Study on Hemogram and the Effect of Thermal Stress on Hemocytes and Development in Dacus ciliatus (Diptera: Tephritidae)

نویسندگان

1 Department of Plant Protection, Faculty of Agriculture, Shahrood University of Techonology, Shahrood, Islamic Republic of Iran.

2 National Institute of Agricultural Research, Avenue Ennasr, BP 415 Rabat principal, 10090 Rabat, Morocco.

3 Delta Research and Extension Center, Mississippi State University, Stoneville, MS 38776. USA.

doi
10.48311/jast.2025.16837
چکیده

This study investigated the hemocyte profile, hemogram across all biological stages, and the morphological and frequency changes of hemocytes in the third instar larvae exposed to temperature stress. Cucumber fruits infected with insect larvae were collected and the third instar larvae were extracted from the fruit tissue. The hemolymph was then collected and, after staining with Giemsa solution, were identified under a light microscope. The hemogram analysis included DHC, THC, and blood volume across all biological stages. In the third instar larvae, plasmatocytes and granulocytes were the most abundant, comprising about 56% of the hemocyte population. In contrast, prohemocytes were most frequent in the first instar larvae, accounting for approximately 37%. THC was highest in the larvae, indicating a direct correlation between hemolymph volume and total hemocyte count. Temperature stress had a significant impact on hemocyte numbers. Heat stress, with temperatures up to 30 and 35°C, led to a notable increase in total cell count, granulocytes, and plasmatocytes. Conversely, cold temperatures resulted in a decrease in prohemocytes, plasmatocytes, granulocytes, and the total cell count compared to the control. Additionally, temperature stress induced hemocyte deformation, with plasmatocytes and granulocytes showing the most pronounced changes, including torn cell walls and loss of cell contents at 35○C. Cold stress had a greater effect on the shrinkage of prohemocytes than on the other cell types. Temperature stress also significantly affected the developmental characteristics of the fruit fly. Heat stress reduced the pupation length and emergence rates, while cold stress more prominently impacted birth rates. This study provides a foundation for further research into the physiological defense mechanisms of this pest.