Hydrothassa hannoveriana (Fabricius, 1775)
Taxonomy: Polyphaga > Chrysomeloidea > Chrysomelidae > Hydrothassa > Hydrothassa hannoveriana
Description
Size: 3.5-5.0mm
Basic colour: Dark metallic blue and orange-yellow or reddish
Pattern colour: Dark metallic blue; pronotum with orange-yellow side margins, elytra with yellowish or reddish median longitudinal stripe and yellowish side margin. These elytral marks may fuse, especially at the rear in females; the median stripe may be broken/absent.
Number of spots: None
Other colour forms: None
Pronotoum: See 'pattern colour' above.
Leg colour: Dark metallic blue
Confusion species: Hydrothassa glabra
, Confusion species: Hydrothassa marginella
Basic colour: Dark metallic blue and orange-yellow or reddish
Pattern colour: Dark metallic blue; pronotum with orange-yellow side margins, elytra with yellowish or reddish median longitudinal stripe and yellowish side margin. These elytral marks may fuse, especially at the rear in females; the median stripe may be broken/absent.
Number of spots: None
Other colour forms: None
Pronotoum: See 'pattern colour' above.
Leg colour: Dark metallic blue
Confusion species: Hydrothassa glabra
, Confusion species: Hydrothassa marginella
Biology
Status: Rare (RDB3) and very scattered; may be under-recorded.
Habitat: tarns, marshes, peat bogs (sometimes forests).
Host plant: Usually on Marsh-marigold (Caltha palustris)
Overwintering: Unknown
Food: Leaves and flowers of host plants (larvae on the undersides of leaves)
Other notes: Similar to H. glabra and H. marginella. Separated from H. glabra by the orange-yellow lateral margins to the pronotum (not present in H. glabra). Separated from H. marginella by the median elytral stripe (not present in H. marginella); in specimens where this is absent, the aedeagus may need to be examined in - in H. hannoveriana, the tip has a slight angle near the tip (lateral view), in H. marginella, the tip is more-or-less straight or slightly curved (no angle).
Habitat: tarns, marshes, peat bogs (sometimes forests).
Host plant: Usually on Marsh-marigold (Caltha palustris)
Overwintering: Unknown
Food: Leaves and flowers of host plants (larvae on the undersides of leaves)
Other notes: Similar to H. glabra and H. marginella. Separated from H. glabra by the orange-yellow lateral margins to the pronotum (not present in H. glabra). Separated from H. marginella by the median elytral stripe (not present in H. marginella); in specimens where this is absent, the aedeagus may need to be examined in - in H. hannoveriana, the tip has a slight angle near the tip (lateral view), in H. marginella, the tip is more-or-less straight or slightly curved (no angle).