Story and photos by Anita Westervelt, Texas Master Naturalist
There’s one super big bug that always gives me pause. I erroneously labeled it as a rhinoceros beetle and was told they kill trees by eating the roots.
Neither is correct. It is an ox beetle, in the scarab family, Strategus aloeus. Ox beetles can measure to 2 inches in length. They are a benign, nocturnal insect that actually benefit the environment by recycling decaying plant material back into the ecosystem, according to an aggie-horticulture.tamu.edu website.
Ox beetles hide during the day by digging holes in the ground or burrowing in a compost pile. They are active May through November in the Valley. Adult ox beetles live four to six months.
As a Texas Master Naturalist, we’re introduced to organizations and citizen science arenas where we can connect with scientists and other experts for information via phone apps, e-mail or Internet sites.
The ox beetles were identified using iNaturalist — a citizen science project accessed with a phone app, or by computer at www.iNaturalist.org, potentially connecting with 750,000 experts.
Minute details distinguish different species in the same family. For instance, a male ox beetle can be either a major or minor variety. Major males have three large projections on the thorax (the part of a beetle between the head and abdomen) with the central one being the longest. Minor males have horns, but the two in back are small and stubby. Female ox beetles have a small raised area in place of horns.
Often this minutiae can discourage novice nature enthusiasts. With the iNaturalist data base, visually similar species will pop up. Numerous photos of individual species are offered to help with identification. Observations are vetted by scientists and other experts to ensure proper species identification.
Knowing the scientific species name allows for further research which in turn benefits the native habitat. From being hesitant about this big bug to the realization that it is actually beneficial was a valuable leap.
Not only is the adult ox beetle a good thing, its offspring are, too. Like the beetle itself, its larvae are giants — especially compared to more familiar grubs of June beetles. Ox beetle larvae, also like June beetle larvae, can feed on roots in the ground and cause dead patches in the grass. Adult ox beetles don’t eat much — decaying roots, fallen fruit and rotting leaves, perhaps. The larvae are voracious eaters, feeding on decaying rotten wood and composted vegetation — the preferred medium where female ox beetles lay their eggs. The larvae stage can last a year or longer.
It’s easy to misidentify any large beetle as a rhinoceros beetle. There are approximately 30,000 scarab beetle species. Rhinoceros beetles are much larger, up to six inches long. They have two horns that are slightly forked at the end. One horn on top and the larger horn which projects forward from the middle of the thorax.
Ox and rhino beetles are found in Gulf and Atlantic coastal states and southward into South America. Neither beetle can bite or sting humans, and they carry no type of poisonous venom. Their main predators are birds, snakes opossums and raccoons.
iNaturalist is a citizen science project and online social network of naturalists, citizen scientists, and biologists built on the concept of mapping and sharing observations of biodiversity across the globe. https://www.inaturalist.org/pages/about