In this paper we use the concept of the evolutionary individual as the basis for an attempt to characterise sex-allocation patterns in aphids. We then examine the various selection pressures involved in the evolution of aphids' sex ratios, and propose a novel explanation for biased sex allocation in host-alternating aphidines, in which inbreeding is impossible. Their production of gynoparae (females that migrate from secondary to primary hosts to produce the sexual females) before males is the clonal equivalent of sex reversal - sequential hermaphroditism. Selection on the timing of the reversal, and thus the overall sex-allocation ratio, should depend largely on the rate of decline of the populations on the secondary hosts in autumn and on how long it takes oviparae (sexual females) to reach maturity. The longer the nymphal period of the oviparae, the sooner investment in gynoparae becomes futile, since both gynoparae and oviparae must mature and oviparae must oviposit before leaf-fall. It is the combination of a deadline - leaf-fall - and a delay - the two generations that must be completed between allocation to gynoparae and oviposition - that determines the selection on the allocation ratios of host-alternating aphidines. Data on Rhopalosiphum padi in Scotland and Sweden show a strong female bias, as the model predicts.

Cellulose acetate electrophoresis was used to investigate genetic variation at 15 enzyme loci in aestivating populations of the sycamore aphid, Drepanosiphum platanoidis (Schrank) (Hemiptera: Drepanosiphidae). The level of polymorphism P (over all loci) was 20%. Of the polymorphic loci, only phosphoglucomutase (PGM), with four alleles, provided consistent, interpretable banding patterns and was subsequently used to investigate population structure and gene flow at various spatial levels in southern Britain. Of 13 aphid aggregations (from single leaves) collected from the lower canopy of a selected tree, only one deviated significantly from Hardy-Weinberg expectations. Genotypic diversity for the PGM locus was generally high and genetic identity measures showed homogeneity between leaf aggregations. Aphid samples collected from eight trees in close proximity, five sites in Hertfordshire and four other sites in southern Britain, also showed homogeneity for alele and genotype frequencies and, in almost all cases, conformed to Hardy-Weinberg expectations. It was concluded that gene flow, facilitated by trivial and migratory flight, was responsible for the genetic homogeneity observed, both within and between host trees.

An answer to this question is proposed on the basis of the assumed evolutionary history of aphids based on palaeontological studies, zoogeographical data and estimated origin of each aphid genus in the world. An adaptive radiation of Aphididae and Lachnidae occurred rather late in the Tertiary on the northern hemisphere, and the tropics acted as a barrier. Most aphid genera endemic to the temperate regions of the southern hemisphere belong to other groups. The life cycles of aphids are discussed, and it is concluded, that the life cycles characteristic to most aphids in the temperate regions of the northern hemisphere are developed as an adaptation to the climatic conditions there.

The Asian pug moth Eupithecia addictata Dietze is newly recorded from Europe (Austria, Slovakia, Greece) and distinguished from E. thalictrata (Püngeler) with which it was previously confused. Syntypes of E. addictata are examined and a lectotype (male) is designated. Variation of the species is discussed; no substantial difference was found between the European and East-Asian populations. The larva feeds on Thalictrum spp. New synonymy Eupithecia addictata Dietze, 1908 = E. danielata Schütze. 1959, syn. n. is introduced.

The suborder Sternorrhyncba (Insecta: Homoptera) includes aphids, whiteflies, psyllids and scale insects; these are all large diverse groups of herbivorous insects that feed on plant sap and that include many of the most damaging agricultural pests. All of these insects are dependent on obligately intracellular procaryotic symbionts for their survival. In this collaborative project between Nancy Moran and Carol von Dohlen, both insect biologists, and Paul Baumann, a bacteriologist, molecular phylogenetic methods have been used to explore the evolutionary history of these mutualistic interactions. Using PCR amplification with procaryote-specific primers, DNA sequences have been obtained for the 16S ribosomal gene of the endosymbionts from approximately 20 species of Sternorrhyncha, including 13 aphids. On the basis of these sequences as well as published 16S sequences from representative procaryotes, a phylogenetic tree has been constructed, using parsimony methods. Results indicate that the primary endosymbionts of aphids belong to a single distinctive clade that has descended from a single infection of a common ancestor of aphids; this conclusion is based on complete congruence between the phylogenetic tree for the endosymbionts and that for the aphid hosts. Based on fossils that give minimal ages for certain of the aphid lineages, the association is at least 80 million years old. The rate of change of the 16S sequence is roughly constant among lineages within the aphid primary endosymbiont clade. Again using fossil dating, we have estimated absolute rates of substitution, and estimates are consistent for three different aphid clades. These rates have been used to test the hypothesis based on a biogeographic argument that the divergence between the Asian and American members of the Melaphidina dates to the Eocene (approximately 50 MY ago): the molecular data are highly supportive of the hypothesis. The 16S genes of secondary endosymbionts of aphids and of endosymbionts of mealybugs and whiteflies have also been sequenced, and results indicate that, for each insect group, endosymbiotic bacteria are descendants of independent infections by other members of the gamma-subdivision of the Proteobacteria for each insect group.

In this mini-review, data on the circadian rhythmicity in ecdysteroid synthesis by the prothoracic glands of final instar larvae of the wax moth (Galleria mellonella), as well as ecdysteroid titers in their hemolymph are summarized. It was found that at the low temperature of 18°C and in continuous darkness (DD), the last instar of the wax moth larvae did not pupate. When these larvae were transferred to 30°C and kept in DD, they immediately initiated development and pupated in a circadian manner. They exhibited the circadian rhythmicity of ecdysteroid titers in their hemolymph, with a period of approximately 24 hours.

The mechanism underlying circadian rhythmicity of ecdysteroid titers in the hemolymph of Galleria mellonella larvae was investigated. It was found that brain removal or head-ligating of larvae in which developmental processes had been synchronized by transfer from 18°C to 30°C, did not abolish daily rhythms of ecdysteroid titers in the hemolymph. The observed rhythms persisted in continuous darkness for 5 days after treatment, which suggests that the circadian clock driving these rhythms is not located within the brain.
In further experiments, it was shown that the prothoracic glands, taken from temperature-synchronized last instar larvae of Galleria, exhibited a daily rhythm of ecdysteroid synthesis, with a maximum coinciding with the peak of ecdysteroid titers found in controls. Therefore, it is suggested that the circadian rhythm of ecdysteroid titers in the hemolymph of these larvae is regulated by a clock, located probably within the prothoracic glands.

Consequences of birth weight for development, survival and fecundity were studied in the offspring of the alate morph Aphis craccivora (Koch), with the aim of testing the hypothesis that birth weight is near optimal. Aphids large at birth were found to mature sooner and achieve higher total reproduction than those born smaller.

A bootstrapping procedure was used to estimate the correlation between birth weight and two measures of fitness (r_m): one calculated from unadjusted life-table data, the other from life tables adjusted to correct for the trade-off between offspring weight and offspring number. The unadjusted data yield a highly significant positive correlation - large neonates are fitter than small ones. The correlation estimated from the adjusted life table is no longer significant - mothers producing large offspring are no fitter than those producing small ones.

The adult feeding preferences of Hylobius abietis were tested at three temperatures, 10, 15 and 20°C, with three different host plants, Pinus sylvestris, Picea abies and Fraxinus excelsior, in simple paired choice tests.

At all temperatures adult weevils showed a marked and significant preference for P. sylvestris over the other two host plants. F. excelsior was not a preferred host plant and there was some evidence to suggest that at higher temperatures, the presence of F. excelsior inhibited feeding.
Adult weevils consumed up to five times as much food at 20°C than they did at 10°C, 252.9 mm² of bark of P. sylvestris at 20°C compared to 47.8 mm² at 10°C , 137.2 mm² of P. abies bark at 20°C compared to 27.3 mm² at 10°C and 24.6 mm² of F. excelsior bark at 20°C compared 4.0 mm² at 10°C. These results are discussed in relation to possible pest management strategies.

Species of the nominotypical subgenus Dryopomera Fairmaire are revised, illustrated and keyed and species-groups are proposed. The following new species are described: Dryopomera (Dryopomera) ceylonica sp. n. (Sri Lanka), D. (D.) sundaica sp. n. (Indonesia), D. (D.) tonkinensis sp. n. (Vietnam), D. (D.) longissima sp. n. (Nepal), D. (D.) nepalensis sp. n. (Nepal), D. (D.) malaccana sp. n. (Malaya), D. (D.) burmanica sp. n. (Burma), D. (D.) rugicollis sp. n. (Malaya) and D. (D.) malayana sp. n. (Malaya). The following new synonymies are proposed: D. (D.) innotata (Pic, 1943) = Mimoncomera innotata var. unicolor Pic, 1943, syn. n., and D. (D.) indica (Fairmaire, 1896) = Oncomera geniculata syn. n. D. (D.) notatipennis (Pic, 1915) comb. & stat. n. is raised to specific status from Oncomera geniculata var. notatipennis Pic, 1915. The following species are transferred to Dryopomera: D. (D.) ingeniculata (Pic, 1915) comb. n. and D. (D.) piceonotata (Pic, 1932) comb. n. from Oncomera Stephens; D. (D.) testaceipennis (Pic, 1932) comb. n. from Oedemera Olivier and D. (D.) coomani (Pic, 1925) comb. n. from Xanthochroa Schmidt.

The intention of this study was to falsify a hypothesis of interspecific avoidance of semiochemicals from egges by ovipositing tortricid females. The oviposition responses of Cydia pomonella (L.) females to apples baited with blends of semiochemicals identified in another tortricid species, Lobesia botrana (Den. et Schiff.) were investigated. Experiments were conducted in binary choice tests using natural oviposition substrates (apples). In each experimental arena, 4 mated females were offered 16 apples (8 treated and 8 untreated) and the number of egges was compared. Females avoid ovipositing on apples treated with a blend of nine components characteristic of methanolic extracts of L. botrana eggs (fatty acids and esters) (complete blend), as well as a binary blend of palmitic acid and methyl palmitate (binary blend). Oviposition avoidance was already observed with these two blends at a dose of 72 eggs equivalent of L. botrana per apple and this effect increased with the dose. The blend of three major esters from complete blend (ternary blend) did not provoke significant avoidance. In the control, only 8.3% of apples bore no egges, this percentage was increased with complete blend and binary blend (720 Lobesia eggs) respectively up to 37.5% and 26.4%, but only to 18.1% of apples with ternary blend. Complete blend and binary blend used at high dose strongly reduced the mean number of eggs/apple on treated fruits (1.6 ± 1.8; 9 compounds) (1.8 ± 2.2; 2 compounds) against 4.6 ± 4.0 in the control. This reduction was not observed with the blend of 3 esters. It is concluded that, from the present results, apples treated with compounds associated with L. botrana eggs are avoided by C. pomonella ovipositing females. Esters alone cannot explain such an avoidance, and palmitic acid may partly cause the avoidance response.

Using time series of estimates of population abundances of moths from a light-trap in Brno, Czech Republic, the usefulness of a number of variability measures was examined. There are two problems that may occur. One is that time series data of population counts usually do not constitute a series of independent data, another is the occurrence of zeros when logarithms need to be taken. It is assumed here that the observed zeros no not represent extinction. All but one of the measures used suffered from the problem with interdependent abundances, making these measures difficult to use in statistical testing. The exception, ln{var(ln[R_i])}, on the other hand, generally, though not always, deals with mutually independent R_i (= y_i/y_(i-1)) and can then be used in statistical tests. This measure, however, measures variability of change rather than overall variability as the other statistics do. Moreover, when series with zeros are included, the arbitrariness of dealing with these zeros detracts also from the usefulness of this measure. Avoiding one of the problems usually forces one to accept the other, except when there are no zeros in the data. It being impossible for us to properly deal with this dilemma, we explored its consequences, especially those of dealing with zeros in one way or another. Any conclusions are purely ad hoc. When, in the literature, zeros presented a problem, they were either replaced by some positive number, the zero replacement value (ZRV), or one used the ln(y_i + z) transformation, with various values of z. We tried both in the present paper. Time series with a mean abundance smaller than 5 were found unreliable and should be omitted from analyses. The ln(y_i + z) transformation should be avoided for series without zeros and does not perform better than the ln(y_i) transformation for series with zeros. No statistically robust solution for the problem with zero values seems to exist, but for both mean and variability of abundance, a ZRV of 0.5 provided the most acceptable log transformation. For correlation between abundance and time the value of ZRV used was unimportant. One can avoid having to take the logarithms of zero by selecting only time series without zeros, but this implies a strong selection against the more variable species. Alternatively one can use ln[CV], or Lloyd's index, although one still has to deal with the interdependence of the data.

The aphid sibling species of Cryptomyzus live sympatrically on the same host plant and their sexual females appeared to be produced in the same period of the year. The circadian rhythm of the production of their sex pheromones, and the activity of the males, differed between the species. The origin of this divergence of mate recognition and the possibility of speciation by reinforcement are discussed.

Selection for resistance to fenpropathrin (a pyrethroid insecticide) was performed by exposing adults of two field-collected populations of the whitefly, Bemisia tabaci, to increasing doses of fenpropathrin for four generations. Concurrently, samples of adults were used for colorimetric measurements of esterase (EST) activity.

The two populations differed in their response to selection. EST activity increased as a correlated response to pyrethroid selection in one population but not in the. other. No changes in either resistance or esterase activity were detected in the unselected control lines. The data suggest that both resistance and EST activity have a genetic basis, and that the frequency of high EST-activity alleles may have been different in the two populations.

Aphis fabae took 3 to 4 hours, after access to a plant, to show the first puncture of a sieve element. A further hour was needed before sustained ingestion started. Early probes did not show sieve element punctures, in general. Within later probes, showing these punctures, the average time needed to reach them was 30 min. Early sieve element punctures were mainly accompanied by the secretion of a watery saliva. The composition of this saliva and the function of its secretion is unknown. It is speculated that this saliva secretion makes the phloem sap more readily available and/or improves its quality for aphids. Further research is needed to test this hypothesis.

In previous papers, the presence of patches of specialized cuticle on the sternites of true bugs of the family Pentatomidae has been reported. The patches, it is thought, are an aid to thermoregulation by aiding heat loss at high temperatures.

In this paper, additional descriptions given of patch patterns in Pentatominae and for the first time in Phyllocephalinae extend the range of variation previously recorded in Pentatomidae.
More than thirty species of Pentatominae in four tribes (Pentatomini, Antestiini, Halyini, Carpocorini) were examined. Patches were extensively developed in African and Asian Halyini. They were absent, however, in all Australian halyines examined, suggesting the existence of different mechanisms of resistance to heat.
Patches were well developed in all 11 species of Phyllocephalinae examined. The most extensive area development of patch cuticle now in Pentatomidae was observed in two phyllocephalines from deserts, Phyllocephala negus and Schyzops aegyptiaca. In Phyllocephalinae, the anatomical distribution of patch cuticle extends to areas of sternite lateral to the spiracles as well as to the laterotergites. Patch areas surfaces in some phyllocephalines are fragmented by bristle-bearing discs.
Concerning the pentatomines examined, possible seasonal area variation and variation correlated with geographical isolation was detected in Nezara viridula, a tendency to ventral mid-line fusion of patches on sternites III observed in Carpocorini, and a possible east-west gradient detected in Asian Plautia fimbriata. A high degree of individual variability was recorded in a sample of Carpocoris pudicus from Turkey.
Epidermal glands, abundant in males, are generally but not invariably absent in areas occupied by patch cuticle. The absence of glands as an additional tissue element might be explained if thier presence retarded heat loss from the patches.

A monoclonal antibody to Bombyx mori eclosion hormone (EH) reacted in whole mounts of the nervous system from pharate and freshly hatched larvae of this species with 4 ventromedial brain neurons and a pair of nerve fibers runing down the ventral nerve cord. Weak immunoreactivity was occasionally detected in similar whole preparations of the nervous system from Antheraea yamamai. In paraffin sections of the nervous system of A. yamamai, an EH-like antigen was found in 4 ventromedial brain neurons, in 2 or 3 pairs of neurons in each of the ventral ganglia, and in a pair of nerve fibers extending through the nerve cord. The intensity of immunostaining in diapausing and post-diapausing pre-hatched larvae, and in the newly hatched first-instar larvae, was similar. Midgut endocrine cells were also examined but no reaction with the anti-EH antibody was detected.

The role of DNA fingerprinting as a tool for studying cereal aphid populations along with the principals behind fingerprinting and the process of obtaining fingerprints using the multilocus probe, ³²P labelled (GATA)₄ are discussed. The successful application of this technique in obtaining fingerprints capable of distinguishing between different clones of Sitobion avenae (F.) is presented.

The supply of carbohydrates to growing galls of four species of aphids (Pemphigidae: Fordinae) that co-exist on Pistacia palaestina trees was studied. Using ¹⁴C labelling we compared the sink strength of the gall of each species for its ability to manipulate the normal phloem transport from different sources. The results indicated that none of the galls had net photosynthetic ability and all of them imported assimilates according to their specific sink strength. The data also demonstrated a correspondence between the ability of galls to draw assimilates from wider sources (sink strength) and aphid reproductive performance. Furthermore, preliminary observations indicated that species which are stronger sinks have a negative impact over other galling aphids on the same leaf or shoot through withdrawal of assimilates and nutrients.

A review is presented of the species included in the Tipula (Yamatotipula) lateralis group. One of these species, T. (Y.) guentheri sp. n. from eastern Turkey, is described. The subspecies previously recognized within T. (Y.) lateralis are given species rank, viz., T. (Y.) lateralis Meigen, T. (Y.) barbarensis Theowald & Oosterbroek, stat. n., and T. (Y.) iranensis Theowald, stat. n. The three subspecies of T. (Y.) montium are considered to belong to two species, viz., T. (Y.) montium Egger and T. (Y.) afriberia Theowald & Oosterbroek, stat. n., the latter with two subspecies, the nominotypical one and T. (Y.) afriberia italia Theowald, Dufour & Oosterbroek, comb. n. Examination of type-material revealed that T. (Y.) lateralis intermedia Eiroa and T. (Y.) subsolitaria Theowald are junior synonyms of lateralis and iranensis respectively (new synonymies). Distributional data are given for the species and subspecies discussed. T. (Y.) afriberia italia is recorded here for the first time from Spain and Portugal.

Larvae of Chrysopa oculata Say mark, chemically, the substrate with a substance secreted from the tip of their abdomen. The effect of paper substrates contaminated with this secretion on the oviposition of C. oculata females was assessed in laboratory choice experiments. The active substance(s) were soluble in chloroform and in water but not in methanol, ethylether or petroleum ether. Paper substrates treated with extracts of the substance remained activeat room temperature for up to three weeks. The effectiveness, in terms of the amount of active secretion produced per unit of larval body weight, was greater for first rather than for third instar larvae. These results indicate the presence of a chemical factor or pheromone that serves to deter females of C. oculata from ovipositing near where larvae of this species are already present.

The analysis of pheromone glands from individual females of the European corn borer, Ostrinia nubilalis (Hübner), originating in South Moravia and Slovakia showed that this population utilizes the ''Z'' pheromone system. The ratio of (Z)- and (E)-11-tetradecenyl acetates was found in the range of 98.5:1.5-99.5:0.5. Field experiments confirmed the identity of the local population as being predominantly of the Z strain. Individuals responding to E and hybrid blends were detected.

The behaviour of Aphis fabae during maiden flight in an automated flight chamber was assessed by their response to the intermittent presentation of a plant-like visual target. As shown previously, alate virginoparae were much more responsive to the target, i.e. indicating foraging flight, during the initial part of maiden flight than were gynoparae. Virginoparae initiated foraging flight after a short behavioural migratory period, i.e. the initial period of flight when the aphid remains unresponsive to the target, (on average 8 ± 5 min) while gynoparae undertook a longer migratory flight (on average 102 ± 19 min). However, if starved for 24 h, under conditions that did not allow flight, both aphid forms initiated foraging flights more readily and the period of behavioural migration was reduced (0.7 ± 0.3 vs 36 ± 11 min, virginoparae vs gynoparae). This observation indicates that the initiation of foraging flight, and thus the duration of migratory flight, can be influenced by factors other than flight per se.

Sphenoptera (Chrysoblemma) anchorifera sp. n. is described from Sahara (Algeria). A differential diagnosis and illustrations of the new species are given. The new species can be distinguished from all known Sphenoptera species by the peculiar shape of the aedeagus (parameres bearing long curved lateral processes). The larva develops in roots of Salsola sp. (Chenopodiaceae).

This paper reviews the evidence for the fundatrix specialization hypothesis and attempts to quantify the relative advantage of host alternation and define the conditions favouring the evolution of this way of life. Contrary to the predictions of the fundatrix specialization hypothesis there does not appear to be a barrier to some host alternating Aphidinae transferring their whole life cycle over to a secondary host plant. The coexistence of plants with asynchronous phenologies supplied the potential and the ability of aphids to produce a number of highly prolific generations in quick succession, which amplify the differences in performance on the two hosts and more than offsets the costs of transfer between hosts, supplies the means of exploiting this potential. That is, host alternation is not maladaptive and maintained by constraint but adaptive, at least in the Aphidinae.

The fossil Miocene genus Lithobibio Beier, 1952 (containing single species L. styriacus Beier, 1952) is redescribed and synonymized with the genus Bibio Geoffroy, 1762. Bibio styriacus (Beier, 1952) is a new combination.

The morphology of spring and summer migrants of Sitobion avenae (F.) from several different environmental conditions were compared using analysis of variance and canonical variate analysis. Both between morph and within morph differences were found for a range of morphometric features and ratios. When aphids of both morphs and from a range of conditions were considered together any morph differences were obscured by phenotypic variability. SimilarIy canonical variate analysis indicated that differences due to environmental variability were greater than those due to morph.

The feeding behaviour of five cereal aphid species in wheat seedlings (measured by the time taken by an aphid to penetrate the phloem and the time spent in committed pholem ingestion) and their performance (measured as mean relative growth rates) were determined as a function of hydroxamic acid concentrations in the seedlings. Lower mean relative growth rates and higher times to attain a committed phloem ingestion were associated with higher hydroxamic acid values. Duration of committed phloem ingestion was not influenced by hydroxamic acid values.

Lepidoptera populations were monitored during 29 years by a light-trap in urban Brno. Compared with other sites in the Czech Republic (Prague-Ruzynì, Èeské Budĕjovice, Černiš) urban Brno was extraordinarily rich in species, richer than the other Czech sites studied and richer than many British sites in an urban to natural gradient. Variability of the more common species at Brno was as high as that at the ruderal/deteriorated agricultural setting at Ceske Budejovice, and generally higher than that in the wet forest environment at Cernis and much higher than in the park-like/suburban/agricultural setting of Prague. Voltinism had no effect on variability from year to year. Most of the more common species in Brno clearly increased in abundance over the years, unlike those at the other sites. Much of the large diversity at Brno, however, was because of a large number of accidental species, vagrants from elsewhere. When considering only the more common species (>= 5 individuals per year), however, Brno is among the most species-poor sites. The common species at Brno were mostly tramp species that could take advantage of whatever food and habitat the city had to offer.

Because of strong correlations in abundance between species at one site with conspecifics at other sites over distances of 150-200 km, the abundances in these populations are apparently strongly affected by large-scale processes such as weather, overriding in part large differences between the habitats or by large-scale dispersal of individuals between sites. Significant correlations also existed between conspecifics in these sites in variability as well as in trends in time, with the curious exception of Cernis, the only reasonably natural habitat, suggesting that these parameters are strongly affected by local habitat characteristics.

The rates of spatial expansion of range following the introduction of animals to new areas are extremely variable between species. Data on a selection of species from a range of taxa show that these rates vary over about five orders of magnitude. The range expansion of a limited number of pest species of aphids have been mapped following colonisation. Studies on rates of colonisation are important as they are central to pest risk analysis. In addition, the observed variation in rates have significant implications for the development of realistic models of metapopulations.

The cold hardiness of two ladybird species from the Czech Republic, Coccinella septempunctata and Semiadalia undecimnotata, was measured in terms of their supercooling point (SCP) and survival at subzero temperatures. The SCP was lower in diapausing beetles in late summer than in active beetles, and the SCP of diapausing beetles decreased slowly until mid-winter. The SCP of S. undecimnotata, which overwinters exposed to air, was lower (to -19°C), that of C. septempunctata, which overwinters at ground level insulated in plant material, was higher (to -15°C). The SCP of C. septempunctata, exposed to extreme fluctuations of temperature in an outdoor insectary, decreased to -21°C. After the termination of diapause, the SCP of C. septempunctata from natural hibernacula increased in the later part of the cold period. In contrast, the SCP of S. undecimnotata and C. septempunctata in an outdoor insectary remained low until spring. The cost of being more cold-hardy is possibly compensated for by a low mortality from fungal disease.