Pollinating insects on bitter melon plant flowers ( Momordica charantia L.)

,


INTRODUCTION
The agricultural sector in Indonesia has great potential to be developed as one of the main pillars, considering the increasing need for food.Currently, existing natural resources have not been utilized optimally, so food self-sufficiency has not been fully achieved (Kuncoro, 2018).One aspect that deserves attention is the production of vegetables, which are horticultural crops with high nutritional content.According to Liska et al. (2023), consumption of vegetables can meet human nutritional needs because they contain minerals and vitamins which are important for maintaining health, so demand for vegetables continues to increase.
One of the horticultural crops currently experiencing an increase is bitter melon (Momordica charantia L.).To optimize commercial bitter melon cultivation, intensive pollination by insects is required because this plant cannot pollinate itself (Clarisa and Kasmara, 2016).Insects that interact with bitter melon plants can act as pollinators, predators or pest parasitizes (Yulianto et al., 2022).This relationship can be considered a mutualistic symbiosis, where the plant provides a food source and shelter for insects, while the plant benefits from pollination which produces bitter melon fruit (Suhri et al., 2022).
Insects also have an important role in agricultural ecosystems, adapting to dynamic and less stable ecosystem changes Susilawati (2016).The interact of insects with plants can be classified into three groups: pest insects, natural enemies, and beneficial pollinator insects.Pollinating insects, such as Trigona spp.and bees, have a role as plant pollinators (Brigitha et al., 2017).
The process of pollination, namely the meeting of pollen with the stigma, is very important in agriculture, and about 80% of agricultural crops depend on this pollination (Zuraida, 2019).Pollinator visits to flowers greatly influence crop yields, and these insects are attracted by factors such as color, size and number of flowers (Leksono, 2017).The color of the flower is an attraction for insects, which visit the flower in search of food, and through this activity, pollination occurs.The visiting behavior of insects looking for food from one flower to another can also influence plant pollination (Tanjung et al., 2019).
Therefore, to increase the yield of bitter melon fruit, it is necessary to observe the insects that visit the bitter melon plant flowers.This research aims to determine the number, role and behavior of insects interacting with the flowers of the bitter melon plant (M.charantia L.).

Equipment and Materials
For this research, several equipment was used such as stationery, vials, stereo microscopes, plastic bags, cameras, and name labels.Meanwhile, the materials used include 70% alcohol and collected insect specimens.

Implementation Method
The method applied in this research is scan sampling, which involves direct observation in the field to count the number of species and individual insect visitors.After collecting the insects, these insects were placed in vials and then taken to the Entomology laboratory, Department of Plant Pests and Diseases, Faculty of Agriculture, Sriwijaya University, Indralaya for identification of the type of insect.

Location Determination
The research location was chosen by looking for horticultural agricultural land that was flowering, so that insects visiting the flowers could be observed.This research was carried out at the Agribusiness Clinic, Faculty of Agriculture, Sriwijaya University, Indralaya.

Sampling
Sampling begins by determining the number of ridges (where plants grow) and the number of plants in each ridge.There are eight mounds with different numbers of plants.Of the eight mounds, four mounds were selected and each had ten mound plants, so that a total of 40 plant samples were observed.Each bund has a size of 1 x 22 meters with a distance between bunds of 0.5 meters.

Implementation Stage
The research implementation phase lasted for five weeks, with observations carried out two days a week.Observations were carried out twice a day, on Tuesday and Thursday, at 06:30 -08:30 WIB (morning) and 16:00 -17:30 WIB (afternoon).During observations, insects visiting bitter melon plant flowers were observed by surrounding each planting area for 1-2 minutes.After that, the visible insects are photographed and put into a vial as a sample.The samples were then given 70% alcohol and identified the type of insect at the Entomology Laboratory, Department of Plant Pests and Diseases, Faculty of Agriculture, Sriwijaya University, Indralaya.

Identify Pests of Bitter Gourd Plants
Identification of insect pests on bitter melon plants was carried out using a microscope at the HPT Entomology Laboratory, Faculty of Agriculture, Sriwijaya University, Ogan Ilir, South Sumatra.Identification is carried out based on the morphology of the pest insect, including antenna segments, body color, wing shape, type of mouthparts and leg segments.Identification of insect pests is based on key identification books, such as "The Insect of Australia" by Anderson (1996) and "Pest of Crops in Warmer Climates and Their Control" by Hill (2008), as well as with support from related journals.

Observation Parameters
The parameters observed included the type and number of insects collected, as well as the role and behavior of visiting insects that interacted with bitter melon plant flowers.

Data analysis
Data regarding insects obtained from direct observation of bitter melon plant flowers at the Agribusiness Clinic, Faculty of Agriculture, Sriwijaya University, Indralaya, will be presented in tabular form and analyzed descriptively.

Visitor Insects Associated with the Flowers of Bitter Melon Plants
This research was conducted at the Agribusiness Clinic, Faculty of Agriculture, Sriwijaya University, Indralaya.The results obtained identified the existence of 6 insect orders, namely Hymenoptera, Coleoptera, Thysanoptera, Lepidoptera, Hemiptera, and Araneae, and succeeded in identifying 8 families and 12 species from these orders.Details of the results of these observations can be found in Table 1.
Based on the results of observations that have been identified, there are six orders of insects, namely Hymenoptera, Coleoptera, Thysanoptera, Lepidoptera, Hemiptera, and Araneae.A total of eight families and twelve species of insects were identified with their respective roles, as listed in Table 1.The insect that dominates visits to bitter melon flowers is the C. carnelius ant from the order Hymenoptera: Formicidae, which acts as a visitor or even as a potential pollinator.The bees A. mellifera and Trigona spp.T. spinipes (Hymenoptera order: Apidae) also acts as a pollinator for bitter melon flowers, with a high visitation rate.The Hymenoptera order dominates the number of visits because various types of insects from this order look for nectar and pollen.
Flower morphology also plays an important role in attracting the types of pollinating insects that visit the flower.Usually, insects are first attracted by the color of the flower crown, because insects have a tendency to like striking colors (Campbell et al., 2010).These characteristics influence the type and visiting behavior of pollinating insects when these insects search for nectar or pollen.Bee visits to flowers during their search for food show certain behaviors that are influenced by the amount and quality of nectar in the flowers.The frequency of visits by bees from one flower to another increases if flower nectar is abundant, but conversely, if the nectar quantity is low, frequency of visits tends to decrease (Nugroho and Soesilohadi, 2015).From the results, during 5 weeks of observations, the average number of visitors to bitter melon plant flowers was obtained in the morning and evening (Table 1).The number of insects obtained during morning observations was greater than observations in the afternoon.According to this, this was due to the volume of nectar in the flowers, high in the morning and continues to decrease until the afternoon, thus affecting insect visits to plants.Naturally, the insect visiting process is influenced by environmental factors such as temperature, humidity and weather conditions (Sulistuyowati and Putra, 2016).The temperature at the location during observation ranged from 26-29ºC with humidity around 65% in the morning while in the afternoon the temperature ranged from 30-34ºC with humidity around 90-95%.Rainfall also affects insect visits to flowers.If it rains there is little chance for insects to visit flowers.

Behavior of Visitor Insects in Relation to Bitter Melon Plant Flowers
Some insects that visit bitter melon flowers do not involve themselves in the act of pollination, and not all of them have the capacity to visit all types of flowers.Factors such as shape, color and size of flowers play an important role in attracting insects.This characteristic also determines the type and behavior of pollinating insects when these insects search for nectar or pollen (Hasan and Atmowidi, 2017).
Insects that function as pollinators have beneficial behavior, such as bees that visit flowers to get the honey located at the base of the flower.When bees collect pollen with their feet, this pollen can fall on the stigma or other parts of the flower, resulting in pollination assisted by the insect.Bees do not differentiate between flowers they have visited before and those they have not, and the insects spend about 3-5 seconds on each flower before moving on to the next.On the other hand, visitor insects that function as pests and predators have a much longer visit duration, ranging from 2-4 minutes or even more per flower.
According to Hasan and Atmowidi (2017), the behavior of visiting insects that interact with bitter melon plant flowers is also influenced by the length of their visit.From the results of our observations, we can see variations in the behavior of visiting insects associated with bitter melon flowers.Each insect that visits flowers has varying behaviors and goals (Table 2).
The types of flowers visited by insects are often places where these insects search for food, and many bees also visit wild plants around bitter melon plants.According to research Susilawati (2016), the existence of a complex environment around plants can increase the diversity of flower-visiting insects, including pollinators.Restrictions on pollinator visitation can result in up to a 50% reduction in crop yields (Arwati, 2018).Apart from pollinating insects, there are also visitor insects that act as pests, such as A. similis Oliver, A. lewisii, H. vigintioctopunctata, Thrips tabaci, S. litura, and N. tenuis in small quantities Table 2. Behavior of visitor insects associated with bitter melon plant flowers.

Apis mellifera
A. melliferahas a yellow abdomen, wings length 0.8-0.95cm.Stroke length 0.55-0.71cm.There are many species of bees that act as pollinators of plant flowers, one of which is A. mellifera, an insect that is beneficial for farmers.These bees settle on the flowers of the bitter melon plant because they have behavior aimed at taking nectar, pollen or both, which are attracted by the fragrant smell and honey liquid produced by the flowers.By sticking out its sucking mouth, this insect sucks the honey liquid at the base of the flower jewellery.At that time, pollen can stick to the bee's body.By shaking the body and rubbing the hind legs, the pollen can be released.If this pollen falls on the stigma, pollination occurs (Botanical Research and Development Center, 1987).

Table 2. Behavior of visitor insects associated with bitter melon plant flowers (continuous) Species Behavior
Trigonaspp.
Trigona spp.black and small in size, with a body length of between 3-4 mm, and a wingspan of 8 mm.This bee has no sting.Likewise with the bee A. mellifera, Trigona spp.also acts as a pollinator.By means of insects landing on one flower, then landing on another flower carrying pollen from the previous flower, it is permanent because every time there are these insects visiting the flowers of the bitter melon plant.

Trigona spinipes
T. spinipes bees have the same characteristics as Trigona spp.The only difference is that the legs are orange and have a round shape.Basically, almost all pollinating insects do the same thing in picking up pollen from plant flowers, that is, when they stick to a flower, they take food, after they leave the flower, the pollen on that flower sticks to their feet and when they look for food on other flowers, the pollen The juice that sticks to the legs will pollinate the pistils.This insect acts as a pollinator which helps pollination and is permanent because it visits the flowers of the bitter melon plant every time, but the number is less than Trigona spp.

Camponotus carnelius
The C. carnelius ant has the characteristics of long antennae, is black and brown in color, has a body size of 0.2 -0.3 cm long, the body is pitch black, the abdomen is oval and bluntly rounded, has a round mouth shape and has a type of mouth.sucker Suriana, 2017).An ant can be said to be a pollinator if, when collecting pollen nectar, its body hits the pollen and when it travels the pollen from its body hits the stigma, the ant helps in the process of pollinating the plant.C. carnelius is sedentary because every time this insect visits bitter melon flowers.

Aulacophora similis Oliver
This insect is a pest of bitter melon plants, better known as oteng-oteng A. similis Oliver.Adults measure 0.7 cm and have a shiny brownish yellow back, and have antennae that are half as short as their body.This insect pest causes the plant to wilt when eaten by beetles, in heavy attacks it can cause many holes in the leaves and sometimes only leaves the bones of the leaves, the aim of this insect pest is in the flowers, they want to eat parts of the flower and are able to inhibit pollination.A. similis Oliver.It is temporary/not permanent because this insect is a pest.

Aulacophora Lewisii
This insect pest is shaped like a beetle which is in the same family as the oteng-oteng pest, only it has a different species and the color of its back is shiny black.This beetle is black, with a golden yellow head.This insect also attacks the leaves of bitter melon plants, causing damage to plant parts.The aim of these insect pests is in the flowers, they want to eat parts of the flowers and be able to inhibit pollination.It is temporary/not permanent because this insect acts as a pest, which only visits at certain times in not very large numbers.

Henosepilachna vigintioctopunctata
This insect acts as a pest.Adult H. vigintioctopunctata is about 7-8 mm long, with 13 black dots on each elite wings.The beetles eat plant leaves.This insect is not permanent, only visiting at certain times with the aim of eating the crown of the flower.
Larvae of the beetle Anatis spp.hairy body and has 6 legs.The length of the larval phase varies between 10 -21 days.This koksi beetle is active during the day.The role of adult koksi beetles and their larvae is that they are predators of soft-bodied insects, such as aphids which are insects similar to aphids.It is not permanent, only seen occasionally when visiting bitter melon flowers.

Thrips tabaci
This insect is small, approximately 0.5 -1.5 mm long.Thrips pests attack plants by sucking plant fluids from young leaves and flowers.Symptoms resulting from thrips pest attacks can be seen on the lower surface of leaves or flowers.This pest acts as a pest that does not settle on flowers because of its nature.

Spodoptera litura
Spodoptera litura including pests that damage plants.Adult insects have a body length of 20 -25 mm, have black triangular spots and yellowish stripes on their sides, these insects act as pests because they eat the leaves and fruit of horticultural plants which cause damage, the same as those in flowers.damaging parts of the flower, it is temporary and not permanent, because this insect pest only visits the flowers of the bitter melon plant.

Nesidiocoris tenuis
The imago of this pest measures ± 3.37 mm in length and is slightly brownish green in color and has vase eyes.According to Budiman et al., (2010) the length of the front legs and middle legs is 1.5 mm and the back legs are 2.5 mm.N. tenuis has a slender body shape with black spots on the body and a brownish green color (Kotambunan et al., 2012).Population and Attack Level N. tenuis attacks flowers so the plant's flowers fall easily or quickly.Thus, N. tenuis can interfere with the reproduction and development of bitter melon fruit.Nymphs and imago suck plant fluids at the base of the flower stalk in circles, causing symptoms in the form of circular black spots on the flower stalk (Rante and Dien, 2012).

Thomisus tenuis
Thomisus tenuis measuring 3-8.5 mm, the body is flat and resembles a crab, the first two pairs of legs are larger than the other legs for catching prey.This insect acts as a predator, this spider is known as the flower crab spider, because it feeds on insects that visit flowers, moves like a crab and the way this insect holds its front legs in a stance is reminiscent of a crab spreading its claws as a threat.

Results of Identification and Direct Observation of Bitter Gourd Flowers
The results of the identification of visitor insects associated with bitter melon flowers indicate the dominance of the Hymenoptera order, the Apidae family, and the species A. mellifera, Trigona sp., T. spinipes, and the Formicidae family with the species C. carnelius (visitor ants) in their visits to the plant flowers.bitter melon (Figure 1).
Based on observations, it was found that various types of pollinator and predator insects visited the flowers of bitter melon plants, each with different behavior.Various insect visitors associated with bitter melon flowers have their respective roles, including the role of pollinators, pests, predators, visitors, and have various behaviors during each visit to the bitter melon flowers.
Observations of insects such as A. similis Oliver, A. lewisii, or oteng-oteng took place around the flower crown, approaching the pollen (Figure 2), then the insects flew to other parts of the plant.Among these insects there are also predators such as T. tenuis (crab spider) and larvae of Anatis spp., which provide benefits to plants.During observations in the morning and evening, the insect that consistently visited many flowers was C. carnelius, which is included in the ant group.
Observations regarding the types and behavior of insects that visit flowers can be useful in efforts to increase the role of pollinating insects and the production of these plants.The daily availability of nectar and pollen can influence the diversity of insects that visit these flowers.Many insects from the order Hymenoptera feed on nectar and pollen, so insects from this order often visit flowers (Khairiah et al., 2012).
Ants have a dual role as visitors and pollinators.The presence of ants on plants, especially flowers, has a positive impact, such as pollinating several types of flowers and improving the nutrient cycle in the soil (Hasyimuddin et al., 2017)., while Figure 2 depicts the behavior of insect pests visiting flowers.

CONCLUSION
There are 12 species of insects belonging to 6 different orders were identified on bitter melon plant flowers, namely Hymenoptera, Coleoptera, Thysanopterap, Lepidoptera, Hemiptera, and Araneae.Apart from that, 8 insect families were found to act as visitors in the morning.The roles of visitor insects associated with bitter melon flowers vary greatly, including the roles of pollinators, predators, visitors and pests.The behavior of these visiting insects involves taking nectar or pollen from flowers as a source of nutrition.The interactions that occur between insects and bitter melon flowers can be categorized as mutualistic interactions.

Table 1 .
Visitor insects associated with bitter melon plant flowers obtained from direct observation (scan sampling)