Are butterflies beneficial insects or pests? A comprehensive analysis of their merits and faults

Butterflies are the collective name for animals of the suborder Rhopalocera, order Lepidoptera, class Insecta, phylum Arthropoda. There are about 14,000 species worldwide, most of them distributed in the Americas, with the greatest variety especially in the Amazon River basin. China has 1,200 species. They are brightly colored, with many stripes on their bodies and rich colors, and their wings and bodies have various markings. Let us take a look below at whether butterflies are beneficial insects or pests!

Are butterflies beneficial insects or pests

Butterflies are pests during the larval stage because they chew on plants, and they are beneficial insects during the adult stage because they pollinate plants through flight. In fact, there are not many species that cause material damage to humans, such as the rice skipper and the rice-eye butterfly that harm rice, the cabbage white that harms cruciferous vegetables (cabbage), the jade-banded swallowtail and the citrus swallowtail that harm citrus, the camphor swallowtail that damages camphor trees, and the common emigrant that damages siamese senna. The vast majority of butterflies are beneficial, such as pollinating plants, maintaining ecological balance, and beautifying nature. If there were no butterflies and bees on Earth, there would be no brightly colored flowers, and the land would lose its luster. In addition, there is the aphid-eating hairstreak that feeds specifically on aphids, as well as other species that can be used for medicine or food.

What do butterflies eat?

1. Larvae: The feeding targets of butterfly larvae vary by species. Most larvae feed on leaves. Some species, such as the pollen butterfly and the orange-banded orange-tip, feed on flower buds. Some species bore into tender pods or young fruits, for example, the pea hairstreak bores into tender bean pods, and the gardenia hairstreak bores into young gardenia fruits. In addition, among the Lycaenidae, a few species of larvae are carnivorous. For example, the coffee mealybug hairstreak feeds on coffee mealybugs, and the bamboo aphid hairstreak feeds exclusively on bamboo aphids. Such carnivorous species are rare beneficial insects among butterflies.

2. Adults: Most butterflies feed on nectar. As for butterflies that feed on nectar, they not only feed on nectar but also prefer the nectar of certain specific plants. For example, the blue swallowtail prefers the nectar of Liliaceae plants, the cabbage white prefers the nectar of cruciferous plants, and the leopard lacewing prefers the nectar of Asteraceae plants, and so on. Some butterflies that do not feed on nectar include the bamboo-eye butterfly, which feeds on the sap of Ficus carica, and the pale purple emperor, which feeds on the sour sap of diseased oak and poplar trees. Some butterflies also feed on the flesh of grapes, and butterflies are commonly seen feeding in grape fields.

The growth process of butterflies

1. Egg: Butterfly eggs are generally round or oval, with a waxy shell on the surface to prevent water evaporation, and a small pore at one end, which is the passage for sperm to enter. The size of butterfly eggs varies greatly among different species. Butterflies generally lay their eggs on the leaf surfaces of plants that the larvae like to eat, preparing food for the larvae.

2. Larva: After the larva hatches, it mainly feeds, eating large amounts of plant leaves. Larvae have diverse shapes, mostly fleshy worms, and a few are caterpillars. Butterflies mainly harm agriculture during the larval stage. As the larva grows, it generally goes through several molts.

3. Pupa: After the larva matures, it turns into a pupa. The larva generally attaches itself in a concealed place on the underside of plant leaves with a few threads, and then directly pupates, without a cocoon.

4. Adult: After the pupa matures, it breaks out of the shell, but it needs a certain amount of time for its wings to dry and harden. At this time, the butterfly cannot avoid natural enemies, and this is a dangerous period. After the wings spread out, the butterfly can fly. The forewings and hindwings of butterflies flap asynchronously, so butterflies fluctuate greatly when flying, with graceful postures. The so-called “dancing lightly” comes from the flight of butterflies. Generally, adult butterflies die before winter arrives after mating and laying eggs, but some species migrate south to spend the winter.