Evolution of sexual conflict in scorpionflies

Area of Science:

• Paleontology
• Evolutionary Biology
• Entomology

Background:

• Sexual conflict, arising from opposing reproductive interests between sexes, significantly drives insect evolution.
• Scorpionflies (Mecoptera) are key models for studying sexual conflict due to varied mating behaviors like nuptial gifting and coercion.
• Palaeontological contributions to sexual conflict studies are limited by the scarcity of well-preserved fossils.

Purpose of the Study:

• To investigate the role of palaeontology in understanding insect sexual conflict.
• To describe and analyze three new fossil male scorpionfly specimens from Cretaceous and Eocene ambers.
• To infer mating behaviors and sexual conflict dynamics in extinct scorpionflies based on morphological evidence.

Main Methods:

• Analysis of notal and postnotal organ structures in extant and extinct scorpionflies.
• Comparison of fossil abdominal configurations with extant relatives to infer mating strategies.
• Examination of Cretaceous and Eocene amber fossils for morphological specializations related to mating.

Main Results:

• Description of three new fossil male scorpionfly taxa from Cretaceous and Eocene ambers.
• Identification of a depression in extant Panorpidae species that matches the female wing fold, suggesting a functional link.
• Fossil evidence indicates a spectrum of mating strategies, from nuptial gifting to coercive behaviors, with one Eocene specimen exhibiting extreme abdominal armature for sexual coercion.

Conclusions:

• The fossil record reveals a late (Eocene) evolution of specialized male abdominal structures in scorpionflies, indicative of oppressive mating behaviors.
• Extinct Panorpoidea exhibited a broader range of mating-related morphological specializations than previously known.
• These findings provide a deep-time perspective on the evolution of sexual conflict and mating behaviors in insects.