What insects start with O? Insects are complex organisms with their biology and behavior.
Their senses, communication systems, and reproductive strategies are unique.
They can survive in nearly any environment and out-competing other organisms for resources.Â
Human activities such as habitat devastation, pollution, and climate change also pose a threat.
Learning about these insects that start with O can provide a window into the natural world and inspire us to revere and appreciate its diversity.
Let’s get started!
1. Oak Clearwing Moth
This is the first on our list of insects that start with O. The Oak Clearwing Moth (Paranthrene optata) is a small moth with transparent wings resembling a wasp shape and color. This mimicry protects the moth from potential predators.
The Oak Clearwing Moth inhabits oak forests throughout its range from Alaska to Mexico. This moth’s caterpillars bore into oak tree branches and feed on the interior bark.
The Oak Clearwing Moth has a brief lifespan of only a few weeks and is thus rarely observed by anyone other than entomologists.
2. Oak Lace Pest
The Oak Lace Bug (Corythucha arcuata) is a small, oval insect that feeds on oak tree leaves.
Oak Lace Bugs are typically less than 14 inches long and have wings with a lace pattern.
These insects are frequently encountered in groups feeding on the leaf sap on the undersides of oak leaves.
The feeding activity of the Oak Lace Bug can cause the foliage to turn yellow and sometimes drop prematurely.
Oak Lace Bugs are not aggressive and pose no danger to people.
3. Oak Leafroller
This is the next on our list of insects that start with O . The Oak Leafroller (Archips semiferanus) is a small moth that deposits its eggs within oak leaf folds.
Oak Leafroller larvae graze on the leaves of oak trees, causing the leaves to curl and twist, which serves as a protective habitat for the larvae.
The Oak Leafroller is found throughout North America and is not considered a significant pest, although it can cause significant leaf damage during intense infestations.
4. Oak Leaftier
The larvae of the Oak Leaftier (Croesia semipurpurana) feed on the foliage of oak trees.
The larvae of the Oak Leaftier produce a silk web that attaches to the ends of oak leaves and binds them together to create a shelter for the larvae.
Oak Leaftier prefers mature oak trees, and excessive infestations can result in considerable defoliation.
5. Oak Lecanium
Oak Lecanium (Parthenolecanium quercifex) is a sap-feeding scale insect.
Commonly found on the twigs and branches of oak trees, these insects can cause the foliage to turn yellow and wilt.
Additionally, large populations of Oak Lecanium can cause branch dieback.
6. Oak Sapling Borer
This is the next on our list of insects that start with O. Oak Sapling Borer (Podosesia syringae), a moth whose larvae bore into the sapwood of oak saplings, causing extensive injury that can lead to the tree’s demise.
Commonly found in nurseries and juvenile oak plantings, the Oak Sapling Borer prefers younger oak trees.
7. Oak Skeletonizer
The Oak Skeletonizer (Bucculatrix ainsliella) is a microscopic moth whose larvae feed on the leaves of oak trees, causing them to become brown and skeletonized.
Oak Skeletonizer larvae construct a protective shelter by winding oak leaves and binding them with silk.
8. Oak Woodworm
Oak Timberworm (Arrhenodes minutus) is a microscopic beetle that feeds on oak tree bark and sapwood.
Oak Timberworm larvae bore into the tree, causing injury that can result in the tree’s demise.
Oak Timberworms are prevalent in oak forests and are capable of causing significant injury to mature trees.
9. Oak Webworm
This is the next insect on our list that starts with O. The Oak Webworm (Archips argyrospila) is a small moth whose larvae cover the edges of oak leaves with silk webs.
Oak Webworm larvae feed on the leaves beneath the webbing, causing significant injury that can result in the tree’s defoliation.
Oak Webworms are widespread across North America and are considered minor pests.
10. Oblique-streaked Leafroller
The larvae of the Obliquebanded Leafroller (Choristoneura rosaceana) feed on the foliage of oak and other trees.
The larvae of the Obliquebanded Leafroller use silk to weave together oak leaves to create a shelter where they can feed on the leaves.
Heavy infestations can result in substantial leaf injury, but the Obliquebanded Leafroller is generally considered a minor pest.
11. Obscure Mealybug
The Obscure Mealybug (Pseudococcus viburni) is a scale insect that feeds on the sap of various vegetation, such as oak trees.
Commonly found on the twigs and branches of oak trees, these insects can cause the foliage to turn yellow and wilt.
Additionally, large populations of Obscure Mealybug can cause branch dieback.
12. Obscure Root Weevil
The larvae of the Obscure Root Weevil (Sciopithes obscurus) feed on the roots of oak and other trees.
The Obscure Root Weevil’s feeding activity can result in tree stunting and even mortality. Its adults feed on the tree’s foliage.
13. Obscure Scale
This insect feeds on the fluid of oak and other trees. Commonly found on the twigs and branches of oak trees, these insects can cause the foliage to turn yellow and wilt.
Large populations of the Obscure Scale are also capable of causing branch mortality.
14. Oceanic Burrowing Insect
This is the next on our list of insects that start with O. The medium-sized Oceanic Burrower Bug (Cyrtomenus ciliatus) inhabits sandy beach environments.
These insects burrow into the sand and prey on other arthropods and small insects. They are prevalent in warm coastal regions worldwide.
15. Oceanic Embroidery
The Oceanic Embiid (Australembia australis) is a minuscule insect native to the southern hemisphere’s coastal regions.
These insects are renowned for their ability to weave silk, which they use to construct protective tubes against predators and harsh environments.
The Oceanic Embiid consumes a wide diversity of insects and other arthropods.
16. Oceanic Cricket
The Oceanic Field Cricket (Teleogryllus oceanicus) is a large cricket that inhabits the Pacific’s coastal regions.
These crickets consume plants, insects, and other small creatures. To attract partners, males of this species emit a distinctive chirping sound.
17. Old Beetle
The Medium-sized Odd Beetle (Strangalia luteicornis) is widespread throughout North America.
These beetles, which depend on oak sap and other trees, are distinguished by their yellow coloring. The Odd Beetle is not a significant nuisance.
18. Odorous House Ant
The Odorous House Ant (Tapinoma sessile) is a minor North American ant species.
These ants‘ names are derived from the foul odor they emit when crushed, which is frequently described as smelling like rotting coconut.
Odorous House Ants are not considered pests, but when they invade homes in search of food, they can be a nuisance.
19. Old House Dullness
The larvae of the Old House Borer (Hylotrupes bajulus) penetrate the structural timbers of buildings.
Old house borers, which exist throughout North America and Europe, can cause significant damage to older residences and other structures.
Old House Borer infestations are often difficult to control and require professional pest management.
20. Ancient Bollworm
This is the next insect on our list that starts with O. The Old World Bollworm (Helicoverpa armigera) is a large moth whose larvae consume the reproductive structures of various plants, including oak trees.Â
The Old World Bollworm is native to Asia but has since colonized numerous other regions, including Europe, Africa, and Australia. It is a significant agricultural parasite.
21. Oleander Aphid
The Oleander Aphid is a small insect with a soft body that inhabits Oleander and Milkweed vegetation.
They reproduce rapidly and can cause considerable harm to their hosts.
22. Oleander Hawk Moth
The Oleander Hawk Moth is a large moth with an impressive appearance that inhabits the southwestern United States and Mexico.
They are well-known for their intricate wing patterns and propensity for pollinating Oleander plants.
23. Oleander Pit Measurement
This parasitic insect feeds on the juice of Oleander plants. They can cause leaf loss and stunted growth in their host plants.
24. Oleander Scale
The Oleander Scale is a small insect with an armored exoskeleton that inhabits Oleander and other ornamental plants.
They feed on the fluid of their hosts and, if left unchecked, can cause significant damage.
25. Olive Fruit Fly
The Olive Fruit Fly is a significant threat to olive trees, causing injury to the fruit and lowering crop yields. It is one of the most economically significant parasites in olive-growing regions.
26. Omnivorous Leafroller
This is the next insect on our list that starts with O. The Omnivorous Leafroller is a small, inconspicuous insect that feeds on numerous plant species.
Their unique rolling behavior, in which they envelop themselves in plant tissue to avoid predators, is well-known.
27. Omnivorous Looper
This is the next on our list of insects that start with O. The Omnivorous Looper is a moth-like insect that consumes numerous plant species.
They are known for their unique looping behavior, in which they travel across their host plants in a looping motion.
28. Onion Beetle
The Onion Aphid is a small sap-sucking insect that can severely damage onion crops. If allowed to increase, it can rapidly infest entire fields if left unchecked.
29. Onion Bulb Fly
Onion crops are plagued by the Onion Bulb Fly, which causes injury to the bulbs and reduces crop yields. The fly is a significant issue in many onion-growing regions.
31. Onion Plant Bug
The Onion Plant Bug is a pest of onion crops that feeds on the plant’s sap and causes harm to the foliage. Unchecked, they can rapidly infest entire fields.
30. Onion Aphid
The Onion Thrips is a small sap-sucking insect that can cause severe injury to onion crops. Unchecked, they can rapidly infest entire fields if allowed to increase.
31. Orange Mint Moth
The Orange Mint Moth is a small, colorful insect inhabiting gardens and meadows across many of the United States.
They are drawn to the blossoms of mint and other Lamiaceae family plants.
32. Orange Spiny Whitefly
The Orange Spiny Whitefly is a citrus crop pest that feeds on the plant’s sap and injures the foliage. It is well-known for its spiny appearance and oily residue.
33. Orange Tortrix
The Orange Tortrix is a small, moth-like insect inhabiting orchards and gardens across many of the United States.
They are well-known for their vibrant orange coloring and propensity to feed on various fruit trees.
34. Orangedog
The Orange dog is a caterpillar that feeds on the foliage of citrus trees, causing defoliation and diminishing the tree’s vitality.
They are called “Orange dogs” due to their orange hue and resemblance to small, writhing dogs.
35. Orange-crowned Maple-worm
The orange-humped tapeworm is a pest that feeds on the foliage of Maple trees, causing defoliation. It is distinguished by the orange crest on its back.
36. Orb Weavers
Orb Weavers are ubiquitous garden and tree-dwelling spiders.
These insects that start with O. all appear to have a swollen abdomen and construct circular webs in which to rest. Many are orange, brown, and black.Â
The legs of an Orb Weaver are typically very long, contributing to the spider’s overall girth. Males are about 6 mm long, whereas females can range from 10 to 20 mm.
Orb Weavers inhabit various habitats, including tall grasses, quiet corners within residences, and protected porches.
The web is a work of art, and the Orb Weaver waits in the center with its head facing downwards for prey to enter.
 If the spider is not in the center of the web, it typically monitors the web through a “signal” line still attached to it.
The signal line vibrates when anything becomes entangled in the web, and the spider emerges to complete its task.
37. Orangetailed Potter Wasp
This is the next insect on our list that starts with O. The Orangetailed Potter Wasp is a species of solitary wasp that is widespread worldwide.
They are known for their orange tail and ability to build intricate nests resembling pottery.
38. Orchid Aphid
The Orchid Aphid is a small, soft-bodied insect that inhabits a broad range of flowering plants, including orchids.
They feed on the sap of their host plants and, if left unrestrained, can cause significant damage.
39. Orchidfly
The Orchidfly is a small, colorful insect throughout the world’s tropical regions.
They are well-known for their intricate wing patterns and propensity to pollinate numerous orchid species.
40. Oregon Wireworm
The Oregon Wireworm is a pest of numerous commodities, including maize and potatoes.
They feed on the roots of their host plants and can result in significant crop yield reductions.
41. Oriental Beetle
The Oriental Beetle is a turfgrass pest that feeds on the roots and causes extensive damage to meadows and golf courses. The C-shaped, soil-dwelling larvae of these insects are well-known.
42. Oriental Cockroach
This is the last on our list of insects that start with O. The Oriental Cockroach is an international cockroach species.
They are well-known for their size and preference for moist, gloomy environments.
