Butterfly Proboscis. A Biomicrofluidic System

Microfluidics involves the study and application of tiny volumes of fluid. Among other areas, research on the feeding habits of insects is important to understand the principles of fluid flow at the microscale. In this experimental study, the principles of interfacial flows were used to carefully analyze and document the feeding rates and proboscis behavior of Monarch butterflies (Danaus plexippus). The challenge is that the butterflies sip very viscous liquids. Sometimes, the pressure drop needed to support this flow is greater than one atmosphere, i.e. it is greater than that any vacuum pump could supply. Using high speed imaging and simple models, we propose a scenario of butterfly feeding which is based on capillary action. This information can be applied to better understand microfluidic principles in the insect world.