Macroevolution of perfume signalling in orchid bees

Area of Science:

• Evolutionary Biology
• Chemical Ecology
• Animal Communication

Background:

• Sexual signalling theory posits that both stabilising and diversifying selection drive the evolution of communication traits.
• These selective pressures maintain signal integrity within species and promote trait diversification across lineages.
• Macroevolutionary patterns of these dynamics are less understood for many signalling traits.

Purpose of the Study:

• To investigate macroevolutionary signatures of sexual signalling in neotropical orchid bees.
• To test if sexual signalling theory predicts patterns in the evolution of their chemical perfume signals.
• To explore the relationship between perfume signal evolution and species coexistence.

Main Methods:

• Analysis of macroevolutionary patterns in orchid bee perfume signals.
• Comparison of evolutionary rates between signalling and nonsignalling traits.
• Sister-pair comparisons to assess divergence and character displacement.
• Correlation analysis between perfume complexity and congener abundance.

Main Results:

• Orchid bee perfume signals exhibit high species-specificity and accelerated rates of evolution compared to nonsignalling traits.
• Perfume complexity correlates positively with the number of co-occurring congeneric species.
• Evidence suggests rapid divergence during speciation and character displacement upon secondary contact.

Conclusions:

• Macroevolutionary patterns in orchid bee perfume signals align with predictions from sexual signalling theory.
• The evolution of these chemical signals may be influenced by the high species diversity in neotropical communities.
• Findings provide insights into the macroevolution of insect sexual communication.