PREY COMPOSITION OF Nepenthes gymnamphora Reinw. Ex Nees AT MOUNT BISMO, DERODUWUR HIKING TRAIL, WONOSOBO, CENTRAL JAVA

Nepenthes gymnamphora (kantong semar, paleotropic pitcher plant) is a carnivorous plant that spreads across the mountains of Java, one of which is on Mount Bismo, Dieng Mountains, Central Java. The prey composition N. gymnamphora has not been studied before. The purpose of this study was to identify the composition of prey of N. gymnamphora in the Deroduwur Hiking Trail, Mount Bismo, Wonosobo, Central Java. The method used was the identification of prey in the pitcher that has been opened, both the upper and lower pitcher types. The main prey of N. gymnamphora are invertebrates from the ordo of Hymenoptera, Blattodea, Diptera, Araneae, and Diplura. Based on the prey composition analysis, there was a tendency for pitcher dimorphism, namely the upper pitcher of N. gymnamphora tended to contain flying invertebrates, while the lower pitcher tended to contain terrestrial invertebrates. This is influenced by the morphology of the pitcher. The upper pitcher tends to be lighter in color than the lower pitcher so that it is more attractive to fly invertebrates. In addition, the pitcher of N. gymnamphora provides a microhabitat for the larvae of Culicidae and Syrphidae.


INTRODUCTION
Nepenthes is a plant known for its uniqueness as a carnivorous plant. The name of the kantong semar is derived from the unique feature of this plant, namely the pitcher-shaped (kantong) trap organ. This organ is a modification of the leaf tip tendril. The adaptation Nepenthes as a carnivorous plant aims to meet nutritional needs because it generally lives in nutrient-poor habitats such as habitats with thin and rocky soil layers, acid soil, undergoing nutrient leaching, secondary ecosystems, or as epiphytic plants (Mansur 2012).
Nepenthes can trap various prey, especially from the class of arthropods to get nutrition. Inside the Nepenthes pitcher, some enzymes and bacteria help to break down protein and chitin molecules from their prey (Siegara and Yogiara 2009). The trapping ability and composition of trapped prey are influenced by several factors such as pitcher structure (Moran and Clarke 2010;Clarke and Moran 2016), pitcher types (Gaume et al. 2016), and external factors such as climate (Moran et al. 2013;Clarke and Moran 2016). Common prey that is found in the Nepenthes pitcher is from the order of Diptera, Blattodea, Coleoptera, Thysanoptera, Hymenoptera, and Lepidoptera (Chin et al. 2014). The dominant prey insect taxa of various Nepenthes in Sumatra and Kalimantan are Formicidae (Chin et al. 2014;Maysarah 2016). However, Nepenthes pitchers are often attractive or modified to trap non-arthropod taxa.
Some species Nepenthes have specific strategies for trapping prey or in symbiosis with organisms from taxa other than arthropods. The pitcher morphology determines the difference in prey preferences, especially in the pitcher lip (peristome), wax zone, and digestive zone (Bauer et al. 2012). For example, Nepenthes albomarginata has a lichen-like peristome structure that attracts a genus of termites and Nepenthes lowii 's pitcher structure allows the mountain shrew Tupaia montana to come and defecate in its pitcher (Pavlovič 2012). This specification mainly appears in species that are in the same habitat to avoid nutrient uptake competition between species (Chin et al. 2014).
Studies on the prey of Nepenthes have been carried out although they have not covered the entire species. In addition, these studies have not represented the entire bioregion of the distribution of Nepenthes, including those on the island of Java. Nepenthes gymnamphora is one of 3 species of Nepenthes in Java whose population is getting depressed due to habitat degradation and poaching. The natural distribution of N. gymnamphora is limited to habitats in the mountains of Java at an altitude of 1000-2750 m asl (Batoro and Wartono 2017). One of the important habitats of N. gymnamphora that is threatened due to increasingly widespread human activities is on Mount Bismo which is included in the Dieng Mountains, Central Java (Iqbal 2015;Syamsul et al. 2017, Mayangsari et al. 2017. Research on the prey composition of N. gymnamphora has been conducted by Rangkuti et al. (2015) whose samples were taken from Mount Aseupan, Banten. However, the study only identified prey from insect taxa.
The purpose of this study was to identify the prey of N. gymnamphora that grows on Deroduwur Hiking Trail, Mount Bismo. Research on the prey composition of N. gymnamphora is one of the basic aspects of understanding the bioecology of this species, especially in terms of prey trapping mechanisms. Research on the prey composition of N. gymnamphora on Mount Bismo is expected to be a comparison, see the potential for prey other than insect taxa, and become the basis for studies of trapping strategies in N. gymnamphora.

RESEARCH METHOD
Data collection was carried out on the hiking trail of Deroduwur Village, a protected forest area of Mount Bismo, Kejajar District, Wonosobo Regency, Central Java, in April-May 2021. The tools used in this study included: sample bottles, measuring tubes, pH meters, and a stereomicroscope. The materials used in this study were ethanol and pitcher fluid samples of N. gymnamphora. The objects observed in this study were pitcher fluids and prey of N. gymnamphora that were found on Mount Bismo.
The pitcher fluid sample was selected by purposive sampling, specifically by selecting pitchers that were already open and filled with prey from all the individuals present at the location. Of the 15 N. gymnamphora at the study site, only 7 individuals were accessible and had pitchers that met the criteria. Obtained 11 samples of pitcher fluid consisting of 4 lower pitchers and 7 upper pitchers from these 7 individuals Fluids were taken from at least one Nepenthes that had been opened from each individual found. Prey was identified from organisms trapped in Nepenthes pitcher fluid. The pitcher liquid containing the prey was preserved by adding 70% ethanol and stored in a sample bottle. Then, these samples were counted and identified using an identification book (Freshwater Invertebrates and Pest of Crops in Indonesia), a website (http://www.bugguide.net), and an artificial intelligencebased identification application (iNaturalist).

Characteristics of Pitcher Fluid
Volume and pH analysis were taken from 10 samples of pitcher fluid from 7 individuals of N. gymnamphora consisting of 4 upper and 6 lower pitchers. Evaluated from the results of the analysis, the upper pitcher tends to have a larger volume than the lower pitcher even though each pitcher has a fairly large volume range (Table 1). While the pH is not much different in each type of pitcher. The liquid N. gymnamphora was identified as having a pH with a weak acid category. The acidity of the Nepenthes is influenced by proton pump activity and/or nutrient ion transport that supports enzymatic activity (Gaume et al. 2016).

Prey Composition
Analysis of prey trapped in 11 pitcher fluid samples (4 lower pitchers and upper 7 pitchers) from 7 individuals. The total trapped prey was 155 individuals in the upper pitcher and 34 individuals in the lower pitcher. The prey taxa are quite numerous from the invertebrate phylum ( Figure 1). The upper pitcher has 12 orders while the lower pitcher contains 8 orders with a total of 14 orders that fall into the classes of Insecta, Arachnida, Myriapoda, Malacostraca, and Gastropods. The most trapped invertebrate orders were Hymenoptera 65.61%, Blattodea 9.03%, Diptera 5.82%, Araneae 5.29%, and Diplura 4.76%.
All of these orders except Diptera are found in each pitcher type. The upper pitcher tends to trap a more diverse order of invertebrates than the lower pitcher. This can be influenced by the number of samples of the upper pitcher which is more than the lower pitcher. However, the difference between the orders of invertebrates trapped in the upper and lower pitches is the order which generally has wings and can fly. The orders of winged and flightless invertebrates found only in the upper pitcher are Diptera and Orthoptera. Meanwhile, the order of invertebrates found only in the lower pitcher is Slocopendromorpha which are generally terrestrial arthropods.
Most prey orders belong to the class of Insecta, namely Hymenoptera, Blattodea, Diptera, Diplura, Coleoptera, and Orthoptera ( Figure 2). The prey composition N. gymnamphora on Mount Bismo was quite different from that of N. gymnamphora on Mount Aseupan, Banten, which consisted of Hymenoptera, Coleoptera, Diptera, and Orthoptera (Rangkuti et al. 2015). Common prey found in the Nepenthes is those of the orders Diptera, Blattodea, Coleoptera, Thysanoptera, Hymenoptera, and Lepidoptera (Chin et al. 2014).  Prey composition of Nepenthes can be influenced by environmental conditions that affect insect diversity as well as field and Nepenthes conditions during sampling. Variations in prey composition can be influenced by pitcher age which affects trapping efficiency (Bauer et al. 2009). Another influence is the level of digestibility of prey in the pitcher. Some taxa of prey, especially small ones such as Diplura and Diptera, will be difficult to identify if a sample of pitcher fluid is taken after secretion of digestive enzymes has occurred. The enzymes chitinase and protease secreted by Nepenthes can digest part or all of the body of these small organisms (Higashi et al. 1993).
The composition of prey in the pitcher type is influenced by the structure of the pitcher. The upper and lower pitchers of N. gymnamphora have different structures, especially in shape and color. The upper pitcher has a dominant color of green with a purplish red pattern with green or reddish lips, while the lower pitcher is predominantly purplish red with green lips. The contrast pattern in the upper pitcher of Nepenthes serves to attract insects that perceive light in the ultraviolet spectrum, especially flying insects (Moran et al. 1999;Baurer et al. 2009). An unattractive lower pitcher serves to reduce the risk of the overabundance of prey which can trigger pitcher rot and protection from herbivores (Moran 1996;Gilbert et al. 2018). Other factors for attracting prey include the diameter of the pitcher opening, the cone of the pitcher, aroma, nectar, and the structure of the pitcher's lip which have not been studied much in N. gymnamphora (Bauer et al. 2009;Bauer et al. 2012;Gaume et al. 2016).
Pitchers of N. gymnamphora are also a microhabitat for Diptera larvae, namely mosquitoes (Culicidae) and hoverflies (Syrphidae) (Figure 3). Most of the Diptera larvae live in the upper pitcher, namely 117 Culicidae larvae and 18 Syrphidae larvae, while 22 Culicidae larvae and 7 Syrphidae larvae are in the lower pitcher. Diptera larvae with Nepenthes are known to form a symbiotic mutualism. The role of Diptera larvae is to assist in the digestion of prey and nutrient sequestration in the Nepenthes gracilis (Lam et al. 2017). Culicidae larvae as organic particle feeders and Syrphidae as scavengers and predators for Culicidae larvae help to decompose the prey of Nepenthes more quickly (Mogi and Yong 1992;Adlassnig et al. 2011;Lam et al. 2019).

CONCLUSION
The prey of N. gymnamphora is dominated by invertebrates from the orders of Hymenoptera, Blattodea, Diptera, Araneae, and Diplura. The upper and lower pitchers of N. gymnamphora have different tendencies in trapping prey due to the effect of pitcher dimorphism. The types of prey that can fly tend to be trapped in the upper pitcher. While the bottom pitcher tends to trap terrestrial invertebrates. In addition, the pitcher of N. gymnamphora is also a microhabitat for larvae of Culicidae and Syrphidae with a symbiotic mutualism relationship.