Ecological Archives M084-007-A1

Heather J. Lynch, Marc Rhainds, Justin M. Calabrese, Stephen Cantrell, Chris Cosner, William F. Fagan. 2014. How climate extremes—not means—define a species' geographic range boundary via a demographic tipping point. Ecological Monographs 84:131–149. http://dx.doi.org/10.1890/12-2235.1

Appendix A. Eleven additional figuress showing the fit of each element of the model to the empirical data available (e.g., bagworm dispersal, male and female emergence phenology, life span, and fecundity).

FigA1

Fig. A1. Bagworm dispersal data (black) and exponential kernel fit (gray, β = 0.18). Average dispersal distance is 5.5 m. Data from Ghent (1999).


 

 

FigA2

Fig. A2. Sample fits of the Gamma distribution cumulative density function to data on emergence for males (black) and females (gray) in the following latitudinal bands: (a) 38.50º–38.75º (b) 39.00º–39.25º (c) 40.00º–40.25º (d) 41.25º–41.50º.


 

FigA3

Fig. A3. Life span of male of female adult bagworms (histogram) with Weibull distribution fit (solid gray line) and Exponential distribution fit (dashed line).


 

FigA4

Fig. A4. Fecundity vs. egg mass (a) and estimated fecundity vs. latitude (b) with linear regression fits.


 

FigA5

Fig. A5. Overwinter egg mortality and logistic regression fit (Eq. 14).


 

FigA6

Fig. A6. Larval survivorship vs. larval abundance (x 1000) per 30 cm shoot. Data from Table 1 of Rhainds and Sadof (2008) and logistic fit (gray).


 

FigA7

Fig. A7. Model estimated female matelessness q* vs. empirical female matelessness q* (1:1 line shown as black line). Inset: Larval carrying capacity vs. latitudinal band as predicted by Eq. 16.


 

FigA8

Fig. A8. Pupal survivorship vs. latitude (a) and mean spring (April–May) air temperatures (b) and associated logistic fits (gray). Bagworms sampled at different sites were classified as either live or dead, based on the following criteria for dead males or females: desiccated, diseased, parasitized, or preyed upon pupa; torn, perforated bag indicating predation / parasitism.


 

FigA9 

Fig. A9. Bagworm population vs. time (top; red = female, blue = male) and Nt+1 vs Nt (bottom; female only in pink) for the southernmost latitudinal band considered.


 

FigA10

Fig. A10. Egg production (top), overwinter survivorship (middle), and female pupal survivorship (bottom) predicted by the model for climate stations along a northeast-southwest axis defined by the first principle component (PCA1) of the geographic coordinates. The solid circles are the median of the values obtained by the simulation for each weather station, and the lines range from the 2.5th and 97.5 percentiles. Sandusky, Ohio, and Fremont, Ohio (indicated by arrows in the bottom panel) are both influenced by adjacent Lake Erie. Both the model and the USDA occupancy map suggest that bagworm populations are not sustainable in this area.


 

FigA11

Fig. A11. Model-predicted egg production, female pupal survivorship, and overwinter egg survivorship for Dobbs Ferry, NY (which is predicted to go extinct; see Fig. 7) and Holtwood, PA (which persists; see Fig. 7). Years 7 and 8 are identified, showing how both sites suffer low egg production and female pupal survivorship in Year 7 but only Dobbs Ferry, NY suffers lower overwinter egg survivorship in Year 8. This Year 8 decrease in overwinter egg survivorship ultimately leads to the Dobbs Ferry, NY population declining to extinction.


 

Literature Cited

Ghent, W. A. 1999. Studies of ballooning and resulting patterns of locally contagious distribution of the bagworm Thyridopteryx ephemeraeformis (Haworth) (Lepidoptera: Psychidae). American Midland Naturalist 142:291–313.

Rhainds, M., and C. Sadof. 2008. Elements of population dynamics of bagworm (Lepidoptera: Psychidae) on hedge rows of white pine. Annals of the Entomological Society of America 101:872–880.


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