Milkweed Herbivory: Summer 2020 | MPG Ranch

Milkweed Herbivory: Summer 2020

September 28, 2020

Maggie Hirschauer describes her findings from insect surveys on MPG Ranch.

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Some insects can add milkweed to a diet that includes other plants, and a few specialize on milkweed and eat nothing else.

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The red-femured milkweed longhorn beetle (Tetraopes femoratus) mainly eats showy milkweed leaves but will also eat the buds and flowers.

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I found several longhorn beetle larvae when digging root cuttings in April.

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Small milkweed bugs (Lygaeus kalmii) feed on milkweed seeds.

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Longhorn beetles and small milkweed bugs avoid each other by feeding on different parts of the plant: roots and leaves for beetles, and seeds for bugs.

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Grasshoppers, although not milkweed specialists, take advantage of many food resources and can cause severe leaf damage when their populations boom.

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I found several egg clusters and larvae of salt marsh moth (Estigmene acrea, below) feeding on showy milkweed leaves, pods, and flowers.