An international consortium has sequenced one of the first genomes of a moth
from the superfamily Noctuoidea: Spodoptera frugiperda, or fall armyworm.
Unlike majority of herbivorous insects, the armyworm is highly polyphagous
and attacks over one hundred plant species, including maize, rice, sorghum,
cotton, and soybean.
The research team first analyzed a group of genes involved in the
recognition of host plants which allows them to feed or lay their eggs. The
researchers found an expansion in the number of genes (230 versus 45-74 in
other Lepidoptera) encoding a certain type of taste receptor. They found
these receptors located on the moth's trump (proboscis) or under their legs,
which allows insects to detect toxins or bitter compounds produced by
plants. The only insect known to have such taste receptor expansions is the
red flour beetle, which also attacks a wide range of foods.
The researchers discovered expansions in two of the four major gene families
for detoxification (encoding cytochrome P450s (CYP) or
glutathione-S-transferases (GST). These genes are for resistance to
pesticides. The team also described a group of genes involved in digestion
of plant tissues.