Protapion apricans (Herbst, 1797)
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POLYPHAGA Emery, 1886
CURCULIONOIDEA Latreille, 1802
APIONINI Schönherr, 1823
PIEZOTRACHELINA Voss, 1959
Protapion Schilsky, 1908
This is a common and often abundant species throughout Europe and most of Asia; east through Kazakhstan, Mongolia and much of Russia except for the far northern and eastern parts. Along with several other species of Protapion, with which it often occurs, this is a pest of cultivated clover; in the U.K. it feeds predominantly on red clover, Trifolium pratense, but more widely a host of clovers host the weevil including T. alpestre L., T. medium L., T. repens L. and T. hybridum L. It is common and usually abundant throughout England and Wales, and more local further north into south west Scotland. It is likely to occur in just about any not too dry habitat where the host thrives; agricultural areas may host large populations but they also occur on wasteland, roadsides and gardens etc. Adults overwinter in the soil or among moss or tussocks etc. close to the host and may feed during mild spells, often they migrate to remote sites beneath trees and hedgerows or under haystacks to overwinter en masse, these will mostly be mated females and will return to the host in the spring. Hence they may occur in abundance on trees and shrubs for a while in the spring and autumn. Following a period of feeding and mating, ovipositing begins in March or April and continues into July or August; females chew holes into flowerheads and insert one or several eggs, moving between buds or laying between stamens on open flowers, each will lay up to 100 eggs. The eggs hatch within a week or so and the larvae burrow down into the florets to consume the ovules, each will pass through three instars and consume about ten ovules. They are fully grown after about three weeks and pupate on the receptacle. New generation adults eclose after a week or so, from the beginning of June, and will feed and mate in the summer but there will be only a single generation in temperate regions, they may diapause during the warmest parts of the summer before feeding in the autumn prior to overwintering, in warmer climates they are known to diapause for years. The density of a pest population depends on the number of parasites etc. and so numbers tend to fluctuate widely from year to year. Agricultural control includes cutting clover before or during the flowering period.
2-3mm. The narrow, elongate and highly-arched form of Protapion will soon become familiar; in lateral aspect the elytral base forms a distinct angle with the base of the pronotum. The entire body is black with a vague leaden or metallic sheen, and the colour of the appendages is critical in identifying the U.K. species. Head slightly elongate with large and weakly convex eyes, the vertex is longitudinally striate with a few large punctures and the base is transversely striate, widely so on the underside. The temples ate long and broadest at the base, the cuticle below the eyes has sparse and coarse pale setae. Rostrum finely punctured and very finely pubescent, long and cylindrical, and broadened a little at the antennal insertions. Antennae brown with the basal segment pale, the setae along the funiculus recumbent. Pronotum slightly elongate and broadest at the base, the lateral margins rounded and constricted before the base and apex. The punctures on the disc are broad, shallow and distinct and each with a very fine seta, the cuticle between smooth. Elytra broadest at or a little behind the middle, the striae deeply impressed and strongly punctured; complete to the apex, the sutural stria abbreviated before the scutellum. The interstices have several rows of fine punctures and very fine pubescence. Pro-coxae yellow, large, convex and smooth (in some species the males have a small tooth on the pro-coxae); meso- and meta-coxae dark. All trocanters pale, as the femora. All femora pale yellow and generally with the apices infuscated. Pro-tibiae pale with the base and apex variously darkened, meso- and meta-tibiae dark brown to black. All tarsi black. Female rostrum longer; as long as the head and pronotum combined, male rostrum shorter than the head and pronotum.