by Graduate Research Assistant Dennis Aubrey

Over 3500 caterpillars were at Mission Creek, waiting to be released

Diapause Survival

Congratulations and thanks are in order for the Taylor’s checkerspot butterfly technicians and staff at Mission Creek Corrections Center for Women (MCCCW), and everyone else who supports the program at Evergreen, the Washington Department of Fish and Wildlife (WDFW), the US Fish and Wildlife Service (USFWS), and the Oregon Zoo. To recap, last season we produced 3624 eggs, which was 180% of our target, then the caterpillars that hatched from those eggs reached summer diapause with 96.6% survivorship. For eight months they have been sleeping in small insect cups beneath overturned terra cotta pots, but now they are awake again and the numbers are in: 98.9% diapause survival.

Fifteen Taylor’s checkerspot caterpillars waiting to be released

After spending the summer being pampered by the inmate technicians at Mission Creek, the bulk of our caterpillars were transported to the established diapause facility at the Oregon Zoo. Five hundred were left behind as a trial group since it was our first season and we wanted to test the over-winter conditions at the greenhouse before risking a whole cohort. Of those five hundred, 100% survived! As always, our success is a credit to the meticulous, dedicated, and compassionate care provided by the inmate technicians. Every step of the way they have gone the extra mile, checking every detail twice as often as required, keeping records that no one ever asked them to take, and proving with every stage’s success that the faith placed in their abilities by our partners was well warranted.

Two teams releasing caterpillars at Glacial Heritage Preserve, near Littlerock, Wa

Post-diapause release

About 3400 of our federally threatened caterpillars are now munching leaves on the prairies at Glacial Heritage Preserve and Scatter Creek Wildlife Area, raising the total number of animals released the butterfly program at MCCCW from 701 to over 4000! Our biggest release of the year is just a week after diapause wake-up, so we had a wild week at MCCCW trying to feed breakfast to so many animals. Our supply of food plants was dwindling rapidly, but relief was in sight: sunny weather was forecast for Monday, March 4. We filled up seven coolers with caterpillar cups and sent them out to the prairie. Once there, a team of about ten biologists, students, and volunteers spent the day crawling backwards from host plant to host plant depositing 2-5 caterpillars on each one. It’s a painstaking process, but it’s important to make sure that the animals have enough host plant material to give them a good chance of making it to pupation, sometime in April.

SPP Graduate Research Assistant Dennis Aubrey helping caterpillars find new homes

Just 185 caterpillars remain in the captive colony at MCCCW. These are considered our “backup breeders”. We will raise them to adulthood so that we can rely on them for eggs if anomalous weather or some other unforeseen event causes wild populations to crash. Every year we aim to produce a new generation from wild-caught females, but the colony of backup breeders is arranged to maintain maximum possible genetic diversity for as long as possible just in case. The butterfly technicians at MCCCW are out there every day taking care of those 185 special recruits, giving them fresh leaves and raising them up like athletes in case they have to pitch in to help save their species.

Taylor’s checkerspot caterpillars enjoying some tasty leaves after being released