The evolution of autotomy in leaf-footed bugs.

Area of Science:

• Evolutionary Biology
• Animal Behavior
• Genomics

Background:

• Autotomy, the voluntary shedding of body parts, is a defense mechanism observed across diverse animal taxa.
• While well-known in lizards, the evolutionary origins and diversification of autotomy remain incompletely understood.
• Independent evolution of autotomy suggests significant adaptive advantages, yet its precise functional shifts are often unclear.

Purpose of the Study:

• To investigate the evolutionary history and diversification of autotomy in leaf-footed bugs and allies (Insecta: Hemiptera: Coreidae + Alydidae).
• To determine the ancestral state of autotomy within this insect group and trace the emergence of rapid autotomy.
• To explore the ecological and morphological factors influencing the variation in autotomy rates across species.

Main Methods:

• Phylogenetic analysis integrating morphological, behavioral, and genomic data.
• Reconstruction of ancestral character states for autotomy.
• Comparative analyses to correlate autotomy rates with ecological and morphological variables (body size, geographic location, appendage enlargement).

Main Results:

• The ancestral leaf-footed bug likely exhibited slow autotomy, potentially for non-predatory escape or injury mitigation.
• Rapid autotomy (<2 minutes) evolved independently multiple times within the lineage.
• Autotomy as an anti-predatory strategy appears to be an exaptation, a co-opted benefit from its ancestral function.
• Body size, distance from the equator, and appendage enlargement significantly explain variations in autotomy rates.

Conclusions:

• Autotomy in leaf-footed bugs originated as a slow process, with rapid shedding evolving later as an exaptation for predator evasion.
• The evolution of rapid autotomy is polyphyletic, arising multiple times independently.
• Ecological and morphological factors play crucial roles in shaping the diversity of autotomy rates within this insect group.