Antonio P. Garonna

Habitat selection by the highly endangered long-horned beetle Rosalia alpina in Southern Europe: a multiple spatial scale assessment

Despite the popularity of the saproxylic cerambycid Rosalia alpina as a flagship species, its ecology is still poorly know, especially in the southern part of its range. Detailed information on its habitat preferences is needed to plan appropriate management. We set our multiple spatial scale assessment of habitat preferences in a beech forest of central Italy whose landscape, featuring both unmanaged forest and two types of grazed open forest, allowed us to look at the influence of different land uses. Preferred trees occurred in open sites, and those close to tall undergrowth were avoided. A range of moribund or dead trees were used: those preferred had a lower percentage canopy closure, significantly thicker bark, and were more sun-exposed, than the average. Logistic regression showed that the most important variables for selection were distance from nearest occupied tree, bark thickness, undergrowth height and irradiation. Occurrence likelihood augmented as the distance from nearest other occupied tree increased. Despite being mostly unmanaged, forest was avoided, whereas open forest (with trees pruned by ‘shredding’) was used more than expected. Although intensive forestry limits the availability of dead wood, closed forest may be unsuitable when shadowing useful substrate. The disappearance of traditional forms of forest management as shredding and moderate cattle grazing may lead to woody vegetation expansion and habitat closure eventually threatening the persistence of R. alpina. The return to traditional habitat management would be beneficial to R. alpina, an issue that conservation plans should carefully take it into account.

Molecular interactions between the olive and the fruit fly Bactrocera oleae

BackgroundThe fruit fly Bactrocera oleae is the primary biotic stressor of cultivated olives, causing direct and indirect damages that significantly reduce both the yield and the quality of olive oil. To study the olive-B. oleae interaction, we conducted transcriptomic and proteomic investigations of the molecular response of the drupe. The identifications of genes and proteins involved in the fruit response were performed using a Suppression Subtractive Hybridisation technique and a combined bi-dimensional electrophoresis/nanoLC-ESI-LIT-MS/MS approach, respectively.ResultsWe identified 196 ESTs and 26 protein spots as differentially expressed in olives with larval feeding tunnels. A bioinformatic analysis of the identified non-redundant EST and protein collection indicated that different molecular processes were affected, such as stress response, phytohormone signalling, transcriptional control and primary metabolism, and that a considerable proportion of the ESTs could not be classified. The altered expression of 20 transcripts was also analysed by real-time PCR, and the most striking differences were further confirmed in the fruit of a different olive variety. We also cloned the full-length coding sequences of two genes, Oe-chitinase I and Oe-PR27, and showed that these are wound-inducible genes and activated by B. oleae punctures.ConclusionsThis study represents the first report that reveals the molecular players and signalling pathways involved in the interaction between the olive fruit and its most damaging biotic stressor. Drupe response is complex, involving genes and proteins involved in photosynthesis as well as in the production of ROS, the activation of different stress response pathways and the production of compounds involved in direct defence against phytophagous larvae. Among the latter, trypsin inhibitors should play a major role in drupe resistance reaction.

A viral chitinase enhances oral activity of TMOF.

In this study we investigate the combined effect on Heliothis virescens (Lepidoptera, Noctuidae) larvae of Aedes aegypti-Trypsin Modulating Oostatic Factor (Aea-TMOF), a peptide that inhibits trypsin synthesis by the gut, impairing insect digestive function, and Autographa californica nucleopolyhedrovirus Chitinase A (AcMNPV ChiA), an enzyme that is able to alter the permeability of the peritrophic membrane (PM). Aea-TMOF and AcMNPV ChiA were provided to the larvae by administering transgenic tobacco plants, co-expressing both molecules. Experimental larvae feeding on these plants, compared to those alimented on plants expressing only one of the two molecules considered, showed significantly stronger negative effects on growth rate, developmental time and mortality. The impact of AcMNPV ChiA on the PM of H. virescens larvae, measured as increased permeability to molecules, was evident after five days of feeding on transgenic plants expressing ChiA. This result was confirmed by in vitro treatment of PM with recombinant ChiA, extracted from the transgenic plants used for the feeding experiments. Collectively, these data indicate the occurrence of a positive interaction between the two transgenes concurrently expressed in the same plant. The hydrolytic activity of ChiA on the PM of tobacco budworm larvae enhances the permeation of TMOF molecules to the ectoperitrophic space, and its subsequent absorption. The permeation through the paracellular route of Aea-TMOF resulted in a spotted accumulation on the basolateral domain of enterocytes, which suggests the occurrence of a receptor on the gut side facing the haemocoel. The binding of the peptide, permeating at increased rates due to the ChiA activity, is considered responsible for the enhanced insecticide activity of the transgenic plants expressing both molecules. These data corroborate the idea that ChiA can be effectively used as gut permeation enhancer in oral delivery strategies of bioinsecticides targeting haemocoelic receptors.

A new embryonic pattern in parasitic wasps: divergence in early development may not be associated with lifestyle.

Comparative embryogenesis of Encarsia formosa and Encarsia pergandiella (Hymenoptera Aphelinidae), two endoparasitoids of whiteflies (Hemiptera Aleyrodidae), revealed two strongly diverging developmental patterns. Indeed, the centrolecithal anhydropic egg of E. formosa developed through a superficial cleavage, as it occurs in Nasonia vitripennis, Apis mellifera, and Drosophila melanogaster. In contrast, the alecithal hydropic egg of E. pergandiella developed through holoblastic cleavage within a specialized extra‐embryonic membrane (EEM). Since this developmental pattern evolved independently in several lineages of hymenopteran endoparasitoids, departures from the superficial cleavage mode have been argued to be strongly canalized in response to a shift from ecto‐ to endoparasitic lifestyle. Coexistence of both developmental patterns in two congeneric species suggests that alterations of early embryonic development may not be correlated with lifestyle. In addition, embryogenesis of E. pergandiella exhibited the following developmental novelties compared to other species possessing a hydropic egg: (i) polar body derivatives early acquired a cytoskeletal boundary prior to any other cellularization event; (ii) cellularization was asynchronous, starting with an early differentiation of a single apical blastomere at the end of the third cleavage; (iii) appearance of cytoskeletal boundaries of embryo blastomeres occurred between the third and fourth cleavages; (iv) the EEM originated through asynchronous participation of three separate lineages of cleavage nuclei, one of which associated with the polar body derivatives in a syncytium. Our results confirm a scenario of high plasticity in the early developmental strategies of hymenopteran endoparasitoids.

First Record of Anthonomus eugenii (Coleoptera: Curculionidae) in Italy

Summary Anthonomus eugenii Cano (Coleoptera: Curculionidae) was observed for the first time in Italy and the Mediterranean Region attacking sweet pepper (Capsicum annum L.; Solanaceae) in greenhouses and in fields in the coastal area of the Lazio Region of Italy. The incursion, detected in Oct 2013, was a heavy infestation of sweet pepper buds and not fully developed fruits, and causing their premature abscission. The outbreak area was delineated by the coast on the west, and hills on the south and east.

The transcriptional response to the olive fruit fly (Bactrocera oleae) reveals extended differences between tolerant and susceptible olive (Olea europaea L.) varieties

The olive fruit fly Bactrocera oleae (Diptera: Tephritidae) is the most devastating pest of cultivated olive (Olea europaea L.). Intraspecific variation in plant resistance to B. oleae has been described only at phenotypic level. In this work, we used a transcriptomic approach to study the molecular response to the olive fruit fly in two olive cultivars with contrasting level of susceptibility. Using next-generation pyrosequencing, we first generated a catalogue of more than 80,000 sequences expressed in drupes from approximately 700k reads. The assembled sequences were used to develop a microarray layout with over 60,000 olive-specific probes. The differential gene expression analysis between infested (i.e. with II or III instar larvae) and control drupes indicated a significant intraspecific variation between the more tolerant and susceptible cultivar. Around 2500 genes were differentially regulated in infested drupes of the tolerant variety. The GO annotation of the differentially expressed genes implies that the inducible resistance to the olive fruit fly involves a number of biological functions, cellular processes and metabolic pathways, including those with a known role in defence, oxidative stress responses, cellular structure, hormone signalling, and primary and secondary metabolism. The difference in the induced transcriptional changes between the cultivars suggests a strong genetic role in the olive inducible defence, which can ultimately lead to the discovery of factors associated with a higher level of tolerance to B. oleae.

Nature protection areas of Europe are insufficient to preserve the threatened beetle Rosalia alpina (Coleoptera: Cerambycidae): evidence from species distribution models and conservation gap analysis

1. Natura 2000 network (N2000) and national protected areas (NPAs) are recognised as the most important core ‘units’ for biological conservation in Europe.

To divide or not to divide: An alternative behavior for teratocytes in Encarsia pergandiella (Hymenoptera: Aphelinidae).

Encarsia pergandiella (Hymenoptera: Aphelinidae) is an endoparasitoid with an unusual embryonic development compared to most of congeneric species and all other members of the superfamily Chalcidoidea. The developmental background of this wasp is based on an alecithal hydropic egg, with the embryo developing inside an extra-embryonic membrane which dissociates at hatching into special larva-assisting cells, the teratocytes. In E. pergandiella many teratocytes at hatching were multinucleated syncytial cells with no evidence of a cellular membrane separating the nuclei. These teratocytes during larval development produced smaller uninucleated teratocytes, through successive divisions obtained by progressive ingrowth of the plasmatic membrane, accompanied by appearance of degeneration symptoms, such as protrusions and blebs. As a consequence of this divisional process teratocytes showed a size reduction and an increase in number of about four times during the second day of larval development. Only on the third day of larval life teratocytes started to decrease in number, until total disappearance at larval maturation. This behaviour is in striking contrast with all other studied systems in which teratocytes do not divide and progressively decrease in number as the parasitoid larva develops.

First report of Toumeyella parvicornis (Cockerell) in Europe (Hemiptera: Coccidae)

Toumeyella parvicornis (Cockerell), the Pine tortoise scale, is reported for the first time from Europe. Pre-imaginal instars and adults were observed starting from the fall of 2014 in several municipalities of Campania (Italy). Since the species is recorded as a harmful pest of several pine species in North America and the Caribbean, the presence of this alien insect in Europe is alarming and represents a possible major threat for native pine species and related economic activities.

Molecular phylogenetic analyses and morphological variation point to taxonomic problems among four genera of parasitoid doryctine wasps (Hymenoptera : Braconidae)

Abstract. Doryctinae (Hymenoptera : Braconidae) is a large and diverse subfamily of parasitic wasps that has received much attention recently, with new species and genera described and phylogenies based on morphological and/or molecular data that have improved higher-level classification and species delimitation. However, the status of several genera is still unresolved, if not controversial. Here we focus on two related groups of such genera, Dendrosoter Wesmael–Caenopachys Foerster and Ecphylus Foerster–Sycosoter Picard & Lichtenstein. We integrated morphological and molecular (COI and 28S–D2 genes) evidence to highlight, by phylogenetic analyses (maximum likelihood and Bayesian) and a posteriori morphological examination, previously overlooked variation, which is here illustrated and discussed. Monophyly of Dendrosoter and Caenopachys and the presence of synapomorphic morphological characters support synonymy of Caenopachys under Dendrosoter. Low genetic differentiation and high variability for putatively diagnostic morphological characters found in both C. hartigii (Ratzeburg) and C. caenopachoides (Ruschka) supports synonymy of D. caenopachoides under D. hartigii, syn. nov. Morphological and molecular evidence together also indicate independent generic status for Sycosoter, stat. rev., which is here resurrected. This work represents a further advancement in the framework of the ongoing effort to improve systematics and classification of the subfamily Doryctinae.