IJERD – International Journal of Environmental and Rural Development (2020) 11-2

Research article
erd

Diversity of Arthropod Natural Enemy Species in Intensive
Monsoon Rice Growing Area, Nay Pyi Taw, Myanmar
WAI ZIN PHYU*
Yezin Agricultural University, Myanmar
Email: waizinphyu209@gmail.com

MOE HNIN PHYU
Yezin Agricultural University, Myanmar

THI TAR OO
Yezin Agricultural University, Myanmar
Received 20 January 2020

Accepted 27 November 2020(*Corresponding Author)

Abstract This study was conducted to investigate the species diversity of arthropod natural
enemy species structure in intensive monsoon rice cultivation areas during 2018. The studysite is Kyee Inn village, Pyinmana Township, Myanmar, and over 550 ha. Data collectedfrom (300 m x 300 m) grid pattern and 56 grid points (G) using a D-Vac vacuum suctionmachine. This study identified eight orders, 30 families, 57 genera, and 28 arthropod natural
enemy species. The highest species richness occurred in Order Hymenoptera, followed by
Order Coleoptera and Order Hemiptera. The diversity of natural enemy was varied widelywith different grid points. The recorded equitability (evenness) was equally abundant in mostgrid points, but some have high single-species dominance. The highest number ofCyrtorhinus lividipennis (Order Hemiptera) found in G18, even though G18 displayed amedium diversity index and low equitability. The population of Cyrtorhinus lividipennis washigher than other species in all grid points. It may due to food sources are abundant during
the growing season. Fortunately, we observed many natural enemy species, and it should
conserve for natural balance to maintain the pest population.
Keywords natural enemy community, species diversity, equitability,
intensive monsoon rice

INTRODUCTION
Rice (Oryza spp.) is the most important and widely cultivated crop globally. It is the staple crop for
more than 60 percent of the world population. Rice is a dietary staple throughout all Myanmar. In
Myanmar, paddy sown total area is 7.28 million hectares (monsoon and summer rice), and riceproduction is 28.32 million metric tons (MOAI, 2014). Arthropods are the most diverse and dominantconstituent of biodiversity in terrestrial ecosystems. It is the largest animal phylum constituting about
85% of all known animals in the world (Odegaard, 2000).
In agricultural fields where pesticide use is minimized, crop production commonly depends onnatural controls provided by a pest's natural enemies. These have an important role in regulating pest
populations (Barbosa, 1998). The importance of natural enemies is particularly highlighted when apest resurgence takes place (Dent, 2000). Indiscriminate use of agrochemicals, such as insecticides,
harms these natural enemies and causes a loss in such beneficial organisms' biodiversity. Agrobiodiversity performs several ecosystem services (Dudely et al., 2005).
The biodiversity of beneficial natural enemies may be a pivotal resource to improve productivity
and sustainability in agriculture (Schmitz, 2007). The arthropods, natural enemies of rice insect pests,
include a wide range of predators and parasitoids such as carabid beetles, aquatic and terrestrial
predatory bugs, and dragonflies. Parasitoids include many hymenopteran wasp species and some
dipteran flies (Bambaradeniya and Amerasinghe, 2003). Beneficial insects provide regulating
ecosystem services to agriculture such as pollination and the natural regulation of plant pestsⒸ ISERD

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IJERD – International Journal of Environmental and Rural Development (2020) 11-2

(Getanjaly, 2015). Although most of the farmers are familiar with some rice insect pests in Myanmar,
they don't know the important role of arthropod natural enemies and are not familiar absolutely. Thus,
it is crucial to study the species richness of natural enemies in their habitat and conserve them toimprove biological control.
OBJECTIVE
This research investigates the species richness and diversity of natural enemies on monsoon rice tosupport farmers' valuable information.
METHODOLOGY
Study Site
The study was conducted in 56 farmers' fields during the monsoon rice season at Kyee Inn village,
Pyinmana Township, Nay Pyi Taw, which lies between 19°70'66''-19°72'62'' N and 96°22'43''96°25'73'' E from July to November 2018. The sampled area is 2.4 Km wide by 3.9 Km long (550ha). The Manawthukha rice variety is grown in the study fields using farmers' usual practices.

Nay Pyi Taw

Kyee Inn
VillagePyinmana TownshipFig. 1 Study areas at Kyee Inn Village, Pyinmana Township, Myanmar
Species Sampling
Arthropod natural enemies were collected on a 300 m by 300 m grid pattern, resulting in 56 grid
points started at 20 days after sowing until harvest time. Five samples were taken at random fromeach rice field. All samples were collected near the center of the plot, at least 5m from the edge, toreduce edge effects using D- Vac Vacuum Insect et - Hand Carry Model 122S (made by Rincon –Vitova Insectaries). The collection from 4-5 hills of rice plant after sowing, but only 2-3 hills after
the rice plant reached maximum tillering at the fortnightly interval. Sampling duration was fixed at
1 to 2 min, depending on the rice's growth stage, and each sampling repeated three times. All samples
inside the enclosure were collected and transferred to plastic bottles containing ethyl acetate withcotton wool, with species identification conducted in the laboratory for identification. All thecollected samples were stored in 90% methylated spirit.
Identification of Species
Species identification was made in the JICA-ELB1 Laboratory, Department of Entomology andZoology, Yezin Agricultural University. All the collected samples were stored in 90% methylated
spirit. Morphospecies identification was made by using the textbooks of Insects of Australia (CSIRO,
1970), Manual of Nearctic Diptera, Volume 1, 2, 3 (McAlpine et al., 1981), and Pests of rice andⒸ ISERD

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IJERD – International Journal of Environmental and Rural Development (2020) 11-2

their natural enemies in Peninsular Malaysia (Vreden and Ahmadzabidi, 1986) with OLYMPUS SZ
61 camera attached microscope (10x × 45x).
Data Analysis
The abundance and species richness of arthropod natural enemies were measured by the ShannonWiener function (Krebs, 1978). Shannon-Wiener function was used to measure the index of species
diversity by the following formula:
𝑆

𝐻= −∑

(𝑃𝑖 ) (𝑙𝑜𝑔2 𝑃𝑖 )𝑖=1

Where;
H = index of species diversity or information content of sample (bits/individual)
S = number of species
Pi = proportion of total sample belong to ith species (Krebs, 1978)
More even or equitable distribution among species will also increase species diversity measured by
the Shannon-Wiener function (Krebs, 1978). Equitability (evenness) measured in;
𝐸 = 𝐻/𝐻𝑚𝑎𝑥
Where;
E = equitability (range 0 – 1)
H = observed species diversity
Hmax = maximum species diversity = log2S
RESULTS AND DISCUSSION
Species Diversity and Abundance of Natural Enemy Species
There were eight orders, 30 families, 57 genera, 28 species identified in this study (Table 1). The
observed arthropod orders are Araneae, Coleoptera, Dermaptera, Diptera, Hemiptera, Hymenoptera,
Odonata, and Orthoptera. In 2014, 44 species from seven orders of natural enemy species wereobserved in Nyaungbingyisu, Nay Pyi Taw (Khin Ngu War Thant, 2016). May Thet Hlaing (2017)
surveyed 118 species in Nyaungbingyisu (Pobbathiri Township), 62 species in Kyarku,
Dekkhinathiri Township, and 105 species Zalaung, Oattarathiri Township, and 103 species in Yezin
Agricultural University Campus. Hurlbert et al., (1989) found that the numbers of species andindividuals and the diversities and evenness values were distinctly different according to habitat, typeof field, and rice growth stage. The criterion used by (Rahayu et al., 2006) holds that species
biodiversity is high when the value is greater than 3, a medium between 1 and 3, and low when lessthan 1. In our study, high diversity index occurs at 11 grid points and a medium at 44 grid points.
The remaining grid points displayed a low level of diversity. Therefore, the overall species diversity
index was considered in the medium criterion (Fig. 2.a, b).
Alatalo (1981) devised an index of species abundance (evenness or equitability) typically on ascale ranging from near 0, indicating low evenness or high single-species dominance, to 1, whichmeans an equal abundance of all species, or maximum evenness. According to the results, therecorded equitability (evenness) of 19 grid points show a low index of evenness, while 37 grid points
are approaching equal abundance (≥ 0.5) (Fig. 3.a, b). According to the results, the recorded
equitability (evenness) of most grid points in the study area was nearly equally abundant, and someare high single-species dominant. The highest diversity index (3.44) is in G31 and the most evenness(0.82) in G32 (Fig. 2.b and Fig. 3.b).
On the other hand, the lowest diversity index (0.99) and least equitability (0.22) occurs in G46(Fig 2.b and Fig 3.b). Therefore, the diversity of natural enemy species varied widely according todifferent grid points due to adjacent habitats, cropping patterns of the area, farmers' practices such as
irrigation, pesticides, fertilizers, and pests.
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Table 1 Recorded natural enemy species from the study area,
Kyee Inn Village, Pyinmana Township, 2018
No.
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
21.
22.
23.
24.
25.
26.
27.
28.
29.
30.
31.
32.
33.
34.
35.
36.
37.
38.
39.
40.
41.
42.
43.
44.
45.
46.
47.
48.
49.
50.
51.
52.
53.
54.
55.
56.

Order
Araneae
Araneae
Araneae
Araneae
Araneae
Araneae
AraneaeColeoptera
Coleoptera
Coleoptera
Coleoptera
Coleoptera
Coleoptera
Coleoptera
Coleoptera
Coleoptera
Coleoptera
Coleoptera
Coleoptera
Coleoptera
Coleoptera
Coleoptera
Coleoptera
Dermaptera
Dermaptera
DipteraHemiptera
Hemiptera
Hemiptera
Hemiptera
Hemiptera
Hemiptera
Hemiptera
HemipteraHymenoptera
Hymenoptera
Hymenoptera
Hymenoptera
Hymenoptera
Hymenoptera
Hymenoptera
Hymenoptera
Hymenoptera
Hymenoptera
Hymenoptera
Hymenoptera
Hymenoptera
Hymenoptera
Hymenoptera
Hymenoptera
Hymenoptera
Hymenoptera
Hymenoptera
Hymenoptera
Hymenoptera
Hymenoptera

FamilyTetragnathidae
Araneidae
Oxyopidae
Linyphiidae
Lycosidae
Lycosidae
Lycosidae
Staphylinidae
Coccinellidae
Anthicidae
Staphylinidae
Carabidae
Carabidae
Coccinellidae
Coccinellidae
Carabidae
Carabidae
Carabidae
Staphylinidae
Carabidae
Carabidae
Hydrophilidae
Staphylinidae
Anisolabididae
Forficulidae
Pipunculidae
Miridae
VeliidaePentatomidae
Reduviidae
Mesoveliidae
Reduviidae
Reduviidae
Reduviidae
Dryinidae
Eulophidae
Dryinidae
Braconidae
Pteromalidae
Formicidae
Eulophidae
Formicidae
Eurytomidae
Diapriidae
Platygastridae
Diapriidae
Braconidae
Formicidae
Formicidae
Formicidae
Formicidae
Halictidae
Ichneumonidae
Braconidae
Formicidae
Ichneumonidae

Genus
Tetragnatha
Araneus
OxyopesAtypena
Hippasa
Trochosa
LycosaBledius
Micraspis
Anthicus
Paederus
Bembidion
Casnoidea
Harmonia
Menochilus
Clivina
Ophionea
Eucolliuris
Lathrobium
AnillusAnoplogenius
Berosus
StenusEuborellia
Doru
Tornosvaryella
Cyrtorhinus
Microvelia
Zicrona
Polytoxus
Mesovelia
Peregrinator
Rhynocoris
Zelus
Aphelopus
Elasmus
Gonatopus
BraconTrichomalopsis
Dorymyrmex
Tetrastichus
Myrmecocystus
Eurytoma
Trichopria
Macroteleia
Trichopria
Phanerotoma
Leptothorax
Pheidole
LasiusManicaSpeciesmaxillosasp.
sp.
formosana
sp.
sp.
sp.
filipescroceasp.
ripariussp.
indicaoctomaculata
sexmaculatus
fossornigrofasciata
fuscipennis
sp.
sp.
sp.
sp.
sp.
annulipes
sp.
oryzaetora
lividipennis
douglasisp.
fuscoviftatus
vittigera
biannulipes
sp.
sp.
sp.
sp.
zealandicus
sp.
sp.
sp.
sp.
mexicanus
sp.
basalissp.
drosophilae
sp.
sp.
sp.
sp.
sp.

CharopsSpathius
Solenopsis
Xanthopimpla

brachypterumsp.
sp.
flavolineataⒸ ISERD

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Mean
18.29
8.60
3.40
3.20
2.40
0.67
0.43
12.40
1.57
1.33
1.33
1.00
0.71
0.50
0.40
0.33
0.33
0.20
0.20
0.17
0.17
0.14
0.14
1.00
0.29
2.57
199.20
3.00
0.71
0.50
0.43
0.33
0.20
0.14
15.60
15.00
7.14
7.00
4.43
4.40
3.67
3.00
1.17
1.00
0.57
0.50
0.40
0.33
0.29
0.20
0.20
0.20
0.20
0.17
0.17
0.17

SE (±)
4.83
3.46
3.16
3.20
1.29
0.49
0.43
12.40
1.41
0.72
0.88
1.00
0.47
0.50
0.24
0.33
0.21
0.20
0.20
0.17
0.17
0.14
0.14
1.00
0.18
1.93
133.46
1.90
0.71
0.50
0.43
0.33
0.20
0.14
15.35
11.66
4.72
5.05
2.36
4.15
2.08
3.00
1.17
0.82
0.20
0.34
0.40
0.33
0.29
0.20
0.20
0.20
0.20
0.17
0.17
0.17

IJERD – International Journal of Environmental and Rural Development (2020) 11-2

Table 1 (contd.)
No.
57.
58.
59.
60.

Order
Odonata
Odonata
Orthoptera
Orthoptera

FamilyCoenagrionidae
Coenagrionidae
Gryllidae
Gryllidae

Genus
Agriocnemis
Agriocnemis
Anaxipha
MetiocheSpeciespygmaeafeminalongipennis
vittaticollis

Mean
5.50
3.29
3.17
0.17

SE (±)
5.50
2.65
1.40
0.17

These results were consistent with the finding of several authors have concluded that theabundance and diversity of predators and parasitoids within a field are closely related to the natureof the vegetation surrounding the field (Hopper, 1989). There is wide acceptance of the importanceof vegetation surrounding the field margins as the reservoirs of crop pests' natural enemies.

(a)

(b)

Fig. 2 Diversity index of natural enemies on rice during monsoon season
in study area (a) grid points 1 to 28 (b) grid points 29 to 56

(a)

(b)

Fig. 3 Equitability in distribution of natural enemies on rice during monsoon season
in study area (a) grid points 1 to 28 (b) grid points 29 to 56
The highest species richness of natural enemies occurs in the Order Hymenoptera, which
includes ten families, 20 genera and six species identified. The second highest species richness from
Order Coleoptera consists of five families, 16 genera and nine identified species. Order Hemiptera
has the third-highest species richness includes five families, eight genera and five identified species.
In Order Araneae, family Tetragnathidae, the highest mean number of Tetragnatha maxillosa(18.29 ± 4.83 individual) occurs at G10. Tetragnatha maxillosa is a spider species that is very active
during the night and preys upon brown planthopper (Nilaparvata lugens), leafhopper (Nephotetteixsp.), and some other insect pest species (Betz and Tscharntke, 2017). Spiders are used as a biologicalcontrol agent of rice pests instead of chemicals (Khan, 2013). In Coleoptera, the highest mean number
of Bledius filipes (12.40 ± 12.40 individual) from the family Staphylinidae occurs in G16. It might
feed on algae and detritus (Mark, 2006). The mean number of Anthicus sp. (1.33 ± 0.72 individual)
from family Anthicidae occurs in G43. Ant-like flower beetles are mainly saprophagous, somespecies being predaceous or anthophilous (feeding on flowers) (Telnov, 2008). Insects are directly
beneficial to humans by producing honey, silk, wax, and other products. Indirectly, they areimportant as pollinators of crops, natural enemies of pests, scavengers, and food for other creatures(Hoffmann and Frodsham, 1993). Under Order Dermaptera, the highest mean number of Euborellia
annulipes (1.00 ± 1.00 individual) from the family Anisolabididae is observed in G56. In Order
Diptera, the highest mean number of Tornosvaryella oryzaetora (2.57 ± 1.93 individual) from thefamily Pipunculidae is in G22. In Order Hemiptera, the highest mean number of Cyrtorhinus
lividipennis (199.20 ± 133.46 individual) belongs to the family Miridae in G18. Predators are mainlyⒸ ISERD

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from Order Heteroptera include Cyrtorhinus lividipennis (Miridae) and Microvelia douglasi(Veliidae), being the most abundant species (Heong et al., 1991).
Under Order Hymenoptera, the highest mean number of Aphelopus sp. (15.60 ± 15.35
individual) belongs to the family Dryinidae and occurs in G7. Noyes (2008) reported that several
species of Eulophidae are important in biocontrol programs throughout the world. Hymenoptera is
the most important insect order due to many insect species that are potential pollinators andparasitoids. Its ecological specialist species are also being used widely for habitat quality assessment(Trevis, 1996). In Order Odonata, the highest mean number of Agriocnemis pygmaea (5.50 ± 5.50
individual) belong to the family Coenagrionidae and occur at G43. In Order Orthoptera, the highest
mean number of Anaxipha longipennis (3.17 ± 1.40 individual) belongs to the family Gryllidae from
G29. Among them, the observed dominant rice natural enemy species is Cyrtorhinus lividipennis
belonging to Order Hemiptera. This result was consistent with the finding of Heong et al., (1990),
who stated that the mirid bug Cyrtorhinus lividipennis was found to predate on the eggs and nymphsof both leafhoppers and planthoppers, preferring mainly BPH eggs. The population density of
Cyrtorhinus lividipennis increase in the abundance of the BPH and WBPH. Brown planthopper andWhiteback planthopper provide a broader range of food sources for an extended period during thegrowing season.
CONCLUSION
This study indicates that, arthropod natural enemy species diversity is medium in most of the grid
points for the study period. Sample results yielded eight orders, 30 families, 57 genera, and 28 speciesof arthropod natural enemies in the study. According to the results, the observed species diversity
index was considered in the medium criterion. The recorded equitability (evenness) of most grid
points was nearly equally abundant, and some are high single-species dominance. The population of
Cyrtorhinus lividipennis was higher than other species in all grid points. Therefore, the diversity ofnatural enemy species varied widely according to different grid points due to adjacent habitats,
cropping patterns of the area, farmers' practices such as irrigation, pesticides, fertilizers, and pests.
Therefore, it may be assumed that the Brown planthopper and Whiteback planthopper populations
are abundant in this and previous year and found vegetation near the field in this study area. Brown
planthopper and Whiteback planthopper provide a wider range of food sources for an extended period
during the growing season. Some insects such as Bledius filipes, Anthicus sp., Berosus sp. from Order
Coleoptera and Manica sp. from Order Hymenoptera are found as beneficial insects because ofvegetation near the field. Proper identification and understanding of natural enemies, as well as
beneficial insects, is the first step in implementing biological control and enhancing pollination
activity. Therefore, Natural enemies and beneficial insects in rice fields play an important role inagriculture. Suppose we create a better environment for natural enemies by using non-chemical
control methods at different rice growth stages. In that case, many natural enemies may suppress pest
populations, which may benefit the farmers. The present study's findings may help provide valuable
information for farmers to improve biological control techniques. Additionally, further studies should
be undertaken to establish the abundance and different natural enemies present in this area.
ACKNOWLEDGEMENTS
The authors would like to thank the generous financial and technical training support provided by
the Japan International Cooperation Agency (JICA) Project for Capacity Development of Yezin
Agricultural University (YAU-JICA TCP). We are also appreciative of the authorized persons fromthe Department of Agriculture (DoA) for facilitating the farmers’ participation in this project.
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