Evaluation of selected biological properties of the hunting web spider (Steatoda grossa, Theridiidae) in the aspect of short- and long-term exposure to cadmium.

The study aimed at comparing the effects of short- and long-term exposure of Steatoda grossa female spiders to cadmium on the web's architecture, its energy content, and ultrastructure of ampullate glands. Simple food chain model (medium with 0.25 mM CdCl2 → Drosophila hydei flies → spider (for 4 weeks or 12 months) was used for the exposure. Analysis of Cd content provided evidence that silk fibers of the web are well protected against its incorporation irrespectively of the exposure period. Long-term exposure to cadmium resulted in the occurrence of numerous autophagosomes with degenerated organelles as well as apoptotic and necrotic cells in the ampullate glands. Concurrently, the individual silk fibers building double and multiple combination complexes were significantly thinner than in the control threads. Moreover, exposed spiders spun net with smaller mean calorific value than did the control individuals. Hence, evaluation of both the diameter of silk fibers and calorific value of the web can serve as biomarkers of the effects caused by exposure of these predators to cadmium.

Effects of food contaminated with cadmium and copper on hemocytes of Steatoda grossa (Araneae: Theridiidae).

The aim of this study was to evaluate the metabolic condition of Steatoda grossa (Theridiidae) spider, from their hemocytes, after a short-term (four-week) exposure to cadmium and copper in sublethal doses by administering them into the body of the preys. The ultrastructure of the dominant types of hemocytes, such as granulocytes, plasmatocytes and prohemocytes, was evaluated using transmission electron microscope (TEM). Quantitative evaluation of apoptotic and necrotic cells, as well as the ones with depolarized mitochondria in hemolymph, was performed using flow cytometry, while ATP concentration and ADP/ATP ratio in hemocytes were measured by luminescent methods. Cadmium, unlike copper, demonstrated proapoptotic and pronecrotic activity. Low ATP levels and high ADP/ATP ratio in hemocytes indicate a disturbance in the energy metabolism of cells and may account for their qualitative and quantitative degenerative changes. The intensification of death processes in hemocytes after an exposure to cadmium-contaminated food may impair the ability of these cells to fight infectious diseases. Copper at the applied dosage was safe for the spiders without causing visible changes in the hemocyte ultrastructure and in the level of analyzed cell death indices.