Bumble bees and their parasites across European communities: Sphaerularia bombi in native and non-native hosts

Catherine Jones

Research output: ThesisDoctoral Thesis

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My research investigated the host-parasite relationships between Bombus species and their generalist parasites, considering both the host community and the parasite community. This research was based in Europe and thus the focus was on European Bombus spp. particularly B. terrestris and B. hypnorum, and their parasites species, particularly the nematode Sphaerularia bombi.

Bumble bees are important pollinators and are in global decline. Thus investigating their parasites, one of the factors that may be driving the decline, is vital both for the continued provision of this ecosystem service and for the conservation of bumble bees.

Initially I investigated the generalist endoparasites, particularly S. bombi, across three European populations of B. terrestris, collected in England, Switzerland and Ireland. I found that parasite prevalence differed across the European populations sampled e.g. the prevalence of S. bombi in B. terrestris queens is highest in Ireland. I also provide details of the bee husbandry and dissection methods used throughout my research.

I focused on England to examine the prevalence and impact of parasite communities found in the non-native species, B. hypnorum, and in five native Bombus host species. I also estimated the genetic diversity of the non-native B. hypnorum, from both the invaded (i.e. England) and native range (i.e. continental Europe), and that of two native Bombus species, B. terrestris and B. lucorum. The invasive B. hypnorum had higher parasite prevalence and lower functional genetic diversity than native species. Although parasites had a higher impact on the invader’s fitness than on native species, parasites and low genetic diversity have not prevented the rapid invasion of the UK by B. hypnorum.

Having observed that infected B. hypnorum queens do not appear to deposit S. bombi parasite larvae in their faeces, I quantified parasite reproduction in infected hosts to examine the competence of the non-native B. hypnorum as a host for this generalist parasite. I found that S. bombi larvae are not deposited in the faeces of infected B. hypnorum queens suggesting that B. hypnorum is not a competent host for S. bombi. The host–parasite relationship between S. bombi and this non-native bumble bee may alter the relationships between S. bombi and congeneric native host species.

Using standard molecular techniques, I investigated the phylogeography of S. bombi across Europe and asked whether the S. bombi parasites, found in non-native B. hypnorum in England, originate from England or from Continental Europe: Did the non-native B. hypnorum acquire parasites in the UK or were they co-introduced with the invading host? I found that the S. bombi population did not appear to be structured across the European native and non-native hosts sampled and therefore I was unable to establish whether these parasites were acquired or introduced.

Finally, I discuss what I have discovered during my research, how has this work added to the current knowledge on the subject and which areas warrant further investigation.
Original languageEnglish
Awarding Institution
  • Royal Holloway, University of London
  • Brown, Mark J F, Supervisor
  • Jansen , Vincent A.A., Advisor
Thesis sponsors
Award date1 May 2014
Publication statusUnpublished - 2014


  • Bombus
  • Sphaerularia bombi
  • Bombus hypnorum
  • Bombus terrestris
  • Apicystis bombi

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