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Adaptations to "Thermal Time" Constraints in Papilio: Latitudinal and Local Size Clines Differ in Response to Regional Climate Change.

Scriber JM, Elliot B, Maher E, McGuire M, Niblack M - Insects (2014)

Bottom Line: Adaptations to "thermal time" (=Degree-day) constraints on developmental rates and voltinism for North American tiger swallowtail butterflies involve most life stages, and at higher latitudes include: smaller pupae/adults; larger eggs; oviposition on most nutritious larval host plants; earlier spring adult emergences; faster larval growth and shorter molting durations at lower temperatures.Unlike lower latitudes, the Alaska, Ontonogon, and Chippewa/Mackinac locations (for P. canadensis) showed no significant increases in D-day accumulations, which could explain lack of size change in these northernmost locations.As a result of 3-4 decades of empirical data from major collection sites across these latitudinal clines of North America, a general "voltinism/size/D-day" model is presented, which more closely predicts female size based on D-day accumulations, than does latitude.

View Article: PubMed Central - PubMed

Affiliation: Department of Entomology, Michigan State University, East Lansing, MI 48824, USA. scriber@msu.edu.

ABSTRACT
Adaptations to "thermal time" (=Degree-day) constraints on developmental rates and voltinism for North American tiger swallowtail butterflies involve most life stages, and at higher latitudes include: smaller pupae/adults; larger eggs; oviposition on most nutritious larval host plants; earlier spring adult emergences; faster larval growth and shorter molting durations at lower temperatures. Here we report on forewing sizes through 30 years for both the northern univoltine P. canadensis (with obligate diapause) from the Great Lakes historical hybrid zone northward to central Alaska (65° N latitude), and the multivoltine, P. glaucus from this hybrid zone southward to central Florida (27° N latitude). Despite recent climate warming, no increases in mean forewing lengths of P. glaucus were observed at any major collection location (FL to MI) from the 1980s to 2013 across this long latitudinal transect (which reflects the "converse of Bergmann's size Rule", with smaller females at higher latitudes). Unlike lower latitudes, the Alaska, Ontonogon, and Chippewa/Mackinac locations (for P. canadensis) showed no significant increases in D-day accumulations, which could explain lack of size change in these northernmost locations. As a result of 3-4 decades of empirical data from major collection sites across these latitudinal clines of North America, a general "voltinism/size/D-day" model is presented, which more closely predicts female size based on D-day accumulations, than does latitude. However, local "climatic cold pockets" in northern Michigan and Wisconsin historically appeared to exert especially strong size constraints on female forewing lengths, but forewing lengths quickly increased with local summer warming during the recent decade, especially near the warming edges of the cold pockets. Results of fine-scale analyses of these "cold pockets" are in contrast to non-significant changes for other Papilio populations seen across the latitudinal transect for P. glaucus and P. canadensis in general, highlighting the importance of scale in adaptations to climate change. Furthermore, we also show that rapid size increases in cold pocket P. canadensis females with recent summer warming are more likely to result from phenotypic plasticity than genotypic introgression from P. glaucus, which does increase size in late-flight hybrids and P. appalachiensis.

No MeSH data available.


Related in: MedlinePlus

An empirically-derived Model of the latitudinal trends in female forewing size and voltinism as a function of “thermal time” (Degree-day accumulations; mean from 1950–1989) from Florida at 27° N to Alaska at 65° N latitude (developmental base 50° F; =10° C). Actual observed size differences (see Table 1) of swallowtail butterfly female forewings (FW) are roughly indicated by the arrow lengths, and show a general cline of decreasing size with increasing latitude (Converse Bergmann’s Rule). In the past decade, increases of roughly 700 D-days F (=400 D-days C; see Figure 3) are represented by the relaxation (upward shift indicated) of the constraints (dotted line) [l]. Selected sites along this 3,500 km latitudinal transect are depicted annually (Figure 1), show consistency of wing lengths during the past 4 decades (Figure 6) for P. glaucus (>2,500 females) and the northernmost P. canadensis (>1,000 females). Note the univoltine “LF”hybrids and “EF” P. canadensis at 43° N latitude, and also the univoltine P. appalachiensis populations in Munroe Co. PA (40° N) and Pendleton Co. West Virginia (39° N) and Rabun & Habersham Cos. GA (36° N). These localized mountain populations have thermal constraints much greater than surrounding populations (as with the Michigan cold pockets, which realize considerably fewer thermal units locally than shown by the general 1950–1989 dotted line).
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insects-05-00199-f007: An empirically-derived Model of the latitudinal trends in female forewing size and voltinism as a function of “thermal time” (Degree-day accumulations; mean from 1950–1989) from Florida at 27° N to Alaska at 65° N latitude (developmental base 50° F; =10° C). Actual observed size differences (see Table 1) of swallowtail butterfly female forewings (FW) are roughly indicated by the arrow lengths, and show a general cline of decreasing size with increasing latitude (Converse Bergmann’s Rule). In the past decade, increases of roughly 700 D-days F (=400 D-days C; see Figure 3) are represented by the relaxation (upward shift indicated) of the constraints (dotted line) [l]. Selected sites along this 3,500 km latitudinal transect are depicted annually (Figure 1), show consistency of wing lengths during the past 4 decades (Figure 6) for P. glaucus (>2,500 females) and the northernmost P. canadensis (>1,000 females). Note the univoltine “LF”hybrids and “EF” P. canadensis at 43° N latitude, and also the univoltine P. appalachiensis populations in Munroe Co. PA (40° N) and Pendleton Co. West Virginia (39° N) and Rabun & Habersham Cos. GA (36° N). These localized mountain populations have thermal constraints much greater than surrounding populations (as with the Michigan cold pockets, which realize considerably fewer thermal units locally than shown by the general 1950–1989 dotted line).

Mentions: Forewing length data from various years (including updates from the most recent 2 very warm decades) for these populations are presented below (in Figure 6 and Table 1). These data, from key long-term sampling sites served as the basis for the empirically-derived size/voltinism/thermal landscape model presented below (Figure 7). Data for the Chippewa/Mackinac Cos. and are not presented graphically (below) due to space constraints (and also due to Ontonogon site at the same latitude), but no significant changes in forewing length through time were present its trend lines (see Figure 6, Table 1).


Adaptations to "Thermal Time" Constraints in Papilio: Latitudinal and Local Size Clines Differ in Response to Regional Climate Change.

Scriber JM, Elliot B, Maher E, McGuire M, Niblack M - Insects (2014)

An empirically-derived Model of the latitudinal trends in female forewing size and voltinism as a function of “thermal time” (Degree-day accumulations; mean from 1950–1989) from Florida at 27° N to Alaska at 65° N latitude (developmental base 50° F; =10° C). Actual observed size differences (see Table 1) of swallowtail butterfly female forewings (FW) are roughly indicated by the arrow lengths, and show a general cline of decreasing size with increasing latitude (Converse Bergmann’s Rule). In the past decade, increases of roughly 700 D-days F (=400 D-days C; see Figure 3) are represented by the relaxation (upward shift indicated) of the constraints (dotted line) [l]. Selected sites along this 3,500 km latitudinal transect are depicted annually (Figure 1), show consistency of wing lengths during the past 4 decades (Figure 6) for P. glaucus (>2,500 females) and the northernmost P. canadensis (>1,000 females). Note the univoltine “LF”hybrids and “EF” P. canadensis at 43° N latitude, and also the univoltine P. appalachiensis populations in Munroe Co. PA (40° N) and Pendleton Co. West Virginia (39° N) and Rabun & Habersham Cos. GA (36° N). These localized mountain populations have thermal constraints much greater than surrounding populations (as with the Michigan cold pockets, which realize considerably fewer thermal units locally than shown by the general 1950–1989 dotted line).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4592633&req=5

insects-05-00199-f007: An empirically-derived Model of the latitudinal trends in female forewing size and voltinism as a function of “thermal time” (Degree-day accumulations; mean from 1950–1989) from Florida at 27° N to Alaska at 65° N latitude (developmental base 50° F; =10° C). Actual observed size differences (see Table 1) of swallowtail butterfly female forewings (FW) are roughly indicated by the arrow lengths, and show a general cline of decreasing size with increasing latitude (Converse Bergmann’s Rule). In the past decade, increases of roughly 700 D-days F (=400 D-days C; see Figure 3) are represented by the relaxation (upward shift indicated) of the constraints (dotted line) [l]. Selected sites along this 3,500 km latitudinal transect are depicted annually (Figure 1), show consistency of wing lengths during the past 4 decades (Figure 6) for P. glaucus (>2,500 females) and the northernmost P. canadensis (>1,000 females). Note the univoltine “LF”hybrids and “EF” P. canadensis at 43° N latitude, and also the univoltine P. appalachiensis populations in Munroe Co. PA (40° N) and Pendleton Co. West Virginia (39° N) and Rabun & Habersham Cos. GA (36° N). These localized mountain populations have thermal constraints much greater than surrounding populations (as with the Michigan cold pockets, which realize considerably fewer thermal units locally than shown by the general 1950–1989 dotted line).
Mentions: Forewing length data from various years (including updates from the most recent 2 very warm decades) for these populations are presented below (in Figure 6 and Table 1). These data, from key long-term sampling sites served as the basis for the empirically-derived size/voltinism/thermal landscape model presented below (Figure 7). Data for the Chippewa/Mackinac Cos. and are not presented graphically (below) due to space constraints (and also due to Ontonogon site at the same latitude), but no significant changes in forewing length through time were present its trend lines (see Figure 6, Table 1).

Bottom Line: Adaptations to "thermal time" (=Degree-day) constraints on developmental rates and voltinism for North American tiger swallowtail butterflies involve most life stages, and at higher latitudes include: smaller pupae/adults; larger eggs; oviposition on most nutritious larval host plants; earlier spring adult emergences; faster larval growth and shorter molting durations at lower temperatures.Unlike lower latitudes, the Alaska, Ontonogon, and Chippewa/Mackinac locations (for P. canadensis) showed no significant increases in D-day accumulations, which could explain lack of size change in these northernmost locations.As a result of 3-4 decades of empirical data from major collection sites across these latitudinal clines of North America, a general "voltinism/size/D-day" model is presented, which more closely predicts female size based on D-day accumulations, than does latitude.

View Article: PubMed Central - PubMed

Affiliation: Department of Entomology, Michigan State University, East Lansing, MI 48824, USA. scriber@msu.edu.

ABSTRACT
Adaptations to "thermal time" (=Degree-day) constraints on developmental rates and voltinism for North American tiger swallowtail butterflies involve most life stages, and at higher latitudes include: smaller pupae/adults; larger eggs; oviposition on most nutritious larval host plants; earlier spring adult emergences; faster larval growth and shorter molting durations at lower temperatures. Here we report on forewing sizes through 30 years for both the northern univoltine P. canadensis (with obligate diapause) from the Great Lakes historical hybrid zone northward to central Alaska (65° N latitude), and the multivoltine, P. glaucus from this hybrid zone southward to central Florida (27° N latitude). Despite recent climate warming, no increases in mean forewing lengths of P. glaucus were observed at any major collection location (FL to MI) from the 1980s to 2013 across this long latitudinal transect (which reflects the "converse of Bergmann's size Rule", with smaller females at higher latitudes). Unlike lower latitudes, the Alaska, Ontonogon, and Chippewa/Mackinac locations (for P. canadensis) showed no significant increases in D-day accumulations, which could explain lack of size change in these northernmost locations. As a result of 3-4 decades of empirical data from major collection sites across these latitudinal clines of North America, a general "voltinism/size/D-day" model is presented, which more closely predicts female size based on D-day accumulations, than does latitude. However, local "climatic cold pockets" in northern Michigan and Wisconsin historically appeared to exert especially strong size constraints on female forewing lengths, but forewing lengths quickly increased with local summer warming during the recent decade, especially near the warming edges of the cold pockets. Results of fine-scale analyses of these "cold pockets" are in contrast to non-significant changes for other Papilio populations seen across the latitudinal transect for P. glaucus and P. canadensis in general, highlighting the importance of scale in adaptations to climate change. Furthermore, we also show that rapid size increases in cold pocket P. canadensis females with recent summer warming are more likely to result from phenotypic plasticity than genotypic introgression from P. glaucus, which does increase size in late-flight hybrids and P. appalachiensis.

No MeSH data available.


Related in: MedlinePlus