Striped Horsefly (Hybomitra expollicata)
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: | Hybomitra expollicata |
| UKSI Recommended Authority: | (Pandellé, 1883) |
| 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: | Appears to have a fairly stable but restricted population with most recent records from Essex and Kent; older records from W Sussex appear not have been repeated, but this could be down to recorder effort. |
| Question 2: | Does recovery/ conservation depend on species-specific actions? |
| Response: | Yes |
| Justification: | Favoured habitat is brackish marshes, one which could be threatened by both climate change and related sea defence work. More specifically drought and lowering of water levels by abstraction or drainage, making soils drier and more compacted, which would be detrimental to larval development. |
| 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: | Yes |
| Justification: | Maintenance and increased areas of brackish marsh in general would undoubtedly be positive |
Species Assessment
| Current step on the Species Recovery Curve (SRC): | 4. Autecology and pressures understood |
| Recovery potential/expectation: | Low - Life history factor/s |
| National Monitoring Resource: | Opportunistic - insufficient |
| Species Comments: | Added to the British list in 1972, appears to be stable in areas of Essex and Kent up until 2013. A few records since in 2016 and 2022 confirm that it was at least present in these areas in the last decade. |
Key Actions
Key Action 1
Proposed Action: Tailored surveys of potential habitat in previously known localities to determine the current populations and species distribution, thus identifying areas where H. expollicata is missing as well as present.
Action targets: 3. National Monitoring Plan agreed and implemented
Action type: Targeted monitoring
Duration: 2 years
Scale of Implementation: ≤ 20 sites
High priority sites: N.Essex (Little Oakley Sea Wall, Old Hall Marshes) and S. Essex (Canvey marshes), E. Kent (Elmley Marshes).
Comments: These are the sites with the most recent records back to 2013, surveying of older recorded sites in other areas would also be useful.
Key Action 2
Proposed Action: Through species focussed advice and support for land managers, aid the prevention and mitigation against lowering water levels through drainage, sea defence work, land reclamation and agricultural intensification.
Action targets: 4. Autecology and pressures understood
Action type: Advice & support
Duration: >10 years
Scale of Implementation: ≤ 20 sites
High priority sites: N.Essex (Little Oakley Sea Wall, Old Hall Marshes) and S. Essex (Canvey marshes), E. Kent (Elmley Marshes).
Comments: Communication with site managers and local authorities. It is about the assessment of threat at each site and what tailored mitigations one could put in place in terms of the threat of coastal squeeze and managed re-alignment. One would end up with a table of threats for each locations, from which action would flow.
Key Action 3
Proposed Action: Influence decisions makers based on the threat assessment table for this species, tweaking the options to maximise recovery and minimise populations losses.
Action targets: 4. Autecology and pressures understood
Action type: Advice & support
Duration: 6-10 years
Scale of Implementation: ≤ 20 sites
High priority sites: N.Essex (Little Oakley Sea Wall, Old Hall Marshes) and S. Essex (Canvey marshes), E. Kent (Elmley Marshes).
Comments:
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.