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Food remains in the guts of Coccinella septempunctata(Coleoptera: Coccinellidae) adults and larvaeTRILTSCH H.Eur. J. Entomol. 96 (4): 355-364, 1999 From 1994-1997 the food of Coccinella septempunctata L. was investigated on the basis of gut dissections of adults and larvae collected in the field. Additionally, the gut contents of adults fed under laboratory conditions were investigated. The likelihood of recovering different prey types during gut dissection was variable, which will be illustrated by presenting some common prey fragments. The food eaten by adult C. septempunctata throughout a year was studied at a locality in Berlin-Staaken. Ladybirds were collected from March 1994 until November 1997 in different crops and habitats on roughly a monthly basis. Aphid feeding was detectable from April until October. In May and June they were the most frequent food type. Fungal spores, in most cases the conidia of Alternaria spp., became most frequent in July. Additionally non-aphid arthropods were frequently preyed upon in July. A very common non-aphid prey item were thrips. Pollen was important in May and September. Comparing the food components of newly emerged adults with those of overwintered adults some remarkable differences were detected. In newly emerged adults non-aphid arthropods and fungal spores were much more frequent than in overwintered adults whereas aphids were less frequently found. The diet of adults and larvae was also investigated in June and July in cereal fields at two other localities, Northern Flaeming and Magdeburger Boerde. No difference in adult diet was found between the three localities. The composition of the larval diet was relatively similar to that of the adults. |
Larval morphology and biology of two species of Aphodius (Plagiogonus) from the Iberian Peninsula (Coleoptera: Scarabaeidae: Aphodiinae)José R. VERDÚ, Eduardo GALANTEEur. J. Entomol. 97 (3): 395-401, 2000 | DOI: 10.14411/eje.2000.060 The larval morphology of Aphodius (Plagiogonus) nanus Fairmaire, 1860 and A. (P.) arenarius (Olivier, 1789) are described and redescribed, respectively. The common characters of both species, and the specific diagnostic characters are provided and discussed. The most important morphological characters of the larvae of Plagiogonus Mulsant, 1842 are the longitudinal alignment of the anterior setae of the stipes, the spatulate form of the posterior-lateral setae of the glossae of the hypopharynx, the slight development of the anal lobe slit, the form of the epitorma of the epipharynx, the slight sclerotization of the pternotormae and the relative length of second antennal segment. A key to the larvae of both species of Plagiogonus is presented along with life history data and the preferred food of these species. This study shows that A. arenarius and A. nanus feeding habits are closer to saprophagy than to coprophagy. |
A south east Asian pest species newly recorded from Europe: Thrips parvispinus (Thysanoptera: Thripidae), its confused identity and potential quarantine significanceLaurence A. MOUND, Dominique W. COLLINSEur. J. Entomol. 97 (2): 197-200, 2000 | DOI: 10.14411/eje.2000.037 The south east Asian pest thrips, Thrips parvispinus is recorded breeding in Europe for the first time, damaging Gardenia plants in Greece. Morphological variation in this species from various Asian countries is recorded and compared to the type specimens. As a result Isoneurothrips jenseni Karny, 1925 and Thrips (Isoneurothrips) taiwanus Takahashi, 1936 are placed as synonyms of Thrips parvispinus (Karny, 1922). In contrast, Thrips compressicornis (Sakimura), a species from the Marquesa Islands of the Pacific that has previously been associated with these taxa, represents a very different species. The quarantine significance of T. parvispinus is emphasised. |
Revision of the genus Macroscytus (Heteroptera: Cydnidae) in Madagascar and adjacent islands, with description of four new speciesLIS J.A.Eur. J. Entomol. 96 (4): 427-437, 1999 A revision of species of the genus Macroscytus Fieber distributed in Madagascar and adjacent islands is presented. Four previously known species [M. fryeri Distant, M. lobatus Signoret, M. madagascariensis (Signoret), M. privignus Horváth] are redescribed, and lectotypes are designated for three of them. Four new species (M. mayottensis sp. n., M. simulans sp. n., M. tamatavei sp. n., and M. viettei sp. n.) are described and compared with their congeners. A key to all species of the genus known from Madagascar and adjacent islands is also provided. |
Effects of structural heterogeneity of a laboratory arena on the movement patterns of adult Eriopis connexa and Hippodamia variegata (Coleoptera: Coccinellidae)Audrey A. GREZ, Paula VILLAGRÁNEur. J. Entomol. 97 (4): 563-566, 2000 | DOI: 10.14411/eje.2000.088 We asked if the structural heterogeneity of a laboratory arena differentially affected the abandonment of the plot, residence time, locomotory rate, pause duration and turning rate of adult Eriopis connexa and Hippodamia variegata (Coleoptera: Coccinellidae). We simulated an increase in heterogeneity by distributing vertically-oriented toothpicks in a circular arena: one control (without toothpicks), one uniform plot (toothpicks every 1 cm) and one random plot (randomly distributed toothpicks). No food was provided inside the arena. Coccinellids were released individually in the centre of each plot and their movement was videotaped. Fewer H. variegata adults left the plots as these become more heterogeneous. E. connexa did not discriminate between plots in their residence time, but H. variegata remained longer in the uniform and longest in the random plots. H. variegata only stayed longer than E. connexa in the random plots. This resulted because adults of H. variegata were stationary for longer periods, moved more slowly and less linearly and explored a higher number of toothpicks than adults of E. connexa in more heterogeneous environments. Thus, the physical structure of the environment differentially affects the movement patterns of insects. Eriopis connexa seems to be less sensitive to structural heterogeneity than H. variegata. |
Adaptive preferential selection of young coccinellid hosts by the parasitoid wasp Dinocampus coccinellae (Hymenoptera: Braconidae)Michael E.N. MAJERUS, Irene E. GEOGHEGAN, Tamsin M.O. MAJERUSEur. J. Entomol. 97 (2): 161-164, 2000 | DOI: 10.14411/eje.2000.030 Dinocampus coccinellae females which eclose in mid-summer have the opportunity to oviposit in overwintered or in newly eclosed coccinellid hosts. Given the short further longevity of overwintered hosts, offspring fitness would be increased by ovipositing preferentially in young hosts. Laboratory choice tests show that female D. coccinellae do exhibit such a preference. |
Improved methods of testing and release of Aphidoletes aphidimyza (Diptera: Cecidomyiidae) for aphid control in glasshousesJeroen Van SCHELT, Sandra MULDEREur. J. Entomol. 97 (4): 511-515, 2000 | DOI: 10.14411/eje.2000.079 The gallmidge Aphidoletes aphidimyza is used commercially to control aphids infesting greenhouse crops such as sweet pepper and tomato. In this study we investigated several different ways of improving its use as a biocontrol agent. In the laboratory there was a very strong relation between the availability of spider's webs and successful mating. When mated in cages containing spider's webs a greater proportion of the females were mated and the females laid more eggs compared to the females in cages without spider's webs. As adults emerging from cocoons can crawl up through 15 cm of vermiculite it is possible to transport and release them from bottles, which can be placed open in a greenhouse instead of having to spread the material around the plants. Dispersal of adults from the bottles was measured by placing sentinel plants around a single release point. Eggs of the gallmidge were found on plants at distances up to 45 m from the release point. Intraguild predation of the eggs of the gallmidge by the mites Amblyseius degenerans and Amblyseius cucumeris was also assessed. |
Description of the early stages of Anomalipus plebejus plebejulus (Coleoptera: Tenebrionidae) from Zimbabwe with notes on the classification of the OpatrinaeDariusz IWAN, Stanislav BEČVÁŘEur. J. Entomol. 97 (3): 403-412, 2000 | DOI: 10.14411/eje.2000.062 Immature stages of a South African tenebrionid beetle, account is the first modern description of the egg and first and older larval instars of the genus Anomalipus and the subtribe Anomalipina. The significance of larval characters of Anomalipus and other relevant taxa for classification of the subfamily Opatrinae sensu Medvedev (1968) [= "opatrine lineage: Opatrini" sensu Doyen & Tschinkel (1982)] are discussed. A synopsis of Anomalipus plebejus plebejulus Endrödy-Younga, 1988, of the tribe Platynotini are described and illustrated. This Platynotini larvae is presented. |
The impact of individual ladybirds (Coccinella septempunctata, Coleoptera: Coccinellidae) on aphid coloniesNicole MINORETTI, Wolfgang W. WEISSEREur. J. Entomol. 97 (4): 475-479, 2000 | DOI: 10.14411/eje.2000.073 Pea aphids (Acyrthosiphon pisum) have been reported to produce winged offspring in the presence of predatory ladybirds. These offspring may leave host plants by flight after they have developed into winged adults. The inter-generational nature of this response raises the question about the chances of survival of aphids developing in attacked colonies. We studied the behaviour of predatory ladybirds on host plants by releasing adult 7-spot ladybirds (Coccinella septempunctata) on bean plants hosting either no prey individuals or colonies of 10 or 30 pea aphids. Interactions between predator and prey were recorded until the ladybird left the plant. Ladybird patch residence time increased with the number of aphids present on a plant but beetles generally left a plant before all aphids were eaten. The time budget of the ladybirds revealed a high proportion of time not spent in feeding activities. Predation rate was about one aphid killed per 10min residence time in both treatments with aphid-infested plants. Aphids that survived an attack by the predator or that were alarmed when a conspecific was attacked often emigrated from the host plant, and their number was of the same magnitude as the number of aphids killed by the predator. On average, pea aphid numbers at the end of an experiment were reduced to less than a third of the initial value. The results of the experiment show that attack by single ladybirds does on average not cause immediate extinction of small aphid colonies. The short patch residence times of on average less than two hours show that a predator individual that induces winged-offspring production in an aphid colony will not any longer be present in the colony when the induced offspring mature. To understand the adaptiveness of predator-induced wing development in pea aphids the probabilities of subsequent attacks on an aphid colony need to be investigated. |
Egg distribution in the large copper butterfly Lycaena dispar batavus (Lepidoptera: Lycaenidae): Host plant versus habitat mediated effectsMark R. WEBB, Andrew S. PULLINEur. J. Entomol. 97 (3): 363-367, 2000 | DOI: 10.14411/eje.2000.055 The large copper butterfly, Lycaena dispar batavus, a subspecies of much conservation interest, is host-specific to the great water dock, Rumex hydrolapathum, but little is known of the relationship between herbivore and host in wild populations. This study investigated the distribution of both R. hydrolapathum plants and L. d. batavus eggs in four different habitat types within the Weerribben National Park, The Netherlands, during the summer of 1993. As expected, host plant distribution strongly influenced that of its herbivore. Further, both species had significantly aggregated distributions, and that of R. hydrolapathum was in agreement with the negative binomial model. Host plant selection for oviposition showed no significant relationship with physical plant characteristics, such as plant height and the number of leaves, and at the scale studied, habitat type was of only limited influence. The possible influence of the vegetational architecture surrounding host plants is discussed. |
Revision of the Oriental genus Idiotrephes (Heteroptera: Nepomorpha: Helotrephidae)Miroslav PAPÁČEK, Herbert ZETTELEur. J. Entomol. 97 (2): 201-211, 2000 | DOI: 10.14411/eje.2000.038 The Oriental helotrephid genus Idiotrephes Lundblad, 1933, is taxonomically revised. Species discrimination is based on male genitalia and female terminalia. Three species groups are recognized. The I. chinai group contains I. chinai Lundblad, 1933 (type species; from Sumatra, Borneo, and West Malaysia) and three newly described species; I. asiaticus sp. n. (from Vietnam, Thailand, and west Malaysia); I. yupae sp. n., and I. polhemusi sp. n. (both from Thailand). The I. maior group contains I. maior Papáček, 1994; I. meszarosi Papáček, 1995 (both from Vietnam), and I. hainanensis sp. n. (from Hainan, China). The I. thai group consists of two newly described species from north and northeast Thailand, I. thai sp. n. and I. shepardi sp. n. In addition, some features of biology and morphology of the ovipositor are also included. |
Male calling, mating and oviposition in Isoperla curtata (Plecoptera: Perlodidae)José Manuel TIERNO DE FIGUEROA, Julio Miguel LUZÓN-ORTEGA, Antonino SÁNCHEZ-ORTEGAEur. J. Entomol. 97 (2): 171-175, 2000 | DOI: 10.14411/eje.2000.032 The reproductive biology (drumming call, mating behaviour, fecundity and egg structure) of Isoperla curtata, an endemic species from the Southern Iberian Peninsula, is described. The male's mating call has a diphasic pattern, with a mean of 17.3 beats per call (range = 8-27; SD = 4.7) and a duration of 792.9 ms per call (range = 228-1312; SD = 307.9). This call differs from that of other species of Isoperla in having two distinct phases with different millisecond intervals, and is species-specific. Mating lasts between 131 and 3864 seconds (mean = 2180.9 s and SD = 1027.8). Since males and females mate more than once (mean number of matings per female was 1.85 and per male 2.25), the species is polyandric and polygynic. The position adopted by the male during mating is different from that described for other stonefly species. Other mating behaviours are interpreted as displacement manoeuvers, tactile stimulation and possibly sexual selection by cryptic female choice. There was a statistically significant correlation between size and the number of matings in females (r = 0.849; p = 0.016), but not in males. Each female laid between one to four egg masses composed of an average of 88.7 eggs. Maximum fecundity was 319 eggs. The mean egg volume was 80.5 × 105 µm3 which is very similar to that of other Isoperla species. An outstanding morphological characteristic of the egg is the lobed outline of the chorion cells. |
New genus and species of Oriental Meligethinae with new observations on the genera Cryptarchopria and Kabakovia (Coleoptera: Nitidulidae)Josef JELÍNEKEur. J. Entomol. 97 (3): 413-418, 2000 | DOI: 10.14411/eje.2000.063 A new genus and species, Horakia kubani gen. n., sp. n., of Meligethinae from Thailand are described and compared with the closely related genus Cryptarchopria Jelínek. Cryptarchopria infima (Grouvelle) is recorded from the islands Ambon and Seram (Maluku, Indonesia), and its association with flowers of the palm Areca catechu L. is established for the first time. Diagnostic characters of the genus Kabakovia Kirejtshuk, 1979 are discussed, and Kabakovia latipes (Grouvelle, 1908) is recorded from Nepal for the first time. |
Dorso-abdominal scent glands and metathoracic evaporatoria in adults of central European Rhopalidae (Hemiptera: Heteroptera), with a discussion of phylogeny and higher systematicsJitka DAVIDOVÁ-VILÍMOVÁ, Markéta NEJEDLÁ, Carl W. SCHAEFEREur. J. Entomol. 97 (2): 213-221, 2000 | DOI: 10.14411/eje.2000.039 The reservoirs of dorso-abdominal scent glands and the occurrence of the metapleural scent gland evaporatoria in the adults of nine central European and one North American species in the family Rhopalidae (Hemiptera) were studied. All published data about the persistence of the dorso-abdominal scent glands in rhopalid adults are reviewed, and systematic and phylogenetic implications are derived from the patterns of variation. |
Fecundity and survival of Anagyrus kamali (Hymenoptera: Encyrtidae) under different feeding and storage temperature conditionsLaurent A. SAGARRA, Charles VINCENT, Robin K. STEWARTEur. J. Entomol. 97 (2): 177-181, 2000 | DOI: 10.14411/eje.2000.034 The parasitoid, Anagyrus kamali Moursi (Hymenoptera: Encyrtidae), has been recently introduced into the Caribbean as a biological control agent against the hibiscus mealybug (HMB), Maconellicoccus hirsutus Green (Homoptera: Pseudococcidae). Storage of A. kamali that is essential for its use in biological control did not affect the longevity of female and male parasitoids (40.3 ± 14.07 and 31.7 ± 9.57 days, respectively) when kept at 20 ± 2°C in absence of hosts and fed ad libitum with droplets of pure honey. At a storage temperature of 27 ± 2°C the longevity decreased by about 10 days. Fed females did not resorb eggs during the first two weeks of storage at 20 ± 2°. Parasitoid ovogenesis ceased when ovarioles/lateral oviducts were full. The lifetime fecundity was not significantly affected by a storage at 20 ± 2°C of up to 14 days. Foraging activities and oviposition were the main factors influencing the lifespan of female A. kamali. |
African-Arabian and Asian-Pacific "Mocis frugalis": Two distinct species (Lepidoptera: Noctuidae)Alberto ZILLIEur. J. Entomol. 97 (3): 419-426, 2000 | DOI: 10.14411/eje.2000.064 It is shown that under the name Mocis frugalis (F., 1775), considered to represent a widespread pest of graminaceous crops in the Eastern hemisphere and the Pacific, two species have been hitherto confused. Populations from Africa and Arabian Peninsula are described as Mocis proverai sp. n. The main characters which distinguish the African-Arabian M. proverai from M. frugalis of Asia and the Pacific are found in the genitalia, especially the configuration of the male vesica and female bursa copulatrix. |
Key life stages of two predatory ladybird species (Coleoptera: Coccinellidae)Pavel KINDLMANN, Hironori YASUDA, Satoru SATO, Katsuhiro SHINYAEur. J. Entomol. 97 (4): 495-499, 2000 | DOI: 10.14411/eje.2000.076 Development and survival of larvae of two predatory ladybird species, Harmonia axyridis (Pallas) and Coccinella septempunctata L. on hibiscus (Hibiscus syridis L.) trees was followed daily outdoors during four seasons. Data were analysed and stage-specific mortality in a stage-structured model was estimated using Manly's (1997) method. Subsequently, key factor analysis was used to determine the life stages in which the daily mortality was best correlated with the total mortality during larval life. Consistently with the results from the first two years, the larvae suffered the greatest mortality during the first and fourth instars. The k-values for these two instars were also best correlated with those for the whole larval life, especially in H. axyridis. |
Experimental hybridisation between Aphis grossulariae and Aphis triglochinis (Sternorrhyncha: Aphididae)Rimantas RAKAUSKASEur. J. Entomol. 97 (3): 377-386, 2000 | DOI: 10.14411/eje.2000.058 Aphis triglochinis and A. grossulariae clones from southern Poland produced fertile hybrid eggs under experimental conditions. Established hybrid clones expressed normal parthenogenetic reproduction but bisexual generations were obtained only in three hybrid clones out of twenty six. Fertile F1 hybrid eggs were obtained in one hybrid clone. Morphological and host-specificity features of A. grossulariae dominated in the majority of hybrid clones. The present results do not exclude the possibility of natural hybridisation of studied aphid species. Natural hybrids may be difficult to detect because of their "pure" morphological and host-specificity features. |
Ecological comparisons across geographical distributions: The thistle gall fly Urophora cardui (Diptera: Tephritidae) on two different Cirsium hostsMark FRENZEL, Sabine EBER, Stefan KLOTZ, Roland BRANDLEur. J. Entomol. 97 (2): 183-189, 2000 | DOI: 10.14411/eje.2000.035 Populations of the specialist gall-forming fly, Urophora cardui (Diptera: Tephritidae), were studied at the western and eastern margins of its distribution. In western Europe U. cardui attacks the creeping thistle Cirsium arvense, whereas in eastern Europe, in the Ural mountains, it attacks Cirsium setosum, a taxon closely related to C. arvense. Gall densities are high in the Ural mountains and can be predicted by environmental variables. Compared to galls on C. arvense, those on C. setosum are on average larger. This indicates better performance of U. cardui on C. setosum in terms of cell numbers per gall. Despite the wide distribution of U. cardui, the dominant parasitoids are the same at the western and eastern ends of its distribution and the interactions between parasitoids and the host are similar. In general, we suggest that the synchronisation between the host plant species, the phytophage and the parasitoids is an important factor in the spatial ecology and evolution of this food web. |
Effects of conspecific and heterospecific larval tracks on the oviposition behaviour of the predatory ladybird, Harmonia axyridis (Coleoptera: Coccinellidae)Hironori YASUDA, Takumi TAKAGI, Kazunobu KOGIEur. J. Entomol. 97 (4): 551-553, 2000 | DOI: 10.14411/eje.2000.085 The effect of the oviposition deterring pheromone (ODP) in the larval tracks of conspecific and heterospecific ladybirds on oviposition in Harmonia axyridis Pallas was studied in semi natural conditions. Gravid females of H. axyridis were deterred from ovipositing on plants contaminated with conspecific larval tracks, but not on those with heterospecific tracks. H. axyridis females spent significantly less time on plants contaminated with conspecific ODP than on those with heterospecific ODP. This behaviour may account for why fewer eggs were laid on plants contaminated with conspecific ODP. |
Effects of imidacloprid on Harmonia axyridis (Coleoptera: Coccinellidae) larval biology and locomotory behaviorCharles VINCENT, André FERRAN, Ludovic GUIGE, Jacques GAMBIER, Jacques BRUNEur. J. Entomol. 97 (4): 501-506, 2000 | DOI: 10.14411/eje.2000.077 The effects of imidacloprid on 1-day-old third instars of Harmonia axyridis were assessed by topical treatment and contact with treated glass plates in laboratory bioassays. When 5 µl of imidacloprid solutions were applied topically, the LD50 was 0.085 g/l per insect after 24 h. Contact with imidacloprid-treated plates had little effect on the number of third instars that became adults. Average duration of larval development was not significantly affected by duration of contact and imidacloprid concentrations. There were no significant differences in maximal larval weight, weight gain and day at maximum larval weight. There were significant differences in average weight gain per day (from third instar to prepupa) after treatments with different imidacloprid concentrations. A temporary knockdown effect was observed with higher concentrations and longer durations of contact with treated plates. Compared with untreated third instars, contact with imidacloprid-treated plates caused an increase in time spent (in seconds) on the glass plates resulting from an increase in number of stops (per second) and angular speed (degrees per second) and a decrease in linear speed, excluding stops (mm/second). The changes in locomotory behavior (i.e., duration of stay on untreated plate, number of stops and angular speed) lasted up to 24 h after contact with imidacloprid-treated plates. |
Application of ubiquitin SSCP analysis in taxonomic studies within the subgenus Orinocarabus (Coleoptera: Carabidae: Carabus)Dieter SEDLMAIR, Roland GERSTMEIER, Ralf EINSPANIEREur. J. Entomol. 97 (3): 387-394, 2000 | DOI: 10.14411/eje.2000.059 SSCP (single-strand conformation polymorphism) analyses of ubiquitin genes were used to investigate evolutionary relationships within the subgenus Orinocarabus of the genus Carabus. After SSCP electrophoresis of PCR-amplified ubiquitin copies, population-specific band patterns were obtained. Ubiquitin-SSCP-analyses of the six central European Orinocarabus species, including three subspecies and thirteen populations, resulted in a dendrogram that differed from that based on morphology. Phylogenetic analysis of mitochondrial DNA (mtDNA) did not support the SSCP dendrogram, but was in good accordance with the taxonomy based on morphological characters. The reason for the discrepancies seems to be evolutionary conservation of the ubiquitin genes. The time that elapsed since the evolution of the closely related Orinocarabus species is too short for concerted evolution of the ubiquitin genes. |
Galaicodytes caurelensis gen. n., sp. n., the first troglobitic species of Platynini (Coleoptera: Carabidae: Pterostichinae) from the western Palaearctic regionVicente M. ORTUÑO, José M. SALGADOEur. J. Entomol. 97 (2): 241-252, 2000 | DOI: 10.14411/eje.2000.041 This study describes Galaicodytes (gen. n.) caurelensis (sp. n.) which was captured in a limestone cave in the lower Cambric of NW Spain. It is the first known cave-dwelling Platynini in the western Palaearctic region and shows unique morphological adaptations to cave life. The taxonomic position is based on comprehensive character analysis, including external anatomical, male genitalic, and female genitalic and reproductive tract characters. Certain problems concerning its taxonomic position in relation to other genera are discussed and different ecologic and biogeographic aspects are analysed. |
Autosomal recessive mutations affecting body colour in Pyrrhocoris apterus (Hemiptera: Pyrrhocoridae)SLAMA K.Eur. J. Entomol. 95 (1): 17-26, 1998 Genetic characteristics of the first three mutants found in P. apterus L.; white (w/w) 1965, yellow (y/y) 1966 and melanotic (m/m) 1973 have been described in detail. Exact Mendelian proportions of 1 : 1 and 3 : 1 in all standard test crosses and absence of sexual linkage revealed that each of these mutations was inherited as a single autosomal recessive gene. The dihybrid and trihybrid crosses showed that the w gene is epistatic over y. The absence of linkage shows that each of the described mutant genes is situated on a different chromosome. During 30 years of sustained rearings of P. apterus, the white (w/w) and yellow (y/y) mutants never originated de novo, whereas the melanotic (m/m) mutants originated independently from the macropterous strain three times. Triple recessive (w y m) white melanotic strain has been maintained and used for some genetic investigations for over 20 years. |
Reproduction of Aphelinus albipodus (Hymenoptera: Aphelinidae) on Russian wheat aphid (Hemiptera: Aphididae) hostsBERNAL J.S., WAGGONER M., GONZALEZ D.Eur. J. Entomol. 94 (1): 83-96, 1997 Reproduction in Aphelinus albipodus (Hayat & Fatima) from China on Diuraphis noxia (Mordvilko) hosts was studied in the laboratory. Studies were conducted at three constant temperatures, 10.0, 21.1, and 26.7°C (± 1.0°C), 14L : 10D photoperiod, and 50-70% R.H. The longevity of both males and females was greatest at 10.0°C (26.0 and 41.5 d, respectively); differences in longevity were not significant (p > 0.05) between 21.1 and 26.7°C in both sexes (males 13.1 vs. 10.0 d, females 20.9 vs. 16.4 d, respectively). Fecundity was greater at 26.7 (294.7 ± 27.6 mummies) and 21.1°C (214.8 ± 33.5 mummies) than at 10.0°C (569 ± 11.7 mummies), but was not significantly different (p > 0.05) between the former two temperatures. Aphelinus albipodus did not successfully develop to adulthood at 10°C, thus rm and Ro values were zero, and Tc (generation time) could not be estimated. At 21.1°C, rm = 0.188, Ro = 68.9, and Tc = 23.9 d; those values were 0.288, 67.4, and 15.2 d, respectively, at 26.7°C. The offspring sex ratio (females) was male-biased at all three temperatures: 0.364 ± 0.061 at 10.0°C, 0.437 ± 0.029 at 21.1°C, and 0.341 ± 0.002 at 26.7°C. Moreover, daily offspring sex ratio decreased with the age of the female parent at all three temperatures (p < 0.05). A pre-oviposition period of 1.5 d was observed in A. albipodus at 10° C, and female offspring were not produced during the first 7.5 d of adult life of mated females. The limited number of ovarian eggs, 6.5 ± 2.5, in newly emerged females (< 6 h old) together with their fecundity schedule indicated synovigeny in A. albipodus. Results are discussed in relation to the colonization in North America of A. albipodus for biological control of D. noxia. |
Book Review: Poluzhestkokrylye Nasekomye (Heteroptera) Sibiri.STYS P.Eur. J. Entomol. 95 (1): 26, 1998 Vinokurov N.N. & Kanyukova E.V.: Poluzhestkokrylye Nasekomye (Heteroptera) Sibiri (Heteroptera of Siberia). Nauka Novosibirsk, 1995, 238 pp. (in Russian). |
Cytogenetic analysis of some aradid species (Heteroptera: Aradidae)GROZEVA S.Eur. J. Entomol. 94 (3): 421-424, 1997 Known sex chromosome mechanisms in Aradidae are XX : XY or compound X(XnY). The present paper adds data obtained from studying testes of adults and stage IV and V larvae of four aradid species. The number of chromosomes and their behaviour during spermatogenesis (in Aradinae for the first time) were documented and illustrated: Aradus cinnamomeus Panter -2n = 35 (32 + X1X2Y); Aradus corticalis corticalis (L.) -2n = 28 (26 + XY); Aradus conspiculus Herrich-Schaffer 2n = 28 (26 + XY); Aneurus avenius Dufour -2n = 27 (24 + X1X2Y). Mechanisms which could have played a role in karyotype evolution in the family are discussed in the context of this study and data from literature. |
Are behavioural changes in parasitised aphids a protection against hyperparasitism?MüLLER C.B., VöLKL W., GODFRAY H.C.J.Eur. J. Entomol. 94 (2): 221-234, 1997 Parasitised aphids often leave the aphid colony before mummification. It has been suggested that this behaviour is an example of host manipulation by the primary aphidiid parasitoid to reduce the risk of hyperparasitism after mummy formation. Mummification site and hyperparasitism risk are surveyed in 16 species of aphid. Mummification away from the colony was not associated with reduced hyperparasitism. In ant-attended species, and in species with well developed parasitoid defence behaviour (such as kicking), mummies formed within the colony tended to suffer less hyperparasitism. In laboratory experiments, two hymenopteran ectohyperparasitoids, Dendrocerus carpenteri (Curtis) (Megaspilidae) and Asaphes vulgaris (Walker) (Pteromalidae), were more successful attacking parasitised aphids [Uroleucon jaceae (L.) (Aphididae)] when the mummies were outside the colony, not surrounded by living aphids. |
Effect of host plant on body size of Frankliniella occidentalis (Thysanoptera: Thripidae) and its correlation with reproductive capacityDE KOGEL W.J.*, BOSCO D., VAN DER HOEK M., MOLLEMA C.Eur. J. Entomol. 96 (4): 365-368, 1999 The effect of different host plants on Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae) body size was investigated. Thrips from three different populations, from the Netherlands, Italy, and USA, achieved greater body sizes when reared on cucumber than on bean. The same thrips grew larger when reared on susceptible than on resistant cucumber. On the latter, reproduction was reduced, suggesting that smaller thrips have a lower reproduction. However, no evidence was found for a correlation between size and reproduction in experiments with thrips from four different populations, from the Netherlands, New Zealand, France, and USA that differed significantly in body size. Also when individual thrips from the four populations were tested, there was no correlation between size and reproduction. It is concluded that resistant cucumber affects both size and reproduction of F. occidentalis. However, lower reproduction in general is not associated with smaller body size. |
Host spatial pattern influences induction of parasitization by Trichogramma (Hymenoptera: Trichogrammatidae)VOINOVICH N.D., UMAROVA T.Y., REZNIK S.Y.*Eur. J. Entomol. 96 (4): 369-373, 1999 The influence of host intrapatch spatial distribution on parasitoid host acceptance behavior was investigated with Trichogramma principium parasitizing eggs of grain moth, Sitotroga cerealella. Single females were placed in Petri dishes, each containing 60 host eggs arranged either as a compact patch or partitioned into 60 or 12 clusters each consisting of 1 or 5 eggs, respectively. Partitioned patches provoked parasitization more often than compact patches. The percentage of ovipositing females (i.e., females parasitizing at least one of 60 host eggs) increased with the number of clusters, while it was independent of the intercluster distance over intervals of 2.5-15 mm. The mean number of eggs parasitized by ovipositing females during 48 h was almost independent of the host egg spatial pattern. As a result, the rate of parasitization was higher when the hosts were sparsely distributed within a patch than when they were aggregated. |



