Kozak V. Trophic activity of forest species of diplopods Rossiulus kessleri and Megaphyllum kievense under the influence of heavy metals and pesticides in a laboratory experiment

The dissertation is devoted to research of influence of chemicals of agrogenic and technogenic origin on organisms of millipedes in laboratory conditions: various concentrations of heavy metals and pesticides on the change in body weight of Rossiulus kessleri (Lochmander, 1927) and Megaphyllum kievense (Lohmander, 1928), on the intensity of feed consumption, the rate of excretion and the fractional composition of their trophic substrate. Concentrations of pollutants that cause diplopod death have been identified. Concentrations of investigated substances less toxic to millipedes have been established. For the first time in the laboratory conditions of Oles Honchar Dnipro National University, we characterized the influence of different concentrations of iron and copper sulfates on the trophic activity of M. kievense. The regularity of toxic effects of lead and cadmium on the body of M. kievense was established and the stimulating effect of concentrations of herbicides Roundup and Urahan Fort on the rate of feed consumption by individuals of R. kessleri was revealed. We determined the dependence of the change in body weight of R. kessleri millipedes on the concentrations of Horus fungicide and established such concentrations of Omite, Penncozeb, Ridomil Gold, Falcon that stop feeding and reduce the intensity of the formation of R. kessleri excrements. We determined the concentrations of insecticides Nurelle D and Actellic, which cause complete death of R. kessleri millipedes. Concentrations of insecticides Nurelle D and Actellic, which cause complete death of R. kessleri millipedes, were also reported for the first time. Different concentrations of the studied pollutants cause changes in the organisms of diplopods. In the gradient of the studied concentrations of FeSO4·7H2O (10–1, 10–2, 10–3, 10–4, 10–5, 10–6, 10–7 and 10–8 mg/g of dry litter) the absence of significant changes in body weight of M. kievense were found. In the process of feeding diplopods accelerated the decomposition of litter with increasing concentrations of iron in the feed. Litter weight decreases by 47.0 ± 0.72 % and by 46.1 ± 1.76 % under the action of 10–1 and 10–2 mg/g of iron. Copper concentration of 10–1 mg/g of litter inhibits the growth of M. kievense body weight. At concentrations of 10–7–10–2 mg copper/g of litter, body weight growth does not differ from control animals that did not consume copper solution. Feed consumption by diplopods does not change depending on the studied concentrations. During the consumption of feed substrate containing different concentrations of copper and iron, individuals of M. kievense changed the fractional composition of the litter. The weight of the fraction > 2.05 mm decreased and the fraction 0.70–1.05 mm increased due to the accumulation of Julidae excrement and crushed plant residues. Harmful metals for diplopods are cadmium and lead. High concentrations of cadmium cause 100 % mortality of M. kievense. The body weight of millipedes at 3 mg/kg cadmium grows more slowly than in the control group. Diplopods significantly reduce weight gain (0.10 mcg/day) compared to the control (0.74 mg/day) under the action of lead concentration of 30 mg/kg of litter. The litter decomposes more slowly by microorganisms under the action of the maximum concentration of cadmium and lead. Feed substrate treated with various pesticides (Actellic, Bi-58, Biotlin, Nurelle D, Omite, Penncozeb, Roundup, Ridomil Gold, Tilt, Thiovit Jet, Urahan Forte, Falcon and Horus) used in agriculture is toxic to Julidae. The herbicides Urahan Forte (2.8•10–10–2.8•10–1 mg/g of litter) and Roundup (3•10–3–3•10–1 mg/g of litter) do not significantly change the body weight of R. kessleri. These two preparations increase the consumption of feed substrate and the rate of excretion of diplopods. Insecticides Actellic, Omite and Biotlin introduced into the litter do not significantly change the body weight of Julidae during 30-day laboratory experiment. Most individuals of R. kessleri cease to consume feed substrate. The rate of excretion is significantly reduced by the action of four insecticides (Nurrel D, Omite, Biotlin and Bi-58). High concentrations of Actellic and Nurelle D cause 100 % death of R. kessleri. Fungicides Penncozeb, Ridomil Gold cause the cessation of feed substrate consumption at the action of concentrations (4.8•10–2 and 4•10–2 mg/g of litter), and Falcon causes consumption only at maximum concentration (1.1•10–1 mg/g of litter). The body weight of millipedes relative to control does not change significantly when feeding food-containing preparations Penncozeb, Falcon and Ridomil Gold. The introduction of these three fungicides in the container significantly reduces the rate of excretion by individuals of R. kessleri. Diplopods stop feeding on food with a low concentration of 1.5•10–3 mg/g of litter of the fungicide Tilt. Preparations Thiovit Jet and Horus do not affect the rate of diplopod feed.