Rivers may form barriers to small but not large dung beetles in tropical forests

We have a new paper out in the Sepilok Bulletin – the journal of the Forestry Department in Sabah – which shows that some dung beetles can fly large distances and cross potential river barriers.

A section of the Segama river showing how the river opened the forest canopy.

We are particularly happy to see this paper out as it is a study conducted by a super enthusiastic bunch of Department of Zoology, University of Oxford undergraduates while on their field trip in Danum Valley Field Centre in Sabah, under the guidance of Prof Eleanor and Dr Jon Parrett.

We used a technique called mark-release-recapture (MRR) to mark up several species of dung beetles with silver marker pens, and then followed them to see how far they moved and if they crossed from one side of the river to the other. We found that large beetles were able to cross the river but that it seemed to form a barrier to smaller species. We also recorded individuals moving between 50-200m in 24 hours, which is important when thinking about spatial independence of trapping designs in the future.

Recaptured large dung beetles. Silver dot patterns on the elytra indicate which trap they were initially caught in.

Understanding the impacts of natural and anthropogenic barriers to animal movement allows insights into how species assemblages form and diverge, and has implications for the effective design of protected areas and management of human-modified landscapes. Yet, there are few studies which assess the movement of animals, partly because many methods to do this are time-consuming and expensive. Here we show the effectiveness of the simple MRR technique to assess the movement of an important group of insects, and provide important data on their movement in a tropical forest.

You can read the full paper here:

http://www.forest.sabah.gov.my/docs/frc/SepilokBulletin30-2021.pdf