The katydid doesn't have warning coloration like monarchs do, so I wondered if katydids eat milkweed to become distasteful, so they are protected from predators.
If you think about it, being distasteful without warning coloration does no good. If the katydid is attacked, then spit out because it tastes bad, it's still dead.
So, I checked Copilot AI. I found the following (lightly edited):
Katydids are known to be generalist herbivores, meaning they munch on a wide variety of leafy plants. While they might nibble on milkweed occasionally if other food is scarce, it’s not a primary part of their diet.
Katydids don’t store milkweed toxins in the same way monarchs do. There’s no evidence that katydids become toxic to predators after consuming milkweed, even if they do ingest small amounts.
Insects that incorporate milkweed toxins
Some insects have evolved to not only tolerate milkweed’s toxic cardenolides but actually use them as a defense against predators. These species are often brightly colored—a warning sign to would-be attackers. Bright coloration that signals danger is termed aposematism.
Monarch butterfly (Danaus plexippus)
- Larvae feed exclusively on milkweed, ingesting cardenolides.
- These toxins make both caterpillars and adult butterflies distasteful or toxic to predators like birds.
Milkweed bugs (Oncopeltus fasciatus, Lygaeus equestris, Horvathiolus superbus)
- These bugs feed on milkweed seeds and store cardenolides in their bodies.
- Some species have evolved resistant Na⁺/K⁺-ATPase enzymes, allowing them to tolerate the toxins.
- Their bright red-and-black coloration warns predators of their toxicity.
Oleander aphid (Aphis nerii)
- Though not native, this aphid specializes on milkweed and accumulates cardenolides.
- Predators like spiders and lacewing larvae often avoid them due to their chemical defenses.
Queen butterfly (Danaus gilippus)
- This close relative of the monarch also feeds on milkweed and sequesters cardenolides.
- It shares similar protective traits and warning coloration.
These insects can eat milkweed because they have evolved adaptations to milkweed toxins.
- The target-site in the monarch has become insensitive to the toxin.
- Specialized tissues store (sequester) the toxins without harming the insect.
- Behavioral strategies: Some insects feed in ways that minimize exposure to latex and toxins.
These adaptations to toxins create a ripple effect:
- Predator-prey dynamics shift as predators learn to avoid toxic prey.
- Coevolution occurs—milkweed evolves stronger defenses, as the insects evolve better. countermeasures.
- Pollination and biodiversity benefit from the presence of these specialized insects.