To each their own! Nectar plasticity within a flower mediates distinct ecological interactions

Area of Science:

• Ecology
• Plant-Animal Interactions
• Chemical Ecology

Background:

• Nectar plays a crucial role in plant-pollinator mutualisms, with well-understood traits.
• Less is known about nectar traits in other mutualisms, such as ant-plant interactions, especially when nuptial and extranuptial nectaries coexist within the same flower.

Purpose of the Study:

• To investigate if nectar secreted by nuptial and extranuptial nectaries exhibits distinct chemical features tailored to different floral visitors.
• To compare nectar secretion dynamics, visitor composition, and chemical profiles of both nectary types in *Amphilophium mansoanum*.

Main Methods:

• Field observations of floral visitors to nuptial and extranuptial nectaries.
• Characterization of nectar composition (sugars, amino acids, specialized metabolites) using high-performance liquid chromatography.
• Comparison of nectar volume, concentration, sugar content, and secretion dynamics.

Main Results:

• Nuptial nectaries were primarily visited by bees, while extranuptial nectaries attracted ants, cockroaches, wasps, and flies.
• Nuptial nectar was sucrose-dominated with specific amino acids (GABA, BABA) and a theophylline-like alkaloid.
• Extranuptial nectar was hexose-rich with a diverse amino acid profile (serine, alanine) and higher tyramine content.

Conclusions:

• Nectar traits from nuptial and extranuptial nectaries differ in energy, nutritional value, and specialized metabolites.
• These differences align with the requirements of distinct floral visitors, suggesting selective pressures shaping nectar composition.