The current case study concerns evaluation of the life history of an insect species living in a demanding habitat, namely a xylem-feeder Aredolpona rubra (Linnaeus) (Coleoptera: Cerambycidae) representing the wood-feeding guild. Growth rate, development time and body size at maturity were studied at different temperature regimes with discreteness of insect growth pattern, associated with moultings, taken into account. Moreover, the temperature effect on reproductive strategy of females was tested, and the general life history was compared with available data within the wood-feeding guild. The results show that: (i) the growth of A. rubra is slow but compensated by prolonged development; (ii) size dimorphism is probably caused by the longer development time of females; (iii) fecundity is at least partly determined by the temperature experienced during the egg-laying period; and (iv) interspecific comparisons reveal that the life strategy of a wood-feeder depends on the niche occupied within the tree, whilst its breeding strategy (whether capital or income) is controlled at a taxonomic level. Control of all the main life history traits at one time provided a unique opportunity to understand the selection pressures on A. rubra species. Moreover, comparison within a feeding guild broadens this context and identifies the sources of heterogeneity in the ‘inside-wood’ habitat. The knowledge so gathered may be applied to pest control in forestry science, as well as to the conservation of rare and endangered insect species living within trees.

The generally accepted assumption on the low mortality pressure for inside-tree habitat was challenged in this study. To achieve this objective, the number of larval instars of xylem-feeding Aredolpona rubra (L.) (Coleoptera: Cerambycidae) was determined using multidimensional statistics, and the life table was constructed based on the head-width distribution of larvae taken from the field. The mean value of natural mortality of an average larva was then compared with data available for other wood-feeding species and contrasted with insects from other feeding guilds. The results show that larvae living in wood experience lower mortality rates than those from other habitats and that, among the wood-feeders, the mortality rate of larvae decreases while development time increases further inside the tree.

The pine sawyer Monochamus galloprovincialis (Olivier) is the vector of the introduced pine wood nematode Bursaphelenchus xylophilus (Steiner & Bührer) Nickle in Portugal, and until recently was considered a secondary forest insect. Under laboratory conditions, a study of biological and reproductive traits of 37 insect pairs was conducted. The longevity of both sexes was similar, being 61.2±6.5 days for males and 64.0±6.3 days for females (mean±SE). Sixteen small-sized insects (22% of the population) died within 20 days and before starting to reproduce. The sexual maturation period (without egg laying) was 20.4±0.7 days (mean±SE), while the oviposition period lasted 54.0±4.2 days (mean±SE). The oviposition rate increased very quickly during the first weeks of life, peaking to almost two eggs per day during days 30–44, and gradually dropping in the following weeks. The females laid an average of 67.0±5.96 (mean±SE) eggs through their lives. The hatch rate was 92.6±1.0%; (mean±SE). There were large individual variations in longevity and fecundity parameters, and principal component analysis based on 16 morphological and biological parameters separated the breeding insects into four distinct groups. Almost half of the reproducing beetles were large-sized insects, with high longevity and fecundity traits. Overall, the reproductive potential of the Portuguese population of M. galloprovincialis seems to be smaller than that described for other Monochamus vectors of the pine wood nematode both in North America and Japan.

The development of a given species in a natural forest depends on a multitude of factors. Insects are one of the factors that have an important impact. We would like to present initial observations about the behaviour of longicorns of the Onciderini tribe and their impact on the development of Dicorynia guianensis.

A study of the development of D. guianensis was conducted in French Guiana (5°18'N, 5°48'W), at the Paracou silvicultural facility. We studied plots where the Dicorynia inventory was extended to trees 1 m tall or over. In order to describe the impact of longicorn activity on a Dicorynia stand in which spatial distribution is aggregative (Kokou 1992), we chose trees (156 observed trees) in a control plot (plot 11, area: 17 500 m2). Height, trunk basal diameter and DBH were measured on each tree. A precise morphological description was established for each tree. It was during morphological description that the signs of longicorn attacks were sought. In all the species of the genus Oncideres, the female girdles the tree by removing the bark and some of the wood using its mandibles. It then digs deep into the wood above the cut and lays its eggs. The branch then breaks and falls to the ground (Hequet 1996). All that is left on the tree is a stump with characteristic signs of insect activity (Figure 1a). When such signs were seen on a plant, the type of structure (trunk, branch) was noted.

Petioles are not usually thought of as a habitat for wood-boring insects. The large, woody leaf petioles of Neotropical Cecropia trees, however, have a diverse coleopterous fauna: 36 beetle species in three subfamilies of Cerambycidae and Curculionidae were recorded from Cecropia leafstalks in Costa Rica. A high percentage of the petioles were colonized by beetles in many patches, though fewer were colonized in sun-exposed sites. Community composition was dependent on forest type, petiole moisture and geographical location, but not on the species of Cecropia. Species of Scolytinae were most abundant though species of Zygopinae and Lamiinae were found regularly. The host-specific scolytine genus Scolytodes dominated in most localities, although species of Hypothenemus, Coccotrypes and Xylosandrus morigerus occurred frequently. Sympatric species of Scolytodes clearly used different parts of the petioles. Brood sizes of scolytine beetles were extremely low, ranging from two to ten offspring on average. However, mortality due to parasitoid wasps or predators was low, and since fresh leaves fall close to the previously fallen ones, mortality due to dispersal may also be low. Thus, large beetle populations can exist despite extremely low brood sizes.