#burrower bug

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Two-Lined Burrower Bug - Pangaeus bilineatus

While researching the White Margined Burrower Bug (recently posted for a more in-depth look earlier this month) for information on that specific insect and some of the other Cydnidae relatives that live in North America, I was drawn to a few genera in particular: Cyrtomenus and Dallasiellus specifically. They are (relatively) large compared to the White Margined Burrower Bug, and seem to be better equipped for digging and burrowing thanks to their robust bodies and spine-covered legs. Thanks to the latter trait, my memory was jogged on this insect I found in the garden, but struggled to identify when first found. Three years later, I believe P. bilineatus to be the closest match given its appearance, coloration (especially the eyes), legs, exposure of wings, antennae and texture of the exoskeleton. However, without close-ups of this insect that are in focus, this is an educated guess made using Bugguide's identification key. With the evidence available, this insect could be a different specie within the Tribe Geotomini (Order> Family > Tribe > Genus > Specie) with spiny legs. Melanaethus was another genus I had considered within the Burrower Bug family.

On the assumption that this is indeed a Two-Lined Burrower Bug, we're very lucky to find this Bug above ground! Compared to its white margined relative, this specie prefers to spend its time in the soil, and is content to nourish itself with juices sipped from plant roots. Since it likes to remain hidden, detection of this insect can be difficult without deliberately digging and investigating roots. Moreover, it is a generalist feeder that has been found on trees, smaller plants and important cultivated species such as pear, peanut and strawberry. Both adults and nymphs feed this way. After overwintering beneath the leaf litter or spent plants from the previous year, the adults emerge and place their eggs at similar sites (likely through scent cues) and diligently watch them until they hatch. Upon hatching, the adult Bug supplies them food for a short while before the nymphs set out on their own. This feeding has a triple function: watch over and protect the young, ensure they are feed, and supply them with essential gut bacteria that will aid their nutrient intake! Their strategy seems foolproof, and yet their numbers don't seem to explode often due to the control exerted from parasitic Twisted-winged Insects (Order Strepsiptera), subterranean worms and modern insecticides used for protecting crops.

White-Margined Burrower Bug - Sehirus cinctus

This specie deserved a revisit after I accidentally classified it into the wrong family on this blog. I had confused the insect families and superfamilies in my haste. As a clarification so others don't repeat my mistake: the White-Margined Burrower Bug is classified as a Burrower Bug (family Cydnidae); it isn't a Shield Bug (family Acanthosomatidae) despite the similar morphological appearance in the broad strokes. The mix-up presented itself when I blanketed both families within the Superfamily Pentatomoidea on this blog. Fixing the classification problem, I researched this Burrower Bug further and now have a bit more to share from a specimen found in my own backyard (thanks to my mom's camera). Compared to the previous post, this individual is smaller (it may be a male) than the one hiding in the lamb's ear. If I had to guess, I'd say the individuals here are 5mm long or less. With a size so small, they could be easily mistaken for tiny garden Beetles, but a closer look at the images will reveal a distinctly Hemipteran head and wings that fold over themselves instead of becoming concealed by a wing case. Of course, there's the white band that goes all the way around the body, ending at the edge of the pronotum just before the eyes.

When researching this specie, I was surprised to learn how many other species closely resemble it. Insects like the Cow-Wheat Shieldbug (Adomerus biguttatus) or Canthophorus impressus are quite similar (those live either in Europe or Asia). However, the White-Margined Burrower Bug of North America that will always have an unbroken white band around its body. That's first part of its name covered, but what about the "Burrower Bug" part? You see, this Bug is an outlier in its own family: it prefers to live and feed in flowering plants rather than take to the soil to feed. Other members of the Cydnidae family will spend their time on or under the soil, remaining close to plants in order to feed. The Bugs that dig do so using their heads and forelegs (look at species within the genera Cyrtomenus and Dallasiellus for examples of diggers, especially the former). The only burrowing this specie does is when it comes time to laying eggs. This specie will create burrows specifically for depositing eggs and will nourish the hatched nymphs with seeds from mints and sages. From the images I've seen, the adults transport seeds by carrying them under their bodies using their rostrum! After a few days of seed-feeding, the nymphs will strike out on their own and feed on the seeds they can find above ground. If you search for the nymphs, look for rounded form with a deep red color on the abdomen (or abdomens...they like to aggregate, but their feeding doesn't seem to be very destructive). The white margin will not appear until the adult molt.

White-Margined Burrower Bug - Sehirus cinctus

This stealthy little shield-shaped insect was found just as I was leaving the Royal Botanical Garden’s Hendrie Park for the day to then go visit the Arboretum. Thank goodness I was able to spot it before it tucked itself away in the lamb’s ear (a plant in the mint family, a feeding preference of this insect). While I couldn’t get too close, we can still see a lot of the insect’s defining features: antennae chopped into 3 distinct sections (5 segments overall, however), an oval body with an enlarged scutellum (the triangular plate), and the white border that outlines the insect’s shell. Said border gives this insect its name, and it’s a beautiful sight to behold. 

Like other True Bugs, it uses a piercing mouthpart to feed on plant juices and seeds. However, according to several sources, it not only seeks out food for itself, but also for its young. Female Burrower Bugs have been observed to guard their eggs after laying them and will subsequently bring them seeds to eat for when they hatch. That’s a lot of dedication considering there can be 150 eggs in a clutch! After a few days, the nymphs venture out on their own to look for food. The nymphs have a dark red coloration and slowly become black over time, with their final molt giving them wings. When winter rolls around, these bugs tuck into the ground and overwinter, beginning the next generation when spring returns.