Checklist of butterflies (Lepidoptera: Papilonoidea and Hesperioidea) in Gunung Pulai Forest Reserve, Johor

This survey was done to provide a checklist of butterflies in Gunung Pulai Forest Reserve, Johor Darul Takzim. Sampling were done between October 2017 to March 2018 for nine sampling days. Butterflies were caught using aerial net and baited traps. The traps were baited with a mixture of rotten bananas and pineapples. A total of 101 individuals comprising 61 species were obtained from this survey. Family Nymphalidae recorded the highest number of species with 30 species, followed by Lycaenidae with 16 species. The most dominant species was Ypthima horsfieldii humei (Nymphalidae) with eight individuals followed by Lexias pardalis dirteana (Nymphalidae) with six individuals. Out of the 61 species, 45 were singletons which accounts for 73.8% of the sample. The Shannon Diversity Index for the butterflies in this area is 3.884 with an Evenness value of 0.941. Three species are considered as new records for the state of Johor. Based on the high value of Shannon Diversity Index and the abundance of singletons, it can be concluded that Gunung Pulai Forest Reserve holds a high diversity of butterflies in the region.


Introduction
Gunung Pulai Forest Reserve is a hill dipterocarp forest located in Johor, the southern-most state in Peninsular Malaysia. This granite-based forest covers an area of approximately 5,300 ha with the highest peak of 654 m. The forest is under the jurisdiction of Johor State Forestry Deparment which oversees forests for the state's socioeconomic benefits. Biodiversity studies that have been done here include benthic macroinvertebrates [1,2], frogs [3], gliding lizard [4], and trees [5,6]. Like most forests in Johor, Gunung Pulai Forest Reserve is threatened by the rapid development that surrounds the area. As of now, the forest is already bordered by the district of Kulai township from the eastern side. The only buffer between the forest reserve and urban developments are the vast oil palm plantations. Based on the 2030 Structural Development Plan of Johor (RSNJ 2030), the areas north and south of Gunung Pulai Forest Reserve will be developed. Hence it is important to obtain as much information on the biodiversity that exist here before they are lost to human interference.
Lepidoptera is one of the most studied insect group, second only to Coleoptera. Their taxonomic hierarchy is relatively stable, making them a great surrogate taxon for flora and fauna within their habitat. They are also well-known as bio-indicator for ecosystem health. These are phytophagous organisms, where their presence is largely dependent on the availability of their host plants. The existence of forest species may indicate that the forest is still in good health, while the presence of urban species may indicate otherwise. The purpose of this study is to provide a preliminary checklist of 2 butterflies in Gunung Pulai Forest Reserve. Hopefully, this information will help conservation managers make well-informed decisions when it comes to the managing the forest reserve.

Methods
Gunung Pulai Forest Reserve was accessed through the amenity forest ( Figure 2). Sampling was done on October 2017, January and July 2018 for a total of nine sampling days. The butterflies were collected manually using aerial net and traps. The traps were baited with a mixture of rotten banana and pineapples to attract fruit-feeding butterflies such as the nymphalids. A 100 m sampling transect was set up along the forest trail. Butterflies were observed and identified from 9 am to 5 pm as this is the time when they are the most active. Identification was done using keys from [7] and field guide by [8].

Result and Discussion
A total of 101 individuals comprising of 61 species were identified throughout the sampling period (Appendix A). For comparison, a similar sampling routine was done in Gunung Belumut which obtained 64 species [9] Bukit Soga with 42 species [10] and Taka Melor with 60 species [11]. Based on these previous studies, the species richness in Gunung Pulai Forest Reserve is quite similar to other forest patches in Johor. The family Nymphalidae recorded the highest number of species with 30 species, followed second by Lycaenidae with 16 species recorded ( Figure 1).

Figure 2. A graph of species richness and abundance of butterflies in Gunung Pulai Forest Reserve
Since fruit baited traps were used in this study, the bias towards nymphalids are to be expected. Most of the fruit feeding butterflies that are otherwise too cryptic to seen, were caught in the traps. The most dominant species caught were were Ypthima horsfieldii humei with eight individuals and Lexias pardalis dirteana with six individuals. Y. horsfieldii or the Malaysian Five Ring is a common butterfly species found in vegetated areas. Their hostplants include Axonopus compressus [12] and Ottochloa nodosa (Kwatrina 2018) which are common in oil palm plantations and human dwellings [13]. This makes sense since part of Gunung Pulai Forest Reserve is an amenity forest which is open to public while being surrounded by oil palm plantations.
Out of the 61 spcies, 45 were singletons which accounts for 73.8% of the sample. This can be seen in the rank abundance curve in Figure 2.  The high proportion of singletons is common in insect communities of tropical rainforest [14]. Three of these species are new records for Johor. These species are Potanthus confucius dushta (Hesperiidae), Arhopala major major (Lycaenidae), and Junonia almana javana (Nymphalidae). Prior to this study, P. confucious were also recorded in Universiti Kebangsaan Malaysia, Bangi [15]. In Singapore, this species was previously considered extinct [16] before being rediscovered by local butterfly enthusiasts. On the other hand, A. major and J.almana are considered rare in Singapore [16]. The genus Arhopala is well known to be myrmecophilous and feeds on Macaranga myrmecophytes [17]. The Shannon Diversity Index (H) for this site is 3.884 with and evenness (E) value of 0.941. The H value for this site is relatively high compared to other forested areas in Johor that is subjected to a similar sampling regime. For instance, Soga Forest Reserve in Batu Pahat has a H value of 3.54 [10]. However, when compared with Endau Rompin National Park with an H value of 4.78 [18], the diversity of butterflies in Gunung Pulai Forest Reserve can be considered average.

Conclusion
Our results demonstrate that the diversity of butterflies in Gunung Pulai Forest Reserve is relatively high for a forest of its type. Since the forest patch is highly fragmented and at risk of disturbance due to the surrounding development, it is important to obtain as much biodiversity data from it as possible.

Acknowledgment
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