I hope everyone had a great Endangered Species Day, I sure did. As mentioned in an earlier post, I’ve recently been working in a lab that studies and maintains a colony of endangered Karner Blue butterflies. Until recently I had never seen an actual adult Karner and had only been worked with eggs and larva. The first adult Karner for the year (in the entire world), named Wilbur, enclosed a few weeks ago. Many more have followed.
Some of you may have, as children, raised a lepidopteran of your own from a caterpillar through adulthood to witness the fascinating process of metamorphosis. If not, I highly recommend this, regardless of what your age is. One guide can be found from clicking here. Kerry has taken this on with some of the imposter moth larva we found in our colony. But of course maintaining a colony of thousands of animals for multiple generations presents a number of challenges you will likely not run into.
For one, a dense population in a confined space is particularly susceptible to disease outbreaks. We recently found this out when we had a case of “black death”, a mysterious ailment that renders a perfectly healthy green caterpillar into a solid black dead body over night. Black Death is found both in the lab and in nature and its cause is unknown, though it likely has multiple contributing factors. We took immediate action to contain the spread by switching out all of the containers, carefully disinfecting all incubators and tools, and adapting our feeding procedure. It appears to be under control.
Next, we have gimps. In nature, as soon as an adult butterfly or moth emerges, it crawls out to a twig in an open space in which it can spread its wings. A very limited amount of time passes in which the wings are still malleable, until they solidify and become permanently formed. If the animal isn’t able to spread out, as sometimes happens in our rearing cups, its wings will be deformed after hardening. We refer to these as gimps and they are rarely able to mate.
Mating itself can be a challenge. While an amateur enthusiast can simply release their creatures into the wild after they enclose, we intend to keep the colony for additional generations. Unfortunately Karners refuse to mate in the green house or in incubators. Only after we cart their mating cages outside onto the lawn during hot, sunny days do they start to get to business. And even then they’re pretty fussy. Today, after three days of attempts, we had our first successful mating.
Last week, Kerry and I took a ride out to Miller Woods (part of Indiana Dunes National Lakeshore) in an attempt to witness the Karner population in the wild. Unfortunately we got there one day before the large emergence occurred and didn’t manage to spot a single one. But the trails were covered with bright blooming purple lupine (Karner’s host plant) and the weather was great for hiking. The purpose of the experiment is to produce a model that can make predictions about how climate change affects the timing of the Karner’s life cycle stages, but the real world may actually turn out to be the most extreme test of all. This year is one of the hottest summers the region has had in recent history, even hotter than our most extreme treatment in the lab, and we don’t really know what affects that will have. Normally Karner Blues go through two generations (called flights) each season, but previous work in the lab suggests high temperatures may result in them having three flights or more. This may or may not lead to problems in synchronization with host plants or other seasonal cues. Butterflies are very sensitive to environmental changes and are kind of an early warning sign of problems that other species may eventually face. The Karner recovery team is making a valiant effort to learn enough about the species to prevent it from further declining, but only time will tell if it will prevail.