Do Invasive Jorō Spiders (Trichonephila clavata) from Asia Avoid Eating Unpalatable Monarch Butterflies (Danaus plexippus) in North America?
Davis AK, Morris WT, Hobbs E and others. Insects, April 2024.
Read the paper Free to read · doi:10.3390/insects15050309
What this paper is about
The joro spider arrived in Georgia from east Asia and is spreading. It has never encountered monarchs, so it has had no opportunity to learn that they are poisonous.
The authors staged encounters at sites in northeast Georgia to see whether the spider rejects them anyway.
Summarised here from the abstract below. Not the authors’ words.
Abstract
An invasive spider from East Asia has established in the U.S. southeast (the "jorō spider," Trichonephila clavata) and is rapidly expanding its range. Studies assessing the impact of this species are needed, including how expansive its diet is. An open question is whether monarch butterflies, Danaus plexippus, are a potential prey item for this spider, given that jorō spiders do not coexist with monarchs in their native range. Since monarch larvae feed on milkweed, they sequester cardiac glycosides into their adult tissues, rendering them unpalatable to many predators. At sites within northeast Georgia, we staged a series of trials (n = 61) where we tossed monarchs into jorō spider webs and, for comparison, performed similar trials with another aposematic species, gulf fritillary (Agraulis vanilla), and a palatable species, tiger swallowtail (Papilio glaucus). We recorded the outcome of the trials, which included whether the spider attacked or did not attack the prey. We also conducted a visual survey during the same fall season to look for evidence of jorō spiders consuming monarchs naturally. Our findings revealed that jorō spiders avoided eating monarchs; spiders only attacked monarchs 20% of the time, which was significantly less than the attack rates of similarly sized or larger butterflies: 86% for gulf fritillaries and 58% for tiger swallowtails. Some jorō spiders even removed monarchs from their webs. From our visual surveys of the surrounding area, we found no evidence of natural monarch consumption and, in general, butterflies made up only a fraction of the jorō spider diet. We conclude that jorō spiders appear to recognize monarch butterflies as being unpalatable, even without having a prior history with the species. This invokes questions about how these spiders can immediately recognize their unpalatability without touching the butterflies.
Abstract reproduced from the published paper, which is licensed CC BY. Copyright remains with the authors.
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title = {Do Invasive Jorō Spiders (Trichonephila clavata) from Asia Avoid Eating Unpalatable Monarch Butterflies (Danaus plexippus) in North America? (listing)},
author = {{Milkweed USA}},
year = {2026},
url = {https://milkweedusa.com/research/do-invasive-joro-spiders-trichonephila-clavata-from-asia-avoid-2024/},
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