Micro- and Macroevolutionary Trade-Offs in Plant-Feeding Insects

Area of Science:

• Evolutionary Biology
• Ecology
• Insect-Plant Interactions

Background:

• A prevailing hypothesis suggests insects specialize on hosts due to trade-offs in adaptations.
• Empirical evidence for these micro- and macroevolutionary trade-offs remains limited.
• Host use evolution may be influenced by epistasis and historical contingency.

Purpose of the Study:

• To investigate micro- and macroevolutionary correlations of host-plant use in Lepidoptera (caterpillars) and Hemiptera (true bugs).
• To determine if host-use trade-offs are universal constraints or historically contingent.
• To assess the role of negative versus positive interactions in insect host-plant evolution.

Main Methods:

• Phylogenetic comparative methods were employed.
• Analysis of host-plant use correlations across 1,604 Lepidoptera and 955 Hemiptera species.
• Examination of host-plant use across 11 major plant orders.

Main Results:

• Lepidoptera showed mixed positive and negative correlations, indicating varied constraints across evolutionary timescales.
• Hemiptera exhibited consistently positive correlations between host-plant use across both timescales.
• Few negative correlations were observed overall, contrary to the trade-off hypothesis.

Conclusions:

• Host-use trade-offs are not universal constraints but appear historically contingent.
• Positive interactions between host-use adaptations seem to be more prevalent than trade-offs in insect evolution.
• This challenges the long-standing hypothesis on insect specialization driven by negative interactions.