Modulations of Haemolymph Parameters in Fifth Instar Silkworm Bombyx Mori L. Parasitized with Beauveria Bassiana

Abstract

The study focused on understanding the impact of Beauveria bassiana infection on the haemotological parameters such as pH, specific gravity and rate of pulsation of the economically significant silkworm, Bombyx mori. Silkworms, due to centuries of domestication, have developed sensitivity to environmental conditions and various micro-pathogens affecting their nutrition, metabolism, and physiological aspects of haemolymph. The researchers used the bivoltine double hybrid silkworm race (CSR2 X CSR27) X (CSR6 X CSR 26) for the investigation. The results revealed that the pH levels of the haemolymph on the first day of the fifth instar in healthy silkworms were 6.615, and on the sixth day, they were 6.596. In the experimental batch, there was a drastic reduction from the first day (6.590) to the second day (6.253), which gradually increased until the fourth day (6.426) of the instar and gradually decreased on the fifth (6.398) and sixth days (6.374). A lower level of specific gravity of the haemolymph was noticed on the first day (1.024) of the 5th instar in silkworms inoculated with Beauveria bassiana. Then a gradual increase was observed till the sixth day (1.038) of the 5th instar. Conversely, in the healthy silkworms, there was a gradual decline in the specific gravity of the haemolymph from the first day (1.025) to the sixth day (1.012) of the fifth instar. The pulse rate in silkworms parasitized by Beauveria bassiana showed a significant increase from the first day (35) to the second day (48), followed by a gradual decrease to the sixth day (32) of the instar. But in control silkworms, the heart rate increased gradually from the first day (35) to the fifth day (45) of the instar and then suddenly decreased on the sixth day (38).