Mortality of Eggs and Newly Hatched Larvae of Lobesia botrana (Lepidoptera: Tortricidae) Exposed to High Temperatures in the Laboratory

The hypothesis that bunch-zone leaf removal reduces infestations of the European grapevine moth, Lobesia botrana (Denis & Schiffermüller) (Lepidoptera: Tortricidae), by increasing egg and larval mortality owing to sunlight exposure was evaluated in the laboratory by subjecting different egg stages (white, red-eyes, and black-head) and newly hatched larvae to high temperatures. Based on temperatures recorded in a northern Italian vineyard on sun-exposed berries belonging to south-west facing bunches, eggs were subjected to constant temperatures of 40 °C and 37 °C for one or two periods of 3 or 6 h, and to 24-h temperature cycle with peak of 40 °C. Larvae were exposed to 24-h high-temperature cycles with peaks of 35, 37, and 40 °C. The results showed partial egg mortality at 40 °C, increasing with exposure hours and periods, and as eggs matured. Egg mortality was not affected by exposure to 37 °C. Larval survival already decreased significantly at 37 °C and was even lower at 40 °C. These laboratory data are in agreement with the hypothesis that temperatures reached by berries exposed to sunlight cause egg and larval mortality. Data on egg and larval susceptibility to high temperatures have also implications for species distribution and effects of climate change.

Identification and phenology of Hyalesthes obsoletus (Hemiptera: Auchenorrhyncha: Cixiidae) nymphal instars

Urtica dioica and Convolvulus arvensis are the main host plants of Hyalesthes obsoletus and play an important role in the epidemiology of Bois noir of grapevines. The earliest survey, which was carried out to compare the phenology of nymphal instars on U. dioica and C. arvensis, had highlighted some problems in the identification of the instars. Therefore, the correct identification of nymphs to species and instar level became a preliminary aim of this research. Adults and nymphs attributable to H. obsoletus were collected during 2008-2010 in three flatland vineyard habitats of northern Italy on U. dioica, C. arvensis and Artemisia verlotorum. Nymphs and morphologically identified adults of H. obsoletus were submitted to molecular identification. Morphometric and morphological studies were carried out on nymphs collected in the field or obtained in laboratory rearings. Molecular methods not only confirmed the identity of adults, but also allowed the assignment of the nymphs to this species. Morphometric and morphological characteristics (e.g. body and head-thoracic lengths, number of thoracic pits) showed the existence of five nymphal instars. Morphometric differences between newly hatched and older first-instar nymphs were observed. A key to distinguish the five instars was proposed. Evident differences between H. obsoletus nymphs studied here and elsewhere were identified. According to differences in adult-flight period, an earlier phenology of nymphs on C. arvensis than on U. dioica was observed. In particular, the typical overwintering instar was the second on U. dioica and the third on C. arvensis.

[Report in Fruili-Venezia Giulia about Aedes cataphylla, Ae. communis, and Ae. pullatus, three rare mosquitoes in Italy]

Data are provided on the ecology and morphology of Aedes cataphylla, Ae. communis e Ae. pullatus (Diptera, Culicidae), rare species for Italy, collected in the Friuli-Venezia Giulia Region (North-eastern Italy).

[Residual mosquitoes in the northern Adriatic seacoast 50 years after the disappearance of malaria]

The Northern Adriatic Sea littoral was heavily malarious; intensive land drainages, agricultural development and socioeconomic improvement were the key factors which led to malaria eradication, sped up by indoor insecticide spraying, achieved soon after World War II. Regular observations on anophelism were carried out by the Istituto Interprovinciale per la Lotta Antimalarica nelle Venezie from middle 20's until early 60's. The main vector was Anopheles sacharovi, a species which typically bred in coastal brackish swamps; other species were An. atroparvus (which was a probable secondary vector) and the usually strictly zoophilic An. maculipennis, An. melanoon, An. messeae and An. subalpinus. From 1995 to 1997 surveys were carried out in order to review the genus Anopheles in the coastal area of Friuli-Venezia Giulia and Veneto regions. A total of 11,346 females were collected from animal shelters (cow-shed, pigsties, horse stables) of 52 sites along 180 km of coast crossing 5 provinces (from North: Gorizia, Udine, Venezia, Padova and Rovigo). All specimens belonging to the An. maculipennis complex were scored for the presence of the differential characters of An. sacharovi, the only species of the complex morphologically characterized at the adult stage. The examination of morphological characters of single egg batches obtained from field collected females was the main diagnostic tool for the other species. Species identification was subject to confirmation by larval chaetotaxy analysis (number of branches of antepalmate hairs of IV and V abdominal segments) in representative samples of laboratory-reared mature larvae, while biochemical analysis (enzyme electrophoresis) on some samples of identified females was performed in the laboratory of Prof. L. Bullini and Dr. R. Cianchi of the University of Rome "La Sapienza" and partly in our laboratory. No An. sacharovi female was recorded. The examination of 6,361 single ovipositions led to the identification of three species of the An. maculipennis complex: An. atroparvus, An. maculipennis and An. messeae; An. claviger s.str. was also recorded. Larval chaetotaxy examination carried out on 1,608 larvae and the biochemical identification of 467 females confirmed the previous diagnosis based on egg characters. The relative frequency of the three species varied depending on the site: An. maculipennis was the most abundant species north of Venice; south of Venice, and particularly in the Po river delta, the most abundant species were An. atroparvus and, in some sites, An. messeae. In view of the high density recorded for An. atroparvus in some sites (corresponding to various thousands females in a single animal shelter), the vectorial capacity values may be significant and should be assessed.

[Observations on subgenus Aedes (genus Aedes, Diptera, Culicidae) in northeast Italy and first italian report of Aedes geminus Peus]

The paper reports some observations on the subgenus Aedes (genus Aedes, Diptera, Culicidae) in northeast Italy. Two species were collected: Ae. cinereus and Ae. geminus, the latter recorded for the first time in Italy. Morphological, ecological and biological data of the two species are presented. The identification is possible only on the male hypopigium; larvae, pupae and adult females show no differential characters. For both species, the larval breeding sites were fresh water marshes mainly within woods; preimaginal development took place twice a year, in Spring and Autumn. The females were strongly anthropophilic. No biological differences between the two species were noticed, but more data are needed to ascertain their relationships and the presence of subtle biological divergences.