Basal leaves of Nicotiana attenuata are frequently found neatly excised at the petiole and piled on rocks or soil in the sun until dry, after which they disappear, sometimes to be found again in the nests of Neotoma lepida. In response to herbivore attack, N. attenuata increases the concentration of nicotine in its leaves, where it functions as an induced defense. Since excision of leaves at the petiole allows for leaf removal without substantially activating this induced defense, and air-drying at high temperatures can volatilize nicotine, we examined the hypothesis that the observed leaf "curing" behavior decreased nicotine contents. In a natural population, replicate bundles of excised leaves were allowed to dry in the sun for up to 96 hours and harvested in 10 intervals. Even though surface temperatures reached 63 °C during drying, no significant loss of nicotine was observed. In the laboratory, significant losses of nicotine were not observed until leaves were dried at 100 °C. Nicotine contents of naturally "cured" leaf piles at 4 populations were found to be marginally higher than those of neighboring intact plants from which the leaves were likely harvested. We conclude that mammalian "curing" behavior does not reduce nicotine contents and may allow the leaves to be used for insect repellant purposes.
Baldwin, Ian T.
""Curing" of Nicotiana attenuata leaves by small mammals does not decrease nicotine contents,"
Western North American Naturalist: Vol. 63
, Article 15.
Available at: http://scholarsarchive.byu.edu/wnan/vol63/iss1/15