Species-specific, age-varying plant traits affect herbivore growth and survival.

Seasonal windows of opportunity represent intervals of time within a year during which organisms have improved prospects of achieving life history aims such as growth or reproduction, and may be commonly structured by temporal variation in abiotic factors, bottom-up factors, and top-down factors. Although seasonal windows of opportunity are likely to be common, few studies have examined the factors that structure seasonal windows of opportunity in time. Here, we experimentally manipulated host-plant age in two milkweed species (Asclepias fascicularis and Asclepias speciosa) in order to investigate the role of plant-species-specific and plant-age-varying traits on the survival and growth of monarch caterpillars (Danaus plexippus). We show that the two plant species showed diverging trajectories of defense traits with increasing age. These species-specific and age-varying host-plant traits significantly affected the growth and survival of monarch caterpillars through both resource quality- and quantity-based constraints. The effects of plant age on monarch developmental success were comparable to and sometimes larger than those of plant-species identity. We conclude that species-specific and age-varying plant traits are likely to be important factors with the potential to structure seasonal windows of opportunity for monarch development, and examine the implications of these findings for both broader patterns in the ontogeny of plant defense traits and the specific ecology of milkweed-monarch interactions in a changing world

Data from: Adaptation to an invasive host is driving the loss of a native ecotype

Locally adapted populations are often used as model systems for the early stages of ecological speciation, but most of these young divergent populations will never become complete species. The maintenance of local adaptation relies on the strength of natural selection overwhelming the homogenizing effects of gene flow; however, this balance may be readily upset in changing environments. Here I show that soapberry bugs (Jadera haematoloma) have lost adaptations to their native host plant (Cardiospermum corindum) and are regionally specializing on an invasive host (Koelreuteria elegans), collapsing a classic and well-documented example of local adaptation. All populations that were adapted to the native host-including those still found on that host today-are now better adapted to the invasive host in multiple phenotypes. Weak differentiation remains in two traits, suggesting that homogenization across the region is incomplete. This study highlights the potential for adaptation to invasive species to disrupt native communities by swamping adaptation to native conditions through maladaptive gene flow

Experiment 3: Measuring the plastic effect of rearing host on adult morphology

Data collected from lab trials for J. haematoloma reared on the hosts K. elegans and C. corindum. This file includes data on morphology (beak length, thorax width, wing length), development time, sex, family, and ancestral location (population, latitude, host plant). Data is also included in this file for individuals from a third ancestral host, C. microcarpum, that is not reported on in the manuscript

Experiment 2: Testing natural selection in the field

Data collected during field feeding trials for J. haematoloma on open and closed seedpods of C. corindum in Key Largo, FL in April 2014. This file includes data on morphology (beak length, thorax width, wing morph), feeding activity (latency time, feeding time), and flight ability. Seedpod treatments are abbreviated C and O (for closed and open pods). The flight.test column indicates whether or not flight behavior was observed when individuals were gently tossed into the air three times. Columns F1-F16 indicate whether or not an individual was observed feeding at each time point during the feeding trial; these are ordered chronologically

Simulated development time code

This file includes: 1) Code for data extraction of development times from Figure 3 of Carroll et al 1997; note that the exact pixel values will differ depending on how you size and crop the image. 2) Code for simulating 1000 (or however many you want) datasets using the means and standard deviations of 1988 and 2013-2014 data. 3) Code for statistical comparison of all 1000 datasets for the complete dataset and within each host plant. Code for model selection is not included (but could be added if requested)

J.haematoloma survival in 2014 (F1, cross-rearing experiment)

Survival data for J.haematoloma in cross-rearing experiment conducted on F1 laboratory generation in 2014. Column heading interpretation: Number=individual identifier (because the datasheet was generated before hatching, some numbers were not used for individuals that never hatched); Family=maternal identifier (field-collected, paternity uncertain); bug.pop=location, either city or island name, from which the parents of that individual were collected; host.pop=location, either city or island name, from which the natal host seeds for that individual were collected; pophost=host species from which parents were collected; nathost=host species on which that individual was reared; hatch date=date the individual hatched; eclosion date=date the individual reached adulthood; death date=date an individual died if they did not reach adulthood (mortality post-adulthood was generally not recorded); sex=M for male, F for female if individuals reached adulthood. Blanks and NAs indicate data types that were not collected

J.haematoloma morphology in 1988 & 2013-2015

Morphological data from 1988 (collected by SP Carroll, first published in Carroll & Boyd 1992) and 2013-2015 (collected by ML Cenzer). Column heading definitions: pophost=host plant species from which individuals were collected in the field; population=location name (city or island name); sex=M for male, F for female; beak=length of beak in mm; thorax=width of pronotum at widest point in mm; wing=length of forewing at longest point in mm; body=length from anterior tip of tylus to distal tip of closed forewing in mm (S indicates short-winged individuals - body length measures were not taken for these); month=collection month; year=collection year. Not all measures were taken for all individuals; NAs and blanks both indicate the measure was not taken. Data from two host plants (Cardiospermum microcarpum & Koelreuteria paniculata) not reported on in the manuscript are also included in this data file

Co-evolution of dormancy and dispersal in spatially autocorrelated landscapes

The evolution of dispersal can be driven by spatial processes, such as landscape structure, and temporal processes, such as disturbance. Dormancy, or dispersal in time, is generally thought to evolve in response to temporal processes. In spite of broad empirical and theoretical evidence of trade-offs between dispersal and dormancy, we lack evidence that spatial structure can drive the evolution of dormancy. Here, we develop a simulation-based model of the joint evolution of dispersal and dormancy in spatially heterogeneous landscapes. We show that dormancy and dispersal are each favored under different landscape conditions, but not simultaneously under any of the conditions we tested. We further show that, when dispersal distances are short, dormancy can evolve directly in response to landscape structure. In this case, selection is primarily driven by benefits associated with avoiding kin competition. Our results are similar in both highly simplified and realistically complex landscapes

Seasonal windows of opportunity in milkweed-monarch interactions.

Many organisms experience seasonal windows of opportunity for growth and reproduction. These windows represent intervals in time when organisms experience improved prospects for advancing their life history objectives, constrained by the combined effects of seasonally variable biotic and abiotic conditions acting independently or in combination. Although seasonal windows of opportunity are likely to be widespread in nature, relatively few studies have conducted the repeated observations necessary to identify them or suggest the factors that structure them in time. Here, we present the results of three experimental studies conducted at different field sites in three different years in which we manipulated the phenology of monarch caterpillars (Danaus plexippus) throughout the growing season. The primary aims of these experiments were (1) to identify seasonal windows of opportunity for successful larval development on milkweed (Asclepias spp.), and (2) to suggest which factors are most likely to constrain these windows of opportunity in time. We found strong seasonal windows of opportunity in the developmental success of monarchs, with distinct periods of higher developmental prospects during each study year. We evaluated the role of seasonal variation in abiotic thermal stress, host plant density, host plant defensive traits, and natural enemy risk as potential factors that may limit seasonal windows of opportunity. By comparing the seasonal patterns of larval success and potential explanatory factors across all 3 yr, we find patterns that are consistent with seasonally variable abiotic conditions, host plant availability, host plant traits, and natural enemy risk factors. These results suggest the potential for seasonal variation in the factors that limit monarch larval development and population growth. More generally, this study also highlights the value of temporally explicit experimental studies that can identify and examine seasonal patterns in species interactions