Laboratory studies on the Effect of different temperatures on Biomphalaria alexandrina snails with emphasis on the consequences of global warming | ||||
| Egyptian Journal of Aquatic Biology and Fisheries | ||||
| Article 55, Volume 26, Issue 2, March and April 2022, Page 877-892 PDF (820.51 K) | ||||
| Document Type: Original Article | ||||
| DOI: 10.21608/ejabf.2022.318086 | ||||
 View on SCiNiTO | ||||
| Author | ||||
| Suzan E. Ali et al. | ||||
| Abstract | ||||
| The objective of the present study was to examine the impact of increasing water temperatures on the survival, growth rate, and reproduction of Biomphalaria alexandrina snails, as well as their susceptibility to Schistosoma mansoni infection. The study examined a range of water temperatures, including 30, 32, and 34°C, and a control group maintained at room temperature. The results indicated that increasing water temperature significantly reduces the survival rate of B. alexandrina snails. The survival rate was 0, 6, 9, and 91% for snail groups at 34, 32, 30 °C, and room temperature, respectively. In contrast, there was no statistical difference between increased temperature (30 and 32 °C) and room temperature on the growth rate of the snails. The mean shell diameters of snails were 9.8 and 9.6 mm at 30 and 32 °C, respectively, compared to 10.03 mm at room temperature. However, the growth rate of snails at 34°C reached 8.4 mm. Increasing water temperature dramatically suppressed the reproduction rate, resulting in fewer egg masses. Snails maintained at room temperature laid eggs in the tenth week and continued to lay eggs till the end of the experiment (14th week). Those exposed to the water temperature of 30 °C were observed to lay eggs in the tenth week; however, after two weeks, they stopped laying. There was no egg laying for the snails exposed to 32 and 34°C throughout the experimental period. This was confirmed by the histological examinations of the hermaphrodite gland, which revealed damage in the gonadal cells, ranging from mild to severe, according to the increase in water temperature. The infection rate of infected snails decreased significantly by increasing the temperature. The total number of produced cercaria decreased sharply by increasing the water temperature. The infected snails produced 2222, 634, and 265 cercariae at 25, 30, and 32°C, respectively. However, at 34 °C, no cercariae were detected in the snails. | ||||
| Keywords | ||||
| Survival rate; Growth rate; Hermaphrodite gland; Egg-laying; Miracidia; Cercaria | ||||
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