Complex sentence: The milkweed plant supplies poisonous glycosides which render both caterpillar and imago Danaids noxious, and the Heliconid caterpillars feed on poisonous "Passiflora" vines.
Split into simpler sentences: The milkweed plant supplies poisonous glycosides which render both caterpillar and imago danaines noxious. Heliconiine caterpillars feed on poisonous "Passiflora" vines.