Bruchus loti Paykull, 1800

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POLYPHAGA Emery, 1886

CHRYSOMELOIDEA Latreille, 1802

CHRYSOMELIDAE Latreille, 1802

BRUCHINAE Latreille, 1802

Bruchus Linnaeus, 1767

Thought to have been native to the Mediterranean region, this species now occurs across the northern Palaearctic region to China and Japan though has so far not become established in North America, it is common throughout Europe as far north as the UK and the south of Fennoscandia and is also widespread North Africa and Asia Minor. In the UK it is common throughout England and Wales though less so in the North West and only occasionally recorded from the West Country, it is widely polyphagous on various Fabaceae and so may occur in almost any natural or disturbed habitat. Adults are active from April until August, peaking in abundance during June and July, although they overwinter and may be found in small numbers at any time of year, they feed on pollen and occur on a variety of flowers including buttercups and dandelion and are often common on blossom, especially on hawthorn (Crataegus monogyna Jacq.) and rowan (Sorbus aucuparia L.). Mating occurs early in the season and gravid females are present through late spring and into early summer, they fly well and visit a range of leguminous plants to oviposit in the seed pods where the larvae will develop. Plants recorded hosting this species in Europe include bitter vetch (Lathyrus linifolius (Reichard)), meadow vetch (L. pratensis L.), spring pea (L. vernus L.)), tuberous pea (L. tuberosus L.), Spanish vetchling (L. clymenum L.), lentil (Lens culinaris), fine-leaved vetch (Vicia tenuifolia Roth), wood vetch (V. sylvatica L.), bird’s-foot trefoil (Lotus corniculatus L.), purple broom (Cytisus purpureus (Scop.)), locoweed (Oxytropis uralensis (L.)) and various species of Sophora L. (all Fabaceae), larvae develop through the summer and pupation occurs in cocoons on the outside of the seed pods. Small numbers of adults remain active into the autumn and will go on to overwinter under bark etc. Sweeping low vegetation or grassland where the host plants are present is the easiest way to obtain adults and on hot summer days they may be appear in very large number, they also appear regularly in flight-interception traps.

Bruchus loti 1

Bruchus loti 1

Bruchus loti 2

Bruchus loti 2

Bruchus loti 3

Bruchus loti 3

1.7-3.0mm. Adults may be recognized by the small tooth on the lateral pronotal margin, evenly distributed dorsal pubescence and the presence of two small teeth on the ventral margin of the hind tibiae. Body broadly oval, entirely black but appearing grey due to recumbent grey pubescence, middle and hind legs black, front legs substantially orange, antennae black with four basal segments orange. Head roughly sculptured between large and deeply incised eyes that curve around the antennal insertions, basal antennomeres (orange)  narrow and elongate to quadrate, distal segments (black) broader and quadrate to transverse. Pronotum broadest across the base and curved laterally to a narrow anterior margin, lateral margin with a small tooth about the centre, surface roughly sculptured and punctured, basal margin produced medially. Elytra quadrate in the male, slightly elongate in the female, smoothly curved laterally to separately rounded apical margins, striae well-impressed to the apex and interstices flat and finely rugose. Pygidium and propygidium evenly punctured and finely pubescent. Apex of hind tibiae with two small teeth on the ventral margin, the inner tooth distinctly longer. Male with two small teeth on the apical margin of the middle tibiae.