Cold hardiness in the black rice bug, Scotinophara lurida |
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Authors: | JUM RAE CHO MINHO LEE HONG SUN KIM YOUNGGYUN KIM KYUNG SAENG BOO |
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Affiliation: | Applied Entomology Division, Department of Agricultural Biology, National Institute of Agricultural Science and Technology, Rural Development Administration, Suwon, Republic of Korea;, Department of Agricultural Biology, College of Natural Sciences, Andong National University, Andong, Republic of Korea;and Department of Entomology, School of Agricultural Biotechnology, Seoul National University, Seoul, Republic of Korea. |
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Abstract: | Abstract. The mechanisms and strategies for winter survival of the black rice bug Scotinophara lurida are investigated along with the relationship between cold hardiness and diapause. The ability of S. lurida to survive subzero temperatures varies depending on developmental stage, temperature and exposure duration. Mean supercooling point (SCP) varies from –7.6 to –10.7 °C with developmental stage, but is not significantly different between stages examined. The SCP also varies with season, being lowest in January and increasing rapidly in February and remaining almost at the same level (–7.3 to 9.6 °C) until April The osmolality of haemolymph of field-collected S. lurida adults rises dramatically from 53.9 mOsm kg−1 in August to 75.3 mOsm kg−1 in December, and then declines linearly to 57.0 mOsm kg−1 in May. Field-collected S. lurida adults show a peak glucose content in October, glycerol content in November and trehalose content in December. Only trehalose content decreases after the application of the juvenile hormone analogue, fenoxycarb, suggesting that trehalose is a cryoprotectant during diapause. These various physiological and biochemical traits related to cold tolerance in S. lurida may be, at least in part, under the control of juvenile hormone through the reproductive diapause programme. |
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Keywords: | Cold hardiness fenoxycarb osmolality polyols reproductive diapause Scotinophara lurida supercooling point |
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