TY - JOUR
T1 - Multitrait, host-associated divergence among sets of butterfly populations
T2 - implications for reproductive isolation and ecological speciation
AU - Singer, Michael C.
AU - McBride, Carolyn S.
N1 - Copyright:
Copyright 2010 Elsevier B.V., All rights reserved.
PY - 2010/4
Y1 - 2010/4
N2 - When populations use different resources, they tend to diverge in traits that affect performance on those resources. The extent and complexity of divergence that is achieved will depend on gene flow, genetic constraints, and the character of divergent selection. We describe divergent host adaptation among Californian populations of the Melitaeine butterfly, Euphydryas editha. Divergence in seven traits created parallel phenotypic suites, each suite associated with the use of a different host species, either Collinsia torreyi or Pedicularis semibarbata. The suites involved alighting responses of adults (probably to visual stimuli), chemosensory responses to leaf surfaces, vertical positioning of adults and larvae (probably due to geotaxis), partitioning of reproductive effort among clutches, and larval performance. Remarkably, the divergent suites did not occur sympatrically, despite ubiquitous co-occurrence of the hosts, and we know of only one site where any Collinsia species is used sympatrically with another host. In contrast, E. editha often uses two host genera sympatrically when neither of them is Collinsia. We suggest that adaptation to Collinsia is incompatible with adaptation to other hosts and may generate extrinsic postzygotic reproductive isolation among populations. Despite the apparent rarity of host-shift-associated speciation in Melitaeine butterflies, adoption of Collinsia as a host may lead to allopatric ecological speciation.
AB - When populations use different resources, they tend to diverge in traits that affect performance on those resources. The extent and complexity of divergence that is achieved will depend on gene flow, genetic constraints, and the character of divergent selection. We describe divergent host adaptation among Californian populations of the Melitaeine butterfly, Euphydryas editha. Divergence in seven traits created parallel phenotypic suites, each suite associated with the use of a different host species, either Collinsia torreyi or Pedicularis semibarbata. The suites involved alighting responses of adults (probably to visual stimuli), chemosensory responses to leaf surfaces, vertical positioning of adults and larvae (probably due to geotaxis), partitioning of reproductive effort among clutches, and larval performance. Remarkably, the divergent suites did not occur sympatrically, despite ubiquitous co-occurrence of the hosts, and we know of only one site where any Collinsia species is used sympatrically with another host. In contrast, E. editha often uses two host genera sympatrically when neither of them is Collinsia. We suggest that adaptation to Collinsia is incompatible with adaptation to other hosts and may generate extrinsic postzygotic reproductive isolation among populations. Despite the apparent rarity of host-shift-associated speciation in Melitaeine butterflies, adoption of Collinsia as a host may lead to allopatric ecological speciation.
KW - Adaptive suites
KW - Clutch size
KW - Euphydryas
KW - Host adaptation
KW - Performance
KW - Preference
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U2 - 10.1111/j.1558-5646.2009.00866.x
DO - 10.1111/j.1558-5646.2009.00866.x
M3 - Article
C2 - 19817847
AN - SCOPUS:77955007182
VL - 64
SP - 921
EP - 933
JO - Evolution; international journal of organic evolution
JF - Evolution; international journal of organic evolution
SN - 0014-3820
IS - 4
ER -