Ticket to Ride Beetle Style.

[nomad]

The beautifully marked Sexton Beetle Nicrophorus vespilloides does a useful job by burying small dead animals and birds. Not being a coleopterist but interested in all insects I saw one of these beetles for the first time recently in a native hill wood in Scotland. The beetle nearly landed on my head but missed and fell clumsily onto a bracken frond. Moving in to get a better view, I was aghast, the beetle seemed to have many parasites. I have since learnt that they are not parasites but Gamasid mites hitching a ride to their food source. These tiny reddish-brown Gamasid mites use the Sexton or Burying Beetle to travel from one location to another, a phenomenon known as phoresy. The mites feed on Carrion Fly eggs and maggots. So phoresy is mutually advantageous to mites and the burying beetle. The mites get a food source and the burying beetle benefits because more rotting flesh is available to its young. I have seen one person call this a symbiotic ecological relationship. Insects really can be weird and wonderful, the stuff of Science fiction in miniature.

[nomad]

I do find it fascinating, if at first a little off putting, that the Sexton Beetle helps to carry around its passengers, the mites to its food source. These smaller beetles can really be interesting and I wonder if many European collectors still make a collection of the smaller species. Take a look at this species that I have recently found on a large expanse of chalk grassland. Not being sure of its identity, i consulted my two volume set of British Beetles by E. F. Linssen which was once a bible for British coleopterist's. I had the identity confirmed by an expert and it was the indeed a Bloody-nosed beetle [ Timarcha tenebricosa ] from the Chrysomelidae family. The larvae feed on Gallium species and Chalky grassland is a good place to find it. This beetle has the strange name of bloody-nosed beetle or blood spewer, because it adopts a form of chemical warfare to help save it from its would be predators especially birds such as Meadow Pipits. Being only 2 cm long and flightless this beetle is able to exclude a bright red fluid that is not only a visual deterrent but is foul tasting to its enemies. Wonderful defense indeed. Although predominately black I still find this a handsome beetle with its blue head and legs and as the beetle expert has told me it has adapted pad-like feet loaded with hundreds of special adhesion hairs that enable them to climb on shiny surfaces even polished glass. They are classic summer beetles observed on sunny days. They remind him of Clockwork beetles as they slowly march on their padded feet.

Below a Bloody-nosed Beetle on Silverweed, it would not stay still.

[Deleted]

Yes- it is very amazing the way such beetles transport around mites. It is actually a very common thing, and does also happen on species of Geotropidae, and many other beetles. 

[nomad]

Yes, perhaps a lot of beetle species carry around mites, but I have never seen anything quite like the very the many and very apparent Gamasid mites on this Sexton Beetle in other British Coleoptera families. Interesting relationship where both species mutually benefit.