Seed Bugs – All You Need To Know

Seed bugs are massively common in North America, so if there is anything you want to know about these critters, this single resource will help you out.

Seed bugs are extremely common in North America, and unfortunately, they are almost all problematic. 

There are a large variety of seed bugs out there that share similar characteristics. 

This article covers these bugs in detail, including their types, habitat, lifecycle, diet, and so much more. Read on to learn more about this family of bugs.

What Are Seed Bugs?

Seed bugs and their kin are scientifically known as Lygaeoids, a group of insects in the Lygaeoidea superfamily

However, you might want to note that the term “seed bugs” doesn’t refer to a single insect species but several.  

All 15 insect families under the Lygaeoidea superfamily, including seed bugs and other related bugs like stilt bugs and big-eyed bugs, are known as Lygaeoids.

As their name suggests, seed bugs primarily feed on seeds by sucking out the juices. Some seed bugs are generalists with a variety of hosts. 

Others are specialist seed bugs, feeding only on a few specific species of plants. 

Seed bugs can be of various colors – reddish brown, black, tan, or bright orange and red areas contrasting darker colors.

Whitecrossed Seed Bug

Types of Seed Bugs

1.    Dirt Colored Seed Bug

The Rhyparochromidae family, or dirt-colored seed bugs, are a group of insects that primarily feed on seeds. A few species are insectivorous and prey on other insects. All bugs of this family are dark brown – much like soil. 

They feature large, red, and bulging eyes on the sides of their heads, while the wing coverings have a bronze tinge to them. 

Most seed bugs of this family visit flowering plants to feed on the seeds at the bases of flowers. However, they don’t cause much damage and hence aren’t deemed a pest.  

2.    Long Necked Seed Bug

This slender bug is a member of the Rhyparochromidae mentioned just earlier, i.e., they’re a dirt-colored seed bug too. 

However, the long-necked seed bug deserves special mention due to its distinct appearance and large population. This bug is very common in agricultural habitats, gardens, and lawns. 

Especially if you live in Kentucky, there’s a good chance that you might encounter long-necked seed bugs. These bugs mostly feed on the seeds of cotton and strawberry plants.

3.    Mediterranean Seed Bug

The Mediterranean Seed Bug is a species of true seed bug that’s quite common in both Europe and North America. Their appearance is rather unique, which makes it easy to identify them. 

This bug is characterized by a bold black triangle on its back, followed by three black patches behind it. An invasive species in North America, the Mediterranean Seed Bug overwinters together in large numbers. 

At the onset of spring, the adults and the larvae emerge and together feed on the same seeds and plants. Although they mostly prefer grass seeds, you can also find them on mint family plants.

4.    Elm seed bugs

The elm seed bug is a well-known invasive pest species native to Europe and the Mediterranean region. As its name indicates, this is a specialist seed bug known to feed on the seed of elm trees primarily. 

This bug is often confused with boxelder bugs – a different seed bug species. Although they don’t cause much damage besides destroying the seeds, they’re a major nuisance pest species. These bugs congregate in homes in large numbers during the winter months. 

Like stink bugs, they also release a foul odor similar to that of bitter almonds when threatened or aggravated.

Elm Seed Bug

5.    Western Conifer seed bug

Interestingly, the Western Conifer seed bug doesn’t belong to any of the Lygaeoid families. 

Despite its feeding habits and its name identifying it as a seed bug, it belongs to the family of leaf-footed bugs, Coreidae. 

Western conifer seed bugs are a serious pest due to the economic damage they cause in pine farms by destroying conifer seeds

In homes, they’re a nuisance pest known to congregate in large numbers and release a foul odor. While they aren’t capable of stinging, they can still hurt you with their proboscis.

The WCSB is a bug that smells like grass when you kill it, a unique thing that many people use to identify it.

6.    White Crossed Seed Bug

Also known as the ragwort seed bug, the white-crossed seed bug is easy to identify. Although the prominent X pattern on its back isn’t very uncommon, its color sets it apart from bugs with such patterns. 

Its back is neatly divided into areas of red and black by a white or pale yellow thin-lined X, which explains its name. 

Although white-crossed seed bugs prefer to feed on ragworts and groundsels, various other plants make suitable hosts too.

7.    Sycamore seed bug

The Sycamore seed bug is a species native to North America. Identified by the triangular plate at the back of their heads, these bugs are a shade of mottled brown. 

Sycamore seed bugs have an elongated body with a long proboscis. Feeding primarily on the sycamore plant and its seeds, this is a specialist seed bug. 

Apart from hindering the spread of sycamore trees by destroying their seeds, these bugs can also be a nuisance due to their large presence. 

They often appear in huge numbers on walkways and parks lined with sycamore trees.

8.    Milkweed Bugs (Small)

In case you wonder why we specified this bug as small, it’s because there are two different species of milkweed bugs. 

We’ll talk about the large one in the next section, but let’s cover the small milkweed bugs first. 

This is a very common and widespread true bug, known to feed on the sap of milkweed seeds, nectar, etc. Interestingly, milkweed bugs are omnivorous and also prey on caterpillars, flies, bees, and beetles.  

Small Milkweed Bug Nymph

9.    Milkweed bugs (large)

Growing to a length of 0.5 inches to 1 inch, these bugs are a larger species of the milkweed bug. Their prominent black and orange pattern not only renders them easily identifiable but also makes them one of the most beautiful true seed bugs. 

The pattern is different from the smaller species of milkweed bugs mentioned earlier. Large milkweed bugs have two orange triangles facing opposite sides on each forewing, divided by a black band in between. 

They have a similar diet as small milkweed bugs, with a preference for the common milkweed plant.

10.  Neortholomus scolopax

The Neortholomus scolopax is quite common, usually found in dry grassy areas. They’re of a mottled brown color, like the dirt-colored seed bugs. 

In case you’re wondering why we mention this seed bug only by its scientific name, it’s because this species does not have a common name. 

Neortholomus scolopax is a generalist seed bug that feeds on various host plant species.

Where Do Seed Bugs Live?

With so many species of seed bugs out there, it’s not surprising that they’re quite widespread across the continents. 

They’re extremely common all over the United States, with some seed bugs being native to North America and the rest being invasive species. 

You’re more likely to find them in prairies, old fields, and other such grassy open areas. 

Seed bugs are also common at the borders of grasslands and woodlands, with a mix of grasses and flowering plants.

Immature Seed Bugs

What Do They Eat?

The seed bugs cannot chew as they have piercing and sucking mouthparts rather than chewing mouthparts. 

Like the other members of the order Hemiptera, they pierce plant matter with their proboscis and suck out the juices. While seed bugs primarily feed on the juices from host plant seeds, leaves and flowers make suitable food sources for many species too. 

Not all of them are garden or agricultural pests, as some seed bugs feed on specific host species like elm or boxelder trees.

What is the Lifecycle of Seed Bugs?

The seed bugs mostly share a similar life cycle, although their overwintering habits may vary. Like other true bugs, they only undergo simple metamorphosis. 

Most of them are gregarious and overwinter in large groups, but some species are migratory and leave for warmer areas in the south during the cold months. 

The overwintering adults emerge again in spring to resume feeding and mate, eventually laying eggs after a while. The females tend to insert their eggs into plant tissue or lay them on host plants.

The Seed bug nymph emerges during late spring or early summer. They spend several weeks feeding on seeds and growing. 

Mediterranean Seed Bug

Larval seed bugs molt through five instar levels, growing more similar to the adults with each instar. Around late summer, the larvae are fully developed and pupate into adults.

Until the onset of fall, adult seed bugs are abundant and can be found feeding on plant matter. As the cold weather begins to set in, they seek refuge inside homes and other sheltered spaces. 

The cycle then repeats, with the adults reemerging in spring and laying eggs for a new generation of seed bugs.

Where Do They Lay Eggs?

Different seed bug species have different preferences in this matter. While some lay their eggs on plants, others prefer to lay eggs among soil and leaf litter. 

Again, some species, like the western conifer seed bug, lay eggs on pine cones or in the tissue of cone scales. With so many different types of seed bugs, it’s hard to point out a few specific egg-laying spots.

Do They Bite or Sting?

Don’t worry – as much of a nuisance as these bugs may be, they cannot sting or bite you. While the lack of chewing mouthparts prevents them from biting, seed bugs do not have stingers either. 

However, some seed bugs can hurt you in other, less serious ways – such as the western coniferous seed bug using its proboscis to poke.

Are They Poisonous or Venomous?

Seed bugs do not pose a threat by being venomous or poisonous either. 

While some seed bug species extract poisonous substances from their food and store the poison to deter predators, their poison isn’t potent enough to harm humans.

Western Conifer Seed Bug

Are They Harmful to Humans as Pests?

Most seed bugs are only nuisance pests that cause trouble by infesting homes in large numbers and/or spreading foul odors. 

They don’t cause much trouble as garden pests, thanks to their feeding habits. However, the western coniferous seed bug can have an economic impact due to the damage they cause in nurseries and plantations where pines are grown.

Can They Come Inside Homes?

Although this isn’t the case for every seed bug species, man seed bugs are notorious for infesting homes. 

Especially during the cold months, they seek warmer places to overwinter, and that is exactly what homes offer. It’s easy to find the gregarious seed bugs overwintering in your home in large numbers.

What Are Seed Bugs Attracted To?

Different seed bug species are attracted to different host plants. For example, you’ll usually find milkweed bugs around milkweed plants, while elm seed bugs mostly stay on or near elm trees. 

Generalist seed bugs have a variety of hosts, including grasses and flowering plants. During winter, indoor areas, wall vents, cracks, and crevices protected from the cold attract them.

Western Conifer Seed Bug

How To Get Rid of Seed Bugs?

Managing the seed bug population in your home isn’t very difficult. Manual removal is the easiest solution, after which you can either kill the bugs or release them outside. 

If there’s a large cluster of seed bugs in your home, a vacuum cleaner can be of help too. However, if it’s one of those stinky seed bugs, vacuuming can cause them to release the odor. 

For the same reason, don’t crush seed bugs when killing them – just drown them in a bowl of soapy water or flush them down the toilet.

Interesting Facts About Seed Bugs

Now that you’ve learned almost everything about seed bugs, here are some interesting facts that you should know:

  • Most seed bugs with contrasting colors of black and bright red or orange sequester toxins by feeding on toxic plants. Their bright colors are a symbol of their toxicity and ward off predators. This isn’t exclusive to seed bugs alone – it’s a rather common occurrence in the animal kingdom.
  • Many non-toxic seed bugs enjoy a different form of protection – camouflage. Their drab or tan colors help them blend into their surroundings.
  • A common characteristic shared by these bugs is the appearance of their hind legs. Each hind leg has a small but distinctly swollen area near the end.
  • Seed bugs don’t need to be exterminated as they aren’t major pests. Besides, these bugs are a colorful and important part of the ecosystem.
Mediterranean Seed Bug

Wrap Up

Seed bugs are rather harmless when it comes to their chances of hurting you or damaging your plants. 

However, if they start appearing on your window frames or inside your home, it’s a good idea to seal cracks and install window screens. 

Although the ability to emit foul odors is a common trait among seed bugs, a bug that smells like apples when killed might also be a brown marmorated stink bug

Hopefully, identifying seed bugs and keeping them out of your home will now be easier for you.

Thank you for reading!

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