Large Plain Stiletto (Thereva cinifera)
Key Details
| Taxonomic Groups: | Invertebrate > insect - true fly (Diptera) > Soldier fly or ally |
| Red List Status: | Near Threatened (Not Relevant) [NT(nr)] |
| D5 Status: | Included in the baseline Red List Index for England (Wilkins, Wilson & Brown, 2022) |
| Section 41 Status: | (not listed) |
| Taxa Included Synonym: | (none) |
| UKSI Recommended Name: | Thereva cinifera |
| UKSI Recommended Authority: | Meigen, 1830 |
| UKSI Recommended Qualifier: | (none specified) |
| Red List Citation: | Drake, 2017 |
| Notes on taxonomy/listing: | (none) |
Criteria
| Question 1: | Does species need conservation or recovery in England? |
| Response: | Yes |
| Justification: | Distribution, as it stands, from the past 15 years in England, is restricted to Kent and E. Sussex from two areas, Dungeness and the Pett Levels, there has been a single record from County Durham in 2018. The fly was only added to the British List in 1992, there is some thought that it may have been confused with other similar looking flies in similar habitats and may be less threatened than assumed. |
| Question 2: | Does recovery/ conservation depend on species-specific actions? |
| Response: | Yes |
| Justification: | With the potential for the species being misidentified there is potentially a need to survey in suitable coastal habitats to see if the fly is as restricted as assumed. The single record from County Durham which is a long way from Kent may indicate that the fly is more widespread with unknown populations in existence. |
| 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): | 4. Autecology and pressures understood |
| Recovery potential/expectation: | Low - Relict or natural rarity |
| National Monitoring Resource: | Opportunistic - insufficient |
| Species Comments: | The two main sites thus far, differ in that Dungeness (VC15) is coastal dunes with shingle and the Pett Levels (VC14), sandy rabbit disturbed parts of the grazing Marsh. Records also exist from the River Usk (2000) on exposed riverine sediments. |
Key Actions
Key Action 1
Proposed Action: Targeted surveying by experienced dipterists to ascertain a more accurate assessment of distribution and populations bearing in mind confusion species. Possible use of Recording Schemes to promote surveying on a more general basis in suitable coastal areas.
Action targets: 3. National Monitoring Plan agreed and implemented
Action type: Targeted monitoring
Duration: 3-5 years
Scale of Implementation: ≤ 50 sites
High priority sites: Dungeness, E Kent, from several sites within the area, A rough central point of TR074185, Pett Levels, E. Sussex TQ907151, Sandwich Bay, E. Kent TR360574; Whitburn Sands, County Durham NZ408612
Comments: May be best approached nationally through recording scheme or Dipterist's forum as well as specifically targeting known sites. If populations can be identified then site specific actions may be implemented as necessary.
Key Action 2
Proposed Action: On coastal sites, once identified, management and protection of dune areas from human disturbance (trampling) and encroachment of developments i.e golf courses should be beneficial.
Action targets: 4. Autecology and pressures understood
Action type: Pressure mitigation
Duration: >10 years
Scale of Implementation: ≤ 50 sites
High priority sites: Dungeness, E Kent, from several sites within the area, A rough central point of TR074185, Pett Levels, E. Sussex TQ907151, Sandwich Bay, E. Kent TR360574; Whitburn Sands, County Durham NZ408612
Comments: Dune sites will be subject to natural forces and any direct actions therefore will be limited.
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.