First long-horned beetle found bearing live young

Four new species of long-horned beetle hailing from Borneo have been identified this week, including the first of the family ever known to give birth to live young.

Long-horned beetles are the fifth largest beetle family in the world, already incorporating around 35,000 different species known to science.

Despite this, relatively little is known about them.

A trio of biologists from the Czech Republic has added to the species list, naming four in a paper published in the journal ZooKeys.

“We studied the diversity of the rarely collected wingless long-horned beetles from Borneo, which is one of the major biodiversity hotspots in the world,” says Radim Gabriš from Palacký University and lead author of the study.

“The mountains of northern Borneo, in particular, host a large number of endemic organisms.”

Among one of the new genera, the researchers found two females with larvae inside their bodies, revealing the first known instance of this trait among the long-horned beetle family.

Most insects lay eggs, allowing embryos to develop outside the female’s body.

In some insect species, however, the eggs remain internal, in the genital tract of the female, until the young are fully developed.

Species that use this mode of reproduction are called ovoviviparous, and the trait has been rarely recorded among beetles.

“During a dissection of female genitalia in specimens belonging to the one of the newly described genera, named Borneostyrax, we found out that two females contained large larvae inside their bodies,” explains Gabriš.

“This phenomenon has been known in a few lineages of the related leaf beetles, but this is the first case for the long-horned beetles.”

The researchers say there could be more ovoviviparous species among the family, and further study is needed to better understand its diverse reproductive methods.