The materials that used in this study were insects caught in light traps (Klaper-X), 70% alcohol, 32x64 mm label paper (Phoenix), and liquid detergent (Rinso). The 70% alcohol used was technical alcohol with a concentration of 70% (v/v), manufactured by OneMed, Indonesia. The label paper used was Phoenix brand label paper, manufactured by Phoenix Paper, Indonesia. The liquid detergent used was Rinso liquid detergent, manufactured by PT Unilever Indonesia Tbk., Indonesia, with a standard commercial formulation available on the market. All materials were used according to the manufacturer's specifications without further modification.

The insects that collected from the field were then taken to the Ecology and Systematics Laboratory at Ahmad Dahlan University to be identified to species level. First, the insects were removed from the plastic bottles and washed with running water to remove any traces of detergent used to kill them. The washed insects were then placed in plastic bottles filled with 70% alcohol. The insects were identified to species level by observing their morphological characteristics, namely the wings, head, body pattern, body shape, antenna segments, leg segments, and body colour. Insect identification was carried out using books from (Ruslan, 2024) and (Ruslan, 2015). In addition to books, identification was also carried out using identification journals from [(Aji et al., 2018), (Amiruddin et al., 2023), (Shahabuddin et al., 1970)]. The identified insects were then photographed and counted to determine the abundance of each species.

The number of individuals from each insect species obtained was then used to calculate the diversity index. The formula for the species diversity index used in a community according to (Odum, 1996) in (Sirait et al., 2018) is as follows:

Notes:

H’ = Shannon diversit index

pi = The proportion of the number of individuals i to the total number of individuals

The criteria for the Shannon–Wiener diversity index value according to (Odum, 1996)in (Sirait et al., 2018) (Table 1) are as follows:

The range of diversity index values, according to (Odum & Gary, 1993), describes the stability of a community. The range of values is divided into three criteria based on the H' index, namely: (1) if H' < 1: The community is unstable or has low diversity with an uneven number of individuals and one species is dominant; (2) if 1 < H' < 3: The community is moderately stable or has moderate diversity with an uneven number of individuals of each species but no dominant species; and (3) H' > 3: The community is stable or has high diversity with an even number of individuals of each species and no dominant species.

The Dominance Index was calculated using Simpson formula of dominance index according to (Odum & Gary, 1993) in (Sirait et al., 2018):

Notes:

D = Dominance index

pi = The proportion of the number of individuals i to the total number of individuals

According to (Krebs, 1972) in (Hoek et al., 1995), the range of dominance index values is as follows: (1) if 0.00 < D < 0.50, species dominance is low; (2) if 0.50 < D < 0.75, species dominance is moderate; and (3) if 0.75 < D < 1.00, species dominance is high.

The data obtained was analyzed using correlation tests to examine the relationship between abiotic factors and the abundance of insects found.

Insects Species in The Vegetative Phase of Maize Plants in Caturharjo Village, Sleman, Yogyakarta.

The results of research and discussion contains the results of the analysis is the answer of the question/ problem of research. The results of this study identified insect species in the vegetative phase of maize plants consisting of 6 orders, 24 families, and 30 species (Table 2). The most abundant insects were from the order Coleoptera, consisting of 8 families and 11 species. The species found in abundance were Lathrobium sp. with 5,301 individuals, Culicoides sp. (4,773 individuals), and Paederus fuscipes (3,020 individuals).

Based on the results obtained, the insect with the highest abundance at the study site was Lathrobium sp. from the Staphylinidae family (Figure 3). This species is a predatory insect that preys on various types of larvae and imagoes of small insects and several soil arthropods (Ardiyanti et al., 2018). Recent studies confirm that rove beetles (Staphylinidae) are generalist predators that feed on various soil-associated invertebrates, including nematodes, mites, springtails (Collembola), and dipteran larvae, rather than exclusively targeting adult flying insects (Stocker et al., 2022). Furthermore, several Staphylinidae species have been documented as soil-dwelling predators that attack immature stages of insects such as pupae and larvae in the soil or organic substrate, supporting their role as important biological control agents in agroecosystems. In addition, species within the genus Lathrobium are described as soil-inhabiting beetles associated with leaf litter and soil microhabitats, where they interact with other soil invertebrates and function as predators within the soil ecosystem (Senda, 2023). These findings indicate that their predatory behavior is primarily directed toward soil-dwelling organisms and immature insect stages rather than adult Diptera. The ecological role of Lathrobium sp. is now described more accurately as a generalist soil predator feeding on small soil-dwelling arthropods and immature insect stages.

The entire prey of this species was found in abundance at the research site, which may have contributed to the high number of Lathrobium sp. individuals in this study. This is consistent with the statement in (Anggraini et al., 2020), which states that the population size of predators follows the number of prey found in a location. In addition, the research site was adjacent to rice fields, which also contributed to the abundance of this species. According to (Shahabuddin et al., 1970)Lathrobium sp. can usually be easily found in rice fields because it follows its prey, which are leafhoppers. This is in accordance with the study by (Shahabuddin et al., 1970), which found Lathrobium sp. in adjacent rice fields and maize fields.

The next species found in abundance in this study was P. fuscipes (Figure 3), which also belongs to the Staphylinidae family. The discovery of this species in abundance in this study was possible because the maize fields were adjacent to rice fields. Paederus fuscipes itself is the main predator of leafhoppers in rice fields and is a keystone species that regulates the dynamics of the leafhopper population in rice fields (Ritanti & Haryadi, 2021). The location of the rice fields adjacent to the maize fields allows this species to move when there is no prey in the rice fields. In addition to preying on leafhoppers, this species can also prey on the eggs and early larvae of S. frugiperda (Karundeng et al., 2024), the larvae of A. albopilosa and the larvae of Scirpophaga sp. [(Atmowidi et al., 2016) ; (Sutiharni et al., 2023)]. The discovery of these prey in this study resulted in this species being found in the maize fields where the study was conducted.

The last species found in abundance in this study was Culicoides sp. (Figure 3), which belongs to the Ceratopogonidae family. Culicoides sp. was commonly found in maize plantations during the vegetative phase because the environmental conditions during this phase were very conducive to the life cycle and activity of this species. The vegetative phase of maize is generally characterised by high soil moisture, availability of organic matter, and low vegetation, resulting in a relatively open soil surface (Darodjah et al., 2024). These relatively open soil conditions will cause an abundance of weeds in the form of grasses that can grow around maize plants. These grasses can be used by this species as a habitat, according to a study (Kameke et al., 2021) that found Culicoides sp. in large numbers in grasslands.

In addition to counting the number of insects, this study also obtained information about the ecological roles of the insects found. Based on the results of the study, the roles of the insects found can be classified as herbivores, maize pests, predators, visitors, detritivores, or pollinators. The most common role of insects found in this study was as predators (33.33%) (Figure 4). Other insect roles found in this study were herbivores (26.67%), maize pests (16.67%), visitors (10.00%), detritivores (10.00%), and pollinators (3.33%).

The results of this study are consistent with the findings of (Melhanah et al., 2020), which found that insects with an ecological role as predators dominated the insects found in maize crops. This may be because during the vegetative phase of maize crops, there is a high population of pests, providing an abundant food source for predators (Jannah et al., 2023). These conditions led to the highest number of insect species found to play a role as predators in this study. Predators play an important role in controlling pest populations that attack maize plants in the early stages of growth (Komunitas Semut (Hymenoptera: Formicidae) Pada Tanaman Padi, 2013) ; (Ainun et al., 2023)]. In addition, several predators from the Staphylinidae and Formicidae families are often found to be active at night (Ainun et al., 2023). The large number of nocturnal insects found to be predators is due to their activity at night, which is opposite to the activity of herbivorous insects, which are mostly active during the day (Melhanah et al., 2020).

Although not all herbivorous insects are diurnal, most herbivorous insects found in this study are active during the day. Therefore, at night, predatory insects find it easier to catch their prey, which is resting (Melhanah et al., 2020). This activity is a form of energy efficiency practised by predatory insects. This is in line with the statement (Novriyanti et al., 2024), which states that one form of energy efficiency in predatory insects is by preying on their prey while they are resting. The ease of finding prey is what causes many predatory insects to be active at night (Novriyanti et al., 2024). In addition, the vegetative phase of maize is a phase that provides abundant food for predatory insects, namely maize pests (Pengaruh Spektrum Warna Pada Perangkap Lampu Terhadap Ketertarikan Serangga Di Area Sawah Sukorejo, 2021). This is the factor behind the high percentage of insects with an ecological role as predators found in this study. According to (Amrullah, 2019) the presence of nocturnal insects that act as predators is very significant in maintaining the balance of agricultural ecosystems because they can suppress pest populations, such as S. frugiperda, which are also active at night. Thus, these predatory insects can reduce crop damage without the need for chemical insecticides. In addition, research (Melhanah et al., 2020) also found that the ecological role of predatory insects in maize fields was 62.50%.

The lowest role of insects in this study was found to be as pollinators. This low role was found in this study because most pollinators are active during the day (Schulz et al., 2020) In addition, maize flowering or opening also occurs during the day (Schulz et al., 2020) This is what caused the role of insects as pollinators to be found with a low percentage in this study. According to (Landoni et al., 2024), maize flowers are pollinated by pollinators from 09:00 to 17:00 WIB. In addition, maize flowers are easily shed and the male and female flowers are separated, which also causes fewer pollinating insects to visit and pollinate them (Landoni et al., 2024). According to (Begcy et al., 2024), some pollinating insects that visit maize plants usually have the ability to perch on maize flowers, so they do not cause shedding on maize plants. In addition, according to (Landoni et al., 2024), maize plant flowers also do not have sufficient nutritional content for pollinating insects, resulting in few pollinators visiting maize flowers.

In addition to the factors mentioned above, the number of insects in this study was also influenced by abiotic factors at the study site. The abiotic factors measured in this study were air temperature (℃), air humidity (%), and wind speed (m/s). The results of the abiotic factor measurements can be seen in Table 3 below.

Based on Table 3, the results of abiotic factor measurements at the research site indicate environmental conditions suitable for insect activity, namely an air temperature range of 26–30°C, with air humidity ranging from 57–75%, and wind speed of 0.8–1 m/s. These abiotic factor measurements are still within the optimal conditions for insects to live. According to (Setiarno et al., 2022), the optimal temperature for insect survival ranges from 25 to 45°C. In addition, the optimal air humidity for insect survival ranges from 50 to 75% (Setiarno et al., 2022). Based on the measurement results, it was found that the temperature and air humidity still support insects to reproduce at the research location, so that the abundance of insects found is also high.

In addition to air temperature and humidity, wind speed also affects the insect population in a location (Begcy et al., 2024). The optimal wind speed for insect movement and migration ranges from 0.8 to 1.65 m/s, so the wind speed measured at the study site still supports optimal conditions for insects to live in that location. According to (Begcy et al., 2024), wind speeds that are not too high allow insects to actively move around in search of food or shelter, which supports the survival of insects in a location. The results of the abiotic factor measurements were then tested using a correlation test to see whether there was a relationship between abiotic factors and insect abundance at the research site. The results of the correlation test can be seen in Table 4 below.

Based on the results of the correlation test between the number of insect individuals obtained and abiotic factors, there was no correlation between the number of individuals obtained and the abiotic measurement results. This means that there is no significant relationship between abiotic factors and the number of insect individuals found, so it is likely that the main factor affecting insect abundance comes from biotic factors found at the study site. These biotic factors include food availability, competition between species, and the presence of predators and parasitoids that can control insect populations. In addition, plant biodiversity and habitat structure also play a very important role in determining insect abundance and distribution, as they provide shelter, food sources, and suitable living space (Allifah et al., 2019).

Diversity (H’) and Dominance (D) Indexes of Insect at Vegetative Phase of Maize in Caturharjo Village, Sleman, Yogyakarta.

Based on the results of the analysis, the diversity index (H’) was found to be 0.83 (Table 5). Based on the Shannon Weiner diversity index (H’) criteria, a diversity index value <1 indicates that insect species diversity is low, and the species dominance value obtained was 0.18. This value falls into the low dominance category. This means that no single insect species dominates the ecosystem.

The H' value obtained in this study was low (H' < 1). This low H' value may have been caused by several factors related to the conditions at the study site. One of the main factors was the availability of food at the study site, which tended to be specific or limited, so that only a few insects were able to make optimal use of these food sources. The total number of insect individuals obtained was relatively high, namely 19.874, but their distribution was uneven due to accumulation in only a few species. This situation indicates an imbalance in the structure of the insect community at the research site, where the very high abundance of a few species causes a low H' value, while the existence of other species remains, but their numbers are much lower so that their contribution to community diversity is small. The H' value is influenced by two parameters, namely the number and type of insects obtained (L. et al., 2025). The fewer types of insects obtained and the higher the number of individuals of a type found, the smaller the H' value will be (L. et al., 2025).

Low H' values are also influenced by environmental factors such as erratic rainfall, which reduces insect activity as they tend to seek shelter to avoid raindrops. High soil moisture due to erratic rainfall can increase the risk of fungal and bacterial diseases in plants and animals, thereby suppressing the population of species that are not resistant to such conditions. The results of this study are in line with study (L. et al., 2025) related to insect diversity in maize crops in the rice fields of Randupadangan Village, Gresik Regency, East Java Province, which produced a diversity index (H') of 0.24. The study found that the low H' value was due to heavy rainfall flooding the soil, which caused the death of soil insects, as well as the eggs and nymphs of insects on plant stems being washed away by the rain. Another negative impact on insects is that when it rains, high air humidity and wind help spread insects, contributing to a decline in insect abundance. Temperature has a limiting effect on the growth of organisms when humidity is extremely high or low, but humidity has a more critical effect on organisms at high or low humidity levels. The smaller the number of species and the variation in the number of individuals per species, the smaller the diversity of an ecosystem. This situation can cause an imbalance in the ecosystem if a disturbance occurs.

Based on Table 5, the dominance value of insect species obtained is 0.18. Low dominance values can occur due to stable environmental conditions, allowing many species to coexist without any one species dominating excessively. The availability of sufficient and diverse resources can support the existence of various species with different ecological needs so that no species dominates. In addition, the presence of plants other than maize planted around the research area increases the food choices available to insects. The more food available, the less likely it is that any species will dominate the location (Putriyani et al., 2024). This is in line with statement (Basna et al., 2017), which states that plant diversity as producers can suppress the dominance of a species in a particular ecosystem. The results of this study are consistent with the results of a study by (L. et al., 2025), which obtained a dominance index calculation result showing that the dominance index value was 0.0002. Judging from the dominance index, if the value obtained is close to 0, it can be said that the dominance index is low. According to (Wijayanti et al., 2021), the results are good if the dominance value in the insect community is low because it can be interpreted that there is uniformity in insect types and the potential for environmental balance in maintaining insect conservation.

In addition, the large number of predators found in this study can also reduce the dominance of a species. Predators usually do not have only one prey (Eksplorasi Serangga Predator Pada Tanaman Kakao (Theobroma cacao L, 2023), although there are also specialist predators (Eksplorasi Serangga Predator Pada Tanaman Kakao (Theobroma cacao L, 2023). The discovery of many predators in this study can suppress the population of herbivorous insects so that they do not dominate an ecosystem through predation (Eksplorasi Serangga Predator Pada Tanaman Kakao (Theobroma cacao L, 2023). As stated in (Winarni et al., 2020), the presence of predators prevents herbivores from dominating a particular area because their populations will always be naturally controlled. In addition to controlling the population of herbivorous insects, predators can also control the population of other predatory insects through competition (Winarni et al., 2020). Competition within a species or with other species in an ecosystem can prevent the predator population from increasing or dominating the ecosystem (Hanizah, 2021). This is in line with the statement (Winarni et al., 2020) that competition among second-level consumers or higher can help maintain the population density of a carnivore below a certain threshold.