Index

• Introduction
• Material and Methods
• Result and Discussion
• Conclusion
• References

Abstract

This research was conducted to identify and found the abundance of predatory insect species of S. frugiperda in Sleman and Gunungkidul Regencies, Yogyakarta Province, Indonesia. This research was conducted in June 2021 - March 2022 on corn plantations in Sleman and Gunungkidul Regencies. Determination of the sampling location was determined by stratified random sampling. Corn land used in sampling was determined by purposive. Insect predator caught by using sweeping net and hand picking. The results showed that there are 3 orders, 8 families, and 16 species of insect predators. 3 orders of the insect predators that found in the Sleman and Gunungkidul Regencies were Coleoptera, Hymenoptera, and Hemiptera. Insect predator families that found in Sleman dan Guungkidul Regencies were Coccinellidae, Carabidae, Staphylinidae, Formicidae, Vespidae, Pentatomidae and Reduviidae. Insect predators species that was most commonly found was Menochilus sexmaculatus with 467 individuals and the least was Sycanus sp. with 1 individual. The conclusion of this study is that there were 16 species of predators from S. frugiperda in Sleman and Gunungkidul Regencies. Practical implications of this research were the insect predators that found in Sleman and Gunungkidul Regencies can be used to maintain the population of Spodoptera frugiperda in two regencies.

Keywords: Abundance, Armyworm, Menochilus sexmaculatus, Predator, Spodopetra frugiperda, Sycanus sp.

Received: 16 November 2022 / Revised: 6 January 2023/ Accepted: 20 January 2023/ Published: 3 February 2023

Contribution/ Originality

This research was the first research that study the species predatory insect of Spodoptera frugiperda in Indonesia, especially in D.I. Yogyakarta, specifically in Sleman and Gunungkidul Regencies.

1. INTRODUCTION

The corn armyworm (Spodoptera frugiperda) is an insect native to the United States that has spread to the Asian continent, including Indonesia. Spodoptera frugiperda was originally found in the Pasaman area, West Sumatra [1] and has spread to Bandung, Garut, Sumedang [2] to Sleman, Gunungkidul, Bantul, Yogyakarta [3]. Armyworm caterpillars have several host plants, especially from the Graminae group such as corn, rice [4] cotton [5] and sorghum [6]. Spodoptera frugiperda had causes losses to corn crops of 8.3 - 20.6 million tons per year with an economic loss value of US $ 2.5 - 6.2 billion per year on the African Continent and Europe.

Control of these caterpillars has been carried out to minimize yield losses from corn plants. So far, armyworms have been controlled using synthetic pesticides [7, 8]. Originally there were natural enemies that have been found to be able to control this pest population in nature [9]. Natural enemies found in nature can disrupt species diversity and populations due to the use of insecticides [10]. One of the natural enemies of S. frugiperda found in nature is from the predator class [11]. Several armyworm predators that have been found include Lycosa sp., and Coccinella transversalis Thunberg [3]. In addition, research in West Lombok conducted by Jannah, et al. [12] found 8 species of predatory insect of S. frugiperda, including Cheilomenes sexmaculata, Coelophora inaequalis, Verania lineata, Polistes gallicus, Polyrhachis dives, Chrysopa sp., and Lycosa sp.

2. MATERIAL AND METHODS

This research was conducted in June 2021 - May 2022 on corn (Z. mays) plantations in 17 sub-districts of Sleman and 18 sub-district of Gunungkidul Regency. Identification of predators was carried out at the Ecology and Systematics Research Laboratory, Faculty of Applied Science and Technology, Ahmad Dahlan University. The materials used in this study were samples of predatory insects from the field and 70% alcohol.

The methods that used in this research were:

2.1. Determination of the Sampling Location

Determination of the location of this sample is determined by a random stratified method. Samples were taken from 17 sub-districts in Sleman and 18 sub-districts in Gunungkidul Regency. Two villages were taken from each sub-district to be used as sampling locations using a random stratified method. Each village is taken one land used in predator sampling. The maize fields used in predator sampling in each village were determined using the purposive. The age of the corn plants used in this study was around 2-3 weeks old and had not yet flowered.

2.2. Sampling and Preservation

Sampling was carried out every two weeks, when sampling there is no repetition in the same land (one field for one sampling), this sampling is carried out by exploring corn plantations in Sleman and Gunungkidul Regencies by determining in advance which village and sub-district to go to by looking at mapsand then tracing the streets around the village and sub-district. Samples were taken in the form of insect predators of S. frugiperda which were carried out mechanically using hands, sweep nets and tweezers. Sampling was carried out by exploring all corn plants affected by S. frugiperda with perforated or damaged leaves. The insect predator that obtained were put into a 50 ml plastic bottle filled with 70% alcohol to preserve the sample.

2.3. Identification of the Insect Predator

Predator sample which had been preserved in 70% alcohol then observed for its morphological characteristics. Identification was carried out by comparing morphological characters including the shape of the mouthparts, body color, number of tarsus on the limbs, and patterns on the wings of the predators which were obtained from books and journals Manting, et al. [13]; Ndiaye, et al. [14]; Fallahzadeh, et al. [15]; Rodríguez-Vélez, et al. [16] and Mayadunnage, et al. [17]. The species of predators that are know were then documented using a cellphoneand the number of individuals was counted to find out which predators have the most and the least number of individuals. 

3. RESULT AND DISCUSSION

3.1. Insect Predator of S. frugiperda in Sleman and Gunungkidul Regency

This study found 3 orders, 8 families, and 16 species of predators from S. frugiperda. Families with species that act as predators of S. frugiperda were most commonly found in the Formicidae (5 species) and Coccinellidae (4 species) families. While the families that act as predators at least are Staphylinidae, Carabidae, Reduviidae and Pentatomidae (1 species) Table 1.

The most common species found as predators of S. frugiperda in this study came from the Formicidae Family. The Formicidae family is an insect belonging to the ant group (Order Hymenoptera). Ants are insects that are widely distributed throughout the world except in the polar regions [14]. The Formicidae family consists of 14 sub-families and based on their role in nature, 29% of ants act as predators. Predator ants are active and strong and prey on smaller insects [15]. Many members of this family are found as predators of S. frugiperda due to the wide range of range of its family members. In addition, ants have pheromone fluids that make it easier for their members to find prey in hidden locations [16].

Apart from the Formicidae family, many members of the Coccinellidae family were also found as predators of S. frugiperda in this study. Many members of the Coccinellidae family were found because around the sampling location there were plants other than corn, such as chili and rice. Both of these plants can affect the distribution of members of the Coccinellidae family [17] because these plants contain aphids. These aphids are the main prey of Coccinellidae [18].

The presence of aphids on plants around the corn field will make members of the Coccinellidae family come to prey on these aphids. The more aphids found on plants around the corn field, the more species and abundance of Coccinellidae members found in that location [19]. This is in accordance with the opinion of Rain, et al. [20] that the diversity and abundance of predatory Coccinellidae depends on the presence or absence of aphids at that location. Apart from surrounding plants, aphids can also be found on corn plants [21, 22].

The presence of aphids on corn plants can become an alternative prey if the population of aphids found on surrounding plants has decreased [18]. The advantage of Coccinellidae members who prey on aphids on corn plants, besides getting prey in the form of aphids, they can also prey on the first and second instar larvae of S. frugiperda found on these corn plants. This is in accordance with research from Nurkomar, et al. [3] who stated that apart from preying on aphids, predatory Coccinellidae found on corn plants also prey on the early instar larvae of S. frugiperda. This opinion is in line with the statement of Malo and Hore [23] which states that the Coccinellidae family is a predator of the eggs and young instar larvae of S. frugiperda.

3.2. Abundance of Insect Predator of S. frugiperda in Sleman and Gunungkidul Regencies

The results obtained in this study indicate that the predators of S. frugiperda that were found mostly on corn, namely M. sexmaculatus with a total of 467 individuals and the next is V. lineata with 301 individuals. Meanwhile, the fewest predators of S. frugiperda found on corn, namely Sycanus sp. with only one individual Table 2.

Menochilus sexmaculatus was most commonly found as a predator of S. frugiperda in this study because this beetle has a wide range of prey [17]. Apart from aphids, M. sexmaculatus is also known to prey on the whitefly Bemisia tabaci Setiawati, et al. [24] and Diaphorina citri [25]. Among the prey that has been mentioned, M. sexmaculatus has a preference for Aphis gossypii. In addition, the large number of chili plants found around the study site allows for an abundance of individuals of A. gossypii as prey for M. sexmaculatus. The more prey available, the higher the abundance of predators following the abundance of their prey [26]. Menochilus sexmaculatus will certainly prefer prey populations that are always available compared to prey that are only available at certain times [26].

Apart from having a wide range of prey, another factor that causes the high population of M. sexmaculatus is because it’s a voracious predator [17]. The first to fourth instar larvae of M. sexmaculatus were able to prey on 347 A. gossypii within 5 days and one adult of M. sexmaculatus was able to prey on 270 prey per day with the same type of prey. The predatory insect species of S. frugiperda that had the second highest number of individuals in this study was V. lineata. The high population of this beetle is because V. lineata does not only prey on S. frugiperda larvae. Verania lineata also known to prey on the brown planthopper (Nilaparvata lugens) [27]. These planthoppers are commonly found in rice plants [28]. However, the rice plants around the study site entered the harvest season, so the population of N. lugens was not abundant. This is why V. lineata also switches to other prey if its main prey is not found. Verania lineata also preys on aphids, thrips, and whitefly. Aphids preyed upon by V. lineata are A. gossypi and A. craccivora that in legumes plant. The legume plants found around the research site are not as abundant as chili plants. This is why the population of V. lineata is not as large as M. sexmaculatus.

Apart from being influenced by other prey preferences, the Coccinellidae family can be found in abundance because they are able to produce a large number of eggs. An adult female of M. sexmaculatus can produce as many as 100-200 eggs during her life cycle, while an adult female of female V. lineata is able to produce as many as 103 eggs during her life cycle. Meanwhile, for the other two Coccinellidae species, the number of individuals was not abundant because an adult female of C. transversalis was only able to lay 100 eggs during its life cycle, and an adult female of E. nigripennis was able to lay 69 eggs during its life cycle. These results also support that the ability of female imago to produce eggs is the highest for M. sexmaculatus and V. lineata, so that in this study both types had the most abundant number of individuals compared to other Coccinellidae species. In addition to finding predators from S. frugiperda with the highest abundance of individuals, this study also found predators from S. frugiperda with the least abundance of individuals.

Apart from being influenced by food factors and the ability to reproduce, the abundance of predators found was also influenced by abiotic factors. The abiotic factors that influenced the number of individual insect predators of S. frugiperda in this study included air temperature and humidity. The air temperature and humidity measured in this study had an average air temperature range of 21.8 – 31.150C and an air humidity range of 52 – 87.78% (Table 3). Menochilus sexmaculatus has a minimum temperature range of 200C, optimum temperature of 250C, and maximum temperature of 300C [29] whereas the humidity range of 66 – 85% [30]. So the temperature and humidity at the study site can support the survival of M. sexmaculatus. This is why the individual abundance of M. sexmaculatus was found to be high in this study. In contrast to M. sexmaculatus, V. lineata was also found in the average air temperature range of 21.8 – 31.150C and humidity range of 52 – 87.78%. According to Syahrawati, et al. [27] V. lineata can be found in the temperature range of 26.7 – 29.20C and humidity of 70.6 – 80.9% so that the temperature and humidity in the study site are able to support the survival of V. lineata. 

4. CONCLUTION

The insects predator species of S. frugiperda found in this research consist of 16 species divided into 3 orders. The predatory type of S. frugiperda with the highest number of individuals was Menochilus sexmaculatus. While the least number of individuals is Sycanus sp.