Flowering Rush Weevil (Bagous nodulosus)
Key Details
| Taxonomic Groups: | Invertebrate > insect - beetle (Coleoptera) > Weevil |
| Red List Status: | (Not Relevant) [(not listed)(nr)] |
| D5 Status: | |
| Section 41 Status: | (not listed) |
| Taxa Included Synonym: | (none) |
| UKSI Recommended Name: | Bagous nodulosus |
| UKSI Recommended Authority: | Gyllenhal, 1836 |
| UKSI Recommended Qualifier: | (none specified) |
| Red List Citation: | (not listed) |
| Notes on taxonomy/listing: | (none) |
Criteria
| Question 1: | Does species need conservation or recovery in England? |
| Response: | Yes |
| Justification: | Currently known from only two areas, may have been lost from historic localities. Rare throughout its range and little known. No red-listing has been completed for weevils as at November 2024, though this species would be at least Critically Endangered. It may have last been recorded in England in 1986 at Wet Moor in Somerset. This site has visited sporadically by coleopterists since then and it has not been refound. |
| Question 2: | Does recovery/ conservation depend on species-specific actions? |
| Response: | Yes |
| Justification: | Not recorded in England since 19th Century. |
| Question 3: | At a landscape scale, would the species benefit from untargeted habitat management to increase habitat mosaics, structural diversity, or particular successional stages? |
| Response: | No |
| Justification: | This species would not benefit from untargeted management |
Species Assessment
| Current step on the Species Recovery Curve (SRC): | 3. National Monitoring Plan agreed and implemented |
| Recovery potential/expectation: | Unknown |
| National Monitoring Resource: | Opportunistic - insufficient |
| Species Comments: | This species is difficult to find even at its known localities. |
Key Actions
Key Action 1
Proposed Action: Search recent localities to see whether species is still present. This will help understand whether it is declining and develop techniques to find it.
Action targets: 2. Biological status assessment exists
Action type: Scientific research
Duration: 1 year
Scale of Implementation: ≤ 5 sites
High priority sites: Somerset Levels, Hawkswick.
Comments:
Key Action 2
Proposed Action: Search likely localities, including historic sites, to see how widespread the species is and understand why it is so much rarer than its foodplant.
Action targets: 4. Autecology and pressures understood
Action type: Scientific research
Duration: 3-5 years
Scale of Implementation: ≤ 20 sites
High priority sites:
Comments: There are many places with stands of the foodplant (Flowering-rush Butomus umbellatus). The current distribution of the weevil comprises two very different localities, Somerset Levels and Yorkshire, suggesting that it could be present at other locations. We need to know how restricted the species is, and if it is very restricted, why. Aquatic weevils are often overlooked or neglected by general beetle recorders, and Bagous are particularly difficult to find unless specific techniques are used, so this is not a species that is well covered by general opportunistic recording.
Key Action 3
Proposed Action: Research how the weevil disperses and whether it has a narrow ecological niche.
Action targets: 4. Autecology and pressures understood
Action type: Scientific research
Duration: 1 year
Scale of Implementation: Not applicable
High priority sites:
Comments: Literature review and interviews with entomologists in UK and abroad to understand what is known about this species. The weevil Red List has stalled and not been finished. Completing that assessment might help with planning and implementing future projects, but it will not by itself tell us anything we do not already know because there is so little data.
Acknowledgment:
Data used on this website are adapted from Threatened species recovery actions 2025 baseline (JP065): Technical report and spreadsheet user guide (Natural England, 2025). Available here.