Meeting Abstract
The butterfly proboscis is the feeding organ for acquiring liquid food from a rich variety of sources. It consists of a pair of C-type fibers, called galeae, which are developed separately in the pupa and when the butterfly emerges from it, these two galeae are still separated. The insect uses an evolved process to bring the galeae together, unite and lock them in place. It has been proposed that saliva glues the galeae together. However, recent analysis of rheological properties of saliva showed that it does not possess any visco-elastic properties or sliminess, suggesting that the lepidopteran saliva is almost inviscid and cannot supply the forces needed to hold the galeae together. We hypothesize that the saliva meniscus is used by Lepidoptera to bring and hold the galeae together while locking the legulae in place. In this research, we applied the Micro CT technology to experimentally study the configuration of the liquid bridge formed between the separated galeae. Based on the experimental observations, we constructed a biomechanics model to describe the meniscus configuration in separated galeae. The image analysis of meniscus profiles confirms the model predictions. The model also suggests that the capillary force induced by this meniscus is sufficient to hold the galeae together.
