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The water conserving physiological compromise of desert insectsZACHARIASSEN K.E.Eur. J. Entomol. 93 (3): 359-367, 1996 Insects living in arid tropical areas may spend long periods without access to free water, and at the end of the dry season they may be severely dehydrated. To survive under such conditions insects have developed a highly restrictive water economy, and tenebrionid beetles from arid tropical areas may lose water at a rate which is a hundred-fold lower than those of insects from humid habitats. |
Chemotaxonomical characterisation of males of Bombus lucorum (Hymenoptera: Apidae) collected in the Czech RepublicKlára URBANOVÁ, Irena VALTEROVÁ, Oldřich HOVORKA, Jiří KINDLEur. J. Entomol. 98 (1): 111-115, 2001 | DOI: 10.14411/eje.2001.017 Labial gland secretions of 26 males of the bumblebee Bombus lucorum (L.), collected in the Czech Republic, were analysed. The secretions consisted of 60 compounds; ethyl (Z)-9-tetradecenoate was the main component (average 53%). Although the males varied in colour, their labial gland secretions were similar in composition, which indicated they belonged to one species. Chemically the B. lucorum occurring in the Czech Republic correspond to the earlier described "blonde form" of this species. |
Development of the solitary larval endoparasitoid Glyptapanteles porthetriae (Hymenoptera: Braconidae) in its host Lymantria dispar (Lepidoptera: Lymantriidae)Christa NUSSBAUMER, Axel SCHOPFEur. J. Entomol. 97 (3): 355-361, 2000 | DOI: 10.14411/eje.2000.053 The development of the solitary endoparasitic braconid Glyptapanteles porthetriae in gypsy moth larvae of different ages was studied. Host larvae were parasitized during the premolt to the 2nd instar (A-larvae), to the 3rd instar (B-larvae) or to the 4th instar (C-larvae), respectively. The percentage of successfully parasitized larvae decreased markedly with the age of the host at the time of parasitization. When parasitization occurred at the premolt to the second or third instar, parasitoid larvae successfully emerged at rates of 68% and 57%, respectively, in contrast to the 17% from larvae parasitized in the premolt to the fourth instar. In all three groups of parasitized larvae the final host instar was significantly longer than the corresponding instar of unparasitized control larvae of the same age. However, the growth and growth rate of parasitized larvae were reduced compared to control larvae. Due to the extremely low rate of successful development of G. porthetriae in C-larvae, parameters of parasitoid development were only recorded in A and B-host larvae. In both the parasitoid growth was slow during the first instar but rapidly increased during the second instar. Total developmental time of the parasitoid was significantly longer in B-host larvae, and the resultant cocoons were heavier than those that developed in A-host larvae, but proportionally fewer of the offspring were females. Within both groups the female wasps took significantly longer to develop than the males. |
BOOK REVIEW: Leather S.R. & Bland K.P.: Insects on Cherry Trees.F. KOCOUREK, A. HONĚKEur. J. Entomol. 97 (2): 154, 2000 | DOI: 10.14411/eje.2000.028 Naturalists' Handbooks 27. The Richmond Publishing, Slough, 1999, 82 pp. |
The use of Harmonia axyridis larvae (Coleoptera: Coccinellidae) against Macrosiphum rosae (Hemiptera: Sternorrhyncha: Aphididae) on rose bushesFERRAN A., NIKNAM H., KABIRI F., PICART J.L., DE HERCE C., BRUN J., IPERTI G., LAPCHIN L.Eur. J. Entomol. 93 (1): 59-67, 1996 Third and fourth instar larvae of Harmonia axyridis were released in spring into rose beds infested by the aphid Macrosiphum rosae. These biological treatments induced stabilization or a decrease of the aphid populations. Their efficiency is comparable with that of chemical treatments performed in neighbouring rose beds and the subsequent development of aphid populations was the same after these two types of treatments. The rearing condition of H. axyridis, particularly its feeding on a substitute prey (lepidopteran eggs), the climate, particularly the rainfall and low temperatures, sometimes near the development threshold of the coccinellid, and possibly the rose bush variety did not seem to affect its potential predatory efficiency. An aphid density of more than thirty aphids per rose bush appears to be necessary for the larvae to remain on the plants, when fifty larvae were released per four bushes. |
Influence of host plants on specialist / generalist aphids and on the development of Adalia bipunctata (Coleoptera: Coccinellidae)Frédéric FRANCIS, Eric HAUBRUGE, Charles GASPAREur. J. Entomol. 97 (4): 481-485, 2000 | DOI: 10.14411/eje.2000.074 The aim of this work was to determine the impact of allelochemicals (glucosinolates/isothiocyanates) from Brassicaceae (Brassica napus and Sinapis alba) at two trophic levels in relation to biological control efficacy. The impact of these plants on aphid Myzus persicae (Sulzer) and Brevicoryne brassicae (L.) and ladybird Adalia bipunctata (L.) biology can be assessed by observation of several developmental parameters: mortality, development duration and adult weight. Sub-lethal toxicity can also be measured through the reproductive parameters of fecundity and/or egg viability. While both specialist and generalist aphids were positively influenced by Brassicaceae species, mixed effects are recorded in ladybird performances following the aphid species/host plant combinations. Significant differences appeared according to aphid host plant and aphid species. This work enhanced the influence of Brassicaceae plants either as cultivated species (B. napus) or as set-aside (S. alba) on both pests and beneficial insects. The allelochemical presence in plants must be taken into account in programs of integrated pest management due to their direct influence on biological control agents. |
Urbanization effects on carabid diversity in boreal forestsStephen J. VENN, D. Johan KOTZE, Jari NIEMELÄEur. J. Entomol. 100 (1): 73-80, 2003 | DOI: 10.14411/eje.2003.015 Carabid abundance, species richness and diversity were compared along an urban-rural gradient in Helsinki, Finland. Increased urbanization was found to result in significant reductions in species richness, though the reductions in abundance and diversity were not statistically significant. Forest habitat-specialist species were scarce in rural sites and virtually absent from urban and suburban sites. There was no evidence of higher diversity at intermediate disturbance levels (suburban sites), as predicted by the intermediate disturbance hypothesis. Species with flight ability and the ability to utilize open habitat were more predominant in urban and suburban sites. Flightless species were more predominant in rural and suburban sites. Carabid abundance data were sufficient to reveal the negative impact of urbanization, so similar studies could be conducted in regions where carabid taxonomy is poorly known. Species composition patterns do, however, provide invaluable information. To conclude, if biodiversity is to be maintained in urban areas, priority must be given to the provision of those habitat features which are essential for sensitive species, such as decaying wood and wet microhabitats. These must be incorporated into urban green networks in particular, if biodiversity and species other than common generalists are to benefit from them. |
Molecular characterization of the gene pool of Exorista sorbillans (Diptera: Tachinidae) a parasitoid of silkworm, Bombyx mori, in IndiaShankar N. CHATTERJEE, Thampiyath P. MOHANDAS, Tanushree TARAPHDAREur. J. Entomol. 100 (1): 195-200, 2003 | DOI: 10.14411/eje.2003.031 Exorista sorbillans, the uzi fly, is a serious tachinid pest of silkworm and is present in all silk producing areas of Asia. Assuming that E.sorbillans was accidentally transported from West Bengal to southern states of India, its population genetic structure was studied using 13 ISSR, 3 RAPD, two sets of universal primers and two sets of primers designed from a lepidopteran repeat sequence. Statistical analyses of DNA markers revealed significant genetic variability between the E. sorbillans populations from 4 different geographic locations (within 400 km of one another) in the southern states and the one from West Bengal (Murshidabad). Multivariate and discriminant function analyses indicate that the E. sorbillans from south India has diverged from the original gene pool of West Bengal and is suitable for studying the microevolution of adaptation to the conditions prevailing in the different cocoon producing areas in India. |
The physiology of cold hardiness in terrestrial arthropodsSOMME L.Eur. J. Entomol. 96 (1): 1-10, 1999 Insects and other terrestrial arthropods are widely distributed in temperate and polar regions and overwinter in a variety of habitats. Some species are exposed to very low ambient temperatures, while others are protected by plant litter and snow. As may be expected from the enormous diversity of terrestrial arthropods, many different overwintering strategies have evolved. Time is an important factor. Temperate and polar species are able to survive extended periods at freezing temperatures, while summer adapted species and tropical species may be killed by short periods even above the freezing point. |
Ant communities (Hymenoptera: Formicidae) of Flemish (north Belgium) wet heathlands, a declining habitat in EuropeDirk MAES, Hans VAN DYCK, Wouter VANREUSEL, Joeri CORTENSEur. J. Entomol. 100 (4): 545-555, 2003 | DOI: 10.14411/eje.2003.082 During a survey of 23 wet heathland sites in Flanders (north Belgium) in 1999 and 2000, using both manual nest searching and pitfall traps as sampling techniques, we found 28 ant species. One species (Myrmica lonae) was new to the Belgian fauna and several rare species were encountered. Three ecological groups could be distinguished based on soil preference: the first group of species was characteristic of sandy soil, the second contained species that were more numerous on peat soil (with Sphagnum spp.), and the third group of species had no soil preference. Ant nest numbers increased strongly between 1999 and 2000, especially on the plots that were inundated during the winter of 1999-2000, but the number of ant species did not differ significantly between years. Ant nest density showed an optimum at a Purple Moor-grass (Molinia caerulea) cover of about 45%; the number of species did not show such an optimum. Pitfall traps yielded more species than manual nest searching; in particular temporary social parasites, species with a large foraging range and winged females from the surrounding habitats were missed by the latter technique. Finally, we give some recommendations for the conservation of, and suitable management measures for, ants on wet heathland. |
BOOK REVIEW: Buchar J. & Ruzicka V.: Catalogue of Spiders of the Czech Republic.T. BLICKEur. J. Entomol. 100 (1): 122, 2003 | DOI: 10.14411/eje.2003.021 Edited by Peter Merrett. Praha, Peres, 2002, 351 pages. |
BOOK REVIEW: Beuk Paul L. Th. (ed.): Checklist of the Diptera of the Netherlands.J. OLEJNÍČEKEur. J. Entomol. 100 (4): 500, 2003 | DOI: 10.14411/eje.2003.076 KNNV Uitgeverij, Utrecht 2002, 448 pp. |
Copula duration and sperm economy in the large thistle aphid, Uroleucon cirsii (Hemiptera: Aphididae)Joachim L. DAGGEur. J. Entomol. 100 (1): 201-203, 2003 | DOI: 10.14411/eje.2003.032 Experiments on copula duration indicate that the nature of mate competition and sperm storage in the large thistle aphid, Uroleucon cirsii (L.), differs from that in the well-studied yellow dung fly, Scatophaga stercoraria (L.). Unlike the situation in the dung fly, second copulas are shorter on average than first copulas for both individual males and females. This suggests that male aphids have a limited amount of sperm at their disposal and that the females capacity to store sperm is limited as could be expected when males were not able to displace sperm from former copulas. |
BOOK REVIEW: Amiet F., Herrmann M., Müller A. & Neumeyer R.: Fauna Helvetica 6. Apidae 3 (Halictus, Lasioglossum).A. PŘIDALEur. J. Entomol. 100 (1): 180, 2003 | DOI: 10.14411/eje.2003.027 Centre suisse de cartographie de la faune (CSCF), Neuchâtel, 2001, 208 pp., 250 figs, 96 distrib. maps. |
BOOK REVIEW: Klowden Marc J.: Physiological Systems in Insects.J. OLEJNÍČEKEur. J. Entomol. 100 (4): 556, 2003 | DOI: 10.14411/eje.2003.083 Academic Press, An Elsevier Science Imprint, San Diego, San Francisco, New York, Boston, London, Sydney, Tokyo, 2002, vii+415 pp. |
Adaptations of Coccinella magnifica, a myrmecophilous coccinellid to aggression by wood ants (Formica rufa group). II. Larval behaviour, and ladybird oviposition location1John J. SLOGGETT, Michael E.N. MAJERUSEur. J. Entomol. 100 (3): 337-344, 2003 | DOI: 10.14411/eje.2003.054 Like adults, larvae of the myrmecophilous ladybird Coccinella magnifica are rarely attacked by Formica rufa ants on foraging trails, but more often attacked on ant-tended aphid colonies. Larvae of the non-myrmecophile Coccinella septempunctata, to which C. magnifica was compared, were more readily attacked by ants in both situations. To avoid or counter ant aggression when foraging for aphids, C. magnifica larvae exhibit three main tactics: they may feed on un- or non-tended aphids; when feeding on tended colonies they often carry prey away, minimising time spent there; and if attacked, they use limited chemical defence. No novel behaviours were found in C. magnifica larvae, not occurring to some extent in C. septempunctata. Coccinella magnifica eggs were laid distant to ant-tended aphids, although closer to un- or non-tended aphids. |
Role of water and moisture in diapause development (A review)Ivo HODEKEur. J. Entomol. 100 (2): 223-232, 2003 | DOI: 10.14411/eje.2003.037 While observational studies led to the assumption that water or moisture (W/M) is a prerequisite for diapause development, the experimental research indicates rather the opposite: usually W/M is needed as late as for the post-diapause resumption of morphogenesis. Recent examples for this type of regulation of dormancy are given: Eggs of the tettigoniid Stictophaula armata, eggs of the grasshopper Oedaleus senegalensis, adults of the bruchid Bruchidius atrolineatus, adults of the endomychid Stenotarsus subtilis (= S. rotundus). In the late diapause of the noctuid Busseola fusca and in eggs of the chrysomelid Homichloda barkeri, moisture is assumed to be the diapause terminating cue. Fall in temperature is assumed decisive for termination of pupal diapause in the saturniid Schausiella santarosensis, although the effect of intense rain after a long dry period has not yet been excluded. Effects of intense changes in environmental conditions and of gradual decrease in diapause intensity with time have often been neglected. |
Natural hybridisation between Aphis grossulariae and Aphis schneideri: morphological evidence (Sternorrhyncha: Aphididae)Rimantas RAKAUSKASEur. J. Entomol. 100 (3): 429-434, 2003 | DOI: 10.14411/eje.2003.065 Morphometric analysis of 176 natural samples of A. grossulariae Kaltenbach, 1843 and A. schneideri (Börner, 1940) was performed, using 308 alate and 750 apterous viviparous females from 25 countries altogether. Morphologically intermediate specimens of presumably hybrid origin were noticed in 63 (35.79%) samples, comprising 12.67% of all apterous and 4.87% of all alate viviparae studied. 31 sample originating from 11 countries had 50% or more intermediate specimens of one or both morphs. "Rich" samples (having 4 or more specimens of the same morph) with the prevailing numbers of hybrid morphotypes were from the Netherlands, Russia (Moscow and Stavropol regions), Moldova, Turkey (Ankara) and Tajikistan (Dushanbe). Present data are discussed in the context of possible natural hybridisation between A. grossulariae and A. schneideri (see also Rakauskas, 1999a, 1999b). Canonical discrimination functions are being advocated as more powerful tools for separating between the two species when compared with single morphological characters or ratios commonly used in the keys. |
Facultative hyperparasitism by the potential biological control agent Aptesis nigrocincta (Hymenoptera: Ichneumonidae)Dirk BABENDREIER, Thomas S. HOFFMEISTEREur. J. Entomol. 100 (1): 205-207, 2003 | DOI: 10.14411/eje.2003.033 This study investigated whether Lathrolestes ensator, a parasitoid released as a biological control agent against the European apple sawfly in Canada, is successfully attacked by the cocoon parasitoid A.nigrocincta. In a no-choice situation in the laboratory, there was no significant difference between the acceptance of unparasitized hosts and hosts containing an egg of L. ensator by females of A.nigrocincta. In addition, A.nigrocincta attacked mature larvae of the larval parasitoid to the same degree as they attacked unparasitized hosts. Survival of A.nigrocincta offspring was close to 100% regardless of whether they developed in unparasitized hosts, in hosts containing an egg of L. ensator or in host cocoons containing mature larvae of L.ensator. This is discussed in the context of the possibility of releasing A.nigrocincta as an additional biological control agent of the European apple sawfly. |
BOOK REVIEW: Furth D.G. (ed.): Special Topics in Leaf Beetle Biology.J. BEZDĚK, A. BEZDĚKEur. J. Entomol. 100 (4): 480, 2003 | DOI: 10.14411/eje.2003.072 Proceedings of the Fifth International Symposium on the Chrysomelidae, 25-27 August 2000, Iguassu Falls, Brazil, XXI International Congress of Entomology. Pensoft, Sofia-Moscow, 2003, 338 pp. |
BOOK REVIEW: Dangerfield P., Austin A. & Baker G.: Biology, Ecology & Systematics of Australian Scelio: Wasp Parasitoids of Locusts and Grasshopers Eggs.J. MACEKEur. J. Entomol. 100 (1): 38, 2003 | DOI: 10.14411/eje.2003.007 CSIRO Publishing, 150 Oxford street (P.O. Box 1139), Collingwood VIC 3066, Australia, 2001, 254 pp. ISBN 0-634 06703-5, price AUD 170.00. |
Emergence of the damselflies, Coenagrion mercuriale and Ceriagrion tenellum (Odonata: Coenagrionidae), at their northern range margins, in BritainBethan V. PURSE, David J. THOMPSONEur. J. Entomol. 100 (1): 93-99, 2003 | DOI: 10.14411/eje.2003.018 Emergence of Coenagrion mercuriale and Ceriagrion tenellum was examined in a mixed population at their northern range margin in Britain. Mortality at emergence was quantified in C. mercuriale. Consistent with their larval diapause characteristics, both species had an asynchronous emergence pattern, typical of "summer" species. Daily emergence of C. mercuriale was positively correlated with the duration of sunlight on the previous day (controlling for season) and its emergence period was found to be shorter than that observed in its core populations in Central and Mediterranean Europe. No differences were found between the patterns of emergence of the sexes in either species. Sex ratio at emergence differed significantly from 1:1 (at 1.35 : 1 - males : females) in C. mercuriale but not in Ceriagrion tenellum (at 1.04 : 1). Body size at emergence declined more steeply with time in females than in males of C. mercuriale because large size may confer a greater reproductive advantage in females (larger females may be more fecund) than males in non-territorial odonates. Percentage mortality of C. mercuriale at emergence was low (4.9% including deformed individuals), the main cause of mortality being deformity. |
BOOK REVIEW: Sartori M. & Landolt P.: Atlas of Distribution of Mayflies of Switzerland.T. SOLDÁNEur. J. Entomol. 100 (1): 186, 2003 | DOI: 10.14411/eje.2003.029 Fauna Helvetica 3, Centre Suisse de Cartographie de la Faune and Schweizerische Entomologische Gesellschaft, Neuchâtel, 1999, 214 pp. |
Review of the genus Paronychiurus (Collembola: Onychiuridae) and description of two new speciesRomuald J. POMORSKIEur. J. Entomol. 100 (1): 187-193, 2003 | DOI: 10.14411/eje.2003.030 A new diagnosis of Paronychiurus Bagnall, 1948 is given. P. ramosus (Folsom, 1917) and P. eous (Christiansen & Bellinger, 1980) comb. nov. are redescribed on the basis of the types and new specimens. Two new species are described: P. probus sp. n., P. hubbardi sp. n. A key to the species in this genus is presented. |
Sarcotoxin II from the flesh fly Sarcophaga crassipalpis (Diptera): A comparison of transcript expression in diapausing and nondiapausing pupaeJoseph P. RINEHART, Steven J. DIAKOFF, David L. DENLINGEREur. J. Entomol. 100 (2): 251-254, 2003 | DOI: 10.14411/eje.2003.040 Many stress-induced genes, including those related to the insect humoral immune response, are upregulated during diapause even in the absence of stress. We further test the relationship between stress genes and diapause in Sarcophaga crassipalpis by cloning sarcotoxin II, a member of the attacin family, and examining its expression pattern in relation to pupal diapause. Unlike several other stress-related genes, sarcotoxin II is not developmentally upregulated during diapause, but it remains fully responsive to immune challenge. Interestingly, the elevation of sarcotoxin II mRNA in response to body wall injury, but not immune challenge, is initiated more slowly and persists longer in diapausing pupae than in nondiapausing individuals. |
BOOK REVIEW: Jolivet P. & Verma K.K.: Biology of Leaf Beetles.J. BEZDĚK, A. BEZDĚKEur. J. Entomol. 100 (1): 24, 2003 | DOI: 10.14411/eje.2003.004 Intercept Ltd, Andover, 2002, 332 pp. ISBN 1-898298-86-6. Price GBP 52.50. |
The spreading of Ostearius melanopygius (Araneae: Linyphiidae) through central EuropeRUZICKA V.Eur. J. Entomol. 92 (4): 723-726, 1995 A complete list of records of Ostearius melanopygius in the Czech and Slovak Republics is given. The opportunistic life strategy of this species and its gradual progress from the coast towards the inland indicates unambiguously that the species has been imparted to Europe. Over the past decades the species has been progressing through Europe eastwards at a rate of approximately 30 km annually. |
Webs, diet, and fecundity of Theridion impressum (Araneae: Theridiidae)Stanislav PEKÁREur. J. Entomol. 97 (1): 47-50, 2000 | DOI: 10.14411/eje.2000.012 Data on the webs, prey spectrum, density and fecundity of Theridion impressum from three different habitats [fields of sunflower, fiddleneck (Phacelia), and apple trees] are presented and discussed. The volume of webs were found to vary between 5 (the first free instar) to 117 cm3 (subadult and adult specimens). The mean density of adult spiders per plant was 0.7 (sunflower), 1.5 (fiddleneck) and 1.2 (per apple branch). Spiders preferred to build webs in the upper part of vegetation or at the extremities of tree branches. The prey spectrum was assessed by collecting webs and identifying their contents. Prey items were primarily aphids (73%), Diptera (7.5%), acid Coleoptera and Hymenoptera (both 5.4%). Pests comprised 90% of the prey; the remaining 10% was accounted for by natural enemies, pollinators and other insects. The number of insects captured in webs differed among study habitats (sunflower > fiddleneck > apple tree) though this difference was not statistically significant. Due to greater numbers of aphids in webs on sunflower, the mean prey length was significantly smaller on sunflowers than in other plots. An index of fecundity was obtained by counting the number of eggs in eggsacs. This varied from 48 to 156 per eggsac and was not significantly different between study plots. The number of eggs was strongly correlated with numbers of prey captured per spider. |
Egg size and hybrid syndrome-dependent embryo mortality in Chironomus hybrids (Diptera: Chironomidae)Klaus HÄGELE, Monika KASPER-SONNENBERGEur. J. Entomol. 97 (1): 1-6, 2000 | DOI: 10.14411/eje.2000.001 Female hybrids of the cross Chironomus t. thummi female × Ch. t. piger male which are largely affected by the sterility inducing Rud syndrome were backcrossed with males of both parental strains. The aim of the study was to provide information about those egg volumes that are insufficient for a normal embryogenesis and to ascertain whether in the hybrids the lethally small egg size represents a new abnormal trait of the Rud syndrome. The egg masses obtained contain eggs of very different sizes with volumes ranging from 0.5 nl to 3.49 nl. Embryo mortality is unusually frequent in those eggs of the backcrosses and of the parental strains that have volumes smaller than 1.5 nl. An egg volume of 1.5 nl represents in Ch. thummi the lower limit for those volumes that are sufficient for a normal embryogenesis. Mortality increases with decreasing egg size, reaching 100% in backcross eggs with volumes of 0.99 nl and smaller. Small egg size is a new trait of the Rud syndrome affected thummi female × piger male hybrids. This trait is part of a postzygotic reproductive isolation barrier between thummi and piger and manifests first in the backcrosses. Most backcross eggs show volumes between 1.5 nl and 2.99 nl. Within this volume range the amount of mortality does not depend upon egg volume. Here, embryo death is great in the backcrosses but normal in the parental strains. The high frequency of embryo death in the backcrosses must be predominantly due to the action of the Rud syndrome and a second hybrid syndrome, called HLE syndrome. Since further characteristic traits of these syndromes could be detected in surviving backcross individuals, the study demonstrates the occurrence of the syndromes in this generation also. Therefore, the postzygotic reproductive isolation mechanism of both hybrid syndromes is effective in the hybrids and in their progeny as well. |
Plumbagin and azadirachtin deplete hemolymph ecdysteroid levels and alter the activity profiles of two lysosomal enzymes in the fat body of Helicoverpa armigera (Lepidoptera: Noctuidae)JOSEPHRAJKUMAR A., SUBRAHMANYAM B.*, SRINIVASAN S.Eur. J. Entomol. 96 (4): 347-353, 1999 The profile of hemolymph ecdysteroid was studied in the gram pod borer, Helicoverpa armigera, during larval-pupal transformation. The changes closely correspond to the developmental events occurring at metamorphosis. Two insect growth regulators, plumbagin and azadirachtin, significantly depleted the content and altered the profile of ecdysteroids at crucial stages, when applied at ED50 doses. The activity profiles of two fat body lysosomal enzymes, acid phosphatase and b-galactosidase, were also significantly affected by the insect growth regulators. It is suggested that plumbagin and azadirachtin treatments primarily modify the ecdysteroid titer, which in turn leads to changes in lysosomal enzyme activity causing overt morphological abnormalities during the metamorphic molt. |