Pictures: Non-nectar feeding butterfly Morpho peleides exhibiting brush-like structure, arrows indicate movement of proboscis (left). Monarch butterfly (right).
External features
Adult butterflies have a sucking mouthpart known as the proboscis (Powell 2009) which is made of two cylindrical chambers that enclose a food canal (Kingsolver & Daniel 1978). They feed by pumping liquid, such as nectar and honeydew (Gullan & Cranston 2010), through this tubular structure (Powell 2009). They lack mandibles and their maxillae form the long proboscis that coils when it’s not in use (Hickman et al. 2011). Butterfly feeding posture allows efficient probing of flowers of different shapes and sizes (Krenn 1997) to find a suitable flower to feed from.
Internal features
The function and operation of the proboscis is a complex feature of butterflies. The uncoiling of a butterfly’s proboscis is caused by hemolymph (insect version of blood) being pumped into the galeae. Coiling of the proboscis is controlled by the galeae muscles, which are a part of the proboscis’ structure (Krenn 1990). A sucking pump in the head allows butterflies to take up fluid in the proboscis’ food pump (Krenn 2010). This sucking pump is located between the proboscis and the esophagus and has many associated head muscles (Krenn 2010) which assist in its function. The contraction of muscles controls the transport of fluid (Krenn 2010) by the proboscis. The frontal ganglion controls the sucking pump muscles (Krenn 2010). These muscles are triggered by the presence of sucrose sensed by the proboscis (Krenn 2010) and taste receptors on the tarsi (Inoue et al. 2008).
External features
Adult butterflies have a sucking mouthpart known as the proboscis (Powell 2009) which is made of two cylindrical chambers that enclose a food canal (Kingsolver & Daniel 1978). They feed by pumping liquid, such as nectar and honeydew (Gullan & Cranston 2010), through this tubular structure (Powell 2009). They lack mandibles and their maxillae form the long proboscis that coils when it’s not in use (Hickman et al. 2011). Butterfly feeding posture allows efficient probing of flowers of different shapes and sizes (Krenn 1997) to find a suitable flower to feed from.
Internal features
The function and operation of the proboscis is a complex feature of butterflies. The uncoiling of a butterfly’s proboscis is caused by hemolymph (insect version of blood) being pumped into the galeae. Coiling of the proboscis is controlled by the galeae muscles, which are a part of the proboscis’ structure (Krenn 1990). A sucking pump in the head allows butterflies to take up fluid in the proboscis’ food pump (Krenn 2010). This sucking pump is located between the proboscis and the esophagus and has many associated head muscles (Krenn 2010) which assist in its function. The contraction of muscles controls the transport of fluid (Krenn 2010) by the proboscis. The frontal ganglion controls the sucking pump muscles (Krenn 2010). These muscles are triggered by the presence of sucrose sensed by the proboscis (Krenn 2010) and taste receptors on the tarsi (Inoue et al. 2008).