Within-plant distribution of the Melaleuca quinquenervia biological control agent Lophodiplosis trifida

The gall-producing midge Lophodiplosis trifida Gagné (Diptera: Cecidomyiidae) is an established biological control agent of the exotic tree Melaleuca quinquenervia (Cav.) Blake, which invades wetland systems of Florida (USA). Host use patterns within the tree canopy were investigated. Plant height affected within-plant distribution of galls as L. trifida attack rates were greater in lower versus higher portions of the M. quinquenervia canopy. Nonetheless, galls occurred even at tree-top levels of 13 m.     

The control of paedogenetic cecid larvae in mushroom beds by the use of thionazin

Thionazin incorporated in the casing layer of mushroom beds was shown to be highly phytotoxic even at 5 ppm, but when incorporated in compost it caused little phytotoxicity up to 20 ppm. A rate of 8 ppm gave satisfactory control of Heteropeza pygmaea Winnertz (Dipt.: Cecidomyiidae), but was less suitable against Mycophila speyeri (Barnes), for which the use of γ-BHC in the casing should be retained. A severe infestation of M. speyeri was shown to depress the total yield of mushrooms by 59% and the saleable yield by 87%.     

Cytological and histochemical gradients on two <Emphasis Type="BoldItalic">Copaifera langsdorffii</Emphasis> Desf. (Fabaceae)—Cecidomyiidae gall systems

Previous ultrastructural and histochemical analysis proposed patterns in the accumulation of substances in galls of Diptera: Cecidomyiidae in some plant species of the temperate region. Similar analyses were done to verify the conservativeness of these patterns in the Neotropical region, where a great number of species of Cecidomyiidae is responsible for a wide diversity of morphotypes. Two gall morphotypes induced by Cecidomyiidae in a unique host plant, Copaifera langsdorffii, were studied. The gradients of carbohydrates and the activity of invertases and acid phosphatases were similar, but the cytological gradients and distribution of proteins evidenced that the sites of the induction as well as the amount of neoformed tissues may be peculiar to each gall system. The production of lipids just in the secretory cavities either in the non-galled or galled tissues indicated a potentiality of the host plant which could not be manipulated by the galling insects. Further, the absence of nucleus in the nutritive tissue, an exclusive feature of the horn-shaped galls, indicates cell death attributed to the feeding habit of the galling herbivore.     

A gall-forming biological control agent suppresses vegetative growth of an invasive tree

Attack by the gall-forming biological control agent Lophodiplosis trifida Gagné (Diptera: Cecidomyiidae), reduced Melaleuca quinquenervia sapling height by 10.1%, leaf biomass by 42%, woody biomass by 42.7%, and root biomass by 30.3%. This provided the first quantitative evidence of the potential of L. trifida to suppress pre-reproductive M. quinquenervia.     

Selection ofAzolla forms resistant to the water lily aphid,Rhopalosiphum nymphaeae Life history of Rhopalosiphum nymphaeae

Genotypic and environmentally determined differences inSalix viminalis L. suitability forDasineura marginemtorquens (Bremi) (Diptera: Cecidomyiidae) growth and survival were investigated in laboratory and field experiments. Earlier studies have documented high neonate larval mortality on certainS. viminalis genotypes. Here we present results from laboratory experiments which show no difference in larval establishment behaviour on resistant and susceptible willow genotypes. These data indicate that larvae are not able to detect the plant characteristic responsible for resistance. In a field study insect performance was measured on willow shoots of dissmilar size. Adult body size was positively correlated to willow shoot length. In turn, body size was positively correlated to potential fecundity. These results are discussed in relation to observed high densities ofD. marginemtorquens in vigorously growing willows cultivated for biomass production.     

Isolation of microsatellite markers for Contarinia nasturtii,a European pest invading the New World

Microsatellite markers were developed for epidemiological studies on Contarinia nasturtii (Diptera, Cecidomyiidae), a native European pest that was introduced to the New World in 1996. Nine loci were found to be polymorphic and suitable for the analysis of 56 male individuals that were collected using pheromone traps. These markers all conform to Hardy–Weinberg expectations in at least one of the two tested populations, and carry an average number of 11 alleles among populations and observed levels of heterozygosity ranging from 0.32 to 0.86. Primers for all markers also successfully amplified fragments from Contarinia pisi and Contarinia tritici.     

New records of Cynipidae (Hymenoptera) from Italy

New records of Cynipid gall wasps and inquilines for the Italian peninsula and Sicily and their new host plants for the Palaearctic Region are listed and commented on. Among them we find: Cerroneuroterus cerrifloralis (Müllner 1901) as new for Italy and new for the Palaearctic region as host on Quercus suber; Andricus multiplicatus Giraud 1859 on Q. suber, as new host for the Palaearctic region; Aylax papaveris (Perris 1839), reported in Italy over a century ago, but later overlooked; Cerroneuroterus minutulus (Giraud 1859), also reported more than a century ago from Sicily, but later overlooked. Among the inquilines are here listed: Synergus variabilis Mayr 1872, emerged from Janetia cerris (Kollar 1850) galls (Diptera Cecidomyiidae), and found for the first time in the Palaearctic Region as host on Q. suber; Saphonecrus haimi (Mayr 1872) and Saphonecrus barbotini Pujade-Villar & Nieves-Aldrey 1986, are new records for Italy.     

Environmental safety of biological control: Policy and practice in New Zealand

Introduction of biological control agents into New Zealand is regulated under the Hazardous Substances and New Organisms Act 1996 (HSNO). The legislation is strongly focused on the health and safety of people and the environment. HSNO is implemented by the Environmental Risk Management Authority, a quasi-judicial body of 6–8 people appointed by the Minister for the Environment. The process by which biological control applications are received and processed is described. Two case studies of weed biological control agents which have been through the HSNO process, and the scientific issues that arose in considering the environmental safety of these agents are discussed. The case studies presented are the applications to release the gall fly Procecidochares alani (Diptera: Tephritidae) to control mist flower Ageratina riparia, and three biological control agents, Macrolabis pilosellae (Diptera: Cecidomyiidae), Cheilosia urbana, and Cheilosia psilophthalma (Diptera: Syrphidae) for biological control of hawkweeds (Hieracium spp.). Both applications were approved for agent release into the environment.     

Behavioural,ecological and genetic evidence confirm the occurrence of host‐associated differentiation in goldenrod gall‐midges

Host‐associated differentiation (HAD) is considered a step towards ecological speciation and an important mechanism promoting diversification in phytophagous insects. Although the number of documented cases of HAD is increasing, these still represent only a small fraction of species and feeding guilds among phytophagous insects, and most reports are based on a single type of evidence. Here we employ a comprehensive approach to present behavioural, morphological, ecological and genetic evidence for the occurrence of HAD in the gall midge Dasineura folliculi (Diptera: Cecidomyiidae) on two sympatric species of goldenrods (Solidago rugosa and S. gigantea). Controlled experiments revealed assortative mating and strong oviposition fidelity for the natal‐host species. Analysis of mitochondrial DNA showed an amount of genetic divergence between the two host‐associated populations compatible with cryptic species rather than host races. Lower levels of within‐host genetic divergence, gall development and natural‐enemy attack in the S. gigantea population suggest this is the derived host.     

A female sex-pheromone in the pea midge, Contarinia pisi

Experiments designed to demonstrate the existence of a female sex-pheromone in the pea midge, Contarinia pisi Winn. (Diptera: Cecidomyiidae) are described. Recordings from antennal receptors of males showed that extract of virgin females elicited an increase in spike activity. Field trapping experiments showed that traps containing virgin females or crude extract of virgin females caught large numbers of males.

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Résumé L'antenne des mâles de Contarinia pisi répond par électro-antennogramme à un courant d'air contaminé par des femelles vierges. Des pièges contenant des femelles attirent de nombreux mâles.

     

Red galls: the different stories of two gall types on the same host

• Several studies have suggested reasons why galls have conspicuous colours, but none of the ideas have been confirmed. However, what if the vibrant colours of some galls are explained simply by the effect of light exposure? This may lead to anthocyanin accumulation, functioning as a defence mechanism against the effects of high light.
• We studied the globoid galls induced by Cecidomyiidae (Diptera) on Qualea parviflora (Vochysiaceae), relating anthocyanin accumulation and chlorophyll fluorescence parameters to light incidence in abaxial and adaxial galls. We also tested if the anthocyanin accumulation patterns apply to another Cecidomyiidae‐induced gall morphotype (intralaminar) within the same plant.
• Adaxial galls are exposed to higher incident light, with more anthocyanin accumulation and therefore red coloration. In galls from angled leaves, the greater the angle of the leaf, the higher the difference between anthocyanins on the sun and shade sides of galls. Photosynthetic pigment concentrations did not differ between abaxial and adaxial galls. However, we found higher (F_m′ ? F′)/F_m′ and F_v/F_m in the abaxial galls. Conversely, NPQ and R_fd were higher in adaxial galls. Finally, the pattern of anthocyanin accumulation was not found in the intralaminar gall.
• Anthocyanin accumulation in galls functions as a photoprotective strategy, maintaining tissue vitality in regions exposed to high light conditions. However, this mechanism may vary even among galls within the same host, indicating idiosyncrasy when it comes to coloration in galls. To date, this is the first study to demonstrate quantitatively why the galls of a specific species may be coloured: the variation in light regimes creates differential anthocyanin accumulation, influencing coloration.

     

Effect of insecticide application and host plant resistance on parasitization of sorghum midge,Contarinia sorghicola coq.

Sorghum midge (Contarinia sorghicola Coq.) (Diptera: Cecidomyiidae) is one of the most important pests of grain sorghum. The effects of different insecticides applied at the complete‐an‐thesis stage for insect control, and host plant resistance on the parasitization of sorghum midge, were studied. Tetrastichus spp. and Eupelmus popa are the major parasites of sorghum midge larvae. Of the several insecticides tested, monocrotophos reduced midge parasitization by half compared with the untreated control. Midge parasitization was lower on midge‐resistant genotypes. Amongst the lines resistant to sorghum midge, the levels of parasitization were higher on the moderately resistant lines IS 10132 and PM 9760 compared to those on IS 3461, IS 7005, IS 9807, IS 19512 and AF 28, etc. Parasite activity closely followed the midge population density across sowing dates. The role of these factors on the effectiveness of midge parasites in integrated pest management are discussed.     

Descriptions of two new endoparasitic cecidomyiids (Diptera: Cecidomyiidae) from Japan

Two endoparasitic species of Cecidomyiidae (Diptera) new to science are reported from Japan. Females of Endaphis psyllophaga sp. nov. lay their eggs on the wing of Calophya nigridorsalis (Hemiptera: Psylloidea: Calophyidae) on Rhus succedanea (Anacardiaceae), and newly hatched larvae bore into the adult body. The six nominal species of the genus Endaphis are endoparasitoids of aphids. The genus Endopsylla, which is morphologically similar to the genus Endaphis, consists of two species whose larvae attack psyllids or tingids. Females of Endaphis muraii sp. nov. lay their eggs near colonies of host aphids and newly hatched larvae bore into the body of aphids such as Macrosiphum euphorbiae and Aphis glycines (Hemiptera: Aphididae). The two new species are described, illustrated, and compared to known congeners, and information is given for the two species on their distribution, host range and ecological traits. Now, E. muraii is considered to be a potential biological control agent against aphids.     

Olfactory response by the aphidophagous gall midge, Aphidoletes aphidimyza to honeydew from green peach aphid, Myzus persicae

Female adults of the aphidopagous gall midge, Aphidoletes aphidimyza (Rondani) (Diptera: Cecidomyiidae), showed an olfactory response to honeydew excreted by the green peach aphid, Myzus persicae (Sulzer) (Hemiptera: Aphididae) under laboratory conditions. The response was only elicited by treatments with honeydew, whereas aphids, aphids with pepper plants or leaves, and pepper plants or leaves were not attractive to the midges. Dose‐dependent responses were observed from whole honeydew, honeydew volatiles extracted in pentane, and honeydew volatiles captured on Porapak Q®. When honeydew was eluted with three sequential pentane washes, a positive response was only observed from the midges for the first wash. Female midges laid more eggs on pepper plants infested with higher densities of M. persicae. The olfactory response of midges to honeydew is discussed with respect to prey location.     

Colonization of apple orchards by predators of <Emphasis Type="Italic">Dysaphis plantaginea</Emphasis>: sequential arrival,response to prey abundance and consequences for biological control

Episyrphus balteatus (DeGeer) (Diptera: Syrphidae), Adalia bipunctata (L.) (Coleoptera: Coccinellidae) and Aphidoletes aphidimyza (Rondani) (Diptera: Cecidomyiidae) are the three most abundant natural enemies of Dysaphis plantaginea Passerini (Homoptera: Aphididae) in Asturian (NW Spain) apple orchards. They attack this aphid in sequence: E. balteatus arrived first, followed by A. bipunctata and then by A. aphidimyza. The cecidomyiids arrived too late to have a regulating effect. The syrphids laid an average of 2.3 ± 1.7 eggs per aphid colony and the coccinellids 18.4 ± 9.9 regardless of the degree of the infestation rates of the apple shoots. This value corresponds to the size of an egg batch laid by one female. Therefore, these aphid predators did not respond numerically to the abundance of the pest. The results of this study indicate that natural populations of syrphids and ladybird beetles are unable to control D. plantaginea, and therefore a more complex strategy than waiting for natural enemies is required.     

Characteristics of sperm ultrastructure in the gall midges Porricondylinae (Insecta,Diptera, Cecidomyiidae), with phylogenetic considerations on the subfamily

 Sperm ultrastructure was studied in ten genera of the Porricondylinae (Cecidomyiidae). Sperm structure is remarkably simplified by the absence of the acrosome and the accessory tubules, as happens in all the cecidomyiid flies. All genera of the Porricondylinae show a peculiar 9+3 axonemal model except Diallactes, which retains the plesiomorphic condition of a 9+2 axoneme, and Winnertzia, which appears to have secondarily acquired a 9+0 model. A cladistic analysis of relevant sperm characters (based on the axonemal model, the number of mitochondrial derivatives and the size and structure of the centriolar adjunct) was performed to infer phylogenetic relationships among six tribes of the Porricondylinae. In this cladogram, the Porricondylini are the sister group to the Asynaptini, Heteropezini and Winnertzini and these four taxa form the sister group to the Dicerurini. The tribe Diallactini are regarded as the group with the most plesiomorphic characters within the family. Accepted: 15 March 1996     

Development and characterization of 21 polymorphic microsatellite loci in the aphidophagous gall midge, <Emphasis Type="Italic">Aphidoletes aphidimyza</Emphasis> (Diptera: Cecidomyiidae)

We have developed and characterized 21 microsatellite markers in the aphidophagous gall midge Aphidoletes aphidimyza (Rondani) (Diptera: Cecidomyiidae). All 21 loci tested were polymorphic: the number of alleles ranged from 2 to 17. Allelic richness and observed heterozygosities were higher in females than in males. Several loci had no heterozygosity in males, suggesting that the loci were located on sex chromosomes or E-chromosomes, common to cecidomyiids. The high polymorphism detected in this study suggests the markers will be of value in analyzing genetic structure of field populations.