A laboratory study was carried out on photoperiodic control of prepupal diapause in the egg parasitoid Trichogramma embryophagum (Hartig). All experiments were conducted with an isofemale parthenogenetic strain. The maternal generation was reared at 20°C and photoperiods of L:D = 3:21, 6:18, 9:15, 12:12, 15:9, 18:6, 21:3 or 24:0. The tendency to diapause in the progeny was estimated by rearing the daughter generation at 15°C in the dark. Experiments revealed a long-day type response based on maternal influence on the progeny prepupal diapause. However, significant endogenous fluctuations in the pattern of the photoperiodic curve were revealed in successive laboratory generations reared under constant conditions. The left threshold day-length was very variable, while the right threshold kept relative constancy. Experiments with individual females sequentially offered new host eggs demonstrated that the probability of the progeny entering diapause depends significantly on maternal age. At 20°C and 18L : 6D, the percentage of diapause was maximal (ca 15%) in the progeny eclosed from the eggs laid during 1st - 2nd days of maternal life. Then the proportion of diapausing progeny decreased to 0-5% at days 9-11 of female life and later slightly increased in 15-17 days old females. Thus, endogenous factors play an important role in maternal influence on progeny diapause, particularly in environments close to threshold temperature and photoperiod.
Phylogenetic relationships among 16 genera of the subfamily Aphidiinae (Hymenoptera: Braconidae) were investigated using sequence data from three genes: the mitochondrial large ribosomal subunit (16S), 18S ribosomal DNA and mitochondrial ATPase 6. All sequences were downloaded from the GenBank database. A total of 2775 base pairs of aligned sequence were obtained per species from these three genes. The results support the existence of three-tribes: Ephedrini, Praini and Aphidiini, with the Ephedrini occupying the basal position; Aphidiini could be further subdivided into three subtribes: Monoctonina, Trioxina and Aphidiina. The genus Aphidius is a paraphyletic group. The taxonomic status of the subfamily Aphidiinae within the Braconidae is probably closer to the non-cyclostome than the cyclostome subfamilies.
The effects of three factors operating during pre-emergence development period on some characteristics of drones were
studied. Weight of newly emerged drones, length of forewing, length of tibia, length of femur, length and width of basitarsus and
number of spermatozoa in drones from colonies in which the workers had access to drone brood (A), the size of brood cells differed
(B) or the colony had a queen or was queenless (C), were determined. For this purpose, 9 colonies were chosen at random from the test apiary and prepared so that each contained one empty Langstroth frame with six small sub-frames containing drone combs, three of which were used to test the effect of one level and the other three the other level of each factor. The results showed that, colony
status had a greater effect on the parameters measured than either the size of the brood cells or whether the workers had access to
sealed brood cells. Most of the parameters were significantly different in C, whereas only a few in B and non in A were significantly
different. The distance between discriminant scores in each experiment enhanced the previous results, as it was highest in C, followed by B and then A. Optimal drone characteristics may be recorded for colonies in which the queens were induced to lay unfertilized eggs in newly built drone combs, and then removed and the drone brood reared in a queen less colony.
Endosymbiotic organisms are known to manipulate the reproductive biology of their hosts. Incomplete prevalence of endosymbiont inducing thelytokous parthenogenesis results in the coexistence of sexual and asexual individuals, and could account for the maintenance of sexual reproduction in certain populations or species. In the parasitoid Venturia canescens, arrhenotokous ("sexual") and thelytokous ("asexual") individuals occur sympatrically. We aimed to determine whether endosymbionts are implicated in the thelytoky of V. canescens. After screening females of the two reproductive modes for several reproductive parasites: bacteria (Wolbachia, Rickettsia, Bacteroidetes, Spiroplasma, Arsenophonus) and Microsporidia, we concluded that thelytoky in V. canescens is not induced by any of these parasites and confirmed its suitability as a biological model for solving the evolutionary enigma of the maintenance of sexual reproduction., Vincent Foray ... [et al.]., and Obsahuje seznam literatury
After comparing the morphology of the genus Hemicrisis Förster, 1869 and Phaenoglyphis Förster, 1869, and examining the sculpturing in this genus, the synonymy between Hemicrisis and Phaenoglyphis is re-established. The specific status of Phaenoglyphis pubicollis (Thomson, 1877) comb. n. is re-established and differentiated from Phaenoglyphis ruficornis (Förster, 1869) comb. n. A new species of Charipinae, Phaenoglyphis evenhuisi sp. n. is described from Andorra. It is characterized by the presence of sculpture on the mesonotum, a character only shared with P. pubicollis. Some illustrations are provided. Notes on all the sculptured Charipinae are provided as well as a key to the genera of Alloxystini.
Pollination of Sedirea japonica (Orchidaceae) by Bombus diversus diversus (Hymenoptera: Apidae), Kenji Suetsugu, KOji Tanaka., and Obsahuje seznam literatury
At a nest site in Northern Italy of females of the weevil-hunting digger wasp Cerceris arenaria L. (Hymenoptera: Crabronidae) the provisioning activity and predator-prey relationship were investigated, in particular their specialization in choice of prey. Females were active from middle of June to end of July, and from 8.00 to 19.00. The wasps made provisioning flights throughout the day, mostly in late morning and early afternoon. Individual wasps generally only hunted for 1 or 2 prey species of all those available, maybe because of their higher abundance. The size of prey, which is positively correlated with that of the female wasps, seems to be the main factor determining choice of prey. The nature of the provisioning flights seems to be related to the size of the prey, being more frequent and shorter for smaller weevils. The correlation between prey and wasp biomass is discussed in relation to the size range of the wasps.
The effectiveness of natural enemies in controlling pests may be determined by many traits linked to their ability to regulate the density of their prey. In this respect, the phenomenon of pseudoparasitism, in which female parasitoids reject a host after inserting their ovipositor into it, is fairly common among hymenopteran parasitoids. However, in spite of this its effect on hosts is rarely reported in entomological and biological control literature. For this reason, in the present study, the pseudoparasitism by the parasitoid Spalangia cameroni Perkins of the Mediterranean pest Ceratitis capitata (Wiedemann) and its effect on several biological parameters of the host were studied under laboratory conditions. The results indicate that the percentage pseudoparasitism by S. cameroni of medfly in the laboratory is high, even slightly higher than host-feeding, which is commonly used to evaluate the potential of parasitoids as biological control agents. In addition, the adults that emerge from pseudoparasitized medfly pupae have a male-biased sex ratio, low levels of survival and are frequently damaged, which results in small adults and an inability to mate successfully. In conclusion, our results indicate that pseudoparasitism is common and enhances the effectiveness of S. cameroni attacking medfly, which highlights the importance of this phenomenon when selecting parasitoids to be included in a biological control programme., Luis De Pedro, Francisco Beitia, Josep D. Asís, José Tormos., and Obsahuje bibliografii
Nuptial flights of Crematogaster teranishii Santschi occur in autumn. Queens and possibly larvae pass the first winter without workers in Okayama, Japan. This study examines and tests the hypothesis that C. teranishii queens regulate not only their own diapause, but also that of their larvae. Some queens collected immediately after their nuptial flight in early October were exposed to a low temperature of 10°C for 3 months before transfer to 25°C; these queens started oviposition approximately 8 days after the transfer. Larvae reared by these previously chilled queens pupated synchronously until day 50. Other field-collected queens reared at 25°C without prior chilling reproduced soon after collection. They started oviposition, but the development of their larvae was arrested and pupation occurred late or not at all within the120 day experimental period. The delay in pupation in colonies in which the queens were not previously exposed to low temperature strongly indicates that many larvae are in diapause. Because eggs and larvae were not exposed to low temperatures, they were unable to determine the developmental pathway providing the best response to environmental factors. Results indicate that queens regulate whether their larvae undergo diapause.
Three species of Ceranisus Walker, 1841 (Hymenoptera: Eulophidae: Entedoninae) were collected recently in Turkey, including C. menes (Walker, 1839) and C. pacuvius (Walker, 1841) in southeastern Anatolia. A new species, C. hirsutus Doğanlar & S. Triapitsyn, is described from Şanliurfa Province. The genus Urfacus Doğanlar, 2003 is synonymized under Ceranisus and its type species, U. bozovaensis Doğanlar, 2003 is transferred to Ceranisus as C. bozovaensis (Doğanlar, 2003) comb. n., and the species is redescribed from the new material. An identification key to both sexes of Ceranisus from Turkey and Europe is provided.