Status: Scattered in England & Wales, old records from Ireland. Scarce (Notable B)
Habitat: Various
Host plant: Loosestrifes (Lysimachia spp.), purple-loosestrife (Lyhtrum salicaria). Also known from chickweed-wintergreen (Trientalis europaea) although the beetle does not appear to feed on it.
Overwintering: As adults in moss and plant litter
Food: Adults on leaves, larvae at roots.
Other notes: Adults parasitised by larvae of a braconid wasp, probably Perilitus sp.

Status: Sparsely scattered, mainly in eastern England. Previously considered rare (RDB3), later revised to Scarce (Notable A)
Habitat: Brackish clay pits and dykes, usally near the coast; sometimes estuaries and inland saline lagoons.
Host plant: Usually fennel pondweed (Potamogeton pectinatus); sometimes beaked tassel-weed (Ruppia maritime), eelgrass (Zostera marina) and horned pondweed (Zannichellia palustris)
Overwintering: Unknown
Food: Adults usually on leaves of P. pectinatus (adults rarely leave the water); larvae probably at roots but this is unconfirmed.
Other notes: Spine at end of elytra usually broader and less sharply pointed than in M. appendiculata. Dissection of aedeagus may be required to comfirm identification.

Status: Widely scattered but Rare (RDB3). Has declined in some areas, especially Scotland.
RDB Category: Rare (RDB3)
Habitat: Canals, rivers, lakes, drainage channels/dykes
Host plant: Various water plants, especially alternate water-milfoil (Myriophyllum alterniflorum) and fennel pondweed (Potamogeton pectinatus).
Overwintering: As pupae and recently emerged adults inside cocoons.
Food: Larvae feed gregariously underwater at roots among mud; adults persumably on leaves, although they rarely emerge from the water.
Other notes: Spine at end of elytra usually thinner and more sharply pointed than in M. mutica. Dissection of aedeagus may be required to comfirm identification.

Status: Introduced into garden centres, unlikely to be able to survive winters to become established, although teneral (recently emerged) adults were found.
Habitat: In the UK, known only from garden centres on imported plants
Host plant: In the UK, found on false-buck's-beard Astilbe japonica, wallflower Erysimum cheiri and roses (various Rosa spp. & varieties, though rarely on red flowers)
Overwintering: Not in the UK
Food: Adults found on flowers, larvae probably feed on roots.