The Chrysalis Incubator

At Settlers Lifestyle Village in Albany the residents got together and under the leadership of Doug Robertson, built a butterfly house with the support of management, the Blokes Shed (part of the Menz Shed network) and the community.

Everyone was very busy over the summer months with monarch butterflies being released consistently.

Doug and Sandy Robertson with Jacqui Knight

Bill Larsen, retired engineer, took action into his own hands to save the last of the monarchs the first season. Read his story:

During April and May 2024 our Butterfly House at Settlers continued to cater for caterpillars, and butterflies that eclosed were released. However, the weather for the latter half of April and May was unkind for monarchs.

April and May 2024 in Auckland was notably colder than usual. In April we experienced unseasonable weather, significant temperature fluctuations and unusual weather patterns. May started with a significant cold front and was characterised by unseasonably cold temperatures throughout. Several weather systems brought heavy rain, strong winds, and thunderstorms, particularly in the early weeks. There were instances of temperatures dropping considerably, with daytime highs falling by as much as 8°C in some areas. These conditions were a marked departure from the typical mild autumn weather Auckland usually experiences. (ChatGPT -edited)

On 14 May, another keen butterfly-lover, Vic Edwards, raised concerns about the chrysalides in the butterfly house that were subject to ongoing cold night-time temperatures, and more wet weather was due to arrive the next day. We agreed to immediately transfer chrysalides, as well as one caterpillar in J-stage and two sick-looking caterpillars, to my large incubator.

We found thirteen chrysalides attached to the frame of the butterfly house and six to swan plant leaves. The chrysalides buttoned to the frame were carefully detached using a small wire cutter and placed temporarily in a padded container together with those buttoned to leaves. Later that afternoon, I superglued the thirteen detached chrysalides to string and tied them to the frame in the incubator so that they hung as if they had buttoned themselves.

I obtained cuttings of swan plants and placed them in water-filled jars together with the cuttings that had chrysalides attached. The two sick caterpillars never ate, one became very agitated, but both faded away.

The incubator was placed outside on our balcony during sunny and warmer days and always taken inside at night to ensure the chrysalides would not endure low temperatures.

From 15 May, when the J-stage caterpillar formed its chrysalis, to 2 June when it eclosed (a period of 18 days) there were 18 eclosures and one that died in its chrysalis. In all there were only seven healthy eclosures – two males and five females, the others having defects that disabled them to form and fully expand their wings. These butterflies could not fly, most had difficulty in hanging on to anything and were euthanised.

The J-stage caterpillar demonstrated the success of the incubator as this caterpillar’s metamorphosis was not compromised. However, our overall success rate was a little more than one-in-three, with the low daily temperatures before transfer to the incubator the likely cause of failures.

Even though being a little late in the season, the transfer was worthwhile producing 7 monarchs to winter over. Otherwise, it is probable all would have perished if they had been left in the butterfly house.

Note:  When I realised that the butterflies could not climb up the string, I adapted that part of the process.