Eastern monarch larval performance may not be affected by

What this paper is about

Milkweed gets tougher and less nutritious as the season goes on, so if warming pushes monarch caterpillars later relative to the plants, the caterpillars should suffer.

The authors tested that directly and found larval performance largely unaffected by the shift in timing.

Summarised here from the abstract below. Not the authors’ words.

Abstract

Interacting species are experiencing disruptions in the relative timing of their key life-history events due to climate change. These shifts can sometimes be detrimental to the fitness of the consumer in trophic interactions but not always.The potential consequences of phenological asynchrony for the monarch butterfly (Danaus plexippus) and its host plant (Asclepias spp.) have not been well-studied. Given that plants generally undergo seasonal declines in quality, if climate change delays the timing of the larval stage relative to the availability of younger milkweed plants, monarch performance could be negatively affected.Here, we explore the potential consequences for the eastern monarch population due to probable asynchrony with milkweed. We used field surveys around Ottawa, Canada, to determine monarch oviposition preference on common milkweed (Asclepias syriaca) plants and the seasonal availability of these plants. To determine the potential fitness consequences when females oviposit on nonpreferred plants, we conducted a field experiment to assess the effect of milkweed size on monarch larval performance (e.g., development time and final size).Preferred oviposition plants (earlier stages of development and better condition) were consistently available in large proportion over the summer season. We also found that declines in leaf quality (more latex and thicker leaves) with plant size did not translate into decreases in larval performance.Our results suggest that even if asynchrony of the monarch-milkweed interaction occurs due to climate change, the larval stage of the eastern monarch may not face negative consequences. Future studies should determine how the relative timing of the interaction will change in the region.

Abstract reproduced from the published paper, which is licensed CC BY. Copyright remains with the authors.

Key terms

PhenologyClimate changeDanaus plexippusoviposition preferenceAsclepias SyriacaPlant–insect Interaction

Milkweeds in this paper

Common Milkweed Asclepias syriaca

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APA

Milkweed USA. (2026). Eastern monarch larval performance may not be affected by shifts in phenological synchrony with milkweed (listing). Retrieved DATE, from https://milkweedusa.com/research/eastern-monarch-larval-performance-may-not-be-affected-by-2022/

MLA

"Eastern monarch larval performance may not be affected by shifts in phenological synchrony with milkweed (listing)." Milkweed USA, 2026, https://milkweedusa.com/research/eastern-monarch-larval-performance-may-not-be-affected-by-2022/. Accessed DATE.

Chicago

Milkweed USA. "Eastern monarch larval performance may not be affected by shifts in phenological synchrony with milkweed (listing)." Last modified 2026-08-01. Accessed DATE. https://milkweedusa.com/research/eastern-monarch-larval-performance-may-not-be-affected-by-2022/.

BibTeX

@misc{milkweedusa_researcheasternmonarchlarval,
  title  = {Eastern monarch larval performance may not be affected by shifts in phenological synchrony with milkweed (listing)},
  author = {{Milkweed USA}},
  year   = {2026},
  url    = {https://milkweedusa.com/research/eastern-monarch-larval-performance-may-not-be-affected-by-2022/},
  note   = {Accessed DATE}
}