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Thermal requirements for development and life table statistics of Aphis gossypii Glover (Homoptera, Aphididae) were determined over a range of constant temperatures from 10 to 30 ~ The lower development threshold and the sum of effective temperatures were 6.9 ~ and 90.1 ~ respectively, for preimaginal development, and 5.8 ~ and 113.6 ~ from birth to the onset of reproduction. Mean total fecundity ranged from 36 larvae per female at 10 ~ to 76 larvae at 30 ~ On a time scale of days, net reproductive rate (Ro) increased with increasing temperature while generation time (T) decreased causing the intrinsic rate of increase (rm) to increase linearly from 0.115 to 0.465. On a day-degree scale rm only varied from 0.019 to 0.028 because the growth of Ro was compensated by an increase in T with increase in temperature. The nearly constant r,~ in terms of day-degrees, over a wide range of temperatures, greatly simplifies the prediction of future population numbers of A. gossypii.

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The Russsian wheat aphid (RWA), Diuraphis noxia (Kurdjumov), is a worldwide pest of cereals. Despite its economic importance, little is known about its genome. Here we investigated physical genomic features in RWA by karyotype analysis using differential staining with AgNO(3), CMA(3), and DAPI, by chromosomal localization of ribosomal DNA (rDNA), H3 and H4 histone genes, and the "arthropod" telomeric sequence (TTAGG)(n) using fluorescence in situ hybridization (FISH), and by measuring the RWA genome size using flow cytometry. The female karyotype, 2n = 10, is composed of four autosome pairs and a pair of X chromosomes, whereas the male karyotype, 2n = 9, has a single X. The X chromosome is the largest element in the karyotype. All three molecular markers used, i.e., 18S rRNA and both H3 and H4 probes are co-localized at one end of the X chromosome. The FISH probes revealed that the AgNO(3)-positive bridge between two prometaphase X chromosomes of females, which is believed to be responsible for the elimination of one X chromosome in aphid oocytes determined to undergo male development, contains clusters of both histone genes, in addition to an rDNA cluster. Interestingly, RWA lacks the (TTAGG)(n) telomeric sequence in its genome, in contrast to several previously investigated aphid species. Additionally, we compared female and male genome sizes. The female genome size is 2C = 0.86 pg, whereas the male genome size is 2C = 0.70 pg. The difference between the DNA content in the two genders suggests that the RWA X chromosome occupies about 35% of the female haploid genome (1C = 0.43 pg), which makes it one of the largest sex chromosomes in the animal kingdom.

Abstract. The sequence diversity in the mitochondrial cytochrome-c oxidase I (COI) gene was evaluated as a tool for resolving differences among species of European adelgids collected from several localities across the Czech Republic. Members of 7 genera and 16 species were examined, and as outgroups, two species of Phylloxeridae were used. Sequence divergences within species were on average less than 0.15%, whereas divergences between species ranged from 0.0 to 4.12% for congeneric and to 13.24% for intergeneric comparisons. It is concluded that DNA barcoding of Adelgidae is a powerful tool for identifying genera, but at the species level it works only in those cases where there are no species complexes. Nevertheless, it can be used as a complement to traditional, morphological taxonomy.

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Intraspecific differences in ecological parameters between several geographic populations and imaginal morphological characteristics in 5 populations of aphidophagous gall midge Aphidoletes aphidimyza (Rond.) were determined. The recorded parameters provide crucial background for the choise of suitable population for mass rearing and its use in the control of aphids in various ecosystems. The critical photophase (at 20 °C) for diapause induction in 50% of specimens was found to be 17.0 h in the population of Leningrad (60 °N), 16.2 h in the population of Gorkii (56 °N), and 15.5 h in the population of Kishinev (47 °N). Significant differences in the developmental times between the populations were recorded. Mean times for the completion of preimaginal development at 17°C, 20 °C, and 25 °C, respectively, were 42.2, 21.0, and 17.0 days for Č. Budějovice 1 (CB 1) population; 45.0, 21.0, and 16.5 days for Chelcice (CH) population; 34.3, 19.5, and 14.0 days for Prague (P) population; 26.0, 20.4, and 15.0 days for Leningrad (L) population. Mortality during the whole preimaginal development at 17°C, 20 °C, and 25 °C, respectively, were 62.3%, 29.9%, 61.2% for CB 1 population; 67.1%, 14.1%, and 41.0% for CH population; 35.7%, 19.5%, and 41.7% for P population; 47.1%, 40.1%, and 27.9% for L population. Preferred relative air humidity for the adults of L population was nearly 100%, and for those of Kishinev (K) population 70%. There were significant differences between the populations in their oviposition rates: 50% of eggs (at 25 °C) were layed within 6.4 days by CB 1 population, 7.2 days by CB 2, 6.8 days by CH, 4.8 days by P, and 5.1 days by L populations. The mean fecundity of females of various populations fluctuated from 110 to 146 eggs and there were no significant differences between the populations. No qualitative morphological differences between the 5 geographic populations were found. Among quantitative indices the height of the male thorax may be used as a supplementary parameter to distinguish various populations. Zusammenfassung Intraspezifische Variabilität der aphidophagen Gallmücke Aphidoletes aphidimyza (Rondani) (Dipt., Cecidomyiidae) und ihre Bedeutung bei der biologischen Schädlingsbekämpfung von Blattläusen. 1. Ökologische und morphologische Populationscharakteristiken Intraspezifische Unterschiede in ökologischen und morphologischen Parametern zwischen verschiedenen geographischen Populationen der aphidophagen Gallmücke Aphidoletes aphidimyza (Rond.) wurden bestimmt. Die kritische Photophase für die Induktion der Diapause bei 20 °C wurde bei 50% der Exemplare mit 17,0 Stunden für die Population aus Leningrad (60 °N) ermittelt, sie betrug 16,2 Stunden für die Population aus Gorkij (56 °N) und 15,5 Stunden für diejenige aus Kischinew (47°N). Es wurden signifikante Unterschiede in der Entwicklungsdauer zwischen den Populationen verzeichnet. Die Durchschnittsdauer der vollständigen präimaginalen Entwicklung bei 17°C betrug 42,0 Tage für die C. Budcjovice Population (CB 1), 45,0 Tage für Chelčic...

The duration of preimaginal stages of Aphidoletes aphidimyza Rond. is determined mainly by temperature. The lower threshold temperatures for egg, larva, pupa and total preimaginal development are 10.1°, 4.3°, 5.7° and 6.2°; the sums of effective temperatures are 25.0 day degrees, 110.9 day degrees, 154.1 day degrees and 280.2 day degrees, respectively. Equations for the dependence of duration of preimaginal stages on constant temperature were calculated. The larval feeding period is only 20% of the total preimaginal development period. Overlapping generations should therefore be maintained to assure a permanent preying activity and thus an effective biological control in glasshouses. ZUSAMMENFASSUNG DIE WIRKUNG DER TEMPERATUREN AUF DIE PRÄIMAGINALEN STUDIEN VON APHIDOLETES APHIDIMYZA (DIPTERA, CECIDOMYIIDAE) Die Entwicklungsdauer der präimaginalen Studien von Aphidoletes aphidimyza Rond. ist hauptsächlich von der Temperatur abhängig. Zwei Charakteristiken — die untere Temperaturschwelle und die Summe der wirksamen Temperaturen — sind wichtig für die Verwendung der aphidiphagen Gallmücke gegen Blattläuse in Glashäusern. Diese Charakteristiken wurden von uns erstmals festgelegt. Die unteren Temperaturschwellen für die Embryonal‐, Larven‐, Puppen‐ und für die ganze Präimaginalentwicklung von A. aphidimyza sind 10.1°, 4.3°, 5.7° und 6.2°; die Summe der wirksamen Temperaturen 25.0, 110.9, 154.1 und 280.2 Gradtage. Die Zeit, während der sich die Larve ernährt und Blattläuse vernichtet, entspricht nur 20% der gesamten Präimaginalentwicklung. Für eine ununterbrochene Aktivität der Larven und damit für eine hohe Wirksamkeit der biologischen Blattlausbekämpfung in Glashäusern ist deshalb unbedingt eine Ueberlappung der Gallmückengenerationen erforderlich.