The semiochemical relationships in a predator-prey-host plant system were studied by a series of multiple-choice field assays. The studied system included predatory flies of the genus Medetera (Diptera: Dolichopodidae), the bark beetles Ips typographus and Pityogenes chalcographus (Coleoptera: Curculionidae: Scolytinae) as prey and Norwegian spruce (Picea abies) as the host plant. Of the nine species of predators collected, only M. setiventris and M. melancholica provided sufficient data for statistical analysis. The response of the predators to monoterpenic products of the host (alpha-pinene, limonene, camphor), pheromone compounds of I. typographus (S-cis-verbenol and 2-methyl-3-buten-2-ol) and a mixture of the pheromones of I. typographus and P. chalcographus were investigated. Our field trials revealed that tree volatiles plus pheromones of the prey, and a pheromone mixture of both prey species were considerably more attractive to M. setiventris and M. melancholica than the individual chemicals. Medetera seem to respond to the stage of tree decay and the intensity of bark beetle infestation via the ratios of tree volatiles and/or prey pheromones.

Fluctuating asymmetry (FA), the small and random departures from perfect symmetry of an organism's bilateral traits, has been used as a measurement of developmental stability and an indicator of stress in endangered populations. We were interested in testing if the level of developmental stability is the same in different populations experiencing the same conditions, as the use of FA as an indicator of ecological stress is only meaningful if this is true. In order to do this, the effect of thermal stress on wing size FA over a range of temperatures was determined on three different lines of Drosophila melanogaster: two lines were maintained at one of two different constant temperatures (18°C or 28°C) and one under a fluctuating thermal regime (18°C and 28°C) for eight years. The differences in viability of these lines, when reared at a range of different temperatures, are associated with the temperature conditions they previously experienced. All lines showed a similar increase in FA at the two ends of the thermal range but with significantly different mean values. The two units of wing development (compartments) differed in their FA response depending on the selective history of each line. We discuss the implication of our results for the use of FA as an indicator of ecological stress.

In Mediterranean habitats, the specialist butterfly Euphydryas aurinia oviposits on Lonicera implexa. Previous work has shown that ovipositing females select and lay a higher number of egg clusters on certain plants. In this paper the results of a field study aimed at assessing whether females use plant size and/or plant or leaf greenness (i.e., chlorophyll concentrations) as cues for oviposition are described. Size of plants did not appear to be an important factor in determining host plant selection, probably because even small plants provide enough resources for the young larvae to reach the diapausing stage and because last instar larvae, the most likely to face resource depletion, can move great distances in search of food. Measurements of both spectral reflectance and chlorophyll concentration of plants failed to reveal differences between host and non-host plants. On the other hand, reflectance and chlorophyll concentration of leaves were found to be important in oviposition choice as egg clusters were generally located on the greenest leaves with the highest chlorophyll contents. This suggests that females use visual cues to select the leaves that will provide optimal growth opportunities for newly hatched larvae. Although there was some indication that plants receiving a greater number of egg clusters also had more leaves of high chlorophyll content, multiple egg batches on single plants could also be a consequence of females being attracted by the presence of conspecific egg clusters.

This paper reports the results of a comparative laboratory analysis of the behavioural responses of the egg parasitoid Trissolcus basalis (Wollaston) (Hymenoptera: Scelionidae) to semiochemical cues from four species of pentatomid bugs, Nezara viridula (L.), Eurydema ventrale Klt., Murgantia histrionica Hahn. and Graphosoma semipunctatum F. (Heteroptera: Pentatomidae). In a Y-tube olfactometer, T. basalis was attracted by volatile chemicals from N. viridula, but not from other pentatomid species. In an open arena, the parasitoid reacted to chemical trails left on filter paper by all the species but most intensely to those left by N. viridula. However, upon encountering pentatomid eggs, T. basalis examined more intensely and probed more frequently the eggs of G. semipunctatum than those of the other species. The parasitoid only parasitized and emerged from eggs of G. semipunctatum and N. viridula; those of the other species were unsuitable. Therefore N. viridula is semiochemically confirmed to be a coevolved host (old association) of T. basalis, whereas G. semipunctatum may be a potential non-coevolved host (new association). The utility of these tests for defining a parasitoids' host specificity and in assessing the risk of non-target effects in biological control is discussed.

A new genus and species of geometrid moths from Tadjikistan is described and its position in the taxonomic structure of the subfamily Larentiinae is analysed. The new genus is grouped, based on the parsimony analysis of 38 morphological characters, to coniferous-feeding genera of the tribe Cidariini as follows: (Thera (Pennithera (Protothera (Pljushtchia gen. n. Heterothera)))). Pljushtchia is characterised by the antennae, unipectinate in males and flat, serrate in females, by a reduced haustellum, the venation of wings and the structure of the genitalia. The Thera firmata species group is validated as a genus Protothera. The tribe Cidariini includes four groups of related genera and is most speciose in southeastern Asia.

Pensoft Publishers, Sofia, xvi + 388 pp. ISBN 954-642-233-9. Price EUR 78.90 (hardcover).

A survey of soil fauna in Poland revealed 30 cases of centipedes carrying mites of the sub-order Uropodina. The 155 phoretic deutonymphs collected belonged to two species of Uropodina - Oodinychus ovalis (C.L. Koch, 1839) and Uroobovella pulchella (Berlese, 1904). These mites displayed a high degree of selectivity in their choice of carrier. The only species of centipede transporting mites was Lithobius forficatus (Linnaeus, 1758), despite the presence of 30 other species in the same habitats. It is possible that the large size and relatively fast speed of movement of this centipede make it a very good mite carrier. The majority of the mites were located on the sides of the centipedes, on segments near the anterior end. The high selectivity in the choice of carrier as well as the point of attachment suggests adaptation by the mites for phoresy by L. forficatus.

The male genitalia of the fritillary butterfly Issoria lathonia (L.) were examined and reconstructed based on sagittal and horizontal sections. Nine intrinsic muscles were identified consistent with previous results. The retractor of the anal tube probably operates the "rectal plate", a large, sclerotised, arched plate present ventral to the rectum and dorsal to the phallus in all Issoria s. str. species. The function of the rectal plate is still largely unknown, but it has presumably an important function during copulation. The retractor of the phallus inserts on the phallus, and also on a small, ventral sclerite in the anellus. The retractor of the vesica is smaller in I. lathonia than its counterpart in other Argynnini and originates more centrally inside the phallus. The tergal sclerite, common in most Argynnini, has no attaching muscle and its evolutionary origin remains unclear. The presence of an intrinsic muscle (i3) originating on the tegumen and inserting on the valve in Argynnini cannot be confirmed here. Though generally absent in butterflies, this muscle has been reported once in the North American Argynnis subgenus Speyeria.

One way of reducing the rapid decline in biological diversity in agricultural landscapes is to establish wildflower areas. The species richness and abundance of heteropteran bugs in twenty 1- to 4-year-old wildflower areas and winter wheat fields were compared, and the effects of succession in the wildflower areas investigated. Vegetation and environmental parameters (plant species richness, vegetation structure, flower abundance, field size, surrounding landscape) and their effects on bug species were explored. Total species richness and abundance of bugs were significantly lower in wheat fields than in wildflower areas but did not differ in the wildflower areas of different ages. The numbers of zoophagous bugs in the wildflower areas were positively correlated with the age of the wildflower areas. Correspondence analysis showed that the bug species composition in the winter wheat fields was very similar but strongly separated from that in the wildflower areas. The species composition of bugs in the wildflower areas became increasingly dissimilar with advancing successional age. In a partial canonical correspondence analysis, the bug assemblage was significantly associated with the number of perennial plant species, the number of annual plant species and vegetation structure, which accounted for 13.4%, 12.6% and 7.2% of the variance, respectively. As wildflower areas clearly increased heteropteran diversity on arable land and bug species composition changed with increasing successional stage, the establishment of a mosaic of wildflower areas of different age is recommended as it enables the survival of heteropteran bugs with different life history traits.

The effects of parasitisation by Aphidius ervi on the feeding behaviour of the aphid Acyrthosiphon pisum were studied. There was progressive increase in the time devoted to xylem ingestion (G waveform) and concomitant decrease in time devoted to phloem ingestion (E2 waveform) in parasitized relative to unparasitized aphids, as the time from parasitisation increased. These changes are interpreted as a way aphids compensate for metabolic changes occurring during parasitisation.

In this paper a combination of characters by which Poecilimon species (Orthoptera: Tettigonioidea: Phaneropteridae) can be recognised as members of the P. sanctipauli group are described. Most important are the wide fastigium, short ovipositor and song characters. The morphological characters are figured and described (Table 1), and the song patterns illustrated by oscillograms. The proposed phylogenetic relationships of the members of this group are written as [P. mytilenensis (P. pulcher, P. lodosi, P. sanctipauli)]. All species of the group are known from southwest Turkey and some east Aegean islands. The three species P. pulcher, P. lodosi and P. sanctipauli are morphologically and bioacoustically quite similar. P. sanctipauli and P. pulcher are distinct species, P. lodosi, however, possesses a combination of the key characters of the other two species. It may be a relict species or, in our opinion more probably, a species of hybrid origin.

The species of the Poecilimon heroicus-group occur around the Caucasus (from north-eastern Turkey to south-eastern Ukraine). We describe the diagnostic morphological characters of all these species and the male calling song of three of the four species. Based on this data the following phylogenetic relationship is derived (P. tschorochensis (P. tricuspis (P. heroicus, P. bifenestratus))). Within the genus Poecilimon, the species can be recognised by a relatively wide pronotum and large tegmina. In one species, Poecilimon tschorochensis Adelung, 1907 (type species of the monotypic genus Artvinia Karabag, 1962, syn. n.; P. rammei Miram, 1938, syn. n.), the tegmina are very large and the song has unusually low spectral components. This species produced di-syllabic echemes at intervals of about 10 s. In two other species of the group, P. heroicus and P. bifenestratus, the calling song of males consists of an uninterrupted dense sequence of long syllables (syllable duration around 0.5 s; ca. 1 syllable/s at 20°C). In these species the auditory spiracles are reduced in size in both sexes, and the females have extremely small tegmina and are unable to respond to the male song acoustically, which would be typical for Phaneropteridae. The change in communication from acoustically responding to mute females has not been previously documented within a group of closely related species.

In the present study the temporal changes in the volume of the corpus allatum in three experimental groups of adult males (macropterous, reproductive brachypterous and diapausing brachypterous) of the flightless bug Pyrrhocoris apterus were determined and related to the size of male accessory glands. The results revealed wing morph- and age-dependent differences in the corpus allatum volume in males of this bug. In 4-14 day old males, the volumes of the corpus allatum and accessory glands were largest in long-day reproductive brachypters, intermediate in long-day macropters, and smallest in short-day diapausing brachypters. The smaller corpus allatum in young macropterous males than in same aged reproductive brachypterous males was due to the spontaneous fasting of the former. Later, starting on day 18 after adult emergence, i.e. when macropterous males were feeding normally, there were no significant differences in the volumes of the corpus allatum between long-day brachypterous and macropterous males. On the other hand, the corpus allatum of 18-28 day old diapausing brachypterous males was significantly smaller than that of same aged long-day macropterous and reproductive brachypterous males. The sizes of the corpus allatum and accessory glands were significantly positively correlated in macropterous and diapausing brachypterous males. This is the first report of corpus allatum volume-dependent wing morph-related differences in the rate of accessory gland maturation in males of insects with a non-functional macropterism. The role of differential activity of the corpus allatum in the different life history strategies of males of the two wing morphs in this wing-polymorphic insect is discussed.

The anomaly that Anopheles culicifacies (Diptera: Culicidae) species B is a major vector of malaria in Sri Lanka, but a non-vector in India, has been noted for several years. In 1999, a Y chromosome dimorphism associated with Plasmodium vivax infectivity within the Indian A. culicifacies species B suggested that this was itself a complex of two sibling species, B and E. A recent cytogenetic analysis shows the sympatric presence of these sibling species in Sri Lanka, a situation similar to that reported from nearby Rameshwaram Island, India. Species E, with a submetacentric Y chromosome, is a more effective vector of P. vivax than species B with an acrocentric Y chromosome. Larval karyotyping, however, is time-consuming and labour-intensive. Recently, the development of a PCR-RFLP assay distinguishing species B and E of A. culicifacies from India, based on differences in one region of the cytochrome oxidase subunit II (COII) gene, was reported. Here we show that whilst this diagnostic approach reveals polymorphism in Sri Lankan A. culicifacies, this variation is not correlated with Y chromosome karyotype. Hence this assay will not be useful for distinguishing species B and E in Sri Lanka. Further, we found no difference between the sequences of Sri Lankan specimens in any of three other regions (ITS2, D3 region of 28S rDNA, and guanylate cyclase intron) often used for species discrimination.

The abundance of Coleoptera, Diptera and Collembola on different species of fungi was investigated in relation to the size and abundance of fungal resources at different spatial scales; i.e., the size of the fungal fruiting body, the quality of resource in terms of number of conspecific sporophores growing within a radius of 50 cm, crowding of the clumps of fruiting bodies, and the quality of resource within a plot (20 m × 30 m). Multiple linear regression analyses showed that the influential spatial scale varied among the arthropod orders. The amount of resource at the scale of a clump made a significant contribution to the abundance of Coleoptera, and the fruiting body size significantly affected the abundance of Diptera on each fungal species. Collembolan abundance was significantly affected by the crowding of the clumps of fruiting bodies and the number of fruiting bodies per plot. These results suggest that the spatial distribution of fungal fruiting bodies may determine whether they are selected by arthropods visited.

Using an opto-cardiograph combined with an infrared gas analyzer regular bouts of abdominal contractions were recorded from last instar larva of Bombus terrestris. The rate of CO₂ release was about 0.7 ml g^-1 h^-1. The bouts of contractions were of two types: weak extracardiac pulsations and vigorous pumping. The frequencies of pulsations and pumping were 25-35 per min and 8-12 per min, respectively. Bouts of extracardiac pulsations and abdominal pumping were independent of each other and sometimes overlapped. Cardiac contractions (heartbeats) were continuous (57-63 pulses/min). This study suggests that the periodically occurring abdominal contractions play an essential role in respiration and/or in haemolymph circulation in larvae of B. terrestris.

Science Publishers, Enfield (NH), USA & Plymouth, UK, 2005, xxi + 817 pp. ISBN 1-57808-262-5 (Set), 1-57808-345-1 (Vol. 1), 1-57808-346-X (Vol. 2). Price GBP 81.40.

Kluwer Academic Publishers, Dordrecht/Boston/London, 2002, viii + 419 pp. ISBN 1-4020-0775-2. Price USD 197.00.

Since 1978, the abundance of Coccinella septempunctata L. has been recorded at a hibernation site in the western Czech Republic. Over the years, abundance varied by two orders of magnitude and a long-term trend for decrease in C. septempunctata abundance was observed beginning in the early 1990s. This recession was correlated with the decreasing abundance of its dominant prey, cereal aphids. The acreage of small grain cereals and other crops suitable for breeding C. septempunctata populations also decreased. The change in abundance of cereal aphids may be associated with a dramatic decrease in fertilizer input after 1990. Decreasing fertilizer use has changed the quality of small grain cereal crops and is reflected in lower yields.

The grasshopper Dichroplus pratensis Bruner is polymorphic and polytypic for a complex Robertsonian system. In this species, centric fusions induce changes in number and position of chiasmata, and thus potentially affect intrachromosomal genetic recombination and genetic variability. Males and females, from 23 populations covering most of the geographic range of the species and spanning 22 degrees of latitude, were studied. We analyzed chiasma frequency in relation to variability in six exomorphological characters. The chromosomal polymorphisms of D. pratensis are widely geographically distributed, and show a central-marginal pattern, in which the central populations (those occupying the ecologically optimal habitats) have high mean frequencies of different fusions per individual (F) of up to F = 3.00 and total chiasma frequencies as low as X_T = 8.98 per cell, while those near the margins of the distribution (central Patagonia and the Andes) have very low levels of chromosomal polymorphisms [down to F = 0.00 in most geographically marginal locations), monomorphic karyotypes and high chiasma frequencies (X_T = 11.66, in the southernmost (Rada Tilly, 45°57´S) and X_T = 12.01 in the northernmost population (Volcán, 23°55´S)]. Increasing chiasma frequencies towards the margins of the range are positively and significantly correlated with increasing levels of morphological variability. The decrease in fusion polymorphism and the consequent increase in genetic recombination (both inter- and intrachromosomal) in the marginal areas, is a result of natural selection favouring higher levels of variability, which could be adaptive in ecologically harsher and changing environments.

The oviposition deterring effects of fresh larval tracks of Cheilomenes sexmaculata (F.), Ceratomegilla undecimnotata (Schneider), Cycloneda limbifer Casey, and Harmonia dimidiata (F.) on C. sexmaculata females were compared in standard laboratory choice tests. Moreover, the persistence of intraspecific effects of C. sexmaculata larval tracks were investigated. Fresh tracks of C. sexmaculata, C. limbifer and C. undecimnotata larvae effectively deterred C. sexmaculata females from ovipositing. The effect of fresh larval tracks of H. dimidiata was not statistically significant. The oviposition-deterring effects of 10 d-old conspecific larval tracks were considerably lower than those of fresh tracks, but remained significant. Clutch sizes were smaller in the blank test without larval tracks than in choice tests with fresh tracks of conspecific, C. limbifer, C. undecimnotata, H. dimidiata larvae and with 10 d-old tracks of conspecific larvae. The study indicates that semiochemicals in the tracks of conspecific and heterospecific coccinellid larvae can contribute considerably to the spacing of C. sexmaculata offspring among prey resources of differing quality and that conspecific as well as heterospecific larval tracks can influence clutch size.

Effect of photoperiod on the duration of summer and winter diapause was investigated in the cabbage butterfly, Pieris melete. By keeping naturally induced aestivating and hibernating pupae under various photoperiods, it was shown that diapause duration of aestivating pupae was significantly longer at long than at short daylengths, whereas diapause duration of hibernating pupae was significantly shorter at long than at short daylengths, suggesting both aestivating and hibernating pupae require opposite photoperiodic signals to promote diapause development. By transferring diapausing pupae, induced under various photoperiods, to 20°C with a naturally changing summer daylength, the diapause induced by short daylengths was easier to terminate than diapause induced by long daylengths. When naturally induced aestivating and hibernating pupae were kept under natural conditions, aestivating pupae had a long diapause (mean 155 days) and wide range of emergence (90 days), whereas hibernating pupae had a short diapause (mean 105 days) and a relatively synchronized emergence (lasted 30 days). Finally, the ecological significance of photoperiodic regulation of diapause duration is discussed.

The phylogenetic relationships of the three major species groups of Tribolium (Coleoptera: Tenebrionidae) were inferred using the simultaneous analysis of 642 bp of the most conserved part of mitochondrial DNA (mt DNA) cytochrome oxidase I (COI) and 448-452 bp of mt 16S rDNA. High sequence divergence was observed for both genes even among sibling species. The analysis of the combined segments of COI and 16S rDNA sequences produced a phylogenetic tree with moderate level of confidence. The tree topology showed monophyly of the genus Tribolium whose species were separated into three groups: "brevicornis" group (with T. brevicornis as the only representative), "castaneum" group (with T. castaneum, T. freemani, T. madens and T. audax) and "confusum" group (with T. confusum, T. anaphe and T. destructor). Sibling species pairs T. castaneum - T. freemani and T. madens - T. audax are clearly resolved. The preliminary results presented here give moderate support to the previously proposed phylogeny based on morphological data.

Tomicus piniperda and T. destruens are sibling species which are extremely difficult to separate by morphological characters. Although several papers report differences between the two species, many characters need confirmation or better description. Moreover, new morphological characters are required for correct species determination. For these purposes, eight populations of T. destruens from Italy, Greece, Spain and Algeria, and ten of T. piniperda from Finland, Poland, Czech Republic, Austria, Sweden and Italy, were investigated considering eleven morphological characters. The morphological differences most useful for the species separation include four previously described characters (colour of the elytra, colour of the antennal club, distribution of the antennal setae, distribution of the punctures along the elytral declivity), and four new characters (body proportions, setation of the first antennal club suture, sculpture of the elytral declivity and striae density of the pars stridens). Distribution of the two species is discussed and an illustrated key is included.

Abstract. The cuticle of Rhysotritia duplicita (Euphtiracaroidea: Euphtiracaridae), Phthiracarus sp., Steganacarus magnus, S. striculus and Tropacarus carinatus (all Phthiracaroidea: Phthiracaridae) was studied by light and transmission electron microscopy. A combination of light and electron microscopy were used to precisely characterize and classify the cuticular layers in oribatid mites and show how they differe in mites and other arthropods. In Rhysotritia duplicata the cuticle of the aspis (upper shield of the prosoma) differs significantly from that of the opisthosoma. Moreover, prosomal cuticle in this species is different from that of all others species studied. There were no structural differences in the cuticle of the prosoma and opisthosoma of species of the superfamily Phthiracaroidea (Phthiracarus, Steganacarus and Tropacarus) in spite of the differences in external apparence. Moreover, in Tropacarus, the rough sculpturing of the cuticle results from the very rough exocuticle, which is unlike the thick smooth cerotegument of the cuticle in Steganacarus.

A fragment encoding melittin cDNA from Apis cerana cerana fused with glutathione S-transferase gene was inserted into the multiple cloning site of the pBacFastHTb to construct a recombinant donor plasmid, pBacHT-GSTAccM, which was transposed to the target bacmid in E. coli (DH10) by Tn7 transposition function. Then the recombinant baculovirus Bacmid-GSTAccM was transfected into Tn-5B1-4 cells of the cabbage looper, Trichoplusia ni, mediated by lipofectin. The expressed protein of about 34 kDa was detected by Western blotting and triple antibody sandwich ELISA, indicating that the recombinant protein is the fusion protein of GSTAccM. Thin layer scanning showed that the expression level of GSTAccM was about 7% of the total cell protein. Purified and recovered recombinant melittin of A. c. cerana showed bioactivity in activating rabbit platelets to aggregate.

The behavioural responses of two species of stored-product beetles, Sitophilus oryzae (L.) and Tribolium confusum Jacquelin du Val, to certain stimuli were studied in laboratory choice tests. The results of these experiments indicated that, with one species present, S. oryzae and T. confusum adults were equally attracted to traps baited with the aggregation pheromone of that species and to traps baited with both pheromones. In contrast, when both species were present, neither S. oryzae nor T. confusum showed specific behavioural trend towards a stimulus. Traps baited with 1 g of a mixture of plant extracts were significantly more attractive for both species than unbaited traps, but this response was highly influenced by the number of individuals of each species released. Traps baited with filter papers that were previously contaminated by live adults of both species were particularly attractive for S. oryzae, but not for T. confusum. Traps that contained 10 seeds damaged by S. oryzae were significantly more attractive than traps containing an oil lure or control traps for S. oryzae, but not for T. confusum. The addition of oil to the seeds did not affect the attractiveness of the trap for S. oryzae. Traps that contained 20 live S. oryzae adults were significantly more attractive than traps containing 20 dead S. oryzae adults or control traps. No significant differences were noted between traps containing 20 dead S. oryzae adults and control traps. The presence of S. oryzae adults in traps did not affect the response of T. confusum.

The ageing trajectory (trend in ageing) and reproduction-longevity trade-off in both sexes of the ladybird Propylea dissecta were studied. The ageing trajectories of both sexes were investigated in terms of reproductive performance, using initial oviposition (egg laying within 24 h of mating) acting as an indicator of the effect of female age and initial viability (percentage of eggs laid within 24 h of mating that hatched) of the effect of male age. Ageing trends were sex dependent, with reproductive performance declining later in females than in males. Initial oviposition of females was largely age dependent and the initial viability of males was age dependent but less so than for females. There is a strong trade-off between number of matings and longevity. Statistical analyses reveal that this trade-off results from an early onset of mortality rather than an increase in mortality rate. A minimum lifespan was observed in this ladybird beyond which the longevity did not further decline.

Nicrophorine beetles use small vertebrate carrion for breeding resource. While Nicrophorus spp. have highly developed biparental care, no form of parental care is recorded for Ptomascopus spp. We examined two effects of resource guarding by Ptomascopus morio. The presence of parents, especially the female, reduced the number of fly larvae on chicken carrion. Parents also enhanced the survival of brood faced with predation by the rove beetle, Ontholestes gracilis. In 6 out of 20 trials, the rove beetle predators were killed by Ptomascopus morio parents. We conclude that Ptomascopus morio has a simple, and possibly primitive form of parental care.

Markers are essential to study movements of insects in their natural habitat. Among the available techniques, trace elements may be applied to insects as small as parasitoids. Rubidium is the most common element used for marking insects. In this study, we propose a simple marking technique for Aphidius rhopalosiphi De Stefani Perez with Rb, when reared on the grain aphid Sitobion avenae Fabricius (Hemiptera: Aphididae) marked on a RbCl incorporated diet. Our results show that the rubidium in an artificial diet is transferred to the aphid and eventually to the parasitoid. The content in rubidium marking did not differ between genders. The aphids stung by a marked parasitoid could not be distinguished from unmarked aphids on the basis of their rubidium content. There were no effects of rubidium on size, fecundity, longevity and sex ratio of the parasitoid, but the marked individuals emerged significantly later than the unmarked. We did not detect differences concerning host acceptance by marked and unmarked parasitoids. This technique may be applicable to other aphidophagous insects after some preliminary evaluations.