I asked several questions. One was about the photos we took of butterflies eating from dead deer
and dead snake
The proboscis is made up of 2 parts (each is a galea) that zip together after the adult emerges from the pupa. You may have seen this on the monarch. When it emerges, the proboscis consists of 2 strands, but it soon begins to coil and uncoil these and the two parts fuse into 1. Each galea has a groove, that when the 2 are fused, the groove forms the food canal (the central hole in your photo). Inside each galea there is a trachea (the smaller tube in your photo) as well as a nerve and muscles. Here is a link with a diagram
that may help.
Butterflies and moths can only feed on liquids or liquids containing particles small enough to fit through the food canal. Zebra Heliconians are unusual in that they can feed on pollen by gathering a ball of pollen on the tip the proboscis and reguritating digestive juices that break down the pollen enough to ingest it. Other butterflies may also spit and slurp such as the Gulf Fritillary feeding on the dead deer. Butterflies will often squirt water from the rear end onto the sand, mud, or bird droppings, and sip up the minerals. Apparently, the digestive tract removes the minerals while water etc goes through the rear.
The proboscis is made up from two galeae (projections of the maxilla) that zip together to form a single tube or food channel. But the galeae have muscles, trachea, nerves and an open circulatory system. The rubbery protein that makes up the galeae keeps the proboscis coiled up. Blood forced into the galeae uncoils it. ...the tubes in your photograph are ... trachea ... bringing oxygen into the proboscis.
Butterflies can only suck up fluids. They do have salivary glands. They don't have saliva tubes in the proboscis but they can eject a drop of saliva to dissolve solid food.
Dr. Wayne Wehling
Regarding feeding on more viscous liquids ... it is similar to flies where they are regurgitating liquid onto the substrate only to suck it back up when nutrients have dissolved in the spit.
Heartfelt thanks to the following special people who graciously took their time to offer direct information, book suggestions, and web links to 'educate' me. I was lost in the land of confusion after taking the cross-cut photograph until they pulled me out.
Book names are linked to Amazon to help you locate these books for a low price.
Names are in alphabetical order:
Amy Casselman - University of Massachusetts Monarch Migration Studies
Dr. Jaret Daniels - University of Florida - Author or co-author of several books including Your Florida Guide to Butterfly Gardening: A Guide for the Deep South (Published in Cooperation With the Institute of Food and Agricultural Sciences)
, Butterflies of Florida Field Guide (Our Nature Field Guides)
as well as field guides to several other states
Dr. Frank Davis - Mississippi State University, home of the Insect Rearing Workshop
, a fantastic learning opportunity for anyone who is rearing insects in mass production
Jeffery Hanson; Vivarium Assistant Manager Butterfly Rainforest
at the Florida Museum of Natural History, Gainesville, FL
Marc Minno (author or co-author of several fantastic butterfly books including the two that we use more than any other books for butterfly and larvae identification and information; Florida Butterfly Gardening: A Complete Guide to Attracting, Identifying, and Enjoying Butterflies
, Florida Butterfly Caterpillars and Their Host Plants
, and Butterflies through Binoculars: A Field, Finding, and Gardening Guide to Butterflies in Florida (Butterflies and Others Through Binoculars Field Guide Series,)
Ba Rae (authored or co-authored several books including Milkweed, Monarchs and More: A Field Guide to the Invertebrate Community in the Milkweed Patch
, Monarch! Come Play with Me
Dr. Chip Taylor - Monarch Watch
, University of Kansas
Dr. Wayne Wehling - USDA APHIS