The first naked-eye-visible animals in exovivaria will almost certainly be insects. Insects can be a problem in trying to balance artificial closed ecosystems, as the experience of Biosphere 2 showed: ants and cockroaches proliferated and overproduced CO2.[1] If properly controlled, however, insect production of CO2 can be a good thing: plants might otherwise be starved of it, as their photosynthesis turns CO2 into oxygen. Insects wouldn't be a new solution to this problem: Victorian Era vivaria survived in part because of the (serendipitous[2]) discovery that plants in closed atmospheres transported over long distances needed the CO2 produced by the insects inside the containers.
Insects can also form multiple links in a food chain, with some insects eating others, and with any insect possibly becoming a meal itself or (through excretion while living and decomposition after death) a source of nutrients for plants and bacteria. Insects have even been proposed as a food source for human beings in space.[3]
Insects might do useful work and produce useful byproducts. Harvesting power from insect motion using piezoelectric devices has been demonstrated.[4] Producing silk on orbit might be possible: Abandoned cocoons, if matted and soaked, then frozen, could form a strong and renewable ice-composite shield against orbital debris strikes.[5],[6] "Cyborg insects" have been controlled by direct muscle stimulation and optical input.[7],[8]
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Bioplastics (possibly electroactive, yielding biomimetic muscles for telebots and power-generation components),[9],[10] dyes (e.g., carmine and sealants might be derived from scale insects living parasitically on plants that have other uses in the exovivarial ecosystem.
A research question of particular interest: what are the minimum requirements for a permanent population of honeybees? Bees can pollinate, to help plants in the exovivarium reproduce. They also produce wax, which might have value as a sealant, as a lubricant, as a fuel,[11] as a strengthener/preservative for strands of fiber derived from exovivarial plants, and as a base for casting. Honey might be used to feed other animals, and even be fermented to produce a burnable fuel (alcohol). Honey could be an export product for exovivaria, a prized item in the larders of (inter)national space stations, space hotels, and expeditionary spacecraft.
- ^ "Human terrarium, Biosphere 2, looking good at 20", Science on MSBNC, 4/26/2011
- ^ David Hershey, "Doctor Ward's Accidental Terrarium". The American Biology Teacher Vol. 58, No. 5 (May, 1996), pp. 276-281.
- ^ "Insects as a Food Source in Space Agriculture", Naomi Katayama, Yoji Ishikawa, Muneo Takaoki, Masamichi Yamashita, Robert Kok, Hidenori Wada, Jun Mitsuhashi, and Space Agriculture Task Force
- ^ "Insect cyborgs may become first responders, search and monitor hazardous environs",Nov 22, 2011, Matt Nixon, University of Michigan News Service
- ^ Powerful artificial muscles based on silk, and driven by humidity cycles, have also been proposed, see e.g., "Spider silk as a novel high performance biomimetic muscle driven by humidity, Ingi Agnarsson1, Ali Dhinojwala, Vasav Sahni and Todd A. Blackledge, The Journal of Experimental Biology, 2009. The temperature gradient between an ice-composite pressure vessel and a solar-thermal dish used for power generation and general industrial heat might provide an excellent basis for a supply of dry and wet air.
- ^ Silk might be further strengthened using silkworms engineered to produce spider silk, see e.g., "Silkworms transformed with chimeric silkworm/spider silk genes spin composite silk fibers with improved mechanical properties", Florence Teul�, et al., PNAS, Nov 28, 2011 doi:10.1073/pnas.1109420109
- ^ "Cockroach Controlled Mobile Robot: Control and Communication in the Animal and the Machine", Garnet Hertz, 23 Dec 2008
- ^ "Cyborg Insects Off The Drawing Board, Into The Air", Evan Ackerman, 8 April 2008
- ^ Chitin is a source of polymers that have been considered for use in Mars rover electroactive bioplastics, see e.g., "Electroactive Bioplastics Flex Their Industrial Muscle", USDA Agricultural Research Service, 2005
- ^ Electroactive polymers are under active investigation as components in Stirling engines, see e.g., "Electroactive Polymers for Free Piston Stirling Engine Power Generation", Benjamin Mattes (PI), Jan 9, 2012, NASA SBIR/SSTR 2011 Phase 1 Awards List, Proposal No. 11-1 S3.03-8593
- ^ Beeswax candles might provide illumination and heat while an exovivarium is in earthshadow
Further reading edit
- Creating and Evaluating Artificial Domiciles for Bumble Bees (PDF). Douglas A. Golick, Marion D. Ellis, Brady Beecham. American Biology Teacher. 2006.