The super-cooling ability and biochemical substances of post-diapause Osmia excavata Alfken
Author of the article:LIU Li1, 3** LI Li-Li1 LI Chao1 OUYANG Fang2 YU Yi1 ZHENG Li1 YE Bao-Hua3 MEN Xing-Yuan1***
Author's Workplace：LIU Li1, 3** LI Li-Li1 LI Chao1 OUYANG Fang2 YU Yi1 ZHENG Li1 YE Bao-Hua3 MEN Xing-Yuan1*** ZHANG Si-Cong1**
Key Words：[Objectives] Osmia excavata Alfken is the major pollinator of fruit trees in north China where it provides the key ecological services of pollination and promoting fruit yield. Clarifying the cold-resistance of the post-diapause stage, and the physiological and biochemical mechanisms of cold-resist
Abstract：
[Objectives] Osmia excavata Alfken
is the major pollinator of fruit trees in north China where it provides the key
ecological services of pollination and promoting fruit yield. Clarifying the
cold-resistance of the post-diapause stage, and the physiological and
biochemical mechanisms of cold-resistance, are important for the conservation
and utilization of this species. [Methods] We systematically measured the super-cooling and
freezing points, water content, fat content, protein content, trehalose levels,
and the activity of catalase (CAT), superoxide dismutase (SOD) and acetylcholin
esterase (AchE), in post- diapause and post-eclosion female and male O. excavata. [Results] There
was no significant difference in cold resistance between the sexes.
Supercooling and freezing points gradually increased, then decreased, after
eclosion in post-diapause individuals. The supercooling and freezing points of
females and males were highest after eclosion; ﹣12.35 ℃, ﹣9.98 ℃ and ﹣12.63 ℃, ﹣8.91 ℃, respectively. Post-diapause males had significantly more fat
than females but females had significantly more protein than males. The fat
content of males and the protein content of females decreased rapidly after eclosion.
Before eclosion, the activity of superoxide dismutase, catalase and
acetylcholinesterase were higher in males than in females. However, enzyme
activity in females increased significantly after eclosion. Trehalose levels in
both sexes decreased significantly post-diapause and trehalose levels in males
on the day after eclosion were 64.5% lower than those on the 190th day after cocooning. [Conclusion] Post-diapause O. excavata have strong
cold-resistance. Cold resistance decreases gradually before eclosion but
increases after eclosion. Trehalose metabolism may be an important energy
consumption pathway in post-diapause O.
excavata. Males are smaller, but have
stronger antioxidant systems, than females.
Key
words Osmia excavata Alfken, post-diapause stage, super-cooling point, freezing
point, biochemical substances