The effect of collecting fluid on the catch results of Hylobius abietis in pitfall traps

K. Voolma and I. Sibul

Institute of Forestry and Rural Engineering, Estonian University of Life Sciences,Kreutzwaldi St. 5, 51014 Tartu, Estonia; e-mail: kaljo.voolma@emu.ee

Abstract:

Two different collecting and killing agents – ethylene glycol and water – were tested in pitfall traps used for trapping adults of the large pine weevil, Hylobius abietis (L.) in clear-felled areas of a massive pine-dominated forest in southern Estonia. The traps were baited with a blend of turpentine and ethanol and filled with a 50%-water-solution of ethylene glycol or clean water without any ingredients and were established in fresh or one-year-old clear-cuttings. During the two-year experiment, 5952 individuals of the pine weevil were caught, of which 50.5% were female and 49.5% male. No significant differences were observed either in the total catch results or in the sex ratios of the pine weevil between the traps filled with ethylene glycol or water.

Key words:

Antennal sensilla in ground beetles (Coleoptera, Carabidae)

A. Ploomi¹, E. Merivee¹, M. Rahi², J. Bresciani³, H. P. Ravn⁴, A. Luik¹ and V. Sammelselg⁵

¹Institute of Plant Protection, Estonian Agricultural University, Kreutzwaldi 64, 51014, Tartu, Estonia; e-mail: angela@eau.ee
²Institute of Zoology and Botany, Estonian Agricultural University, Riia 181, 51014 Tartu, Estonia
³Veterinary and Agricultural University, Bülowsvej 13, DK 1870, Frederiksberg C, Denmark
⁴Danish Forest and Landscape Research Institute, Hoersholm Kongevej 11, DK 2970, Hoersholm, Denmark
⁵Institute of Physics, University of Tartu, Riia 142, 51014 Tartu, Estonia

Abstract:

The antennal sensilla of male and female ground beetle species Bembidion lampros Hbst., Bembidion properans Steph. and Platynus dorsalis Pont. (Coleoptera, Carabidae) were investigated by using a scanning electron microscope. The filiform antennae of ground beetles consist of the scape, pedicel and 9 flagellomeres. Thirteen different sensillar types were distiguished. These were: four types of sensilla chaetica, two types of sensilla trichodea, six types of sensilla basiconica, pit-organs sensilla coeloconica, and small domes sensilla campaniformia. Sensilla chaetica 4 occur only on the antennae of P. dorsalis, and sensilla trichodea 1 only on the antennae ofBembidion species. No sexual differences in the types of sensilla were found on the antennae of these three species. The possible functions are discussed and three types of sensilla were considered as olfactory, sensilla trichodea 2 and sensilla basiconica 1 and 2. Olfactory sensilla trichodea 2 and sensilla basiconia 1 form clear dorsal and ventral sensillar fields on the flagellomeres, which seems to be common in ground beetles.

Key words:

antenna, Bembidion lampros Hbst., Bembidion properans Steph., Carabidae, Coleoptera, ground beetles, morphology, number, Platynus dorsalis Pont., sensilla, typology