The transition to flying insects: lessons from evo-devo and fossils

Area of Science:

• Evolutionary biology
• Paleontology
• Developmental biology

Background:

• Insect flight is a key innovation driving their evolutionary success.
• The fossil record for the transition from nonflying to flying insects is incomplete.
• Evolutionary developmental (evo-devo) studies and paleontology offer complementary evidence.

Purpose of the Study:

• To review recent advances in understanding insect wing origins.
• To integrate evo-devo and paleontological findings.
• To identify future research directions in insect evolution.

Main Methods:

• Analysis of fossil evidence from the Paleozoic era.
• Examination of developmental genetics and gene expression patterns (evo-devo).
• Integration of data from both paleontological and evo-devo approaches.

Main Results:

• Recent studies support a hypothesis where an ancestral exite (leg outgrowth) incorporated into the body wall contributed to wing formation.
• Paleontological evidence indicates lateral body outgrowths in the thorax and abdomen served as early wing precursors, possibly for respiration.
• The debate on insect wing origin is reframed by locating an ancestral precoxa leg segment with an exite within the hexapod lateral tergum.

Conclusions:

• The evolution of insect wings is a complex process involving the integration of ancestral leg structures and body wall tissues.
• Understanding the role of pleuron and tergum tissues is crucial for wing evolution.
• Future research should address the evolution of metamorphic development in insects.