Investigations on the life cycle and nutrition of Criocephalus rusticus L
The longhorn beetle Criocephalus rusticus L or Arhopalus rusticus (L) is widely distributed in Europe and Asia. It attacks softwoods. The primary host trees are pines, ie freshly felled, unbarked logs, dying standing trees and stumps. After feeding under the bark the larvae enter the sapwood and also the heartwood. Timber to be used for building purposes may be rendered useless by their tunnelling activity. Occasionally some larvae survive in the wood in situ and emerge as beetles. The thus caused pattern of damage is sometimes mistaken for that caused by the house longhorn beetle Hylotrupes bajulus (L). In the Bundesanstalt für Materialprüfung (BAM) a culture of Criocephalus rusticus has been maintained for several years. It was based on one single female. This culture offered the possibility of following the life cycle of the insect quite closely. Research was concentrated on three main aspects, ie on the timber species which are most suitable for the development of the insect, on the influence of the wood moisture content on its development and on the environmental factors inducing pupation. Moreover some studies were made to find out whether turpentine oil which - as an essential oil contains many wood extractives of pine - has an attracting effect on the beetles for oviposition or on the recently hatched larvae. Present knowledge of Criocephalus rusticus is primarily based on numerous individual observations of different authors. Data on this beetle and related species are therefore often found in shorter contributions. Moreover Criocephalus rusticus is mentioned in more comprehensive works on longhorn beetles or on wood pests. In 1954 and 1958 this species was studied in more detail by J DOMINIK. The species Criocephalus tristis F (= Arhopalus ferus Mulsant or Criocephalus polonicus Motsch) was investigated by H R WALLACE in 1954. The appearance and biology of this species is very similar to Criocephalus rusticus, the regions of distribution of these two species overlap, but Criocephalus tristis is still distributed farther south than Criocephalus rusticus. As Criocephalus tristis was imported into New Zealand in about 1962 several investigations were made there - although up to this time not very comprehensive ones (G P HOSKING, 1970). The results obtained in the BAM will be presented in the journal "Materials and Organisms" after a complete evaluation of the test results and considering the available literature. The preliminary results are summarised here.