Editing Erysimum (section)

=== Escape from herbivory ===
The evolution of novel chemical defenses in plants, such as [[cardenolide]]s in the genus ''Erysimum'', is predicted to allow escape from herbivory by specialist herbivores and expansion into new ecological niches.<ref>{{Cite journal|last1=Weber|first1=Marjorie G.|last2=Agrawal|first2=Anurag A.|date=2014|title=Defense mutualisms enhance plant diversification|journal=Proceedings of the National Academy of Sciences|volume=111|issue=46|pages=16442–16447|doi=10.1073/pnas.1413253111|pmid=25349406|issn=0027-8424|pmc=4246327|bibcode=2014PNAS..11116442W|doi-access=free}}</ref> The crucifer-feeding specialist ''[[Pieris rapae|Pieries rapae]]'' (white cabbage butterfly) is deterred from feeding and oviposition by cardenolides in ''[[Erysimum cheiranthoides]].''<ref>{{Cite journal|last=Feeny|first=Paul|date=1977|title=Defensive Ecology of the Cruciferae|journal=Annals of the Missouri Botanical Garden|volume=64|issue=2|pages=221–234|doi=10.2307/2395334|jstor=2395334|bibcode=1977AnMBG..64..221F |url=https://www.biodiversitylibrary.org/part/40250}}</ref><ref>{{Cite journal|last1=Renwick|first1=J. A. A.|last2=Radke|first2=Celia D.|date=1987|title=Chemical stimulants and deterrents regulating acceptance or rejection of crucifers by cabbage butterflies|journal=Journal of Chemical Ecology|volume=13|issue=7|pages=1771–1776|doi=10.1007/bf00980217|pmid=24302344|bibcode=1987JCEco..13.1771R |s2cid=24473740|issn=0098-0331}}</ref><ref>{{Cite journal|last1=Renwick|first1=J. A. A.|last2=Radke|first2=Celia D.|date=1985|title=Constituents of host- and non-host plants deterring oviposition by the cabbage butterfly, Pieris rapae|journal=Entomologia Experimentalis et Applicata|volume=39|issue=1|pages=21–26|doi=10.1111/j.1570-7458.1985.tb03538.x|bibcode=1985EEApp..39...21R |s2cid=86713452|issn=0013-8703}}</ref><ref>{{Cite journal|last1=Dimock|first1=M. B.|last2=Renwick|first2=J. A. A.|last3=Radke|first3=C. D.|last4=Sachdev-gupta|first4=K.|date=1991|title=Chemical constituents of an unacceptable crucifer,Erysimum cheiranthoides, deter feeding byPieris rapae|journal=Journal of Chemical Ecology|volume=17|issue=3|pages=525–533|doi=10.1007/bf00982123|pmid=24258803|bibcode=1991JCEco..17..525D |s2cid=32639023|issn=0098-0331}}</ref><ref>{{Cite journal|last1=Sachdev-Gupta|first1=K.|last2=Radke|first2=Cd.|last3=Renwick|first3=J. A. A.|last4=Dimock|first4=M. B.|date=1993|title=Cardenolides from Erysimum cheiranthoides: Feeding deterrents toPieris rapae larvae|journal=Journal of Chemical Ecology|volume=19|issue=7|pages=1355–1369|doi=10.1007/bf00984881|pmid=24249167|bibcode=1993JCEco..19.1355S |s2cid=258932|issn=0098-0331}}</ref> Similarly, ''Anthocharis cardamines'' (orange tip butterfly), which oviposits on almost all crucifer species, avoids ''[[Erysimum cheiranthoides|E. cheiranthoides]].''<ref>{{Cite journal|last1=Wiklund|first1=Christer|last2=Åhrberg|first2=Carl|last3=Ahrberg|first3=Carl|date=1978|title=Host Plants, Nectar Source Plants, and Habitat Selection of Males and Females of Anthocharis cardamines (Lepidoptera)|journal=Oikos|volume=31|issue=2|pages=169|doi=10.2307/3543560|issn=0030-1299|jstor=3543560|bibcode=1978Oikos..31..169W }}</ref> ''Erysimum asperum'' (western wallflower) is resistant to feeding and oviposition of ''Pieris napi macdunnoughii'' (synonym ''[[Pieris marginalis]]'', margined white butterfly).<ref>{{Cite journal|last=Chew|first=Frances S.|date=1975|title=Coevolution of pierid butterflies and their cruciferous foodplants|journal=Oecologia|volume=20|issue=2|pages=117–127|doi=10.1007/bf00369024|pmid=28308818|issn=0029-8549|bibcode=1975Oecol..20..117C|s2cid=29074343}}</ref><ref>{{Cite journal|last=Chew|first=Frances S.|date=1977|title=Coevolution of Pierid Butterflies and Their Cruciferous Foodplants. II. The Distribution of Eggs on Potential Foodplants|journal=Evolution|volume=31|issue=3|pages=568–579|doi=10.2307/2407522|issn=0014-3820|jstor=2407522|pmid=28563490}}</ref> Two crucifer-feeding beetles, ''Phaedon'' sp. and ''[[Phyllotreta]]'' sp., were deterred from feeding by [[cardenolide]]s that were applied to their preferred food plants.<ref>{{Cite journal|last=NIELSEN|first=JENS KVIST|date=1978|journal=Entomologia Experimentalis et Applicata|volume=24|issue=1|pages=41–54|doi=10.1111/j.1570-7458.1978.tb02755.x|issn=0013-8703|title=Host Plant Discrimination within Cruciferae: Feeding Responses of Four Leaf Beetles (Coleoptera: Chrysomelidae) to Glucosinolates, Cucurbitacins and Cardenolides|bibcode=1978EEApp..24...41N |s2cid=84602063}}</ref><ref>{{Cite journal|last=NIELSEN|first=J. K.|date=1978|journal=Entomologia Experimentalis et Applicata|volume=24|issue=3|pages=562–569|doi=10.1111/j.1570-7458.1978.tb02817.x|issn=0013-8703|title=Host Plant Selection of Monophagous and Oligophagous Flea Beetles Feeding on Crucifers|bibcode=1978EEApp..24..562N |s2cid=85648914}}</ref> Consistent with the hypothesis of enhanced speciation after escape from herbivory, phylogenetic studies involving 128 ''Erysimum'' species indicate diversification in Eurasia between 0.5 and 2 million years ago, and in North America between 0.7 and 1.65 million years ago.)<ref name=":1" /> This evolutionarily rapid expansion of the ''Erysimum'' genus has resulted in several hundred known species distributed throughout the northern hemisphere.<ref name=":1" /><ref name=":3" /><ref name=":4" /><ref name=":5" /><ref name=":6" /><ref name=":7" />