Protapion trifolii (L.) - Lesser Clover Seed Weevil.

Systematic position.

Class Insecta, order Coleoptera, family Apionidae, genus Protapion. Closely related to P. schoenherri Boh.; the latter differs in weak semi-erased punctation of pronotum and in 5th segment of antennal funicle, which is about 2 times longer than adjoining segments.


Apion aestivum Germar.

Biological group.

Pests of seed clover crops.

Morphology and biology.

Body length, 1.7-2.1 mm, not including the head. Rostrum long; male rostrum as long as and female rostrum 1.2-1.3 times longer than head together with pronotum. Male rostrum parallel-sided between its base and bases of antennae, somewhat narrowing distad; female rostrum subcylindrical. Antennae of both sexes are similar, entirely black, without erect hairs; 5th funicular segment is not longer than adjoining segments. Male antennae are inserted somewhat behind mid length of the rostrum; female ones are inserted between mid length and basal third of the rostrum. Pronotum is square, with large deep punctation and with longitudinal sulcus in front of scutellum. Interspaces between punctures are smaller than pucture diameter. Elytra short ovate, widest in the middle. Body, antennae, and tarsi are black. Fore coxae and trochanters are reddish or dark-reddish, distinctly darker than femora. Femora yellow-reddish. Mid and hind tibiae are black or dark-brown; fore tibia is lighter. Aedeagus subparallel-sided, gradually curved dorso-ventrally and widely rounded at apex.


Widely distributed in Europe to latitude 68°30'N, in Northern Africa and Middle East. In the former USSR it inhabits the European part northward to Baltic States, Karelia, Leningrad and Kirov Regions; the Caucasus, the South of Western Siberia and the Northwest of Kazakhstan.


It is a mesophilous meadow species, having biology rather similar to that of P. apricans. Both species often coexist on Trifolium pratense L., T. medium L., T. alpestre L., T. repens L., but being more common on T. pratense. P. apricans is more numerous in Leningrad Region and Belarus, wheras P. trifolii sometimes predominates southwards. Adults have diurnal activity, meeting from April to October. Oviposition begins comparatively later, about 20 days before blossoming of the T. pratense plants. Female lays eggs on clover inside buds or flowerheads. Blossoming clover flowerheads are the most favorable sites for oviposition; female lays eggs between stamens. Oviposition lasts about 3 months during the period of maximum abundance of clover flowerheads. Fertility is 80-130 eggs. Embryogenesis takes 2-11 days. Larva has 3 instars, developing inside the clover buds and inflorescences. Larval stage lasts 19-27 days. Right before pupation, the larva gnaws a cavity in the clover receptacle and forms enclosed cradle. Pupa develops 6-11 days. In the 2nd half of summer, adults migrate to the surrounding forests, where they meet on leaves of hazel, birch, poplar, willow, apple, and cherry. Females average about 40% of population. Spintherus linearis (Pteromalidae) is a parasite of the P. trifolii larvae and pupae. Sometimes they are infested by Metarrhizium anizopliae (Metsch.).

Economic significance.

The pest damages mainly in larval stage. Larva destroys 7-8 ovaries on the average. Early drying of some flowers in clover flowerheads is usually caused by larvae injuring 16-20% of the ovaries. Yearly growing of clover on the same field causes increasing abundance of the pest. Control measures include mowing of clover during mass oviposition and hatching of larvae. Larvae, pupae, and eggs perish after the clover ensilage. T. hybridum cultivar is the most resistant one to the pest.

Reference citations:

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Baitenov M.S. 1974. The weevils (Coleoptera: Attelabidae, Curculionidae) of the Middle Asia and Kazakhstan. Alma-Ata: Nauka, 286 p. (in Russian).
Ioannisiani T.G. 1972. The weevils (Coleoptera, Curculionidae) of Byelorussia. Minsk: Nauka i Tekhnika, 352 p. (in Russian).
Isaev A.Yu. 1994. Ecological and faunistic review of the weevils (Coleoptera: Apionidae, Rhynchophoridae, Curculionidae) of the Ulyanovsk region. Ulyanovsk: Branch of the Moscow University, 77 p. (in Russian).
Ismailova M.Sh. 1993. Ecological and faunistic review of the weevil (Coleoptera: Apionidae, Rhynchophoridae, Curculionidae) from the low-lying and submountain territories of Daghestan. PhD Thesis. St. Petersburg, 23 p. (in Russian).
Korotyaev B.A. 1983. Family Curculionidae. In: Kopaneva L.M., ed. Keys to harmful and useful insects and mites on the annual and perennial grasses and leguminous plants in the USSR. Leningrad: Kolos, p. 115-127 (in Russian).
Mormyleva V.F. & Tralenko G.Ya. 1991. Threshold of harmfulness of the clover seed weevils on the Trifolium pratense, T. hybridum and T. repens. In: Samersov V.F. Plant protection (16). Minsk: Belarus. NIIZR. P. 3-9 (in Russian).
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Rakhmanova A.V. 1969. About clover seed weevils (Coleoptera, Apionidae), connected with wild leguminous plants in Leningrad Region. Entomol. obozr. 48 (4): 802-810 (in Russian).
Shchegolev V.N., ed. 1955. Agricultural Entomology. Leningrad & Moscow: Sel.khozgiz. 616 p. (in Russian).
Shernin A.I. 1974. Order Coleoptera. In: Shernin A.I. ed. Fauna of the Kirov Region (2). Kirov: Kirov Ped. Inst. P. 111-227 (in Russian).
Silfverberg H. 1992. Enumeratio Coleopterorum Fennoscandiae, Daniae et Baltiae. Helsinki-Helsingfors: Helsingin Hyonteisvaihtoyhdistys, 94 p.
Solodovnikova V.S. 1970. Zoogeographical peculiarities of the fauna of the Genus Apion Hrbst. (Coleoptera, Apionidae) from the East Ukraine. Entomol. obozr. 49 (4): 810-818 (in Russian).
Vasil'ev K.A. 1936. Apions as a pest of clover seeds and their control. Moscow: All-Union Academy of agricultural sciences. 96 p. (in Russian).
Vasil'ev K.A. 1940. About control measures against Apion apricans Herbst and Apion aestivum Germ. In: Khamidullin G.Z., ed. Results of the research efforts (1). Ufa: Bashgosizdat. P. 78-106 (in Russian).

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