Biotechnological Function Of Vespa Orientalis Wasp Cuticle

The cuticle acts as a biological solar cell, converting light energy to electrical energy. Under experimental conditions, voltages of several hundred mV, and currents of several tenths of nA were recorded. These measurements were taken at optimal temperature for biological activity of the organism, on wasps: alive and active, alive and narcotised, and dead.(Ishay, 1991) Level of activity is correlated with intensity of exposure to UV light (insolation); for example more intense flight activity is observed with stronger insolation. This data was obtained from experiments on a sample population of adult V. Orientalis, that had been arbitrarily separated into two boxes. One box was exposed to UV light and the other to total darkness. (Plotkin, 2009)

Moreover, the electrical resistance of the cuticle drops at optimal temperature for the wasps biological activity. This was discovered by measuring electrical potential along the dorsal axis whilst warming the specimen; the voltage was found to increase linearly before reaching a plateau at the biological optimum temperature. Initial electrical potential values differed widely across the specimens; this is thought to be due to physiological polymorphism as adult organisms have become specialised to specific roles within the colony. (Ishay, 1991)

A further function of the potential difference across the cuticle (negative relative to outside) is that it allows for movement of electrons through the semiconductive cuticle layer; this results in the promotion of biomineralisation of calcium carbonate, which precipitates into the cuticle and strengthens the insect`s shell. (Plotkin, 2010)

The cuticle in V. Orientalis is the site of metabolic reactions, usually occurring in the fat body of other animals (which the V. Orientalis lacks). Reactions resembling liver functions instead take place in the yellow granule layer of the cuticle. The 2009 Plotkin experiment (paragraph 1) also obtained data to support this. The sample hornets were anaesthetised and the yellow granules removed; a preparation of these was centrifuged and its components analysed. In the sample from the population exposed to UV light there was a lower production of many enzymes involved in metabolism (eg: creatine kinase, alanine aminotransferase, aspartate transaminase...). The higher levels of metabolic enzymes observed under low insolation may be explained by the fact that the living quarters of the V. Orientalis are mainly subterranean and they therefore spend the majority of time in the dark - it is under low insolation therefore that enzyme activity is most required. (Plotkin, 2009)

These results indicate that solar power, on conversion to electrical energy, is used as a direct energy source for the V. Orientalis.

This has biotechnological applications in: solar energy harvesting and direction, UVB harvesting, and nanotechnology. Dye-sensitive solar cells use organic photopigments instead of synthetic compounds and offer different performance criteria and capabilities (in this case including the ability to harvest high energy UVB). Researchers have tested a xanthopterin- sensitised solar cell, based on the V. Orientalis pigment. (The Biomimicry Institute, 2012)

The solar light reaching the V. Orientalis cuticle is directed to the photopigment with a specific system of nanostrutures - ongoing research will explore these structures and look towards developing specialised nanostructure coatings for materials that direct light. (The Biomimicry Institute, 2012) Both described applications could help development of solar cells and using solar power as a viable source of renewable energy.

References:

Ishay, J. Et al. (1991). Electrical properties of the oriental hornet (Vespa Orientalis) cuticle. Comparative Biochemistry and Physiology, Part A. 100), p233-271. URL: http://www.sciencedirect.com/science/article/pii/030096299190469S

Plotkin, M. Et al. (2010). Solar energy harvesting in the epicuticle of the oriental hornet (Vespa Orientalis). Naturwissenschaften. 97, p1067-1076. URL: http://www.asknature.org/strategy/9b67f98df667a56bbe0462034a440537

Plotkin, M. Et al. (2009). Some liver functions in the Oriental hornet (Vespa orientalis) are performed in its cuticle: Exposure to UV light influences these activities. Comparative Biochemistry and Physiology, Part A. 153, p131-135. URL: http://www.sciencedirect.com/science/article/pii/S1095643309000300

The Biomimicry Institute. (2012). Hornet Electricity. Available: http://www.asknature.org/product/373b38ac2b6519a3ca639e5a8aaf02d5. Last accessed 22nd Nov. 2013. URL: http://www.asknature.org/product/373b38ac2b6519a3ca639e5a8aaf02d5