Rehydration is a specialized process in entomology that restores flexibility to the dried tissues of an insect specimen, making it pliable for mounting and display. This step is necessary because dried butterfly tissues become extremely brittle, causing the antennae, legs, and wings to snap off when manipulated. The procedure involves introducing moisture back into the dried body and wing muscles. A properly rehydrated specimen will have wings that can be gently flexed and positioned on a spreading board for permanent preservation.
Essential Tools and Setup
Assembling the necessary materials creates a controlled environment for reintroducing moisture. The main component is an airtight container, such as a plastic box or Tupperware, which serves as the rehydration chamber. Inside, a damp material, such as a soaked sponge, wet cloth, or layered paper towels, generates high humidity. A layer of material, like plastic mesh or Styrofoam, is needed to suspend the butterfly above the wet surface.
Anti-mold or anti-fungal agents are recommended, as high humidity promotes mold growth that can destroy the specimen. Common preventative agents include moth crystals (naphthalene) or chloro-cresol crystals, placed within the chamber away from the butterfly. Other necessary items for the subsequent pinning stage include entomological pins, specialized insect pinning forceps, and a dedicated spreading board.
Constructing and Using the Rehydration Chamber
To construct the rehydration chamber, a layer of damp material is placed at the bottom of the airtight container. If using water, many enthusiasts prefer hot or boiled water, as the resulting steam and increased evaporation rate speed up the rehydration process. The anti-mold agent is then placed around the perimeter of the damp material to inhibit fungus growth on the specimen.
A non-absorbent barrier, such as plastic screening or Styrofoam, is placed above the damp layer to prevent the specimen from directly contacting the water source. Direct contact with saturated material can ruin the delicate wing scales and cause decomposition. The dried butterfly is placed on this barrier, often still enclosed in its paper triangle envelope with the corners clipped to allow moisture penetration.
The container is sealed, and the specimen rehydrates in the humid environment for a period depending on its size. Smaller butterflies may become pliable within 24 hours, while larger specimens like swallowtails or birdwings may require 48 to 72 hours. Monitor the chamber regularly and remove the specimen immediately once the wings become flexible to prevent mold or decomposition.
Handling and Pinning the Rehydrated Butterfly
Once the specimen is removed from the chamber and its wings are flexible, it is ready for pinning. Handling should be done with insect forceps, gripping the thorax or the thickest part of the wings near the body to avoid rubbing off the colorful scales. The primary insect pin, typically a size #2 or #3, is inserted vertically through the center of the thorax, ensuring it passes straight through the body.
The pinned butterfly is then placed onto the spreading board, pushing the pin into the central groove until the bases of the wings are level with the board’s surface. The wings are positioned using a fine-tipped insect pin or needle, placed just behind a strong vein on the forewing, and carefully pulled forward. The goal is to move the forewing until its rear margin forms a 90-degree angle with the body.
To secure the wings in this position, narrow strips of wax paper or glassine are laid over them and pinned down on the board. Make sure the pins go through the paper and into the board, not through the wing itself. The hindwing is then moved forward so its leading edge slightly overlaps the base of the forewing, and it is also secured with paper strips and secondary pins. The antennae and abdomen may also be temporarily secured with small pins to achieve the desired final pose.
Final Drying and Display Preparation
After the wings and body are positioned and secured on the spreading board, the specimen must be allowed to dry completely. This drying phase is where the butterfly’s tissues harden into the desired display position. The required duration varies based on the specimen’s size and local humidity, typically ranging from one to three weeks.
The specimen should be left undisturbed in a warm, dry area away from pests and direct sunlight. After the drying period, the wings will feel rigid and fixed in place when the restraining strips are gently tested. All secondary pins and paper strips are carefully removed before the butterfly is lifted by the main pin for transfer to a permanent display case. The final display may be a shadow box or a Riker mount, where the pin is pushed into the foam or cork backing for long-term preservation.