the occurance of oil palm weevil, elaeidobius … occurance of oil palm weevil... · figure 3.3...

THE OCCURANCE OF OIL PALM WEEVIL, Elaeidobius kamerunicus (ORDER:

COLEOPTERA) AND THE PRODUCTIVITY OF OIL PALM, Elaeis guineensis

(FAMILY: ARECACEAE)

Siti Khadijah Bt Abdul Khalid

(28244)

Bachelor of Science with Honours

Animal Resource Science and Management

2013

THE OCCURANCE OF OIL PALM WEEVIL, Elaeidobius kamerunicus (Order:

Coleoptera) AND THE PRODUCTIVITY OF OIL PALM, Elaeis guineensis (Family:

Arecaceae)

A project is submitted to partial fulfillment of the requirement for the degree of

Bachelor of Science with Honours

(Animal Resource Science and Management)

Department of Zoology

Faculty of Resource Science and Technology

UNIVERSITI MALAYSIA SARAWAK

2013

Declaration

I hereby declare that the thesis is based on my original work except for citation which has

been duly acknowledgement. I also declare that it has not been previously or concurrently

submitted for any other degree qualification at UNIMAS or any others institution or

university of higher learning.

___________________________


Animal Resources Sciences and Management Program

Department of Zoology

Faculty of Resources Sciences and Technology

Universiti Malaysia Sarawak

I

ACKNOWLEDGEMENT

First and foremost, praise to Allah S.W.T for giving me inner strength to continue

pursuing my research work despite the hardship faced. Secondly, I would like to

express my gratitude towards my supervisor, Dr. Chong Yee Ling for all the

guidance, advices and support throughout the process of completing this thesis. My

appreciation also to Miss Siti Nurlydia bt Sazali@Piksin and Professor Sulaiman B

Hanapi for sharing their valuable information and thoughts.

Besides that, I also liked to thank the Felcra Berhad for their permission to conduct

my field work in Bangka Semong Oil Palm Plantation. My gratitude also addressed

to all workers in Bangka Semong Oil Palm Plantation for proving guidance, facilities

and materials during the sampling.

Moreover, my gratitude is also express to my colleagues, Nor Azlini Bt Mat Isahak

Zaki and Nur Aini Bt Mohd Nasri during sampling at the field and encouragement as

well as companies. In additional, I would like to thank to all my friends form

Department of Zoology, Department of Plant and my housemate for all the support

and guidance during my ups and downs.

Above and beyond, I would like to give special thanks to the angel of my heart,

Shazana Zawani, Shahrul Ikhwan, Mohd Effandy, Mohammad Najib and Khairul

Liza for all the encouragement and support given.

II

TABLE OF CONTENTS

CHAPTERS CONTENTS PAGES

ACKNOWLEDGEMENT I

TABLE OF CONTENTS II

LIST OF ABBREVIATIONS IV

LIST OF TABLES V

LIST OF FIGURES VI

LIST OF APPENDICES VIII

ABSTARCT

1

1.0 INTRODUCTION 2

1.1 Background of study

2

2.0 LITERATURE REVIEW 5

2.1 Pollination 5

2.1.1 Insect pollination of oil palm 5

2.2 The potential of E. kamerunicus as

pollinators in Malaysia

6

2.3 Oil palm weevil, E. kamerunicus 7

2.4 The African oil palm, Elaeis guineensis

Jacq.

9

2.4.1 Descriptions of Elaeis guineensis 10

2.4.2 Inflorescences 12

2.4.3 Fruiting 13

2.5 The productivity of oil palm 14

2.6 Previous studies on pollinator and oil palm

production.

17

3.0 MATERIALS AND METHODS 18

3.1 Study site 18

III

3.2 Field method and sample collection 19

3.3 Data analysis 24

4.0

RESULTS

4.1 The occurrences of male flowers

inflorescence during anthesis and oil palm

weevil, E. kamerunicus in Bangka Semong

Oil Palm Plantation.

4.2 The harvest of the fresh fruit bunch (FFB) in

Bangka Semong Oil Palm Plantation.

4.3 The correlation between the prevalence of

E.kamerunicus and the yield of oil palm in

Bangka Semong oil palm plantation.

25

25

27

29

5.0 DISCUSSION

5.1 The occurrences of the oil palm weevil,

E.kamerunicus

5.2 Numbers of spikelet per bunch of male

flower inflorescences with anthesis

5.3 The productivity of oil palm in Bangka

Semong Oil Palm Plantation.

32

32

34

35

6.0 CONCLUSION AND RECOMMENDATION 39

REFERENCES 40

APPENDICES 45

IV

LIST OF ABBREVIATIONS

FFB Fresh Fruit Bunch

CPO Crude Palm Oil

CPKO Crude Palm Kernel Oil

FELCRA Federal Land Consolidation and

Rehabilitation Authority

One –way ANOVA One- way analysis of variance

SPSS Statistical Package for the

Social Sciences

HQ Head quarters

M Meter

Cm Centimeter

Mm Millimeter

% Percentage

Kg Kilogram

G Gram

V

LIST OF TABLES

Table Pages

Table 4.1 Oil palm weevil, E. kamerunicus on the male

flowers during anthesis.

27

Table 4.2 The harvest of fresh fruit bunch (FFB) at different

blocks in Bangka Semong Oil Palm Plantation

29

VI

LIST OF FIGURE

Figure Pages

Figure 2.1 Lateral view of E. kamerunicus 8

Figure 2.2 African Oil Palm (Elaeis guineensis Jacq.) at Bangka

Semong Oil Palm Plantation.

10

Figure 2.3 The different types of fruit varieties (a) Dura, (b)

Tenera and (c) Pisifera.

12

Figure 2.4 Male and female inflorescences at stages of

development (a) The male inflorescences before

anthesis, (b) the male inflorescences during anthesis,

and (c) the female flowers during anthesis.

13

Figure 2.5 Oil palm fruits (a) The cross section of oil palm fruit,

(b) the bunch of fruit that is ready to be harvested.

14

Figure 3.1 Study site at Bangka Semong Oil Palm Plantation in

Kota Samarahan, Sarawak

18

Figure 3.2 Blocks (A-J) division at Bangka Semong Oil Palm

Plantation. HQ indicates the main office for the

plantation area.

19

Figure 3.3 Sampling plot at each block. 20

Figure 3.4 Measuring the diameter of the FFB. 21

Figure 3.5 Collecting and calculating the weevil on male flowers 21

Figure 3.6 Materials used to calculate the weevil (a) 70% of

ethanol for preservation, (b) filter paper, (c)

22

VII

magnification lens and (d) plastic bottles.

Figure 3.7 The male (a) and female (b) weevil under the

microscope

22

Figure 3.8 The colony of the weevil in spikelet on male flower (a)

early anthesis period and (b) late anthesis period

23

Figure 4.1 Scattered plots show (a) The correlation between

numbers of spikelet and the numbers of weevil, (b) The

correlation between the numbers of FFB per tree and

the numbers of weevil, (c) The correlation between

average diameter of FFB and the numbers of weevil.

30

VIII

LIST OF APPENDICES

Appendix Pages

Appendix A

Appendix 1 Data collection for Plot G1 from Bangka Semong oil

palm plantation on 23 February 2013, 2.05 pm. The

weather of condition is sunny day.

45


palm plantation on 24 February 2013, 12.35 pm. The

weather of condition is raining.

47


palm plantation on 23 February 2013, 10.20 am. The


49

Appendix 4 Data collection for Plot A1 from Bangka Semong oil

palm plantation on 2 March 2013, 9.30 am. The


51


palm plantation on 2 March 2013, 1.35 pm. The


53



weather of condition is cloudy

55

Appendix 7 Data collection for Plot F1 from Bangka Semong oil


57

IX

weather of condition is cloudy.

Appendix 8 Data collection for Plot F2 from Bangka Semong oil


weather of condition is cloudy.

59

Appendix 9

Data collection for Plot F3 from Bangka Semong oil



62

Appendix 10 Data collection for Plot D1 from Bangka Semong oil

palm plantation on 10

March 2013, 9.25 am. The weather of condition is

sunny day.

65




68



weather of condition is raining.

71

Appendix B

Appendix 13 Normality Test for (a) total numbers of weevil and

(b) total numbers of spikelet

74

Appendix 14 Mann-Whitney U Test for 95.5% Confident Interval

for (a) Numbers of weevil and (b) 95.5% Confident

Interval for Numbers of spikelet per bunch.

75

Appendix 15 One-way ANOVA and Tukey Method for Numbers 76

X

of FFB

Appendix 16 One-way ANOVA and Tukey Method for Average

diameter of FFB

78

Appendix 17 Spearman Correlation analysis for numbers of

spikelet against the numbers of pollinator

80

Appendix 18 Spearman Correlation analysis for average numbers

of fresh fruit bunch against the numbers of pollinator

80

Appendix 19 Spearman Correlation analysis for numbers of fresh

fruit bunch against the numbers of pollinator

80

Appendix 20 Print screen of correlation test using the (a) Minitab

16 and (b) SPSS 17.0

81

Appendix C

Appendix 21 The data collection and recorded based on the

condition in the Bangka Semong oil palm plantation;

(a) the dorsal view of FFB that have been damages by

pest, (b) the dorsal view of ripe FFB that have in oil

palm plantation, (c) the dorsal view of female

inflorescence before anthesis, (d) the dorsal view of

the female inflorescences at anthesis stage of

development, (e) the lateral view of the male

inflorencences at before anthesis stage of

developmen, (f) the lateral view of the male

inflorescences during anthesis stage of development,

82

XI

(g) the view of the no production tree of fruits and

male inflorescences,(h) the view of the production

tree contains FFB, (i)The view of the tree that are

affected by pest and disease, (j) The condition of the

tree cause by the pest and disease,(k) another

condition of the tree also cause by the pest and

disease, (l) the lateral view of the incomplete

pollination occur in several tree, and (m) the view of

the potted seedling in plantation.

1

The Occurrence of Oil Palm Weevil, Elaeidobius kamerunicus (Order:

Coleoptera) and The Productivity of Oil Palm, Elaeis guineensis (Family:

Arecaceae)


Animal Resource and Management Programme

Faculty of Science and Technology

Universiti Malaysia Sarawak

ABSTRACT

Malaysia has the most developed oil palm industry in the world and this affects the overall agriculture

development of the country. The oil palm tree in Malaysia is Elaeis guineensis (African oil palm) and

the main pollinating agent is Elaeidobius kamerunicus (oil palm weevil). This study was conducted in

Bangka Semong oil palm plantation, Kota Samarahan, Sarawak to verify the occurrence of E.

kamerunicus in response to the productivity of oil palm. The result from this study showed that there

is a low occurrence of male flower inflorescences that anthesis (<1%) from 660 oil palm trees

sampled. The occurrence of oil palm weevil is higher in block F compared to A (Mann-Whitney U

test). The numbers of fresh fruit bunches sampled were significant different comparing four different

blocks (one-way ANOVA). The numbers of weevil presence is positively correlated with the numbers

of spikelet based on Spearman Rank Correlation test. However, there are no linear relationships

between the presence of weevils and the number of fresh fruit bunches or the average diameter of fruit

bunches. The findings of this study could provide the useful information on the relationship between

the occurrence of oil palm weevil and productivity. In addition, this study can serve as reference for

future studies and knowledge on the biology of these insects which is vital for better management of

oil palm yields.

Keywords: Elaeidobius kamerunicus, Elaeis guineensis, pollinator agents, occurrence of weevil,

productivity of oil palm

ABSTRAK

Malaysia mempunyai industri kelapa sawit paling maju di dunia dan ini memberi kesan kepada

pembangunan pertanian secara keseluruhan di negara ini. Pokok kelapa sawit di Malaysia adalah

Elaeis guineensis (kelapa sawit Afrika) dan ejen utama pendebungaan adalah Elaeidobius

kamerunicus (kumbang kelapa sawit). Kajian ini telah dijalankan di ladang kelapa sawit Bangka

Semong, Kota Samarahan, Sarawak untuk mengesahkan jumlah E. kamerunicus dan produktiviti

kelapa sawit. Hasil kajian menunjukkan pendebungaan bunga jantan adalah rendah (<1%) dari 660

batang pokok kelapa sawit. Jumlah kumbang kelapa sawit didapati tinggi di blok F berbanding blok A

(Mann-Whitney U test). Bilangan tandan buah segar berbeza signifikan berbanding empat blok yang

lain (One-Way ANOVA). Bilangan kumbang yang hadir berkorelasi positif dengan bilangan spikelet

berdasarkan kepada Spearman Rank Correlation test. Walaubagaimanapun, tiada hubungan selari

antara kehadiran kumbang dan bilangan tandan buah segar atau purata diameter tandan buah. Hasil

kajian ini boleh memberikan maklumat yang berguna mengenai hubungan antara kumbang kelapa

sawit dan produktiviti. Selain itu, penyelidikan ini boleh dijadikan sebagai rujukan untuk kajian masa

depan dan memberi pengetahuan mengenai biologi serangga yang penting untuk pengurusan hasil

kelapa sawit yang lebih baik.

Kata kunci: Elaeidobius kamerunicus, Elaeis guineensis, agen pendebungaan, jumlah kumbang,

penghasilan kelapa sawit

2

CHAPTER 1

INTRODUCTION

1.1 Background of Study

Over the past 30 years, the area for the plantation of oil palm (Elaeis guineensis

Jacq.) has increased more than 150% worldwide. Most of these areas are located in

Southeast Asia, with the outstanding production increases in Malaysia and Indonesia

(Fairhurst & Mutent, 1999). Nowadays, the oil palm industry has become the major

source of income that contributes to the politics and socio-economic stabilization in

Malaysia. This has been proven during the World Economy Crash between 1997 and

1998, when the oil palm industry saved Malaysia from being dependent on other

countries for survival (MPOIP, 2008). According to Corley & Tinker (2003),

Malaysia is one of the countries that have the oldest oil palm industry in the world

and the development is rapidly moves.

Interaction between the pollinator and host plant can have an important influence on

the dynamics of the production of fruit (Mitchell et al., 2009; Adaigbe et al., 2011).

The oil palm, Elaeis guineensis Jacq., is considered as entomophilous crop which

belonged to the family Arecaceae (also known as Palmae). According to Syed

(1981), there are ten species of insects that were identified to benefit the oil palm

plantation in West Africa and these species are Elaeidobius kamerunicus,

Elaeidobius singularis, Elaeidobius subvittatus, Mystrops coastaricensis, Thrips

hawaiilensis and some bee species.

3

As an erect monoecious plant, oil palm produces separate male and female flowers

on the same plant and they are cross-pollinated (Corley & Tinker, 2003; Verheye,

2010). According to Syed (1979), E. kamerunicus, from the Order of Coleoptera

(beetles), is the main pollinating weevil of the oil palm. It is the only live beetle in oil

palm flowers and will flies from male flowers to female flowers (Corley & Tinker,

2003). In order to improve the pollination efficiency of oil palm, E. kamerunicus was

the first imported beetles species from Cameroon, West Africa to the oil palm

plantation in Malaysia (Mohd Basri et al., 1983).

Before the existence of this weevil, Lespesme (1946), Alibert (1945) and Beirnaert

(1935) believed that insect is not essential in pollination of oil palm and the oil palm

was mainly pollinated by wind. Pollination failures may relate with a low proportion

of male inflorescences during the pollination (Corley & Tinker, 2003). In 1948,

Henry suggested that insects may have played some part during the pollination,

although they are not required for pollination (Corley & Tinker, 2003). According to

Siregar (2006), weevils are host-specific and their adaptation depended on the

seasons, whether it is summer or rain. These weevils were also capable on

transferring pollens in the same quantities in young or old crop. On the other hand,

Syed (1979) found that the oil palm was mainly pollinated by the insects and the

wind played only some part in pollination based on his study in Malaysia and

Cameroon.

The production of the fruit bunch of oil palm and the value of the fruit set are

affected by the several factors. According to the Harun & Noor (2002), the changes

in the population of the E. kamerunicus was affected by the production and fruit set

4

of the fruit bunch. When the population of the weevils increased, the production of

the fruit increased and vice versa. Based on Hutauruk & Syukur (1985) and

Ponnamma (1999), when the population densities of E. kamerunicus increased in

around 20,000 per hectare, it increased the value of the fruit set from 36.9 % to 78.3

% and the good fruit set value was above 75%. According to Donough et al. (1996),

the weevil population was correlated with fruit set which was in turn correlated with

the male inflorescences numbers. Apart from pollinator, there are others factors that

contribute to the production of fruits such as climate change, soil, fertilizer, and

harvesting management (Corley & Tinker, 2003; Sunarko, 2007). According to

Corley & Tinker (2003), natality, mortality and migration of the weevils can cause

fluctuation on the population of the weevil. The introduction of the weevil as an

effective pollinator in 1970s, this successfully ended the costly and inefficient hand

pollination process and resulted in the increase in yields in many oil palms producing

regions (Fairhurst & Mutent, 1999).

This study was done with the objective to investigate the occurrence of oil palm

weevil, E. kamerunicus and correlation with the productivity of oil palm, E.

guineensis. There have been many studies done on the numbers of spikelet, fruit

weight and others parameter such as temperature and soil condition to determine the

productivity of oil palm. However, no study has been done to investigate the

relationship between the pollinator and the fruit productivity based on the diameter

and the numbers of Fresh Fruit Bunch (FFB).

5

CHAPTER 2

LITERATURE REVIEW

2.1 Pollination

The process of transferring pollen from the anther of one flower to the stigma of

another or the same flower is called pollination (Kevan, 1999). According to

Sparnaaij (1969), pollination of oil palm can occur through weevils or wind.

Pollination is the first step in the reproductive process of plants after production of

the sexual organs. Pollination occurs by wind, water and gravity is known as abiotic

pollination while pollination that is facilitated by the animals is known as biotic

pollination (Kevan, 1999). According to Risza (2006), the pollination of the oil palm

can also be done through human assistance. The animals or the flowers visitors

which feed on flowers also known as anthophiles, which mean they seek the pollen,

nectar, oil and floral tissue for food (Kevan, 1999). Some specialized flowers provide

profit (i.e. pollen) for their specialized pollinators and become host to certain species

of insect (Bernhardt & Thien, 1987).

2.1.1 Insect pollination of oil palm

Insects are the most important pollinators in plant, especially the bee species. Others

groups of insects (e.g. moths and beetles) also help in plant pollination (Chiu, 1984;

Kevan, 1999). Animals that can pollinate the plants are called pollinators. In the

good old days, the pollinator of oil palm in Malaysia was Thrips hawaiiensis,

6

although it was present, it had apparently not adapted to the oil palm and does not

fully contributed to pollination because they were absent from young plantings.

Other than that, some pollen was dispersed by micromoth, Pyroderces sp (Tan &

Basri Wahid, 1985). Micromoth, Pyroderces sp and T. hawaiiensis is the pollinating

agents for oil palm before the introduction of E. kamerunicus into West Malaysia

(Syed, 1979, 1981; Sipayung & Soedharto, 1982). Even though T. hawaiiensis is the

pollinator, it was not efficient in pollinating because it has minimum pollination

activity under the cloudy and raining day (Corley & Tinker, 2003). In Sabah, hand

pollination of young palms was necessary because there is no T. hawaiiensis and

only a few other insects were found in the oil palm (Chiu, 1984).

2.2 The potential of E. kamerunicus as pollinator in Malaysia.

In Cameroon, Syed (1982) initiated the study of life cycle and host specificity of

three species of Elaeidobius which has potential to be introduced into Malaysia. The

three species were Elaeidobius kamerunicus, Elaeidobius subvittatus and

Elaeidobius plagiatus. He determined whether the Elaeidobius spp. could be used to

pollinate the oil palm and to ensure that the weevil do not damage the oil palm or

other plants (Syed, 1982). He found out that the entire weevils did not oviposit on the

others flowers but only to oil palm. During the receptivity, the weevil carried the

pollens and visited the female inflorescences and did not injure the female flowers or

the fruits. Syed (1982) concluded that three weevils are safe to be introduced to

Malaysia and E. kamerunicus is the most suitable weevil to pollinate the oil palm

because of its ability to pollinate in wet and dry seasons and carried more pollen

compare to the other species.

7

The person that responsible in introducing the pollinating weevil, E. kamerunicus

into Malaysia is Dr. R.A. Syed in 1979 at Cameroon (Chiu, 1984). During that time,

he found a dozen species of insects visited both the male and female flowers during

anthesis of the oil palm. The species that affect the pollination process is E.

kamerunicus (Corley & Tinker, 2003). The first batch of E. kamerunicus was

imported into Malaysia in July 1980 by Unilever, which is the multinational

company with oil palm plantation in Cameroon and Malaysia (Mohd Basri et al.,

1983). During the quarantine, Malaysian Department of Agriculture carried out host

specificity test on the weevil and the result was comparable to study by Syed (1982).

After the quarantine period, this weevil was released to the Pamol and Mamol

Estates on February 1981 near Kluang, Johore and after a month later at Pamol

Estate in Sabah (Syed, 1982). The weevil had been introduced and has been spread to

all oil palm estate in Malaysia by April 1982 (Mohd Basri et al., 1983).

2.3 The oil palm weevil, E. Kamerunicus

Scientific classification of oil palm weevil (Figure 2.1):

Kingdom : Animalia

Phylum : Arthropoda

Class : Insecta

Order : Coleoptera

Family : Curculionidae

Genus : Elaeidobius

Species : Elaeidobius kamerunicus

8

Figure 2.1 Lateral view of E. kamerunicus (Source: http://www.padil.gov.au)

The morphological characters of the E.kamerunicus include a dark brown body in

which the body is divided into three parts: head, thorax and abdomen. They have a

pair of wings in the thorax: the tick wings called ‘elytra’ and the membranous thin

wings. There are size differences between a male and female weevil in which the

male is bigger compare to female. The average size of the adult is between 1.8 to 4.0

mm (O’Brien & Woodruff, 1986). The male weevil has shorter proboscis or the

mouthpart than female. Others than that, the body appearance of the male weevils is

more hairy compare to female (Harumi, 2011). At the end of the elytra, the male

weevils have marginal setae which are not found in female (O’Brien & Woodruff,

1986; Kurniawan, 2010).

According to Syed (1982), the duration period for the weevil to develop from egg to

adult is between seven to 14 days in the field and the average of the adult longevity is

from 15 to 17 days. In another study by Tuo et al. (2011), the average of life

expectancy for the E. kamerunicus is 59.18 ± 8.53 days and for the life cycle time

was 10.27 ± 0.34 days. The life cycle of the female is around 65 days and for male is

9

46 days (Arif et al., 2009). The adult weevil is attracted to both male and female

inflorescences by the strong aniseed smell (Corley & Tinker, 2003; Susanto et al.,

2007). Although this weevil is specific to oil palm, the adult could survive on

Eugenia aqueous flowers (only for one week) and Cocoa nucifera flowers (only for

two weeks) but not oviposit. Against these all plant species, the weevil only

attracted to the flowers of E. guineensis because the flower provided the food and

become host to the weevil (Corley & Tinker, 2003). According to Adaigbe et al.

(2011), E. kamerunicus were able to differentiate host and non-host species through

the olfactory response by odour emitted from inflorescences plant. The population of

the male and female weevils in the field is 1:2.

According to Tandon et al. (2001), the time visitation of the weevil from the male

flowers to female inflorescences started around 7.00 am until 3.00 pm and the

maximum activity was observed between 11 to 12 noons. The total visitation

frequencies of E. kamerunicus on female inflorescences were 128 weevils per 30

minutes (Anggriani, 2010). This weevil also becomes less active during the raining

season or cloudy days and after the downpours (Syed, 1982). The population of the

weevils also was lower during the wet season (Syed, 1982).

2.4 The African oil palm, Elaeis guineensis Jacq.

Malaysia is one of the countries that have the oldest oil palm industry in the world

and the overall development of the country is moving rapidly as well as oil palm

plantation (Guerts, 2000). Oil palm is the usual crop of the rainy tropical lowlands.

The trees required a deep soil, light intensity, stable in high temperature and

10

continuous moisture through the year (Verheye, 2010). Dry periods of more than two

to three months do not specifically damage vegetative growth but affect the

production and quality of the fruit bunches seriously (Verheye, 2010). Oil palm yield

is not only determined by the vegetative growth and production but also by the

control of pests and diseases (Verheye, 2010).

2.4.1 Descriptions of E. guineensis Jacq.

Oil palm (E. guineensis Jacq.) is derived from three words namely Elaeis, derived

from the Greek, word, Elation means oil, guineensis originated from Guinea

language (west coast of Africa) and Jacq. came from the name of the American

Botanical, Jacquin (Figure 2.2).

Figure 2.2 African Oil Palm (Elaeis guineensis Jacq.) at Bangka Semong Oil Palm Plantation (Photo

credit by Siti Khadijah Bt Abdul Khalid)

the occurance of oil palm weevil, elaeidobius … occurance of oil palm weevil... · figure 3.3...

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