Mononychus punctumalbum (Herbst, 1784)

Gültekin, Levent & Korotyaev, Boris A., 2012, Ecological Description of Two Seed-Feeding Weevils of the GenusMononychusGermar (Coleoptera: Curculionidae) onIris ibericaHoffmann andIris spuriaL. in Northeastern Turkey, The Coleopterists Bulletin 66 (2), pp. 155-161 : 159

Mononychus punctumalbum (Herbst, 1784)

Biology. Adults feed mainly on flowers of I. spuria . They were very active during sunny days, on which they gnawed on young fruits and pierced them with their rostrum. During cloudy weather, adults rested individually or in pairs at the junctions between leaves in the upper parts of the plant ( Fig. 9 ). The beetles usually copulated at this same place on the plants. Adults were seen in highest numbers in the middle of June. Females laid pearl-white eggs in holes in the seeds that were drilled by the rostrum. Oviposition holes were sealed by the female to protect the eggs from desiccation and predators. Usually two or three eggs were laid in a seed capsule, but several oviposition and feeding sites were detected on one fruit ( Fig. 10 ). The holes where eggs were laid were not easily distinguishable from feeding holes, but on close examination the latter were not closed with secretions by the female. Seeds that were damaged externally by adults turned blackish brown and were somewhat shrunken ( Fig. 11 ). During feeding and oviposition, adult weevils were closely followed by ants which usually tried to grasp the tip of the weevil’ s abdomen ( Fig. 8 ). Oviposition began in the first week of June and lasted until the end of the month.

The legless, white larvae with brown head capsules developed inside a seed and, after having consumed it, entered an adjacent one. In most cases, a larva completed development after consuming two seeds ( Fig. 12 ), occasionally three when the seeds were small. Two or three larvae usually developed in one seed capsule. A mature larva often passed through the pupal stage in vacant areas where two seeds were eaten ( Fig. 12 ). Most larvae passed to the pupal stage by the middle of August. Both pupae and the seeds of I. spuria turned white in this period. As seed capsules ripened, they started to dry from the tip and turned completely brown towards the end of the season. From the first week of September, a new generation of adults appeared and emerged from the seed capsules by opening a hole after resting some days inside. The species produces one generation per year and adults hibernate under stones or in soil, displaying aggregation behavior.

Distribution. Mononychus punctumalbum has a large distribution area in the western Palearctic region ( Colonnelli 2004). In this study, weevils in association with the host plant were found in three Turkish provinces in the Aras and Karasu River valleys.

Material Examined. Erzurum Prov.: 50 km S of Köprüköy, Aras River Valley , 1750 m, 23 VI 2003 (3 adults) ; Erzincan Prov.: 6 km E of Tercan, Karasu River Valley , 39°45.905′N 40°17.947′E, 1389 m, 17 VI 2003 (54 adults) ; Iğdır Prov.: 1 km W of Aralık, Aras Valley , 850 m, 10 VI 2003 (23 adults) .

Host Plants. According to Perju et al. (1997), M. punctumalbum attacks Iris aphylla L., Iris dichotoma Pall. , Iris forrestii Dykes , Iris longipetala Herb. , Iris milesii Baker ex Foster , Iris pallida Lam. , Iris sibirica L., and Iris sikkimensis Dykes in the Botanical Garden of Cluj-Napoca ( Romania). Dieckmann (1972) reported Iris pseudacorus L. as a host. Scherf (1964) indicated the same host and Iris germanica L. in Europe, and I. spuria was recorded as a host in northeastern Turkey by Gültekin (2008). In the plains of Krasnodar Territory (Northwestern Caucasus, Russia), M. punctumalbum is common on the semiaquatic I. pseudacorus , although it also occurs in urban environments in Krasnodar and on Iris sp. (with yellow flowers) in cemeteries (but not on other cultivated irises with large bicolored flowers).

Iris spuria is a perennial plant occurring in wet meadows and sandy riparian plains at elevations of 800–1,900 m. It is distributed in northern and northwestern Iran, Caucasus, and Anatolia. In Turkey, it is known in Iğdır, Kars, Erzincan, Erzurum, Muş, Van, Hakkari, and Niğde Provinces ( Mathew 1984, 1988; Güvenç et al. 2005).

Figures

Figs. 6–12. 6) Iris spuria; 7) Habitat of I. spuria; 8) Adult of Mononychus punctumalbum and an ant following the adult; 9) Pair of adults resting on the host plant; 10) Feeding and ovipositing holes on a seed capsule; 11) Seeds damaged by adults; 12) Larva feeding on a seed and a pupa of M. punctumalbum resting in a seed capsule of the host plant.