Question

Herbivory (plant eating) has evolved repeatedly in insects, typically from meat-eating or detritus-feeding ancestors (detritus is dead organic matter). Moths and butterflies, for example, eat plants, whereas their “sister group” (the insect group to which they are most closely related), the caddisflies, feed on animals, fungi, or detritus. As illustrated in the following phylogenetic tree, the combined moth/butterfly and caddisfly group shares a common ancestor with flies and fleas. Like caddisflies, flies and fleas are thought to have evolved from ancestors that did not eat plants. There are 140,000 species of moths and butterflies and 7,000 species of caddisflies. State a hypothesis about the impact of herbivory on adaptive radiations in insects. How could this hypothesis be tested?

Short answer

The Caddisflies are genetically related to flies but prefer to feed on animals, fungi, and detritus. It can be a hypothesis that the caddisflies evolved from common non-herbivorous ancestors. The insects underwent adaptive radiation depending on their habitat condition.

The change in the ancestral habitat would have changed with an abundance of plants. Hence a random event of genetic drift would have occurred.

In support of natural selection, the herbivorous population spread to different plant-dominated habitats. This would have led to the evolution of herbivorous flies from non-herbivorous ancestors. One can test the hypothesis by observational and comparative observation.

Step-by-step solution

Feeding habits

The organisms that use plants as their primary and sole nutrient source are called herbivores. These organisms can digest the complex sugar obtained from the plants.

Herbivory is seen in certain animals and insects. While carnivores feed on other animals, the herbivores stick to plants and their products. Organisms adapt to various feeding habits due to their adaptation.

Hypothesis regarding the evolution of herbivorous insects

One can hypothesize that the change in the habitat attributed to the creation of a new plant-eating population that was later naturally selected. The increase in the plant-eating flies compared to the animal and fungus-eating Caddisflies support the hypothesis for the natural selection of plant-eating flies.

Testing the hypothesis

One can follow several approaches; one of the approaches is thecomparative method.The evolutionary and phylogenetic analyses can be made to determine the common ancestors of the plant-eating flies such as moths and butterflies and non-herbivorous insects such as Caddisflies.

One can see that the varied diversity of moths and butterflies show their higher natural selection.