PRVI NALAZ ENTOMOPHAGA MAIMAIGA (ENTOMOPHTHORALES: ENTOMOPHTHORACEAE) U POPULACIJAMA LYMANTRIA DISPAR U GRČKOJ I REPUBLICI MAKEDONIJI

The entomopathogenic fungus Entomophaga maimaiga Humber, Shimazu & Soper (Entomophtorales: Entomophtoraceae) was found for first time in populations of gypsy moth, Lymantria dispar (L.) (Lepidoptera: Erebidae), in Greece and the Former Yugoslavian Republic of Macedonia (FYROM) after its introduction in Bulgaria in 1999. Monitoring studies were conducted in 2012 in oak stands in three sites in the Xanthi region in Greece, and in three sites in FYROM in the Prilep region. Gypsy moth larvae, predominately in fourth to sixth instar, were collected in May and June. During laboratory rearing, mortality of gypsy moth larvae collected in two sites in Greece ranged from 36.4–89.3%. Larval mortality of L. dispar in the three sites in FYROM ranged from 16.7–87.8%. Dead larvae were analysed under light microscopy for presence of E. maimaiga and other entomopathogens. E. maimaiga was recorded from one site in Greece (Kidaris vill.), and in all study sites in FYROM (Toplica, Belovodica and Krushevo vill.). Azygospores of E. maimaiga were found in the bodies of 78.6% of gypsy moth larvae from Kidaris, and in 8.3–16.3% of the larvae from sites in FYROM. Recent records of E. maimaiga in Serbia and the European part of Turkey, and present findings in Greece and FYROM, indicate that the fungus most probably has invaded gypsy moth populations in other parts of Balkan Peninsula.Entomopatogena gljiva Entomophaga maimaiga Humber, Shimazu & Soper (Entomophtorales: Entomophtoraceae) prvi je puta utvrđena u populacijama gubara, Lymantria dispar (L.) (Lepidoptera: Erebidae) u Grčkoj i Republici Makedoniji nakon introdukcije ovog patogena u Bugarsku 1999. godine. Tijekom 2012. godine obavljen je pregled hrastovih sastojina na tri lokacije u području Xanthi u Grčkoj i na tri lokacije u okolici Prilepa u Makedoniji. Gusjenice gubara sakupljane su većinom u četvrtom do šestom larvalnom stadiju u razdoblju svibanj–lipanj. Tijekom laboratorijskog uzgoja smrtnost gusjenica sakupljenih u Grčkoj iznosila je od 36,4 do 89,3 %. Smrtnost gusjenica s lokaliteta u Makedoniji bila je između 16,7 i 87,8 %. Uginule gusjenice analizirane su pomoću svjetlosnog mikroskopa na prisutnost E. maimaiga i ostalih patogena. Patogena gljiva E. maimaiga utvrđena je na uzorku s jednog lokaliteta u Grčkoj (Kidaris) i na uzorcima svih lokaliteta u Makedoniji (Toplica, Belovodica i Kruševo). Azigospore E. maimaiga utvrđene su u 78,6 % uginulih gusjenica s lokaliteta Kidaris i između 8,3 i 16,3 % uginulih gusjenica s tri lokaliteta u Makedoniji. Nedavni nalazi E. maimaiga u Srbiji i europskom dijelu Turske te najnoviji nalazi u Grčkoj i Republici Makedoniji ukazuju na vjerojatnost da je ovaj patogen već inficirao populacije gubara u ostalim dijelovima balkanskog poluotoka

Egg parasitoids of Thaumetopoea pityocampa in the region of Gyumyurdzhinski Snezhnik in Eastern Rhodopes, Bulgaria

The region of Gyumyurdzhinski Snezhnik in the Eastern Rhodopes is the closest in Bulgaria to the Aegean Sea. However, the climate is characterized by specific parameters that are determined by its relief. It is poorly protected from the invasion of cold air masses from the north. From the south, the Gyumyurdzhinski Snezhnik hill restrains the Mediterranean influence. The orography of the area favors the retention of cold air masses and a further drop in temperatures. The experimental material for the study includes 5 generations of Thaumetopoea pityocampa (2016, 2017, 2018, 2019, and 2022), collected in 31 locations of four State Forestry Enterprises: Kirkovo, Ardino, Momchilgrad, and Zlatograd. The sample for analysis included 693 egg batches with 148420 eggs in them. Seven primary egg parasitoids were established in this region: Ooencyrtus pityocampae, Baryscapus servadeii, Pediobius bruchicida, Anastatus bifasciatus, Eupelmus vesicularis, E. vladimiri, Trichogramma sp. and one hyperparasitoid (B. transversalis). Dominant parasitoids were B. servadeii and O. pityocampae, and E. vladimiri and P. bruchicida – occasional parasitoids. The hyperparasitoid B. transversalis participated in the complex with a relatively low share. The survival of the egg parasitoids in the laboratory conditions, in which the samples were kept, was low. The total mortality of the parasitoids in larval and adult stages was 47.8%. After collecting the samples, in laboratory conditions, a total of 442 individuals of the hyperparasitoid B. transversalis emerged, of which 56.3% were females and 43.7% were males. The average number of pine processionary moth eggs in a batch was 214.2. 70.8% of all the eggs in the samples hatched successfully. The egg parasitoids are a very serious natural factor, regulating the density of the pine processionary moth, but their impact varied from 2.1% to 30.3%. The natural characteristics of the area, the air temperature during the stages of eggs and young larvae, are favorable for the development of the pine processionary moth. Unhatched larvae without the influence of entomophages were 7.2%

Monitoring of the health status of Castanea sativa in the Belasitsa mountain, southwest Bulgaria

In the period 2017-2023, a survey for the assessment of the phytosanitary condition of sweet chestnut (Castanea sativa) was conducted in a permanent sample plot (PSP) Belasitsa, which is part of the European large-scale network for monitoring the health status of forest ecosystems under the International Co-operative Program ‘Forests’. The PSP is set in a natural chestnut stand in Belasitsa mountain at an altitude of 643 m. Data collected from the first years of the monitoring determined a slight deterioration in the health status of the chestnut trees caused by an infection with the fungal pathogen Cryphonectria parasitica. An improvement in trees’ vitality and lack of active necrosis were observed in 2022-2023. On the wounds, initiation of callus along the wounded edges was reported. Currently, the introduction of new and dangerous invasive insect pests Dryocosmus kuriphilus, Corythucha arcuata, etc., has not been detected. Attacks of both pests could further deteriorate the health status of the sweet chestnut in Belasitsa

Doubly Uniparental Inheritance of Mitochondria As a Model System for Studying Germ Line Formation

BACKGROUND: Doubly Uniparental Inheritance (DUI) of mitochondria occurs when both mothers and fathers are capable of transmitting mitochondria to their offspring, in contrast to the typical Strictly Maternal Inheritance (SMI). DUI was found in some bivalve molluscs, in which two mitochondrial genomes are inherited, one through eggs, the other through sperm. During male embryo development, spermatozoon mitochondria aggregate in proximity of the first cleavage furrow and end up in the primordial germ cells, while they are dispersed in female embryos. METHODOLOGY/PRINCIPAL FINDINGS: We used MitoTracker, microtubule staining and transmission electron microscopy to examine the mechanisms of this unusual distribution of sperm mitochondria in the DUI species Ruditapes philippinarum. Our results suggest that in male embryos the midbody deriving from the mitotic spindle of the first division concurs in positioning the aggregate of sperm mitochondria. Furthermore, an immunocytochemical analysis showed that the germ line determinant Vasa segregates close to the first cleavage furrow. CONCLUSIONS/SIGNIFICANCE: In DUI male embryos, spermatozoon mitochondria aggregate in a stable area on the animal-vegetal axis: in organisms with spiral segmentation this zone is not involved in cleavage, so the aggregation is maintained. Moreover, sperm mitochondria reach the same embryonic area in which also germ plasm is transferred. In 2-blastomere embryos, the segregation of sperm mitochondria in the same region with Vasa suggests their contribution in male germ line formation. In DUI male embryos, M-type mitochondria must be recognized by egg factors to be actively transferred in the germ line, where they become dominant replacing the Balbiani body mitochondria. The typical features of germ line assembly point to a common biological mechanism shared by DUI and SMI organisms. Although the molecular dynamics of the segregation of sperm mitochondria in DUI species are unknown, they could be a variation of the mechanism regulating the mitochondrial bottleneck in all metazoans

New tachinid parasitoids on pine processionary moth (Thaumetopoea pityocampa) (Diptera: Tachinidae) in Bulgaria

The tachinid parasitoids (Diptera: Tachinidae) of the pine processionary moth (Thaumetopoea pityocampa) were studied in 2019 and 2020 in the Eastern Rhodopes (Fotinovo, Kandilka and Sarnak vills.), the Western Rhodopes (Dobrostan vill.) and the Struma Valley (town of Sandanski). In total, 1193 larvae and pupae of T. pityocampa were collected in 40-50-year-old Pinus nigra plantations. They were transported and observed in laboratory conditions at 20-22 °С. Three parasitoids, Compsilura concinnata, Exorista (Exorista) fasciata and Phryxe vulgaris were reared from the host. In this study, E. fasciata was established for the first time in trophic association with T. pityocampa. In addition, P. vulgaris was confirmed as a parasitoid of the host. The mortality of the pine processionary moth caused by tachinids in different localities was 0.5-5.3%, with an average of 2.6% for the country

New tachinid parasitoids on pine processionary moth (Thaumetopoea pityocampa) (Diptera: Tachinidae) in Bulgaria

The tachinid parasitoids (Diptera: Tachinidae) of the pine processionary moth (Thaumetopoea pityocampa) were studied in 2019 and 2020 in the Eastern Rhodopes (Fotinovo, Kandilka and Sarnak vills.), the Western Rhodopes (Dobrostan vill.) and the Struma Valley (town of Sandanski). In total, 1193 larvae and pupae of T. pityocampa were collected in 40-50-year-old Pinus nigra plantations. They were transported and observed in laboratory conditions at 20-22 °С. Three parasitoids, Compsilura concinnata, Exorista (Exorista) fasciata and Phryxe vulgaris were reared from the host. In this study, E. fasciata was established for the first time in trophic association with T. pityocampa. In addition, P. vulgaris was confirmed as a parasitoid of the host. The mortality of the pine processionary moth caused by tachinids in different localities was 0.5-5.3%, with an average of 2.6% for the country

A review of Trichogramma Westwood parasitoids on eggs of Thaumetopoea pityocampa (Denis & Schiffermüller) in habitats of the Balkan Peninsula and Asia Minor

Studies on egg parasitoids of the pine processionary moth (Thaumetopoea pityocampa) were conducted during the period 1991-2018 in native localities of the pest on the Balkan Peninsula and in Asia Minor. In Bulgaria the biological material (2510 egg batches and 579273 eggs) was collected in 48 host localities. A number of 650 egg batches and 135611 eggs were studied from the Balkan countries (North Macedonia, Bosnia and Herzegovina, Albania and Greece), and in the Asian part of Turkey (Asia Minor), the biological material was examined from nine habitats. Eight species of egg parasitoids (Ooencyrtus pityocampae, Baryscapus servadeii, B. transversalis, Pediobius bruchicida, Anastatus bifasciatus, Eupelmus vesicularis, E. vladimiri and Trichogramma sp.) were found. The total regulating effect of egg parasitoids in Bulgaria was on average 17.6%, and in the other Balkan countries – 24.9%. Trichogramma sp. was found in 63.1% of the analysed samples in Bulgaria and in 55.6% from the neighboring countries. The percent of parasitism of T. pityocampa eggs by Trichogramma sp. was low - on average 0.39% for Bulgaria and 0.73% for the other Balkan countries. The relative share of the species in the total percentage of parasitised eggs for Bulgaria and the other countries was 2.2% and 2.9%, respectively.

Egg parasitoid complex of the pine processionary moth (Thaumetopoea pityocampa) on the Thasos Island, Greece

The egg parasitoid complex of the pine processionary moth (Thaumetopoea pityocampa) was surveyed for the first time on the Thasos Island, Greece. A total of 96 egg batches containing 20391 eggs were collected between 06 and 10 of September, 2017 from Aleppo pines (Pinus halepensis) at four sites (Skidia, Thimonia, Alyki and Panagia). Four primary parasitoids were identified (Ooencyrtus pityocampae, Baryscapus servadeii, Anastatus bifasciatus and Trichogramma sp.), as well as the hyperparasitoid B. transversalis. Among the parasitoids groups, O. pityocampae was the most common, followed by B. servadeii, whilst the number of other species was low. The highest survival rate was reported for three species: O. pityocampae, B. servadeii and A. bifasciatus, while the highest was the mortality in Trichogramma sp. All emerged adults of O. pityocampae and B. servadeii were female specimens and in A. bifasciatus – males. The number of females of B. transversalis was three times higher than the one of males. Ooencyrtus pityocampae and B. servadeii were the most important parasitoids of T. pityocampa, destroying respectively 27.1% and 9.9% of the host eggs

Factors affecting Thaumetopoea pityocampa emergence in laboratory conditions

To investigate the factors affecting the emergence of the pine processionary moth (Thaumetopoea pityocampa) in laboratory conditions, a number of 1487 larvae, prepupae and pupae were collected in the period February-May 2019 from five pest habitats: Fotinovo and Kandilka villages (inhabited by a summer phenological form), Sandanski and Klisura towns (winter phonological form occurs) and Sarnak village (both forms occur). At the date of collection, the rate of parasitism was very low (0-0.1%). Throughout the study, significant differences in the characteristics of pupal stage and mortality between both phenological forms were established. The rate of emerged adults varied from 21.4% to 77.6% in the observed habitats. The sex ratio between female and male specimens was almost equal. Only 0.6% of samples emerged in the second year, after diapause. In four localities (Fotinovo, Kandilka, Sandanski and Sarnak), the rate of infection by entomopathogens was between 6.0% and 20.8%, and the parasitism caused by tachinids – between 0.9% and 3.4%. The flight period of the summer and winter phenological forms of T. pityocampa were clearly differentiated with about a month. In summer form, the flight began in late May and ended in the last decade of June, and in winter form – from early July to the end of August. The duration of the flight period in both forms lasted 30 to 50 days with an equal number of emerged male and female specimens