drive mimicry in multiple other Lepidoptera, including Heliconius species (Fig.…”

Camouflage Variations on a Theme of the Nymphalid Ground Plan

“…Most studies focused on the microevolutionary aspects of camouflage generation. For example, research on the industrial melanism shown in peppered moths deciphered both the adaptive significance (Cook et al 2012) and the genetic basis of cryptic color variation (Cook and Saccheri 2013;van't Hof et al 2016). Studies on the seasonal polyphenism of the butterflies Araschnia levana (Koch and Bückmann 1985), Bicyclus anynana (Brakefield and Larsen 1984;Monteiro et al 2015), and Polygonia c-aureum (Fukada and Endo 1966;Endo 1984;Endo et al 1988) have also uncovered hormonal switches in the generation of the cryptic patterns matching dry or autumnal color environments.…”