Scientists found that butterflies tear open and drink from the bodies of Caterpillars no matter if they are dead and alive. Scientists found this in matured milkweed butterflies in North Sulawesi, Indonesia. The result is based on the examination of the micro claws. The study was published in Journal Ecology.
Male butterflies search compounds produced by milkweed, which repel predators and help the butterflies produce pheromones that attract females. The Caterpillars are stuffed with juices from chewed-up plants, and they become an easy target for butterflies that are planning to chemically boost their attractiveness to females.
These alkaloids are also used in the mating pheromones, which are transferred to females in the males’ sperm packet as a nuptial gift. The danainae family butterfly species are found in Asia, but four species live in North America, one of which is the colorful monarch butterfly. The male butterflies are called leaf-scratching, in which adults supplement the plant sap they absorb as hungry Caterpillars by scraping at milkweed leaves with their tiny claws to release alkaloid-loaded sap for drinking through their long proboscis. Sometimes males gather by the hundreds to scratch and sip on milkweed leaves.