WHAT WAS LEARNED
The announcement of our Monarchs in Space project in November generated many questions, the most common of which was: "Why send monarchs into space?" Here are the two main reasons we participated in this program:
The following text summarizes what we have learned from our observations of both the Experimental Habitat aboard the International Space Station and the Control Habitat maintained in the laboratory of BioServe Space Technologies at the University of Colorado in Boulder. What the students learned from participating in this program will be the subject of another text.
Early on Sunday morning the 15th of November 2009, each habitat was stocked with a special artificial diet and three early fourth instar monarch larvae provided by Monarch Watch. The habitats were placed in a special chamber and transferred to NASA personnel who delivered the chamber to the space shuttle Atlantis later that day.
At 2:28pm EST on the 16th of November, Atlantis lifted off from Launchpad 39A at the Kennedy Space Center in Florida. Atlantis docked with the International Space Station (ISS) on the 18th and the chamber with the monarch habitat was transferred from Atlantis' mid-deck to an experiment rack in the Kibo Laboratory on the ISS.
Over the next 25+ days the three caterpillars fed, molted, pupated, emerged, and expired in both the Experimental and Control Habitats, but they did so differently in the two habitats. In brief, the caterpillars in the Control Habitat performed all life functions as expected. The monarchs in the Experimental Habitat in space were affected by microgravity at every stage; however, they surprised us with their adaptability.
At the outset, we envisioned at least five challenges for the Monarchs in Space: clinging to the substrate, molting to the chrysalis/pupa stage, affixing the cremaster to the silk pad, emerging from the pupal cuticle, and expanding the wings.
So how did the monarchs perform each of these functions in the Experimental and Control habitats?
Clinging to the substrate, feeding and location.
Hanging up, forming Js.
Shedding skin, attaching the cremaster to the silk pad.
Emerging, expanding the wings
Earthbound monarchs seem to respond to gravity and perhaps even utilize gravity while progressing from the caterpillar to the adult stage. The results indicate that pupation and emergence were strongly affected in the near weightless conditions aboard the ISS. The inability of all three caterpillars in the Experimental Habitat to properly attach the cremasters to the silk pads during pupation was striking. Similarly, the nearly constant movement of the butterflies expanding their wings, and the amount of time taken to go through this process, suggests that, on earth, gravity does play a role in the expansion of the wings.
The overall results of both the Experimental and Control groups, as well as the well-known patterns of monarch behavior on earth, indicate that monarchs have a sense of gravity. This conclusion raises the most interesting question of all: How do monarchs caterpillars and adults sense gravity and where is the gravity sensor (or sensors) located? Further, is it possible that gravity sensors in adults are different from those in larvae?
Vertebrates have balancing organs, usually in the inner ear, that work together with vision to maintain proper orientations with respect to gravity. Plants have well known tropisms and show both negative and positive responses to gravity under different conditions. The genetic basis for some of these plant responses is also known but relatively little is known about how invertebrates sense gravity.
This study shows that although monarchs are well studied and much of their biology is known, there is still much to learn.
DONATE NOW! (pretty please)
Monarch Watch is a non-profit program based at the University of Kansas and we need your financial help to allow us to continue to offer educational, conservation, and research programs. If you enjoy and/or appreciate all that Monarch Watch offers throughout the year, please consider making a donation today - it's quick, easy, secure, and fully tax-deductible. You can even set up a recurring gift (monthly or annually) if you'd like. We rely on contributions from Monarch Watchers just like you to keep the program going - thank you for your continued support!
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