| Summary: | 碩士 === 國立宜蘭大學 === 生物資源學院碩士在職專班 === 104 === Recent studies have shown that variety pesticide residues could be detected in pollens and nectars that collected by honey bees in the field. Although the amount of pesticide residues, do not kill bees immediately, it seems to have long term impacts on the duration of returning flight, larvae growth, eclosion and the learning ability of honey bees. It is a concerning direction nowadays. The literature search revealed that most of the pesticide in pollen and nectar residue chlorpyrfos. This research would discuss about the sublethal effects of chlorpyrifos on the larvae and adult workers of honey bees (Apis mellifera L.). In the aspect of adult bees, this research recorded the honey bees consumed respectively 5.1, 10.2, 20.4, 30.6 ppm chlorpyrfos syrup continuously 5 times. It also recorded the time from feeding utensils to beehives. The result showed that the bee consuming time is abnormal and this situation related to concentration of chlorpyrfos and the times of continuous ingestion. When the bees only consumed one time chlorpyrfos syrup, the abnormal ingesting situation did not happen in every concentration of chlorpyrfos. When they consumed the syrup second time, there were 36.7% (consuming 30.6ppm chlorpyrfos) and 3.3% (consuming 20.4 ppm chlorpyrfos) of bees would not return to the feeding utensils to ingest syrup. Along with the continuous ingestion time increasing, the disappearance phenomenon of bees also gradually increased. When it is the fifth time for the bees to ingest the syrup, only some bees which consumed 5.1 ppm chlorpyrfos would still ingest at the normal time duration. However, there were over 86.7% bees disappeared in the syrup with 30.6 ppm. In the testing of honey bee larvae, this research selected the 1-day-old larvae which were fed respectively 6.4, 12.9, 25.7, 128.5, 257.0, 514.1 ng/larvae of chlorpyrfos and to observe whether these dosages do have an effect on the capped-brood of larvae and the eclosion of adult bee. The results indicated that 257.0 ng/larvae of chlorpyrifos decreased the capping and eclosion rates (capped-brood=60.4％，eclosion=42.5％) ; there was no significant difference between control group when the concentration below of 128.5 ng/larvae. These results show, the sublethal dosage of chlorpyrifos is 128.5 ng / larva. This research was followed by feeding larvae with the sublethal dosage of chlorpyrifos and below. However, honey bee larva consumed with chlorpyrifos less than 128.5 ng/larva revealed significantly low learning ability than that of consumed 12.9 ng chlorpyrifos in adult bees which is doing the proboscis extension reflex (PER) test. In conclusion, our results proven that sublethal dosage of chlorpyrifos could potentially influence on honey bee growth and high dosage of chlorpyrifos would lead to acute toxicity to adult honey bees in the field. The research result showed after bees consuming chlorpyrfos syrup within 5.1 to 30.6 ppm, all the bees returned to the feeding utensils on time. However, when bees consuming 50 μg/liter imidacloprid syrup one time, it showed abnormal behovior. The difference between two effective concentrations in researches are higher than 600 times. Our research data did not appear to have “delay” on the behavior, which is different from the low concentration imidacloprid which showed “delay”behavior and the high concentration imidacloprid which made bees “missing”. The adult honey bees and bee larvae fed with chlorpyrifos dosage higher than 12.9 ng would have dramatic influence on bees’ learning behavior. And the existing research showed feeding bees with imidacloprid 0.04 ng also influence the learning behavior on bees. The effective concentration of result showed imidacloprid is 300 times more than chlorpyrifos. According to the academic document, it showed the dosage of chlorpyrifos from nectars that larvae consumed is 34.68 ng (>=12.9 ng/larva), and 17.85 ng/bee (>=12.9 ng/larva) from pollens. Then we can know if larvae were fed by the food in the honeycomb, it would affect the learning ability after eclosion. In conclusion, our study proven that the sublethal dosage of chlorpyrifos could potentially influence on honey bee growth and the high dosage of chlorpyrifos would lead to acute toxicity to adult honey bees in the field.
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