Fourth-instar gypsy moth (Lymantria dispar; Lepidoptera: Lymantriidae) larvae, infected with the gypsy moth baculovirus (LdNPV), show an elevated and prolonged extension of the hemolymph ecdysteroid titer peak associated with molting. The ecdysteroid immunoreactivity associated with this peak elutes as two peaks following HPLC on a C₁₈  reverse-phase column. Both peaks elute in a region more polar than 20-hydroxyecdysone, but less polar than the highly polar ecdysteroid immunoreactivity associated with the apolysis peak of control animals. Glycosylated ecdysteroid standards, produced by in vitro incubation of UDP-glucose with ecdysone or 20-hydroxyecdysone and culture medium from LdNPV-infected gypsy moth cells, show elution times identical to the two immunoreactive peaks. Enzymatic hydrolysis studies verified this identity. The data suggest that the hemolymph of LdNPV-infected L. dispar larvae contains both glucose-conjugated ecdysone and glucose-conjugated 20-hydroxyecdysone which, by analogy with the literature, are presumably 22-O-beta-D-glucopyranoside and 20-hydroxyecdysone 22-O-beta-D-glucopyranoside.

The Anthaxia (Haplanthaxia) collaris is species-group from the Oriental region is revised including keys and illustrations. A. lubopetra sp. n. from Vietnam is described and new synonyms are proposed: Anthaxia auricollis Kerremans = A. achardi Obenberger, syn. n., = A. serenissima Obenberger, syn. n.; A. virescens Kerremans = A. strandiella Obenberger, syn. n.

We have previously isolated from the beetle Tenebrio molitor, cDNAs coding for two glycine-rich cuticular proteins named ACP-20, ACP-22 and ACP-17 and an alanin-rich cuticular protein named LPCP-22. The ACP-20, ACP-22, ACP-17 mRNAs are detected by Northern blot and in situ hybridization analysis only in epidermal regions secreting heavily sclerotized cuticle during the pharate adult stage. The LPCP-22 mRNA is detected in most epidermal regions during the secretion of larval and pupal cuticles. Then, its presence is restricted to the epidermal zones secreting intersegmental soft cuticle in the newly ecdysed pupa. This stage- and tissue-specific gene system seems to be a convenient model for studying the regulation of sequential gene expression by ecdysteroids and juvenile hormone.

The non-steroidal ecdysone agonist, RH-5992, is effective in inducing an incomplete molt in the spruce budworm, Choristoneura fumiferana (Clemens), only when it is fed to the larvae prior to the appearance of the endogenous ecdysteroid peak. When this compound is administered after the ecdysteroid peak, the larvae molt normally into the next stage. However, because of its persistence, the agonist induces an incomplete molt in the subsequent larval stage. The effect does not appear to be due to ecdysone responsive tissues becoming refractory after the ecdysteroid peak. Choristoneura hormone receptor 3 (CHR3), a homologue of Manduca hormone receptor 3 (MHR3), is induced in the epidermis, fat body and midgut of 6th instar larvae treated with RH-5992 during all days of the 6th stadium. Possible reasons for this age specific effect are discussed.

Photoperiodic sensitivity was examined in adults of a bivoltine bug, Aelia fieberi Scott, by exposing insects to long-day or short-day conditions al 25°C. The adult diapause of A. fieberi is facultative, induced by short-day photoperiod. Adults reared from eggs under long-day conditions began to lay eggs, whereas those reared under short-day conditions entered diapause. Both nondiapause and diapause adults were sensitive to photoperiod. The adults of the first and the second generation collected from the field were also sensitive to photoperiod. However, after overwintering, adults did not show photoperiodic sensitivity.

The ovipositional patterns of Sitophilus granarius females have been studied over time, and in response to different numbers of available wheat grains. The female fecundity and the degree of grain infestation show a maximum by 20th day of adult life, and a significant decrease after 30th day. Increasing grain availability leads to a rise of both female fecundity and grain infestation, until saturation is reached. The frequency distribution of the numbers of eggs per grain shows a contagious pattern due to a tendency of females to lay more than one egg within the same grain. This behaviour is independent of female age and grain availability, and consequently the possibility that it may be an adaptive reproductive strategy is discussed.

We review data on the structure and expression of the Broad Complex, a key gene in the response to ecdysterone (20E) in Drosophila cells.

The 2B3-7 X chromosome region, containing an early (20E) inducible puff, was saturated with mutations in the genes dor, hfw (swi) and BR-C that cause disturbances in the normal ecdysterone-inducible puffing sequence. By analysis of chromosome rearrangements localized on the genetic, cytological and physical maps, the BR-C locus has been mapped exactly within the 2B3-5 puff. Homozygous mutations for BR-C result in the multiple distortions of metamorphosis and female fertility due to loss of sensitivity of the genes in this chromosomal region to ecdysteroids.
Using interstrain larval ovary transplantation, the causes of female sterility were studied in females mutant for the BR-C. Transplantation of BR-C ovaries into females heterozygous for a dominant sterility mutation followed by genetic analysis of the progeny demonstrated that the transplanted ovaries were capable of normal function. The sterility of the BR-C mutant females is therefore associated with a somatic extra-ovarial defect rather than a germ line malfunction.
According to cytogenetic and molecular analysis, the BR-C occupies more than 115 kb and contains at least three regulatory elements. One of these elements (in position 146.5-161 kb) may respond to 20E and this results in puff activation in the salivary gland cells. The second element (at 99-120 kb) is located upstream in the first exon and is necessary for transcription activation, while the third element (to the left of 99 kb) is necessary for normal fertility.
The strongest BR-C mutations result in underdevelopment of almost all ecdysterone-inducible puffs. In animals homozygous for the weaker BR-C mutations (rbp group) which survive until organ formation in the pupa, the larval salivary glands do not histolyse until at least 72 hour after pupariation (Restifo & White, 1992). Analysis of polytene chromosomes has shown that in the rbp⁴ mutant all ecdysterone-inducible puffs are extremely reduced in 0, 3, and 10 h prepupae. Some of the puffs including the 2B3-5 are active until 24 h pupae.

The family Agelenidae (sensu Maurer, 1992) is represented in Bulgaria by 35 species, included in 10 genera (Agelena 3, Cicurina 1, Coelotes 8, Cryphoeca 2, Cybaeus 2, Histopona 3, Lycosoides 1, Maimunn 1, Tegenaria 12, Textrix 1, Tuberta 1). This number was established after a taxonomic revision of all available collections containing agelenid spiders in Bulgaria. One new record is also added (Tegenaria zirzulusensis Dresco).

Species of the family Agelenidae are distributed in all districts in Bulgaria, occurring in lowland, forest, mountains, caves and buildings or close to them. Regarding their distribution by altitude, there are only 5 species which inhabit the high mountain zone, but only Cryphoeca pirini Drensky is characteristic of the alpine belt. According to their current distribution, the Bulgarian agelenid spiders can be split into 11 zoogeographical categories, grouped into 5 complexes (Cosmopolitan, Palaearctic, European, Southeast European, Mediterranean). The Southeast European complex is the best represented (40%) and shows quire well the local character of this fauna and the main role of the Balkan peninsula in its origin and formation.

3-Dehydroecdysone (3DE) is the major secretory product of crayfish moulting glands. The metabolic fate of 3DE in the crayfish Orconectes limosus was investigated after in vivo injection of [³H]3DE and after incubation of various tissues with [³H]3DE in vitro. Metabolites in whole body and tissue extracts were analysed by HPLC. In vivo [³H]3DE is efficiently reduced and hydroxylated to [³H]20-hydroxyecdysone (20E), which is one of the major metabolites observed in our study and also the major circulating ecdysteroid. 3 beta-reduction and 20-hydroxylation were the predominant enzymatic activities obtained after in vitro incubation of [³H]3DE with various tissues. Under the conditions utilised here, antennal glands and CNS (abdominal ganglia) exhibited highest reductase activity per mg wet weight; epidermis, gonads, midgut gland and hindgut had moderate activities; muscle had the least and hemolymph was inactive. 3DE conversion by Y-organs differed moulting stage dependently. 20-hydroxylation activities were similarly distributed in all organs except for ovaries, in which 20-hydroxylation exceeded the 3 beta-reduction. Ovaries were also the only tissue containing a significant 3 alpha-reductase activity.

Developmental profiles of total RNA and four silk protein mRNAs exhibit different correlations with ecdysteroid titre changes in course of the 180 hr-long last larval instar. Total RNA and heavy-chain fibroin mRNA increase gradually until 168 hr and 156 hr, respectively, dropping sharply afterwards. The content of sericin1 mRNA rises for 120 hr, remains high until 168 hr and then drops. The amounts of ligh-chain fibroin mRNA and sericin2 mRNA increase sharply at the start of the instar; the former rises until 168 hr, whereas the latter begins to decline already at 120 hr. The pupation-inducing ecdysteroid surge at 144-168 hr causes a drop in all examined RNA classes. Similar drop is induced precociously with exogenous ecdysterone, while a slow decrease of RNA contents to similar bottom levels occurs when the larvae are ligated behind prothorax.

The effects of 20-hydroxyecdysone (20E), ponasterone A (PoA) and both dibenzoylhydrazine-based ecdysteroid agonists RH-5849 and RH-5992, were tested on in vitro-cultured imaginal wing discs of last-instar larvae of the beet armyworm, Spodoptera exigua (Hübner). In each case, the response was qualitatively similar to that induced by 20E, although the concentrations required to induce response varied widely. The EC₅₀ of both ecdysteroids 20E and PoA to elicit wing disc evagination in 50% of the discs was 89.8 and 2.57 nM, respectively; for both nonsteroid agonists RH-5849 and RH-5992 this was 870 and 11.7 nM, respectively. Binding competition studies using whole imaginal wing discs, showed that I₅₀ of 20E, PoA, RH-5849 and RH-5992 to displace 50% of [³H]PoA-binding was 290, 7, 1100 and 33 nM, respectively, which is in the same order as the respective concentration to elicit a biological response.

Severe defoliation of Prunus padus saplings in spring 1987 significantly affected growth and nutrient characteristics for the next five years. Trees that experienced 50% or greater defoliation at age 2 and 3 years were significantly smaller than the controls for up to three years after experimental defoliation had ceased. After five years, trees that had experienced the most severe defoliation were still significantly smaller than those trees that had experienced less severe defoliation regimes. Trees that had experienced high levels of defoliation had significantly higher total leaf nitrogen levels and significantly lower calcium levels two years after defoliation than lightly defoliated trees. Four years after the initial defoliation treatments the situation was reversed, nitrogen levels were higher and calcium levels lower in the controls and lightly defoliated treatments than in the heavily defoliated treatments.

The colonisation of the trees by insect herbivores was significantly affected by the initial defoliation treatments. The number of overwintering eggs of the specialist bird cherry feeding aphid Rhopalosiphum padi were significantly greater on the control and lightly defoliated treatments from 1987-1990. Only in 1991 were egg numbers not significantly different between treatments, and in that year populations overall were extremely low. In addition, damage by mid-season generalist herbivores was significantly lower on those trees that had experienced severe initial defoliation. In all other years bar 1989 and 1991, damage levels were significantly higher on those trees. Colonisation by the other bird cherry specialist, the small ermine moth Yponomeuta evonymellus, did not occur until 1991. All trees colonised were from the severe defoliation treatments. These results are discussed in relation to the probable effects on the population dynamics of the two bird cherry specialists.

Developmental interactions between the solitary koinobiont endoparasitoid Venturia canescens, and two of its hosts, the pyralid moths Plodia interpunctella and Corcyra cephalonica, were investigated. Wasps reared from second (L2) through fifth (L5) instars of Corcyra were larger than those from the corresponding stages of Plodia, but took longer to complete development and generally suffered higher mortality. Starved L5 Plodia of a given mass produced significantly larger wasps than starved L5 Corcyra. Adult wasp size was positively correlated with the number of ovulated eggs in Venturia emerging from both hosts; thus, the larger wasps that emerged from Corcyra had higher egg complements than the smaller wasps from Plodia. The final size of parasitized L2-L4 Corcyra was influenced by Venturia, with all three instars significantly smaller than unparasitized larvae.

For Venturia, developmental flexibility and host regulation are important adaptive mechanisms that allow the parasitoid to develop in a wide range of host instars. However, for koinobiont parasitoids differences in the biology of the host species strongly influence their development and fitness.

The synthesis of dopamine melanin in the wing scales of Precis coenia depends on pattern specific activity of dopa decarboxylase (DDC) at the end of pupal development when hemolymph ecdysteroids decrease. DDC activity in forewings increased in 6 days old pupae and is maximal on day 6 at midnight. DDC activity increased also in isolated wings incubated in Grace's medium on day 5 at midnight, following the same time profile as in vivo. The wings developed their typical colour pattern. However, at most time points DDC activity in vitro was lower than in vivo. Wings incubated in medium containing 10 µg/ml 20-hydroxyecdysone (20E) did not melanize. 20E inhibited the DDC activity in a dose dependent manner.

A new technique was used to continuously supply 20E to an almost intact pupa. The pupal cuticle covering the left forewing was removed and the wing was hung in medium containing different concentrations of 20E. 20E was distributed in the pupa and inhibited melanization in the intact right pupal wing. In control incubations with pure Grace's medium different coloured portions of the wing pattern showed different DDC activities being high in the black eyespot and medium and low in grey and white wing pieces, respectively. A high concentration of 10 µg/ml 20E supplied to the left wing totally inhibited DDC in all differently coloured wing pieces. With decreasing ecdysteroid concentrations, DDC activity increased earlier and to higher levels in black than in grey wing pieces and was almost constant in white pieces. Therefore, melanin synthesis started earlier and was at a higher level in black than in grey scales, which caused their different pigmentation. This result suggests that the time point of initial melanin synthesis in differently melanized scales is triggered by the decreasing ecdysteroid titer causing differential activation of the DDC.

A strategy is described for receptor-based phytochemical screening of plant extracts for ecdysteroid agonists and antagonists. Milligram amounts of seed are methanol extracted. Lipids and pigments are removed by hexane partioning. Agonist and antagonist activities are detected with a microplate-based specific bioassay using the Drosophila melanogaster ecdysteroid-responsive BII cell line. Extracts are also screened with ecdysteroid-specific RIAs to identify extracts containing phytoecdysteroids. Over 1,700 species of plant have been screened in this way so far. Extracts are being sought which (i) contain large amounts of phytoecdysteroid, (ii) which contain novel phytoecdysteroids, (iii) which contain non-steroidal agonists and (iv) which contain antagonists. The aim of this paper is to describe the rationale behind the strategy, to describe its operation and to present, as an example, the results obtained with members of the Poaceae and of one genus, Briza, in particular. It is hoped that this approach will result in the identification of new sources of phytoecdysteroids, provide new phytoecdysteroid structures for structure/activity relationship studies, throw light on the phylogenetic distribution of phytoecdysteroids in the plant kingdom and provide useful agonists and antagonists for the investigation of ecdysteroid receptor function and as potential lead compounds for new classes of insect control agents.

Female penultimate instar larvae of Gryllus bimaculatus show a maximum in haemolymph ecdysteroid titer as well as in hormone release in vitro by prothoracic glands on day 4, two days before final larval moult. Ovary and abdominal integument of the larvae contain considerable amounts of ecdysteroids, but no significant hormone release is detectable during a 16 h in vitro incubation of these tissues.

In last instar larvae, the prothoracic glands reach their maximal ecdysteroid release on day 5. This peak is followed by a maximal release of hormones by the ovary as well as by the abdominal integument on day 6. The highest titer of ecdysteroids in haemolymph is found on day 7, two days before imaginal moult. The haemolymph titer is governed only by free ecdysteroids. The prothoracic glands and the abdominal integument release free ecdysteroids, whereas from the ovary considerable quantities of apolar conjugates appear. The abdominal integument of day 6 last instar larvae converts [³H]5 beta-ketodiol into [³H]ecdysone in vitro.
From these results it can be concluded that in last instar larvae of G. bimaculatus the prothoracic gland as well as the ovary and the abdominal integument are involved in the changes of haemolymph ecdysteroid titer in relation to imaginal moulting. The data indicate an ecdysteroid synthesis outside the prothoracic gland in G. bimaculatus last instar larvae.

The types of the following species of subgenus Empis s. str. described by G. Strobl are revised: Empis (Empis) alpicola, E. (E.) apfelbecki, E. (E.) assimilis, E. (E.) baldensis, E. (E.) cantabrica, E. (E.) ciliatopennata, E. (E.) dusmetii, E. (E.) fascialata. 2 holotypes are identified and 6 lectotypes designated.

In response to a blood meal, the fat body of the female mosquito produces several yolk proteins (YP) which are accumulated by the developing oocytes. 20-hydroxyecdysone (20E) stimulates high levels of YP gene expression in fat bodies cultured in vitro, but initiation of this expression was eliminated with cycloheximide. In the 1.5 kb upstream region of the gene encoding vitellogenic carboxypeptidase, a mosquito YP, there are several putative regulatory sequences that resemble steroid response elements (SRE), but they do not match the ecdysteroid response element (EcRE) consensus. A cDNA encoding a mosquito ecdysteroid receptor (AaEcR) has recently been cloned and found to possess P-Box and D-Box domains nearly identical to those found in the Drosophila and Chironomus EcRs, indicating that its DNA binding sequence will likely match the EcRE consensus. Taken together, these results indicate that the control of YP genes in the vitellogenic mosquito fat body by 20E is indirect. It may involve several factors in a hierarchy, with a factor other than the AaEcR directly controlling the YP genes.

In the mosquito fat body, lysosomal enzymes are involved in termination of YP secretion. The mRNA of a mosquito lysosomal aspartic protease (LAP) reaches its peak 12 hr before the peak of LAP protein and enzymatic activity. The level of LAP protein rises as the titer of 20E declines. This suggests a translational inhibition of LAP mRNA by a high titer of 20E. We obtained direct experimental confirmation of this novel function of 20E. In addition, the 5'-untranslated region of the LAP mRNA shares similarity with elements conferring negative translational control by steroids. The LAP gene is controlled by dual promoters, one of which is dominant during enhanced expression. The identification of putative regulatory elements should help in determining the regulation of the gene during both housekeeping and enhanced expression.

The two nonsteroidal ecdysteroid agonists, RH 5849 and RH 5992 were tested in the epithelial cell line from Chironomus tentans. Both compounds induce all effects elicited by 20-OH-ecdysone in this cell line, namely differentiation, arrest of cell growth and regulation of chitin metabolism. Usually, the cell line forms multicellular vesicles consisting of a squamous monolayer. Treatment with ecdysteroids or RH compounds leads to the formation of a stratified columnar epithelium. This differentiation is accompanied by changes in protein pattern. Ecdysteroids and RH compounds also interfere with chitin metabolism. Chitin synthesis is inhibited, whereas synthesis and secretion of chitinolytic enzymes are increased. The efficiency of RH 5849, RH 5992 and 20-OH-ecdysone to evoke the above mentioned responses corresponds with their affinity for the ecdysteroid receptor.

A short and intensive pitfall trapping was performed in an apple orchard to estimate the species richness of the ground-dwelling spider assemblage present. Calculation of the total number of species was achieved by an extrapolation performed in two steps:

1. Establishing a series of species Counts corresponding to increasing sampling efforts. Simulation of increasing sampling efforts was achieved by computer sub-sampling.
2. An asymptotic function, derived from the theory of island bio-geography, was established to describe the sampling curve. The asymptotic value of this function provided the estimated total species number, corresponding to a sampling effort that would have covered the whole sampled area.
The method gave a robust and singular result. This method can be useful in comparative biodiversity studies of animal assemblages.

The proportion of melanic (with dark elytra) and non-melanic (yellow-brown elytra) adults of Agriotes ustulatus (Schaller) was established in populations from central Europe (Bohemia, Czech Republic) and the Mediterranean region (Veneto, northern Italy). Both areas, although separated by only 500 km distance, have dramatically different climate. The average proportion of melanic individuals was slightly (by 8%) but significantly greater in populations from Veneto than from Bohemia. The frequency of melanics was identical in both sexes and stable over a 11 year period as well as during the season. The apparent stability of morph frequencies in A. ustulatus contrasts with other insect species where melanic frequencies often vary greatly, both in space and in time.

Radiotracer experiments were performed to analyze the interaction of metabolites of ecdysone with proteins in adult Drosophila melanogaster females. [³H]Ecdysone was injected into the abdomen and after 4 h of incubation the flies were dissected. PBS-soluble material of the ovaries, haemolymph, gut and abdominal carcass were separated by gel-filtration. In all samples, two peaks containing radioactivity eluted with macromolecules (probably proteins) of an apparent molecular mass of more than 1,000 kDa (peak I) and about 500 kDa (peak II). In the extracts of the ovaries an additional peak in the molecular weight range of about 50 kDa (peak III) was detected. In all samples free ecdysone metabolites, which did not interact with macromolecules were detected. The radioactivity in the ovary-specific peak III was mainly due to ecdysone 22-phosphate. The high molecular weight peak I contained radioactive 22-fatty acyl esters of ecdysone and the radioactive material of peak II consisted of a highly complex mixture of ecdysteroids.

The structural elucidation of acetylated ecdysteroids isolated from dried roots of Ajuga reptans var. atropurpurea, based on spectroscopic procedures, is reported. Among them 2-O-acetyl- and 3-O-acetyl-20-hydroxyecdysone (20E2Ac, 20E3Ac) and 3-O-acetyl-29-norcyasterone (29NCY3Ac) had previously been only partially described and 3-O-acetylcyasterone (CY3Ac) was heretofore unreported.

A twig-lining population of Latouchia swinhoei Pocock, 1901 (Ctenizidae) was found in Okinawa in a habitat also densely populated by other trapdoor spiders (Ryuthela nishihirai, Mesothelae). Specimens were tested in the laboratory for their utilization of objects offered to them for attachment to the rim of the burrow. The behavioural capacity of twig-lining is discussed in comparison with other trapdoor spiders.

Respiratory functions have been monitored by microrespirographic scanning method in immature and adults of Chelifer cancroides (L.) (Pseudoscorpiones) and male adults of wind scorpions Galeodes sp. (Solifugae). Both species exhibited a more or less continuous respiratory pattern with relatively constant, acyclic CO₂ output and CO₂/O₂ ratio of 0.72-0.73 under conditions of high relative humidity, and during feeding or intensive locomotion. Conversely, under dry environmental conditions, during starvation or arrested locomotion while watching for prey, both pseudoscorpions and much larger wind scorpions exhibited a wide range of respiratory cycles with various frequencies and amplitudes. These cycles are characterized by discontinuous emissions of free, gaseous CO₂ from haemolymph or tissue buffers. During emissions, CO₂ is released at rates surpassing several times the rate of O₂ consumption. It is similar to the Prague respiratory cycles found in some insects.

In starved adult Chelifer (3 mg body mass, 25°C, dry environment), O₂ consumption rate was 5.7 nl per min (136 µl O₂.g^-1.h^-1) with regular Prague respiratory cycles in CO₂ release. Duration of each cycle was 4.93 min; the emissions of CO₂ lasted 0.9 min, the amount of CO2 released in one emission was 22.8 nl (corrected for simultaneous O₂ uptake). Total average rate of CO₂ release was 4.16 nl per min (99.8 µl CO₂.g^-1.h^-1): R.Q. 0.729. The emissions of gaseous CO₂ were limited only to bursts; the initial rate of CO₂ emission exceeded four times the rate of O₂ consumption.
In starved adult Galeodes sp. (200 mg, 27°C, dry environment, motionless position) the rate of O₂ consumption was relatively low (105 µl O₂.g^-1.h^-1); the emissions of 3.9 µl CO₂ lasted 4 min with 16 min duration of the whole respiratory cycle. During emissions: gaseous CO₂ was produced at 5-times faster rate than that oi O₂, consumption.
Both the investigated tracheate arachnids can actively regulate breathing by adjusting frequency and amplitude of the respiratory cycles to external or internal physiological conditions. Possible involvement of a special nervous mechanism, similar to the autonomic, parasympathetic-like, nervous system (coelopulse) of insects is indicated.

Chromatography of nuclear extracts from Calliphora vicina on heparin-agarose separates two fractions binding ponasterone A. One does not bind calf-thymus (ct) DNA, has a molecular mass of 100 kDa, and may represent an ecdysteroid receptor monomer. The other binds to ctDNA and is 180 kDa, indicating this to be a receptor complex of two or more heteromeric partners. The formation of this DNA-binding complex is promoted by the presence of high-affinity ligand and of DNA itself.

Food stress experienced during larval and adult life in Coccinella septempunctata L. results in variation in the rate of production of eggs per unit time and in the size of egg clusters but not in egg size. This lends support to the suggestion that egg size is constrained by the minimum size at which first instar larvae can capture active prey and/or complete their development before prey become scarce. When supplied with an excess of food large beetles produce larger clusters of eggs than small beetles. This is associated with the large females having more ovarioles in their gonads than small females. As the proportion of eggs that give rise to larvae remains the same for clusters of from 6 to 60 eggs there appear to be no costs, in terms of increased predispersal sibling cannibalism, to laying larger clusters of eggs.

Gelis longulus (Zetterstedt), reared from pupae of Ocnerostoma piniariellum Zeller collected on Pinus cembra L. in northern Italy, is redescribed. The lectotype designation is reported. Notes on its biology, distribution and other known hosts and a short list of other natural enemies of Ocnerostoma piniariellum Zeller in Europe are given.

In holocylic aphid species many different morphs are produced during the phase of parthenogenetic reproduction. Because these morphs differ in their life-histories, research has been focused on how individual life-histories can be explained in the framework of maximizing the Malthusian parameter r_m. All these different morphs are produced by the same genotype. Since it is the genotype that selection acts on it is questionable whether the intrinsic rates of increase of individual morphs can be used to make inferences about the fitness of the genotype. A simple model is developed to investigate the relationship between individual r_m and clonal fitness in the case of wing dimorphism of aphids in summer. In the model, survival and fecundity of winged and unwinged morphs depend on the quality of their host plants, and unwinged aphids have to decide which morph to produce in the next generation to maximize the number of eggs produced at the end of the season. The model shows that clonal fitness depends on the sequence of morphs produced and that the relationship between individual and clonal rate of increase is not straightforward. The decision as to which morph to produce is influenced by the quality and distribution of the host plants and depends also on the time of the year. It is suggested that r_m-values of individual morphs should be treated with care when aphid life-history is to be explained.

The effect of temperature on development of populations of the rice stem borer from Hsilo (23.8°N), Tounan (23.7°N) and Pingtong (22.7°N), Taiwan, was investigated. The development rates of these populations increased with increasing temperature from 20 to 30°C. The mean developmental periods of eggs, larvae, and male and female pupae in the Hsilo population were 7.7, 33.0, 7.6 and 7.1 days at 25°C under 14L : 10D photoperiod and the theoretical threshold temperatures for development were 8.9, 9.2, 10.4 and 10.5°C, respectively. Effective temperature sums for development were 124, 521, 111 and 103 day-degrees, respectively. These results suggest in Hsilo population that 4 or 5 generations occur annually in central and southern Taiwan. In the Tounan and Pingtong populations, which require lower effective temperature sums for larval development than the Hsilo population, 5 or 6 generations may occur in a year.