Csóka, György and Kovács, Tibor (1999): Xilofág rovarok - Xylophagous insects. Hungarian Forest Research Institute. Erdészeti Turományos Intézet, Agroinform Kiadó, Budapest, 189 pp. The fossil remnants of longhorn beetles are known from the early tertiary. 35, 000 species of them have been described so far. The largest beetle in the World (Titanus giganteus, up to 15 cm long) belongs to this group. More than 220 species of longhorn are known from Hungary. The species occurring in Hungary range from 3-60 mm in size. Longhorn beetles are usually slender with long antennae. They move fast and fly well. Most of them can produce a squeaking noise (the Hungarian name of the family is based on this noise). They create this noise in two different ways. One group rubs the inner edge of the hind femur on the margin of elytra. This method is called "playing a violin" in Hungarian. The other way is moving the prothorax back and forward and rubbing some chitin discs together. Sexual dimorphism is sometimes pronounced. The males have longer antennae, stronger legs and occasionally different coloration from the females. Species with extremely long antennae are found in some genera. For example, the antenna of male Acanthocinus aedillis can be more than 6 times longer than his body. 80 % of the longhorn species occurring in Hungary develop in woody plants, and the other 20 % feed in stalks and roots of herbaceous plants. The majority of the xylophagous species feed under the bark or in the heartwood of dead trees or dead parts (dead branches for example) of living trees. Only species in a few genera develop in living trees and branches. The majority of species are oligo-, or polyphagous, but there are also strictly monophagous species. Most species are neutral from an economic point of view, but serious pests are also in this group (Hylotrupes bajulus for example). Larval development takes 1-5 years, but the environmental conditions (humidity of the wood for example) can have a serious influence on the time required. Their galleries are characteristic, although less species-specific than those of the bark beetles. Below we list a few characteristic gallery types, using species included in this book as examples.
The flattened larvae of longhorn beetles are ivory-coloured, and taper towards their rear end. Their head capsules are strongly sclerotised and most of it- just like the mandibles - is hidden in the prothorax. The larvae of species in the Laminae subfamily are legless. Their pupae are free. The majority of the species prefer warm and sunny conditions, and adults can be found on flowers of herbaceous and woody plants, on stems, branches and sap-flows of trees and shrubs and on wood piles. The remaining species typically become active at dusk, and some species are attracted to lights. These species hide during the day beneath bark, in crevices or inside wood piles. Adult longhorn beetles feed on pollen, leaves, pieces of dead or fresh bark, stalks of herbaceous plants, or on woodsap and fermenting fruits. Some species must feed to become sexually mature ("maturation feeding). Adult females oviposit on dead branches, in bark crevices, or on debarked trunks of woody plants. Some species even glue the eggs onto the surface of the foodplant. Some other species prefer branches already ringbarked by the jewel beetle Coraebus florentinus. In some genera (Anaerea, Compsidia, Oberea) species belonging to the subfamily Laminae show relatively advanced care for individual eggs. The ovipositing females carefully prepare oviposition sites and lay single eggs in each one. [ Contents ] [ Previous ] [ Next ] [ Hungarian Version ] |
Forest Pests: Insects, Diseases & Other Damage Agents |
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