| Honeybee is an important economic insect that can help agricultural plant in pollinating, so that yield and quality of agricultural products can be significantly increased. However, along with development of facility agriculture, people pay more and more attention to the harm on honeybee caused by large-scale use of pesticide etc in agro- ecological environment. In order to protect bees to pollinate for crops and natural plants, it’s necessary to research toxicity mechanism of harmful environmental substances on bees and establish a set of flexible and accurate risk assessment technology. The research starts from influences of several main pesticides on biology of bee with dosage of sub-lethal damage and research on the influence on reproduction of bee group. At the meanwhile, influence rule as well as influence mechanism of sub-lethal dosage of DM on free calcium ion concentrate ([Ca2+]i) inside brain nerve cell of honeybee (Apis mellifera ligustica Spinola) developed in vitro, and following results were achieved through the test:1. With sub-lethal dosage, bifenthrin, deltamethrin and Tau-fluvalinate shall obviously reduce egg amount laid by queen bee; bifenthrin and deltamethrin shall obviously reduce capping rate and successful developmental rate of honeybee(Apis mellifera ligustica Spinola) and obviously extend the period for worker bee to grow from egg to adult bee. Above research result shows that the three kinds of pesticides shall obviously influence normal reproduction of bee group under sub-lethal dosage.2. A complete set of method is established for culture honeybee brain nerve cell in vitro and for calcium ion measuring technique. Establishment of the measuring technique shall be good for creating a set of fast and accurate system to evaluate risks of environmental toxic substances on honeybee by taking cell [Ca2+]i as measurement index, so as to change present method to evaluate toxicity by biological significance of honeybee.3. The test has clarified influence rule of DM on brain nerve cell of bee [Ca2+]i:(1) Even DM with low concentration shall rapidly and obviously impact [Ca2+]i inside cell; (2) As time goes by, there are obvious differences among different tests with different DM concentration:when DM concentration>0.25 mg/L, [Ca2+]i shall still maintain high though influence of DM is removed then. It shows that high DM concentration cause death of cell due to overload of Ca2+; when DM concentration is<0.25 mg/L, [Ca2+]i shall gradually recover without influence of DM. It shows that cell is still alive and has recovery function; (3) Compared with normal cell, final recovery rate of cell [Ca2+]i has obvious difference when DM concentration is reduced to 0.03125 mg/L, it shows that DM with lowest concentration shall cause irreversible influences on cell and exert influences on normal physiological activity of bee’s nerve and organism.4. The test has clarified that major target position for nerve cell [Ca2+]i increasing of bee(Apis mellifera ligustica Spinola) caused by DM stimulation is the voltage-dependent defect T-type of calcium ion passage protein, and DM can specifically open T-type of calcium ion passage, so that Ca2+ outside the cell shall enter into the cell and cause fast increase of [Ca2+]i inside cell.5. After feed worker bee (Apis mellifera ligustica Spinola) with sub-lethal dosage of DM in different duration, to find whether mRNA expression of T-type of calcium ion passage protein a-1H subunit are different. The research shows that deltamethrin with sub-lethal dosage shall obviously cause different for mRNA expression of T-type of calcium iron passage protein. |
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