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Detecting olive grove abandonment with Sentinel-2 and machine learning: The development of a web-based tool for land management
Full text linkThe Cuticular Hydrocarbons of Dasineura Oleae Show Differences Between Sex, Adult Age and Mating Status
Full text linkAbstract: In insects, cuticular lipids prevent water loss and act as semiochemicals. Because of their ecological function, the profile change across the insects’ sex and development offers insight into insect biology and possible tools for pest management. Here, the first work on cecidomyiid cuticular extracts is proposed considering Dasineura oleae (Diptera: Cecidomyiidae) males and females at different adult ages (0–12 h, 12–24 h, 24–36 h) and distinct sexual conditions (virgin and mated). A set of 49 compounds were recorded (12 alkanes, 1 monomethyl alkane, 11 fatty acids, 4 esters, 1 aldehyde, 1 allylbenzene, 1 amine, 1 flavonoid, 1 ketone, 1 phenol, 1 steradiene, 1 sterol, 1 terpene, 1 triterpene and 11 unknown compounds), and 18 of them showed significant differences between groups. Among alkanes, hexacosane (nC26) exhibited a decreasing trend from the youngest to the oldest females, while pentacosane (nC25) and nonacosane (nC29) showed a decreasing trend from 0 to 12 h to 12–24 h virgin females. In addition, nonadecane (nC19) was significantly more abundant in the youngest males compared to older males and females. The alkanes nC25, nC26 and nC29 have been reported to be age-related also in other dipterans, while nC19 has been described as gender-specific chemical cue for platygastrid parasitoids. Further behavioural trials and analyses are required to assign the specific ecological roles to the characterized compounds. Our results may contribute to develop new low-impact control strategies relying on the manipulation of D. oleae’s chemical communication (e.g. disruption of mating or species recognition). Highlights: • Cuticular hydrocarbons are often involved in dipteran intraspecific communication. • We explored the cuticular profile of D. oleae at different age, sex, mating condition. • Five alkanes and one mono-methyl alkane showed differences among groups. • Linoleic acid is the most abundant compound in virgins, absent in mated insects. • Eleven compounds disappear in mated insects, but were present in all virgins. Graphical Abstract: [Figure not available: see fulltext.
Infestation of the gall midge Dasineura oleae provides first evidence of induced plant volatiles in olive leaves
Full text linkIn this study, we present the first characterization of herbivore-induced plant volatiles (HIPVs) released from infested olive leaves. The gall midge Dasineura oleae is a specific pest of Olea europaea and endemic of the Mediterranean Basin, an area in which severe outbreaks currently occurred. Little is known about the damage caused by the pest and the relationship with its host. Since gall formation and larval feeding activity may lead to the release of specific plant volatile compounds, we investigated the volatile profiles emitted from infested plants compared with healthy plants under both laboratory and field conditions. Additionally, the volatiles emitted from mechanically damaged plants were considered. A blend of 12 volatiles was emitted from olive trees infested by D. oleae. Of these, β-copaene, β-ocimene, cosmene, unknown 1 and unknown 3 were found to be exclusively emitted in infested plants. The emission of germacrene-D, (E,E)-α-farnesene, and (Z,E)-α-farnesene, α-copaene, (E)-4,8-dimethylnona-1,3,7-Triene, (E)-β-guaiene and heptadecane significantly increased in infested trees. Linalool, β-copaen-4-α-ol, β-bourbonene, β-cubebene, β-elemene, β-copaene and δ-Amorphene were found only in the field trial and showed differences depending on the level of infestation and the plant stage. (Z)-3-Hexenol, (E)-4-oxohen-2-enal, and 2-(2-butoxyethoxy)-ethanol, were exclusively emitted from the leaves after mechanical damage. In a field trial in Italy, we also demonstrated spring synchronization between adults of D. oleae and O. europaea trees. Analyses of morphoanatomical malformations of gall leaves showed that tissue alterations occur at the spongy parenchyma causing an increase of the leaf blade thickness. We speculate that tissue alterations may lead to HIPV release, in turn potentially attracting D. oleae natural enemies
Observations on an infestation by green peach aphid (Homoptera: Aphididae) on greenhouse tomatoes in Italy
No full textThe ecology and biology of green peach aphids, Myzus persicae (Sulzer), were studied on greenhouse tomatoes with the goals of learning more about the biology of the species in these conditions and of measuring parameters to implement a computer simulation that could be used in programs for resistance management. Control groups and groups of tomatoes ('Ausonio' and Acor') treated with deltamethrin were observed throughout the growing season, and selected plants were observed in detail. At weekly intervals, the following measurements were recorded: height of the plant, number of leaves and flower clusters, health condition, phenological phase of the plans, presence-absence of M. persicae (and if present, the numbers for each life stage on each leaf or flower bud), and the presence-absence of other parasitoids and predators. Although the trial demonstrated the efficacy of chemical treatments in reducing the number of aphids, the infestation did not seem to have consistent effects on fruit production
Shedding Light on Dasineura oleae Parasitoids: Local and Landscape Effects
Full text linkDasineura oleae was considered a minor pest in olive orchards. However, in the last decade, outbreaks have been reported all over its distribution area. Little is known about D. oleae biological control strategies; therefore, investigations into the biology and ecology of D. oleae parasitoids are urgently needed. In this scenario, the present field study reported the flight period of D. oleae parasitoids, evaluating their relative abundance over other parasitoids living in olive orchards. Furthermore, it estimated the effect of local and landscape features on D. oleae parasitoids within the frame of the overall parasitoid community. Lastly, we aimed to provide useful insights into the effectiveness of parasitoids for D. oleae population management. Hymenopteran parasitoids were sampled using Malaise traps in six sampling sites in central Italy. Results showed that Platygaster demades was the most abundant D. oleae parasitoid. Its presence was associated with high rates of D. oleae parasitism. The abundance of this parasitoid was influenced by the abundance of seminatural habitats
Soluble proteins in chemosensory organs of plasmids
No full textSoluble proteins of low molecular weight have been purified from chemosensory organs of five species of Phasmids. On the basis of their N-terminal aminoacid sequences, two classes can be identified, Polypeptides of 14 and 15 kDa, expressed in the antennae and legs of Eurycantha calcarata and Extatosoma tiaratum, as well as in the antennae of Carausius morosus, bear a close similarity (around 45% identity) with a soluble protein associated,vith the sensilla coeloconica of Drosophila melanogaster. Two proteins of 19 and 18 kDa, isolated from the antennae and the maxillary palpi, respectively, of Acrophylla wuelfingi, are 59 and 75% identical, in their N-terminal region, to a 19 kDa antennal protein of Carausius morosus, Similarity between members of the two classes is not significant, being limited to two to three identical aminoacids in the most favorable cases, Finally, a 17 kDa protein, specifically expressed in the antennae of Sipyloidea sipylus, did not show any homology with other proteins, The expression in sensory organs and the characteristics of these proteins may suggest a function in chemosensory transduction. Copyright (C) 1996 Elsevier Science Lt
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