Insects Diversity and Abundance in Coastal and Inland Forest of Perhentian Island, Terengganu, Peninsular Malaysia

Abstract

Perhentian Island is one of the most famous tourism sites in Terengganu, Peninsular Malaysia. The impact of tourism activities as well as high construction of infrastructure and facilities can pose a threat to flora and fauna, particularly on insects. Therefore, this study aimed to determine the insects' diversity and abundance in the coastal and inland forest of Perhentian Islands using three insect's traps which were; Malaise traps, yellow pan traps, and pitfall traps. The traps (i.e. three points per plots) were left for seven days before the insects were collected. A total of 1382 individuals of insects consisting of 11 orders were successfully collected with order of Diptera and Hymenoptera dominate the number of individuals collected. The insect's individuals were slightly higher in the coastal forest with 699 individuals (11 orders) than in the inland forest with 683 individuals (9 orders).However, there was no significant difference (P>0.05) of insect's abundance recorded between the coastal and inland forest of Perhentian Island. The Shannon-Weiner Diversity Index (H') showed that the diversity of insects in the coastal forest was higher with H'=1.51 than inland forest with H'=1.35 respectively. We conclude that the insects' diversity and abundance in Perhentian Island is relatively high in coastal forest but low in inland forest. This research provides a basic information and dataset of insects' diversity and abundance which may useful for further ecological research at Perhentian Island in the future.

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Bioscience Research
Print ISSN: 1811-9506 Online ISSN: 2218-3973
Journal by Innovative Scientific Information and Services Network
RESEARCH ARTICLE BIOSCIENCE RESEARCH, 2019 16(SI): 53-58. OPEN ACCESS
Insects Diversity and Abundance in Coastal and
Inland Forest of Perhentian Island, Terengganu,
Peninsular Malaysia
Salmah Mohamed1*, Khairunnadia Mohd Zamri1, Aishah Zullkeflee1, Mohammad
Hailmi Sajili1, Marina Roseli2, Khairil Mahmud2
1School of Agriculture Science and Biotechnology, Faculty of Bioresources and Food Industry, Universiti Sultan
Zainal Abidin, Besut Campus, 22200 Besut, Terengganu, Malaysia
2Faculty of Agriculture, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor, Malaysia
*Correspondence: salmahmohamed@unisza.edu.my Revised: 06 Oct. 2019, Accepted: 08 Oct. 2019 e-Published: 11 Nov.
2019 Reviewed by: Dr. Moneruzzaman Khandaker, Dr. Norhayati Ngah
Perhentian Island is one of the most famous tourism sites in Terengganu, Peninsular Malaysia. The
impact of tourism activities as well as high construction of infrastructure and facilities can pose a threat
to flora and fauna, particularly on insects. Therefore, this study aimed to determine the insects’ diversity
and abundance in the coastal and inland forest of Perhentian Islands using three insect’s traps which
were; Malaise traps, yellow pan traps, and pitfall traps. The traps (i.e. three points per plots) were left for
seven days before the insects were collected. A total of 1382 individuals of insects consisting of 11
orders were successfully collected with order of Diptera and Hymenoptera dominate the number of
individuals collected. The insect’s individuals were slightly higher in the coastal forest with 699
individuals (11 orders) than in the inland forest with 683 individuals (9 orders).However, there was no
significant difference (P>0.05) of insect’s abundance recorded between the coastal and inland forest of
Perhentian Island. The Shannon-Weiner Diversity Index (H’) showed that the diversity of insects in the
coastal forest was higher with H’=1.51 than inland forest with H’=1.35 respectively. We conclude that the
insects’ diversity and abundance in Perhentian Island is relatively high in coastal forest but low in inland
forest. This research provides a basic information and dataset of insects’ diversity and abundance which
may useful for further ecological research at Perhentian Island in the future.
Keywords: Insects, diversity, population, forest, island
INTRODUCTION
Insect is an important component of the most
natural and transformed landscape. They play an
important role in ensuring the delivery of various
ecosystem services that are important to some
aspects of human life such as agriculture, tourism,
and natural resource (Kehinde et al., 2014).
Insects are the world’s most diverse group of
animals and covered more than 58% of the global
biodiversity (Adler and Foottit, 2009). Therefore
insects can be found unbelievably great from the
tropical rainforest canopy including in the island
forest. Ecologically, insects are functionally
important for forest ecosystems as pollinator,
herbivore, decomposer, predator or parasitoid
(Idris and Hasmawati, 2002). The islands located
in the east coast of Peninsular Malaysia is very
heavily forested and may provide a very important
ecological role (Cronk, 2001). The islands offer a
place for endemic, endangered and migratory
species as previously evident in the same
forested islands in Southeast Asia (Turner et al.,

Salmah et al. Insects Diversity and Abundance in Perhentian Island Forest
Bioscience Research, 2019 volume 16(SI): 53-58 54
2002).
The tourism industry is one of the largest
services industries in Malaysia and Perhentian
Island is one of the most popular tourist sites of
Terengganu in Peninsular Malaysia. The forest of
Perhentian Island is endowed with high
biodiversity of flora and fauna (Pesiu et al., 2017).
However, the impact of tourism activities on the
environment has spread in various components
which directly affected ecological and natural
resources (Ramdas and Mohamed, 2014). The
high construction of infrastructure and other
facilities that aiming for increasing number of
tourists threatens the habitat surrounded by flora
and fauna. Constant destruction of the forest in
Perhentian Island will have an impact on insects’
abundance that eventually lead to the extinction
of certain species. Thus, the destruction of forest
greatly influenced the insect’s abundance to
inhabit in the forest island due to the decrease in
the plant diversity that acts as the food sources
and shelter to them. To date, there is no details
study was conducted in assessing the insect
diversity and abundance of coastal and inland
forest at Perhentian Island. We suspect the
diversity and abundance of the coastal forest and
inland forest at that area may different. Therefore,
this study was conducted to determine the
diversity and abundance of insects between the
coastal and inland forest of Perhentian Island. The
data observed can be used for further ecological
research at Perhentian Island in future.
MATERIALS AND METHODS
Sampling Site
This research was conducted at Big
Perhentian Island, Besut, Terengganu, Peninsular
Malaysia. It is located 20 km (10 nautical miles)
from the north-eastern coast of Peninsular
Malaysia with the maximum elevation is 70 m
above sea level (asl). The samplings were carried
out at two different forest types namely the coastal
forest viz. 1 to 30 m asl (Plot A) and the inland
forest viz. 50 to 70 m asl (Plot B). Each plot
consists of three sampling points and the
selection of trapping points in each sampling point
is done randomly.
Insects sampling were carried out with three
distinct types of trapping techniques such as
Malaise trap, yellow pan trap and pitfall trap. In
each sampling points, one Malaise trap and three
yellow pan traps and three pitfall traps were set
up. The traps were left in the forest for seven days
(from 5 August 2018 – 12 August 2018). The
insects collected were preserved in the collecting
bottles containing 70% ethanol before brought
back to the laboratory for sorting and identification
process.
Insects Identification
The samples were brought to the Laboratory
of Entomology, Faculty of Bioresources and Food
Industry, Universiti Sultan Zainal Abidin (UniSZA)
for the identification process. All insects collected
were sorted out according to their order by using
forceps. The insects were pinned to preserve the
structure of the sample. The identification of
orders was based on their morphological and
physical characteristic under stereoscopy
microscope (Olympus SZ51, Japan). All the
specimens were identified based on Triplehorn
and Johnson (2005).
Data Analysis
T-test analysis was conducted in comparing
the insect abundance between the coastal and
inland forest. One-way ANOVA was used for
comparing the abundance of insects between
orders. Both T-test and One-way ANOVA were
analyzed using Minitab software version 2018.
Analysis of the insect's diversity, richness and
evenness were done by the Shannon-Weiner
Diversity Index, and Margalef’s Richness Index
using Bio-Dap software. Shannon-Weiner
Diversity Index of species diversity is commonly
used to ascertain the species diversity (Izsák and
Papp, 2000).
RESULTS
The abundance of Insects in the Coastal and
Inland Forest of Perhentian Island
A total of 1382 individuals of insects were
successfully collected from Perhentian Island
forest which comprised of 11 insect orders (Table
1). The orders were identified as Diptera,
Hymenoptera, Lepidoptera, Coleoptera,
Collembola, Homoptera, Orthoptera, Hemiptera,
Dermaptera, Isoptera and Blattodea. From the
total sample collected, 699 individuals were
collected from the coastal forest comprised of 11
orders (Table 2) and 683 individuals were
collected from the inland forest comprised of nine
orders (Table 3). Nonetheless, there was no
significant difference (P>0.05) occurred of the
insect abundance between the coastal and inland
forest of Perhentian Island (Figure 1).
Table 1 showed that the Diptera and
Hymenoptera recorded significantly the highest

Salmah et al. Insects Diversity and Abundance in Perhentian Island Forest
Bioscience Research, 2019 volume 16(SI): 53-58 55
individual number of insects in Perhentian Island
compared to other orders with 543 (39.3%) and
537 (39.9%) individuals, respectively and followed
by Lepidoptera (82 individuals, 5.9%). Whilst the
lowest number of individuals collected was
Blattodea with only 2 individuals (0.1%). The
remaining 15.8% of the number of individuals
collected were Coleoptera, Collembola,
Homoptera, Orthoptera, Hemiptera, Dermaptera,
and Isoptera. Overall, the insect abundance
according to the order in Perhentian Island had
shown a significant difference (P<0.05).
Similarly, for both forests, Diptera and
Hymenoptera order recorded the highest number
of individuals with represented 75.6% from the
total individuals collected at the coastal forest
(Table 2) and 81% in the inland forest (Table 3).
However, there was no significance differences
observed for insect’s abundance between inland
and coastal forest of Perhentian Island (P>0.05)
(Figure 1).
Table 1; Total composition of Insect
abundance of different orders in Perhentian
Island.
Order
Average
Insect ( ± SE)
Total
Insect
%
Diptera
4.33 ± 0.26a
543
39.3
Hymenoptera
4.39 ± 0.21a
537
38.9
Lepidoptera
2.50 ± 0.21b
82
5.9
Coleoptera
2.52 ± 0.17b
80
5.8
Collembola
2.12 ± 0.37bc
67
4.9
Homoptera
1.50 ± 0.26bcd
32
2.3
Orthoptera
0.98 ± 0.15cd
17
1.2
Hemiptera
0.73 ± 0.73cd
11
0.8
Dermaptera
0.69 ± 0.40cd
7
0.5
Isoptera
0.55 ± 0.55cd
4
0.3
Blattodea
0.33 ± 0.21d
2
0.1
Total insects
1382
100
Mean with the same letters was not significantly
different at P<0.05
Figure 1; Insect abundance between the
coastal and inland forest of Perhentian Island.
Table 2: The composition of insect abundance
of different orders in the coastal forest of
Perhentian Island.
Order
Average Insect
( ± SE)
Total
Insect
%
Diptera
4.41± 0.40a
294
42.1
Hymenoptera
4.23± 0.36ab
234
33.5
Lepidoptera
2.63± 0.39abc
48
6.9
Coleoptera
2.51± 0.06abc
37
5.3
Collembola
2.52± 0.47abc
45
6.4
Homoptera
1.33± 0.23bcd
12
1.7
Orthoptera
0.99± 0.31cd
9
1.3
Hemiptera
1.10± 0.9cd
10
1.4
Dermaptera
1.39± 0.00cd
4
0.6
Isoptera
0.55± 0.55cd
4
0.6
Blattodea
0.00 ± 0.00d
2
0.3
Total insects
699
100
Mean with the same letters was not significantly
different at P<0.05
Table 3; the composition of insect abundance
of different orders in the inland forest of
Perhentian Island.
Order
Average Insect
( ± SE)
Total
Insect
%
Diptera
4.25 ± 0.40ab
249
36.5
Hymenoptera
4.56 ± 0.26a
303
44.5
Lepidoptera
2.37 ± 0.24bcd
34
5.0
Coleoptera
2.73 ± 0.39bc
43
6.3
Collembola
1.71 ± 0.53cd
22
3.2
Homoptera
1.68 ± 0.51cd
20
3.0
Orthoptera
0.96 ± 0.14cd
8
1.2
Hemiptera
0.00 ± 0.00cd
1
0.1
Dermaptera
0.35 ± 0.35d
3
0.4
Total insects
683
100
Mean with the same letters was not significantly
different at P<0.05
Insects Diversity, Richness, and Evenness
Table 5 showed a summary of Shannon-Weiner
Diversity Index, Evenness Index and Margalef’s
Richness Index in the coastal and inland forest of
Perhentian Island The insect’s diversity in the
coastal forest is H’=1.51 and was higher than the
inland forest with H’=1.35. But no significance
different (P>0.05) of diversity was recorded
between those forest. The result of species
evenness showed similar value among coastal
forest (E’=0.63) and inland forest (E’=0.62).
Species richness (R’) of coastal forest showed
a
a
0
100
200
300
400
Coastal forest Inland forest
Insects abundance
(±SE)
Plot area

Salmah et al. Insects Diversity and Abundance in Perhentian Island Forest
Bioscience Research, 2019 volume 16(SI): 53-58 56
higher value at 0.42, compared to the inland forest
with lower value at 0.34.
Table 5; Shannon-Weiner Diversity Index,
Evenness Index and Margalef’s Richness
Index of insects at Perhentian Island forest.
Index
Coastal
Forest
Inland
Forest
Diversity (H’)
1.51
1.35
Evenness (E’)
0.63
0.62
Richness (R’)
0.42
0.34
DISCUSSION
The abundance of insects between the
coastal and inland forest of Perhentian Island is
non-significant (p>0.05). This might be due to the
highest altitudes of the sampling site was only 70
m above sea level (a.s.l). According to McCoy
(1990), the distribution of insects varies with every
100 m increase in elevation. His statement
supported that the height of the sampling site in
Perhentian Island was not high enough to meet a
variety of insects. Besides that, Purcell (2010)
reported that insects usually attribute at a lower
elevation than higher elevation. For example,
Khairul Husna et al. (2018) reported that the
abundance of Diptera in Gunung Datuk, Negeri
Sembilan had the highest number of individuals at
low elevation (200 m asl) compared to high
elevation (700 m asl). In addition, McCoy (1990)
reported that the number of insects tends to
decrease with elevation increase.
Results also showed that Diptera and
Hymenoptera were the dominant insect orders in
both types of Perhentian Island forest while
Leidoptera was the third abundance order in both
forests. The findings are similar to Koike et al.
(1998) and Siti Aishah et al. (2017) which they
reported that Diptera and Hymenoptera dominate
the inside canopy structure in the tropical
rainforest of West Kalimantan and Gunung Datuk,
Negeri Sembilan, respectively. The reason for the
highest number of Diptera recorded in Perhentian
Island due to the Diptera as one of the largest
groups of insects and make up the largest
gathering of insects in the world (Brown, 2005).
Diptera is important in balancing the ecosystem
as it plays an important role as a pollinator,
scavenger, predators and vector (Khairul Husna
et al., 2018). Thus, hymenopteran species such
as bees and ants as well as lepidopteran
(butterflies) are also known as good pollinators for
various vegetation. Previous studies conducted in
Perhentian Island showed that about five species
of bees were recorded (Adanan et al., 2016) while
32 species of butterflies were identified (Turner et
al., 2003) and another 26 species of butterflies
also were recorded at both Perhentian Island and
Bidong Island (Rosmidi et al., 2017).
Meanwhile, the insect in the inland forest was
less diverse might be due to a smaller number of
trees to provide shelter or host for insects (Fara
Nazuha, 2019). According to Abdul Hafiz et al.
(2015), the diversity of insects in the coastal forest
was higher due to the variation of plant species on
the coastal island. Sanchez-Rodriguez and Baz
(1995) stated that several factors contribute for
the declines of insect richness at high elevation
(i.e. inland forest) such as reduced habitat area,
reduced resource diversity, reduced primary
productivity and increasingly un-favourable
environment at high elevations. According to
Magurran (2004), the typical values of diversity
are generally between 1.5 and 3.5 in most
ecological studies, and the index is rarely greater
than 4. However, referring to the diversity index
value (H’) for Perhentian Island which was
between 1.5 (coastal forest) and 1.35 (inland
forest), it can be considered that the diversity of
insects was relatively high in coastal forest but low
in inland forest. Furthermore, insect diversity and
abundance are also influenced by biotic and
abiotic factors and their interactions (Matilda,
2012). Some of the environmental factors that
influence the abundance of insects were the
temperature and humidity. Therefore, for the
future, vegetation species, distribution and abiotic
factor (i.e temperature (°C), relative humidity (%)
and rainfall (mm) can be taken into consideration
in determining the abundance and diversity of
insects in Perhentian Island.
CONCLUSION
As the conclusion, the overall result showed that
abundance of insects was not significantly
different between the coastal and inland forest of
Perhentian Island due to a small range of the
elevation of the forest. Nonetheless, the insect’s
diversity of coastal forest was relatively higher
than inland forest of Perhentian Island. Diptera
and Hymenoptera were the most common order
found in Perhentian Island forest followed by
Lepidoptera order. They are functionally important
for the well-being of the ecosystem. This study

Salmah et al. Insects Diversity and Abundance in Perhentian Island Forest
Bioscience Research, 2019 volume 16(SI): 53-58 57
provides basic information on the insects’
abundance and diversity of insects at Perhentian
Island. Further ecological research is required to
investigate this pattern and the association with
the distribution of vegetation at Perhentian Island
in future.
CONFLICT OF INTEREST
The authors declared that the present study was
performed in the absence of any conflict of
interest.
ACKNOWLEGEMENT
The authors would like to thank the Universiti
Sultan Zainal Abidin (UniSZA) for the financial
grant support under Dana Penyelidikan Universiti
(UniSZA/2017/DPU/07) during this study period.
AUTHOR CONTRIBUTIONS
SM designed and performleed the experiments
and also wrote the manuscript. KMZ and AZ
performed data collection and data analysis. MR
help with experimental design and data analysis.
KM and MHS reviewed the manuscript. KM is the
project leader for this research. All authors read
and approved the final version.
Copyrights: © 2019@ author (s).
This is an open access article distributed under the
terms of the Creative Commons Attribution License
(CC BY 4.0), which permits unrestricted use,
distribution, and reproduction in any medium,
provided the original author(s) and source are
credited and that the original publication in this
journal is cited, in accordance with accepted
academic practice. No use, distribution or
reproduction is permitted which does not comply
with these terms.
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