title: Co-gradient variation in growth rate and development time of a broadly distributed butterfly.
abstract: Widespread species often show geographic variation in thermally-sensitive traits, providing insight into how species respond to shifts in temperature through time. Such patterns may arise from phenotypic plasticity, genetic adaptation, or their interaction. In some cases, the effects of genotype and temperature may act together to reduce, or to exacerbate, phenotypic variation in fitness-related traits across varying thermal environments. We find evidence for such interactions in life-history traits of Heteronympha merope, a butterfly distributed across a broad latitudinal gradient in south-eastern Australia. We show that body size in this butterfly is negatively related to developmental temperature in the laboratory, in accordance with the temperature-size rule, but not in the field, despite very strong temperature gradients. A common garden experiment on larval thermal responses, spanning the environmental extremes of H. merope's distribution, revealed that butterflies from low latitude (warmer climate) populations have relatively fast intrinsic growth and development rates compared to those from cooler climates. These synergistic effects of genotype and temperature across the landscape (co-gradient variation) are likely to accentuate phenotypic variation in these traits, and this interaction must be accounted for when predicting how H. merope will respond to temperature change through time. These results highlight the importance of understanding how variation in life-history traits may arise in response to environmental change. Without this knowledge, we may fail to detect whether organisms are tracking environmental change, and if they are, whether it is by plasticity, adaptation or both.
authors.affiliation: Department of Zoology, The University of Melbourne, Parkville, Victoria, Australia.
authors.forename: Madeleine
authors.initials: M
authors.lastname: Barton
authors.affiliation: School of Biological Sciences, Monash University, Clayton, Victoria, Australia.
authors.forename: Paul
authors.initials: P
authors.lastname: Sunnucks
authors.affiliation: School of Biological Sciences, Monash University, Clayton, Victoria, Australia.
authors.forename: Melanie
authors.initials: M
authors.lastname: Norgate
authors.affiliation: Department of Genetics, La Trobe University, Melbourne, Victoria, Australia.
authors.forename: Neil
authors.initials: N
authors.lastname: Murray
authors.affiliation: Department of Zoology, The University of Melbourne, Parkville, Victoria, Australia.
authors.forename: Michael
authors.initials: M
authors.lastname: Kearney
mesh_terms: D000222:Adaptation, Physiological; D000818:Animals; D001315:Australia; D005838:Genotype; D007915:Lepidoptera / Q000502:physiology*; D010641:Phenotype
references.citation: Ann N Y Acad Sci. 2009 Jun;1168:100-29
references.pmid: 19566705
references.citation: Evolution. 1967 Dec;21(4):725-741
references.pmid: 28563073
references.citation: Annu Rev Physiol. 2010;72:147-66
references.pmid: 20148671
references.citation: Trends Ecol Evol. 2011 Jun;26(6):285-91
references.pmid: 21470708
references.citation: Proc Natl Acad Sci U S A. 2008 Sep 9;105(36):13492-6
references.pmid: 18757740
references.citation: Trends Ecol Evol. 1995 Jun;10(6):248-52
references.pmid: 21237029
references.citation: Integr Comp Biol. 2004 Dec;44(6):413-24
references.pmid: 21676727
references.citation: Trends Ecol Evol. 1997 Jun;12(6):235-9
references.pmid: 21238056
references.citation: Oecologia. 2002 Nov;133(3):430-438
references.pmid: 28466206
references.citation: Trends Ecol Evol. 1998 Oct 1;13(10):403-7
references.pmid: 21238360
references.citation: Evolution. 1997 Apr;51(2):630-632
references.pmid: 28565350
references.citation: Oecologia. 1997 Feb;109(3):342-352
references.pmid: 28307530
references.citation: Integr Comp Biol. 2004 Dec;44(6):498-509
references.pmid: 21676736
references.citation: J Evol Biol. 2010 Jun 1;23(6):1278-85
references.pmid: 20456566
references.citation: Integr Comp Biol. 2004 Dec;44(6):471-9
references.pmid: 21676733
references.citation: Physiol Zool. 1949 Oct;22(4):359-72
references.pmid: 15396613
references.citation: Oecologia. 1980 May;45(2):202-208
references.pmid: 28309531
references.citation: Oecologia. 1978 Jan;35(3):343-356
references.pmid: 28310278
references.citation: Oecologia. 1994 Sep;99(3-4):281-289
references.pmid: 28313882
references.citation: J Evol Biol. 2003 Sep;16(5):996-1005
references.pmid: 14635915
references.citation: Nature. 2008 Jul 24;454(7203):511-4
references.pmid: 18548005
references.citation: PLoS One. 2009 Nov 24;4(11):e7950
references.pmid: 19956696