One of the things that sets Wildlife Preservation Canada apart from other conservation organizations is that we focus heavily on hands-on initiatives for critically endangered species. This means that our recovery strategies build upon a framework that is anchored by our conservation breeding programs. Our recovery programs for the Taylor’s checkerspot butterfly and for bumble bee species at-risk have challenged the teams in our Native Pollinator Initiative to pioneer new techniques in the realm of captive breeding for arthropods—an approach to conservation that has been highlighted in the long-term recovery strategies of these and closely related species at-risk.
Pioneering new techniques and refining existing protocols in conservation breeding for these pollinator species has been, and continues to be, a meticulous and challenging endeavour for our staff, and for the many husbandry technicians who support them. But, leading the way in these programs is our specialty, and every year, we develop new strategies that help us increase the overall success of our conservation programs.
If you’re an avid follower of our blogs and e-news then you’ve been by our side through our many successes and challenges. However, sometimes we get so caught up in our progress that we forget to take step back and bring in the full picture. With that, we think it’s about time we give you a sneak-peek behind the scenes of a conservation breeding program of a rare and wonderful species – the Taylor’s checkerspot butterfly. Enjoy!
There is no quick and easy way to detail the husbandry that goes into a conservation breeding program, but we’re going to try by giving you a look at some major milestones in the life cycle of the Taylor’s checkerspot butterfly, a critically endangered species that is found only along the coast of Washington, Oregon, and British Columbia. Another day, we’ll give you a similar glimpse at conservation breeding milestones for the yellow-banded bumble bee in Ontario—you’ll see just how different, and species-specific, these programs are!
Taylor’s checkerspot butterfly (Euphydryas editha taylori)
The fun thing about the Taylor’s checkerspot butterfly is that its life cycle is quite unique. Because each life stage can be collected from the field, a conservation breeding program can be initiated at any of these stages. This gives Wildlife Preservation Canada’s team an opportunity to explore each of these stages in more detail, and every year we move closer and closer to improving our understanding of which stages are most vulnerable. We are then able to determine potential reasons as to why the species might be so threatened.
Regardless of whether or not an individual has been sourced from the wild population or has been born in the program, each of the life stages has its own unique husbandry needs, and some stages can be quite finicky! The Taylor’s checkerspot butterfly is unique because it lays its eggs in clusters. Egg clusters are harvested with a portion of the host plant, and together they are transferred to the conservation breeding facility. Egg clusters on host plants are placed in a hatching unit, and environmental conditions are kept just right to allow the eggs to develop. Each egg will develop over two to three weeks, and when it is ready to hatch, it will usually turn from yellow to a greyish colour.
When larva emerge from the egg, they are transferred to small containers that have lots of food to keep them satiated—TCB larvae like to eat a lot, and they only eat the foliage of plants in the figwort family. These plants contain chemicals that, when consumed by the larvae, offer some protection from predation. This stage is known as the 1st instar, and is the first of five instars in the Taylor’s checkerspot butterfly life cycle. As they eat, the larvae grow and mol their exoskeleton at the end of each instar in order to permit that growth.
Development through the five instars ends with diapause. In the insect world, diapause is akin to hibernation, and it is a period that allows survival though the cold Canadian winters. Larvae in diapause wrap themselves in a protectant layer of webbing, and they preserve their energy reserves as best they can by limiting movement.
For our husbandry staff, it is important to prevent disturbance during diapause so that the larvae are not tempted to move and use up their energy reserves. Diapause, like the majority of the other stages, usually ends when the temperature and amount of sunlight are just right. The post-diapause larvae will now either return to diapause for a second time (when necessary), or they will begin the transformation between immature and mature life stages by pupating.
Like many butterfly species, Taylor’s checkerspot larvae will seek overhanging structures to pupate. The larva will secrete a substance called meconium that it will use to glue itself to the overhanging structure, hanging from it in a “J” position. It is important for husbandry staff to be mindful here not to disturb the enclosures such that the pupa falls from the overhanging structure. Often times, when pupa fall to the ground it is difficult for adults to eclose, or emerge, from the chrysalis successfully.
As always, when the environment is just right—temperature, humidity, light levels—adult butterflies will eclose from their chrysalis. These eye-catching adults can then be bred in the conservation breeding program, and/or be released to breed in the wild. In either case, these adults born in our conservation breeding program have provided a means by which Wildlife Preservation Canada and its conservation partners have been able to augment Canada’s only remnant population of Taylor’s checkerspot butterfly since 2014.
Conservation breeding programs are becoming a necessary component of recovery strategies for species that are on the brink of extinction, and Wildlife Preservation Canada is proud to be a leader in this field. While there are challenges inherent in the development and implementation of programs like these, critically endangered species continue to benefit from the efforts of those who are unwilling to give up after a failed season, an overwhelming season, or a season like no other that leaves them with more questions than answers.
– Native Pollinator Initiative