Males and females of nearly all animals differ in their body size, a phenomenon called sexual size dimorphism (SSD). The degree and direction of SSD vary considerably among taxa, including among populations within species. A considerable amount of this variation is due to sex differences in body size plasticity. We examine how variation in these sex differences is generated by exploring sex differences in plasticity in growth rate and development time and the physiological regulation of these differences (e.g., sex differences in regulation by the endocrine system). We explore adaptive hypotheses proposed to explain sex differences in plasticity, including those that predict that plasticity will be lowest for traits under strong selection (adaptive canalization) or greatest for traits under strong directional selection (condition dependence), but few studies have tested these hypotheses. Studies that combine proximate and ultimate mechanisms offer great promise for understanding variation in SSD and sex differences in body size plasticity in insects.

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Sex differences in phenotypic plasticity affect variation in sexual size dimorphism in insects: from physiology to evolution.

Olive fruit fly, Bactrocera oleae (Rossi) (Diptera: Tephritidae), is the major pest of commercial olives worldwide. Various aspects of its biology, ecology, management, and impact on olive production are highlighted. With the discovery of insecticidal resistance in some populations frequently treated with organophosphates, old and new control options are being investigated. The potential of biological control is examined. Surveys suggest that a small group of braconids in the Opiinae subfamily best represent the primary parasitoids attacking olive fruit fly in its native range. These species include Psyttalia lounsburyi, P. dacicida, P. concolor, P. ponerophaga, and Utetes africanus. Bracon celer, another braconid but in the Braconinae subfamily, is also reared from the fruit fly in its native range. The potential of these and other natural enemies is discussed with respect to olive fruit fly biology, commercial olive production, and biological constraints that may limit their success. We suggest that numerous species exist that should be further investigated as control agents for olive fruit fly in the many climatic regimes where the pest is found.

Olive Fruit Fly: Managing an Ancient Pest in Modern Times

Species in the family Botryosphaeriaceae are common pathogens causing fruit rot and dieback of many woody plants. In this study, 150 Botryosphaeriaceae isolates were collected from olive and other hosts in Spain and California. Representative isolates of each type were characterized based on morphological features and comparisons of DNA sequence data of three regions: internal transcribed spacer 5.8S, β-tubulin, and elongation factor. Three main species were identified as Neofusicoccum mediterraneum, causing dieback of branches of olive and pistachio; Diplodia seriata, causing decay of ripe fruit and dieback of olive branches; and Botryosphaeria dothidea, causing dalmatian disease on unripe olive fruit in Spain. Moreover, the sexual stage of this last species was also found attacking olive branches in California. In pathogenicity tests using unripe fruit and branches of olive, D. seriata isolates were the least aggressive on the fruit and branches while N. mediterraneum isolates were the most aggressive on both tissues. Isolates of B. dothidea which cause dalmatian disease on fruit were not pathogenic on branches and only weakly aggressive on fruit. These results, together with the close association between the presence of dalmatian disease symptoms and the wound created by the olive fly (Bactrocera oleae), suggest that the fly is essential for the initiation of the disease on fruit. Isolates recovered from dalmatian disease symptoms had an optimum of 26°C for mycelial growth and 30°C for conidial germination, suggesting that the pathogen is well adapted to high summer temperatures. In contrast, the range of water activity in the medium for growth of dalmatian isolates was 0.93 to 1 MPa, which was similar to that for the majority of fungi. This study resolved long-standing questions of identity and pathogenicity of species within the family Botryosphaeriaceae attacking olive trees in Spain and California.

https://apsjournals.apsnet.org/doi/pdf/10.1094/PHYTO-12-09-0343

Characterization and Pathogenicity of Botryosphaeriaceae Species Collected from Olive and Other Hosts in Spain and California

Olive products are premium food products. Their inherent chemical composition and sensory attributes make them highly appreciated worldwide. Olive products quality and composition are severely compromised by diversified agricultural and technological factors, among which olive pests play a key factor, particularly the olive fly Bactrocera oleae (Rossi) (Diptera: Tephritidae). This pest reveals cultivar oviposition preference being the cause of severe economic damages caused each year. Losses goes from the field and tree to consumers table. The damages caused by olive fly, seen by an economic perspective, as well as their influence in olive products classification, quality, composition, stability, nutritional, bioactive and functional properties are discussed in the present revision.

A review of Bactrocera oleae (Rossi) impact in olive products: From the tree to the table

Over two consecutive seasons, 16 olive orchards with trees exhibiting dieback symptoms on branches were surveyed in southern Spain. The six dominant fungal species recovered were characterized by means of phenotypic observations, DNA analysis (by sequencing of the internal transcribed spacer, β-tubulin, and large subunit nuclear ribosomal DNA regions), and pathogenicity tests. Additionally, three isolates collected from Tunisian olive trees showing similar dieback symptoms, one isolate of Colletotrichum godetiae, and a reference isolates of Neofusicoccum mediterraneum were included. The resistance of the 11 most important table cultivars to N. mediterraneum and Botryosphaeria dothidea, the causal agent of “escudete” (small shield) of fruit, was studied by the inoculation of branches and immature fruit, respectively. The species Cytospora pruinosa, N. mediterraneum, Nothophoma quercina, Comoclathris incompta, and Diaporthe sp. were identified. Only N. mediterraneum and C. incompta were able to induce the t...

https://apsjournals.apsnet.org/doi/pdf/10.1094/PDIS-06-16-0806-RE

Identification of Fungal Species Associated with Branch Dieback of Olive and Resistance of Table Cultivars to Neofusicoccum mediterraneum and Botryosphaeria dothidea

Within the framework of research concerning the application of techniques alternative to chemical pesticides for control of parasites, the CRA Experimental Institute for Olive Growing for many years has been performing a large investigation in order to detect sources of genetic resistance in olive germplasm In the present study we observed the behavior related to the olive fly (Bactrocera oleae) infestation and Camarosporium dalmaticum infection of ten olive cultivars farmed under the same agronomic and climatic conditions in Calabria, Southern Italy The sampling and the data collecting were carried out in three different ripening times The drupe amount of oleuropein and cyanidine was detected by laboratory analyses in order to verify a possible correlation between these molecules and the level of infestation/infection of the above-mentioned parasites The obtained data were submitted to analysis of variance In relation to the fungal infection the results displayed that cvs Tonda nera dolce showed the lowest susceptibility, while the cv Giarraffa turned out to be the most susceptible The less susceptible cultivars to the phytophagous were Tonda nera dolce and Bhardi Tirana Since the less susceptible cultivar to olive fly attacks are the same observed in relation to the susceptibility to olive fruit rot, it is suggested a relation between the olive fly infestation and the fungal infection It suggests the utility to achieve these results both to transfer directly to the farmers' world and to emphasize ecosystem health and biodiversity conservation

Assessment of susceptibility of olive cultivars to the Bactrocera oleae (Gmelin, 1790) and Camarosporium dalmaticum (Thüm.) Zachos & Tzav.-Klon. attacks in Calabria (Southern Italy).

Vincenzo Ripa

Papers

Assessment of susceptibility of olive cultivars to the Bactrocera oleae (Gmelin, 1790) and Camarosporium dalmaticum (Thüm.) Zachos & Tzav.-Klon. attacks in Calabria (Southern Italy).