Lepidoptera (butterflies & moths) are one of the many major insect orders. Defined by a shared presence of scales across their bodies, they are one of the most species rich and well studied group of insects. They are arguably the largest single radiation of plant feeding insects, and are vital components of our ecosystem, acting as pollinators as well as prey.
Here I'll provide a brief background and insight into the wonderful world of Lepidoptera.
Who are the Lepidoptera?
Lepidoptera are an Order of insects that include moths and butterflies. They are one of around 30 orders belonging to the Class Insecta. They group with the other holometabolous insects, which means that they undergo complete metamorphosis, with different lifestages including egg, larva, pupa, and imago (adult).
This image is a cladogram showing the relationships between all major groups of arthropods. Insects belong to Hexapoda (arthropods that have 6 legs). Within insects, the largest Orders (in terms of number of species) all belong to the holometabolous insects.
Lepidoptera are one of the largest groups of insects with ~180,000 known species in 126 families, and likely many more undescribed species.
Moths are thought to have first emerged ~250 million years ago. The order shares a common ancestor with the caddisflies (Trichoptera), which suggests that the very first moths may have been found living in humid forests with their caterpillars associated with damp soil or moss (caddisfly larvae are aquatic).
The very first moths were likely small, scaled flying insects, similar to modern day Micropterix species (left). These early lineages did not feed on nectar like most species, and instead of a proboscis they had mandibles, suitable for feeding on pollen or fern spores.
The Lepidoptera proboscis evolved with the emergence of the Glossata clade, which contains the vast majority of lepidopteran diversity. Early branching lineages in the group Eriocranioidea use their proboscis to drink water or sap, and are thought to be a precursor for the nectar feeding lineages which dominate the Order. As such, this incredible diversity is thought to have co-evolved with the emergence and diversification of flowering plants.
Phylogeny of lifestyles
Lepidoptera are not only diverse in numbers, but also diverse in life history traits. These two factors are undoubted evolutionary linked, with diversity resulting in novel behaviours and vice versa. Around 250 million years of evolution has crafted an astonishing array of feeding habits, ecological niches, and behaviours for the 126 lepidopteran families present today.