Ozaena ground beetles likely parasitize ants throughout their life cycle

January 16, 2019, Public Library of Science

Ozaena. Credit: Wendy Moore (2019)
Ozaena ground beetles likely have anatomical adaptations enabling them to parasitize ant nests throughout their life cycle, according to a study published January 16, 2019 in the open-access journal PLOS ONE by Wendy Moore from the University of Arizona, USA, and colleagues.

Some ground beetles in the genus Paussus ("ant nest beetles") are known to live in and parasitize ant societies for their entire life cycle, for example secreting chemicals as larvae to attract ant prey. However, ground beetles in the genus Ozaena were previously thought to be free-living, with larvae digging burrows to ambush their prey.

The authors of the present study examined ground beetles of the species Ozaena lemoulti, using adults collected from the Parajito Mountains of Arizona, eggs from previously-preserved , and hand-reared larvae. They examined the beetles' anatomy in all three life stages and molecularly-sequenced adult beetle gut contents to confirm , hoping to find clues to the species' lifestyle and behaviors. They also compared O. lemoulti to the closely-related Goniotropis beetle, which is known to be a free-living, burrow-digging predator.

The authors found anatomical features which might indicate that O. lemoulti parasitizes ant nests throughout its lifecycle, unlike other Ozaena beetles. Compared with Goniotropis larvae, O. lemouti larvae have morphological modifications to their mouthparts, head and abdomen which indicate that they are free-living mobile hunters in ant nests instead of immobile burrow-dwellers. The eggs lack the spongy air layer which in Goniotropis eggs protects against extreme weather conditions, indicating that they may be laid directly in the protected conditions of the ant nest. The gut sampling of O. lemoulti adults revealed that these beetles appear to exclusively feed on ant fluids, unlike Goniotropis adults.

While previous studies have indicated a possible link between adult Ozaena and ant societies, the authors state that this is the first research to indicate that an Ozaena species might exploit throughout its . Further research might use larger sample sizes and observe more directly the behavior of the beetles. Nonetheless, the authors believe that their research strongly indicates that O. lemoulti beetles, independently of the Paussus ant nest beetles, have adopted a lifestyle exploiting the rich food supply and safety found in ant nests.

The authors add: "DNA sequencing of gut contents and comparative anatomy of three life history stages reveals that Flanged Bombardier Beetles in the genus Ozaena have adopted a new, obligate parasite strategy for living with and exploiting ants as their sole source of food. Unique morphological modifications of the head and abdomen indicate that Ozaena larvae do not live in burrows but rather are free-living, mobile hunters. We hypothesize that the main motivation to leave the burrow is the opportunity that affords the larva to feed on non-mobile food, specifically ant brood, the most treasured, soft, protein rich, and fat rich resource in the nests."

Explore further: Brazilian scarab beetles found to be termitophiles

More information: Moore W, Di Giulio A (2019) Out of the burrow and into the nest: Functional anatomy of three life history stages of Ozaena lemoulti (Coleoptera: Carabidae) reveals an obligate life with ants. PLoS ONE 14(1): e0209790. doi.org/10.1371/journal.pone.0209790

Related Stories

Brazilian scarab beetles found to be termitophiles

January 13, 2015

Termite soldiers are able to chemically detect intruders in their colonies. While most trespassers are swiftly dealt with, some spiders, centipedes, millipedes, and insects are allowed to find shelter within termite nests. ...

Study shows how beetle larvae adapt to different bee hosts

September 11, 2018

A team of researchers at the University of California has discovered adaptations made by a species of beetle to survive in different geographic locations. In their paper published in Proceedings of the National Academy of ...

Ambrosia beetles have highly socialized systems

October 4, 2011

(PhysOrg.com) -- Ambrosia beetles have long eluded scientists when it comes to being able to study their natural social structure. These beetles live deep within the solid wood of trees and when you disturb their natural ...

Common genetic toolkit shapes horns in scarab beetles

October 4, 2018

Horns have evolved independently multiple times in scarab beetles, but distantly related species have made use of the same genetic toolkit to grow these prominent structures, according to a study publishing October 4, 2018 ...

Recommended for you

Archaeologists discover Incan tomb in Peru

February 16, 2019

Peruvian archaeologists discovered an Incan tomb in the north of the country where an elite member of the pre-Columbian empire was buried, one of the investigators announced Friday.

Where is the universe hiding its missing mass?

February 15, 2019

Astronomers have spent decades looking for something that sounds like it would be hard to miss: about a third of the "normal" matter in the Universe. New results from NASA's Chandra X-ray Observatory may have helped them ...

What rising seas mean for local economies

February 15, 2019

Impacts from climate change are not always easy to see. But for many local businesses in coastal communities across the United States, the evidence is right outside their doors—or in their parking lots.

The friendly extortioner takes it all

February 15, 2019

Cooperating with other people makes many things easier. However, competition is also a characteristic aspect of our society. In their struggle for contracts and positions, people have to be more successful than their competitors ...


Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.