Sexually transmitted mutualist nematodes promote host growth across dung beetle species

Many symbionts are sexually transmitted and impact their host’s development, ecology, and evolution. While the significance of symbionts that cause sexually transmitted diseases (STDs) is relatively well understood, the prevalence and potential significance of the sexual transmission of mutualists remain elusive. Here, we study the effects of sexually transmitted mutualist nematodes on their dung beetle hosts. Symbiotic Diplogastrellus monhysteroides nematodes are present on the genitalia of male and female Onthophagus beetles and are horizontally transmitted during mating and vertically passed on to offspring during oviposition. A previous study indicates that the presence of nematodes benefits larval development and life history in a single host species, Onthophagus taurus. However, Diplogastrellus nematodes can be found in association with a variety of beetle species. Here, we replicate these previous experiments, assess whether the beneficial effects extend to other host species, an..., Dung beetle husbandry: Onthophagus taurus (originally collected in North Carolina, United States), Onthophagus binodis (Western Australia, Australia), and Digitonthophagus gazella (Florida, United States; and Queensland, Australia) were housed in large plastic containers filled with a two parts sand and one part soil mixture. Colonies were fed twice a week with ad libitum cow dung. The O. taurus and O. binodis colonies were held at 24ºC while the D. gazella colonies were held at 29 ºC.
Identification and maintenance of nematode cultures: Diplogastrellus nematodes were collected from the genitalia of multiple Onthophagus taurus males, originally collected in North Carolina. Dauer larvae were collected from the male aedeagus and suspended in 1ml Dulbecco’s phosphate buffered saline (DPBS). 10µl of this solution was then added to 10 Falcon tubes that were each filled with ca. 20ml of previously frozen cow dung. Each Falcon tube was closed with a lid that contained a mesh for ventilation an..., , # Sexually Transmitted Mutualist Nematodes Promote Host Growth Across Dung Beetle Species

[https://doi.org/10.5061/dryad.j3tx95xnn](https://doi.org/10.5061/dryad.j3tx95xnn)

Many symbionts are sexually transmitted and impact their host’s development, ecology, and evolution. While the significance of symbionts that cause sexually transmitted diseases (STDs) is relatively well understood, the prevalence and potential significance of the sexual transmission of mutualists remain elusive. Here, we study the effects of sexually transmitted mutualist nematodes on their dung beetle hosts. Symbiotic *Diplogastrellus monhysteroides* nematodes are present on the genitalia of male and female *Onthophagus* beetles and are horizontally transmitted during mating and vertically passed on to offspring during oviposition. A previous study indicates that the presence of nematodes benefits larval development and life history in a single host species, *Onthophagus taurus*. However, *Diplogastrellus* nemato...