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Biowissenschaften

Hong Kong Polytechnic University - PolyU HK

2016

Emil C. ©
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Hong Kong Polytechnic University

2017-2018 (Semester 1)

 ELC3121 English for Scientific Communication

Neonicotinoid Reduces Honeybee Health

Which Helps the Growth in Crops


Inhaltsverzeichnis

1. Introduction. 3

2. Methods4

2.1 Group members’ participation. 4

2.2 Methods of the experiments5

2.3 Methods used to gather data in results section. 5

3. Results6

3.1 Country-specific response of neonicotinoid. 6

3.2 Chronic exposure reduced health of honeybees7

3.3 Low risk for Bombus impatiens9

3.4 Beneficial to wheat and oilseed rape. 10

4. Discussion. 11

5. Conclusion. 12

Reference. 13

1. Introduction

The proper use of neonicotinoid in crops is especially crucial because of the main role and function of this pesticide in seed coating and the control of soil insects, foliar insects, and some detrimental pests that jeopardize the growth of crops.

Nevertheless, the use of neonicotinoid could pose a threat to honey bees, leading to the decline of pollinators as well as crop yield. In recent years, the possibility that the reduction on the lifespan of honeybees by neonicotinoid, might further decreased crop yield was suggested. From then on, substantial research work such as A field study examining the effects of exposure to neonicotinoid seed-treated corn on commercial bumble bee colonies (Christopher & Cynthia, 2014) has been dedicated to investigating the influences of variable concentration of neonicotinoid on crops, yet there is still not common acceptance as to whether neonicotinoid can cause genuine decline of honeybees and thus the crop yield.

Most researches like Risks of neonicotinoid insecticides to honeybees (Fairbrother, Purdy, Anderson & Fell, 2014) and Country-specific effects of neonicotinoid pesticides on honeybees and wild bees (Woodcock et al., 2017) in past few years have resolved this question by measuring either the population of honeybees or crop yield upon the treatment with neonicotinoid.

Few studies have been conducted to approach the problem from correlating the mortality in honeybees with crop yield. It is inadequate to know about the crop pollens propagated by honeybees when neonicotinoid is used.

This research will examine the crop yield accompanied with mortality of honeybees upon the use of neonicotinoid. Firstly, general terms regarding neonicotinoid and its chemical structure will be explained and the practical condition of analytical methods will be demonstrated.

Relationships between honeybee colonies and concentration of neonicotinoid discharged on the crop with regard to its impacts on mortality of honeybees, as well as the interactions between the fate of neonicotinoid residues in honeybee colonies and crop yield are then discussed.


2. Methods

2.1 Group members’ participation

In our group, each one was responsible for a specific section of this scientific report. Our group members collected the bibliographic information in 2017/18 academic year Semester 1 week 4. First, found information about concentration of the neonicotinoid used in the crops, which is an important parameter to determine whether it might affect the health of honeybees seriously and whether the quantity of pests is under control.

Secondly, Kasper was responsible for seeking the information about the responses of honeybees to neonicotinoid in different countries and their impacts on crop yield. All of the bibliographic information found by and Kasper were sourced from the filtered Peer-reviewed Journals by using the One Search of PolyU library.

Finally, Miles and Jacky focused on analyzing the data of specific figures and graphs from the selected bibliographic information. After all referenced journals were digested, some useful data and graphs were obtained to explain the relationship between the amount of neonicotinoid added and the mortality of honeybees as well as the crop yield. The discussion section was done by .


2.2 Methods of the experiments

This scientific report is going to analyze the dilemma between high crop yield and the mortality of honeybees. In order to find out the relationship between crop yield and neonicotinoid, it was necessary to know the quantity of neonicotinoid added to the crops.

The quantity of neonicotinoid added was required to justify that whether the yield of the crops was directly proportional to the amount of neonicotinoid. Additionally, the health of honeybees was a perfect evidence to reveal the negative effects of neonicotinoid. By comparing the advantages of having higher crop yield and the disadvantages that exposed to the health of honey bees, restrictions on the neonicotinoid can be determined to impose or not.


2.3 Methods used to gather data in results section

In order to gather the data, a series of experiments had been done by researchers. One kind of neonicotinoid was added at around 12 to 18 grams of active ingredient per hectare as a pesticide to detect the response of the bees. To identify the impact of neonicotinoid exposure, experimenters had removed sealed brood from the treated colonies and controlled them after the first 3 weeks of exposure.


3. Results

3.1 Country-specific response of neonicotinoid

Colony size was used to illustrate the amount of honeybees and wild bees by pooled standard deviation, instead of counting individually, which saved a lot of time. The asterisk (*) indicated a significant difference between the control and seed treatment determined from the predicted marginal means. Honeybees and wild bees had different response to neonicotinoid-treated seed in different countries.

Fig.1 Country-specific response of honeybees and wild bees to the neonicotinoid-treated seed.

Adapted from: Woodcock, B., Bullock, J., Shore, R., Heard, M., Pereira, M., Redhead, J., Ridding, L., … Pywell, L. (2017).

The result reflected the various responses of honeybees and wild bees to seed treatment with neonicotinoid in terms of effect size in different countries. As is shown in Figure 1, both Hungry and United Kingdom had negative pooled standard deviation of colony size from -1.5 to -2. The negative effect to the colony size was revealed in Hungary and United Kingdom under the exposure of neonicotinoid within a year.


3.2 Chronic exposure reduced health of honeybees

Clothianidin is a kind of neonicotinoid that functions as pesticide. The reducing health condition of honeybees can be observed by hygienic behavior.

Fig.2 Chronic exposure of clothianidin harm health of honeybees.

Adapted from: Tsvetkov, N., Samson, O., Sood, K., Patel, H., Malena, D., Gajiwala, P., Maciukiewicz, P., … Zayed, A. (2017).

Hygienic behavior implied the ability of bees that help them to resist the adversity in nature. It could be seen from Figure 2C that there was a substantial fall of hygienic behavior of colonies of honeybees from 45% to 35% under chronic exposure of clothianidin, compared with unexposed.


3.3 Low risk for Bombus impatiens

Bombus impatiens is a common species of honeybees. Effects (mean ± SD) on commercial Bombus impatiens colonieswhen exposed during pollen shed to corn grown from neonicotinoid-treated seed.

Table 1: Neonicotinoid-treated seed is low risk to Bombus impatiens.


Table 1. effects on Bombus impatiens colonies when exposed while pollen shed to corn grown from neonicotinoid-treated seed.

Adapted from: Christopher, G., & Cynthia, D. (2014).


As the findings in Table 1 revealed that, in general, there was no significant impact on Bombus impatiens colonies when presented while pollen shed to corn plants grown from neonicotinoid-treated conventional seed. All colonies of Bombus impatiens are classified as in a healthy condition after the exposure.

Fig.3a the relationship between amount of neonicotinoids applied and year

Adapted from: Goulson, D. (2013).


Fig 3b. The relationship between year and the yield of wheat and oilseed rape

Adapted from: Goulson, D. (2013).


According to Figure 3a, the positive relationship between neonicotinoid and year has been shown. In particular, the weight of neonicotinoid applied increased from 0 to approximately 85000 kg during 1992 to 2010. Figure 3b uncovered the increasing trend between yield of different crops (wheat and oilseed rape) and year.

Specifically, the yield of wheat and oilseed rape climb from 6.7 to 8.0 tonnes per ha and 3.0 to 3.2 tonnes per ha respectively. Combining the two figures, it was found that the more amount of neonicotinoids used, the more yield can be obtained. Therefore, neonicotinoids were beneficial to wheats and oilseed rapes.


As a result, they cannot grow in a healthy condition. However, it is also mentioned that neonicotinoid does not reveal its negative effects in the somatic size of their colony in some countries, such as Germany. This could be related to the wide range of species of bees. Since neonicotinoid may affect different kinds of bees, that serious effects may disperse to other bees instead of honeybees.

As a result, their somatic size may not be affected (Fairbrother et al., 2014).


Not only is the somatic size affected, but also the hygienic behaviors. In fact, honeybees have the ability adapt to adversity in nature. However, the findings seem to indicate that neonicotinoid is likely to reduce their hygienic behaviors. This may be attributed to the use of neonicotinoid. According to Tsvetkov et al. (2017), neonicotinoid will damage the social immune system of honeybees.


Apart from their size and hygienic effects, there is a direct relationship between the crop yield and the amount of neonicotinoid that used. According to Goulson (2013), due to the properties of high toxicity to insects and low toxicity to crops of neonicotinoid, it is used as a seed dressing in a wide range of crops, such as potatoes, oilseed rape, beets, cereals and sunflower.

It is probably beneficial to the growth of crops effectively as the insects will not damage them. This can explain the reason why the crop yield is directly proportional to the amount of neonicotinoid that used.


5. Conclusion

In this report, neonicotinoid was discharged to the environment. Impacts on the bees population and hygienic behavior were found in different countries. As for the health condition of honeybees, the crop yield and amount of neonicotinoid used were analyzed by the researchers. It was found that the response of honeybees to neonicotinoid was country-specific.

It suggested, therefore, they would die easily. For the reason why neonicotinoid was beneficial to crops yield is that it could protect the crops from insects. A more thorough field study is required to explain how the mortality of honeybees are increased by using neonicotinoid to further reduce the crop yield. Investigation of the crop pollens propagated pathways for the honeybees’ pollination activity in the release of neonicotinoid is suggested.

Reference


Christopher, C. G., & Cynthia, S. D. (2014). A field study examining the effects of exposure

to neonicotinoid seed-treated corn on commercial bumble bee colonies. Ecotoxicology,  23(9), 1755-1763. Retrieved from

 

     insecticides to honeybees. Environmental Toxicology and Chemistry / Setac, 33(4), 719–

     731. Retrieved from

 

Goulson, D. (2013). REVIEW: An overview of the environmental risks posed by

neonicotinoid insecticides. Journal of Applied Ecology, 50(4), 977-987. Retrieved from

 

Tsvetkov, N., Samson, O., Sood, K., Patel, H., Malena, D., Gajiwala, P., Maciukiewicz,  

     P., … Zayed, A. (2017). Chronic exposure to neonicotinoids reduces honey bee health

     near corn crops. Science (New York, N.Y.), 356(6345), 1395-1397. Retrieved from 

    

 

Woodcock, B., Bullock, J., Shore, R., Heard, M., Pereira, M., Redhead, J., Ridding, L., …

     Pywell, L. (2017). Country-specific effects of neonicotinoid pesticides on honey bees and

     



Appendix


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