Aquatic Symbionts: Assessing the Abundance of Torix Group Rickettsia in Aquatic Insects around the World

Symbionts are known to be an important aspect of almost every living organism. Invertebrates are no exception. They display a remarkable range of symbiotic relationships with bacteria, which are capable of altering reproduction, defence against natural enemies, and play a role in nutrition. Up until now, most work has centred on a bacteria called Wolbachia which is commonly found in insects.

Wolbachia is relatively rare in Odonates (dragonflies and damselflies) and other aquatic insects, but recent work has suggested the presence of another similarly pervasive microbe. Our work has revealed that the bacterium Rickettsia is carried in 40% of midge species, and the Azure Damselfly (Coenargrion puella) can carry one or two strains of infection. Data suggests that Rickettsia is a common but underrepresented feature of freshwater invertebrates and our aim is to see how true this theory is.

Our Aims:

  • Establish the prevalence of Torix group Rickettsia in aquatic invertebrates through screening of specimen DNA for the symbiont.

Why this is important:

  • The presence of Rickettsia could represent an uncharacterised part of aquatic invertebrate biology.
  • The presence of the symbiont may interfere with characterisation of insect diversity through mitochondrial DNA barcoding.

What do we want help with?

Collecting! We would like a diverse range of invertebrates from many different habitats; ponds, lakes, streams, canals, rivers.

Species we do want:

Any freshwater invertebrate including: Snails, Leeches, Freshwater Shrimp, Whirligig beetles etc.

You can either focus on collection of one particular species (for instance, if you are a caddis fly expert, on caddis flies). In this case, we would like 20 individuals of each species, although any specimen is welcome.

Alternatively, collections from pond dips are also useful – these can be sorted into species and then the symbiont presence ascertained.

However you decide to collect, you must record: date, place of collection and who collected it for each insect. If you are also able to identify the species, this is also very useful.

Species we don’t want:

Screening for Rickettsia is destructive, insects must be killed before DNA is taken for molecular screening.

We do not want any endangered species.

For similar reasons we do not want specimens from sites of scientific interest/conservation importance, unless these are taken as “bycatch” from ongoing studies for which a permit has been obtained.

From all other sites, we would like to limit any removal to <10% of a population to avoid disturbing the community.

How to collect:

Catch flying insects with a butterfly net and pond/river invertebrates through pond dipping.

To preserve DNA of specimens, place catches directly into ethanol. If you wish, place catches in fridges/ice to anesthetise them before submerging, this will not affect DNA preservation. To avoid damage to DNA do not preserve with ethyl acetate.

How we can help:

We will send you sealed tubes containing ethanol to preserve material and cover postage costs.

Feedback from the project:

Our project can only progress with the help of expert volunteer, we are grateful for your support. We will send you a report explaining what is found in terms of rickettsia infection in your species and the overall outcome at the end of the project.

For enquiries:

Panupong Thongprem: pongthq@liverpool.ac.uk

Helen Davison: hlhdavi5@liverpool.ac.uk

Prof. Greg Hurst: g.hurst@liverpool.ac.uk

  0151 7954520

Lab webpage: https://sites.google.com/site/hurstlab/home