Upon the first impression, insects and bugs are not precisely on top of anyone's list when tending their garden. Usually, you would need a bottle of pesticides, and your problems are over. However, that is not always the case—besides, pesticides can have some side effects, and not all bugs are that bad. This scenario is where beneficial insects come into play.
If you are unfamiliar with mutual and symbiotic relationships between angiosperms (to put it simply, flowering plants) and pollinating animals, here is an example. Take honeysuckle and a bee, for instance. A honeysuckle flower requires reproduction for many more of it to grow, but its stationary structure hinders it. On the other hand, Bees need to produce honey for the hive, but they require nectar from a flower for that to happen. So, in this case, the bee would suck the nectar from the flower all while the honeysuckle's pollen sticks to the bee's hairs, helping the flower to cross-pollinate, breed, grow and produce food. Both help keep the cycle of life turning, and without either one, bees would starve to death, and a majority of plant life would disappear.
Beneficial insects, to start with, are any number of species that perform services such as pest control and pollination. However, the term helpful regarding these insects may be subjective and only arises in light of desired outcomes from a perspective. And in cases like these, insects that hinder this outcome are then classified as pests. In organic farming, encouraging beneficial insects by providing suitable living conditions is a pest control strategy. Beneficial insects do not just pollinate crops, but they also aid in making medicines and pharmaceuticals, producing silk and textiles, honey, wax, and breaking down organic matter.
While there are highly-favored insects such as bees, butterflies, and moths, there are some of the more common beneficial bugs you can have in your garden, which include ladybugs. While they may look friendly and seem like little red polka-dotted ornaments peacefully cruising on the leaves, ladybugs happen to be deadly predators against aphids and tiny pests, and an average ladybug larva can consume up to a whopping forty aphids per hour. Spiders, especially the particularly intimidating Huntsman spider, are highly effective in pest control. They eat live insects since they have a penchant for moving prey. The yellow-striped hoverflies are another excellent insect to keep watch on your plants, even more so for their larvae, as they can be some of the deadliest predators against plant pests by ingesting their bodily juices. Ground beetles are versatile, beneficial bugs, as they eat a wide range of insects, including nematodes, slugs, silverfish, and weevils. Soldier beetles are a significant predator of other species of beetles, aphids, and caterpillars, and they are attracted to plants with compound blossoms. Robber flies are perhaps one of the best options for a beneficial insect, as they go after a wide variety of garden pests, all while remaining harmless and un-intrusive to humans.
Like every living thing, beneficial insects rely on basic needs like food, water, and shelter to survive. And as a gardener, it is a bonus to attract these insects to your garden to keep pests at bay. Some insects directly contribute by pollinating flowers and crops, and some take the chaotic-good route by eating parasitic pests. Some go for indirect and subtle by forming parasitic relationships with these creeping, crawling problems and eliminating them from within, so it would be ideal if all three were to be "employed" in your garden. You can keep them well at home in your garden by creating an insectary for them—putting it simply, insectaries are garden plots made just for insects to give them food and shelter, and one usually places them near the garden. Some plants and flowers that can work as food and shelter are umbels, yarrow, fennel, carrots, dill, and taller flowers for flying insects, including daisies, Queen Anne's Lace alyssum, and cosmos. You may also use mint, sage, lavender, and lemon balm.
Another thing to do is use your pesticides responsibly; applicable as they are, the beneficial insects may also be in the vicinity. It would be better to choose your pesticides carefully in cases like these, preferably those targeting pests rather than specific beneficial bugs. Some pesticide alternatives would be horticultural oils, botanical insecticides, and soaps, as they do not leave long-term damage or side effects and are less likely to harm your beneficial insects. A water source will also help hydrate these insects, usually in puddles or a watering hole. And finally, beneficial insects require shelter as much as we do, as most do not scour up high-dwelling areas but instead patrol the ground, usually at night, for pests and prey. During the day, your miniature armies need shelter from the sun's heat, so one thing you can do to help keeps the soil mulched. Mulching keeps the soil's water quantity and gives them a shortcut to a water source. Stepping stones can also work as a shelter, as many insects tend to thrive under flat surfaces and rocks when they are off on a break from hunting pests.
To conclude, insects are not "good" or "bad" from an objective standpoint, as they only survive through any means necessary to their being. But as a gardener, these beneficial insects help take the frustration of dealing with pests and diseases of our hands, especially in much-needed multitudes. In any existing ecosystem, the diversity you put in your garden is one way to keep these insects and plants mutually thriving. Oddly, your backyard ecosystem is a cafeteria of insect-plant food chains put under your careful management, and without these little security guards around, the balance of the ecosystem would tip over. We cannot access the resources we have today and witness the beauty of our surroundings if not for the coexistence of insects and plants as a considerable part of the biosphere.