Six-spotted Cranefly (Idiocera sexguttata)
Key Details
| Taxonomic Groups: | Invertebrate > insect - true fly (Diptera) > Fly |
| Red List Status: | (Not Relevant) [(not listed)(nr)] |
| D5 Status: | |
| Section 41 Status: | (not listed) |
| Taxa Included Synonym: | (none) |
| UKSI Recommended Name: | Idiocera sexguttata |
| UKSI Recommended Authority: | (Dale, 1842) |
| 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: | Eight English records since 1989, three from Axmouth in Devon (2016, 1998. 1989), four from the New Forest, Stony Moors (2021, 2019, 2018, 2000) and one from West Dorset (2005). |
| Question 2: | Does recovery/ conservation depend on species-specific actions? |
| Response: | Yes |
| Justification: | With a known site Stony Moors (SZ2199) there are policies in place to protect and manage the site. The Axmouth site (SY250890) is a stretch of soft cliffs from Axmouth to Lyme Regis and is a NNR. Further surveys to establish ecology and habitat niche for larvae may be useful even though it appears that the populations, at least in the New forest appear stable. |
| 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: | The New Forest site is apparently small so may suffer from external pressure. Further scientific studies to understand exact habitat requirements may make any further targeted actions more effective. |
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: | Combination - insufficient |
| Species Comments: | There is an established population in North Wales which may give more insight to the required habitat niche. Bare silty muds interspersed with carpets of brown moss and tussocks of black bog-rush Schoenus nigricans. The New Forest site is on an outcrop of marl with individuals caught in a number of different habitats. |
Key Actions
Key Action 1
Proposed Action: Site assessment and study to ascertain more detail on larval requirements, habitat niche and threats to these.
Action targets: 4. Autecology and pressures understood
Action type: Scientific research
Duration: 2 years
Scale of Implementation: ≤ 5 sites
High priority sites: Axmouth - Lime Regis Undercliffs (SY250890), Stony Moors, New Forest (SZ2199)
Comments: Assessment of occupied sites and those adjacent unoccupied sites to explore habitat niche and any see if any specific requirements can be identified.
Key Action 2
Proposed Action: Tailored surveys of potential habitat in known or potential habitat localities to determine the populations and species distribution, thus identifying areas where L. similis 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: ≤ 10 sites
High priority sites: Axmouth - Lime Regis Undercliffs (SY250890), Stony Moors, New Forest (SZ2199)
Comments: Baseline surveys of potential sites both to establish where present but also where missing. Lime regis undercliffs will potentially need a full risk assessment for surveyors; the New forest site has studies published so these should be utilised to produce the optimum survey plan. The optimum survey period should be when adults are flying in June.
Key Action 3
Proposed Action: Maintenance of water levels, prevention of abstraction from surrounding aquifers and at the New forest site potentially, blocking of drainage channels to help maintain water levels as the larvae are most likely dependant on wet areas to develop.
Action targets: 2. Biological status assessment exists
Action type: Habitat management
Duration: 6-10 years
Scale of Implementation: ≤ 5 sites
High priority sites: Axmouth - Lime Regis Undercliffs (SY250890), Stony Moors, New Forest (SZ2199)
Comments: Exact habitat requirements within are still unknown due variability of vegetation, grazing impacts and water levels within the previously known sites. Lime undercliffs are subject to natural impacts and may be difficult to directly affect with actions beyond actively ensuring that aquifers and other sources of water that supply seepages are protected and abstraction is mitigated against preferably prevented.
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.