AUTHOR=Song Yingying , Liu Li , Cui Hongying , Guo Wenxiu , Lv Suhong , Ye Baohua , Li Lili , Yu Yi , Men Xingyuan 

TITLE=Evaluation of Osmia excavata (Hymenoptera: Megachilidae) sensitivity to high-temperature stress

JOURNAL=Frontiers in Sustainable Food Systems

VOLUME=7

YEAR=2023

URL=https://www.frontiersin.org/journals/sustainable-food-systems/articles/10.3389/fsufs.2023.1124310

DOI=10.3389/fsufs.2023.1124310

ISSN=2571-581X

ABSTRACT=<p>The population of <italic>Osmia excavata</italic>, an important pollinator in commercial orchards, has been in serious decline over recent years. To evaluate the risk of high-temperature stress on <italic>O. excavata</italic>, we evaluated the high-temperature tolerance and potential physiological and biochemical responses of <italic>O. excavata</italic> after a series of high-temperature stresses. The results showed that the mortality rates of <italic>O. excavata</italic> increased gradually with increases in temperature and duration of stress (<italic>R</italic><sup>2</sup> = 0.88–0.99; <italic>p</italic> &lt; 0.05). The larvae of <italic>O. excavata</italic> were more sensitive to temperature stress than adults, and the median lethal time (LT<sub>50</sub>) value of the former was smaller than the latter in the acute response test. By comparing the results of acute and chronic responses of <italic>O. excavata</italic> to high-temperature stress, we found that the LT<sub>50</sub> values of natural cocoon-break adults at slightly higher temperatures (35°C and 40°C) were smaller than those of artificial cocoon-break adults, but the LT<sub>50</sub> values were similar under extreme high-temperature stress (45°C). Furthermore, the acute and chronic responses on the fat content of adult Osmia obtained by artificial and natural cocoon-break methods were significantly different (<italic>F</italic> = 5.03; <italic>p</italic> &lt; 0.05). Additionally, the mortalities of the young larvae and artificial cocoon-break adults were both significantly and positively correlated with trehalose content (<italic>r</italic> = 0.78–0.82, <italic>p</italic> &lt; 0.05). However, the mortality of the natural cocoon-break adults was negatively related to the acetylcholinesterase activity (<italic>r</italic> = −0.93, <italic>p</italic> &lt; 0.001). Overall, these results suggested that <italic>O. excavata</italic> has a low tolerance to high-temperature stress and provide evidence of causes that could be contributing to the population decline of <italic>O. excavata.</italic></p>