Biological effects of essential oils on Tribolium confusum DuVal and Tenebrio molitor L. (Coleoptera, Tenebrionidae)

Abstract

<p>Tenebrio molitor (Linnaeus, 1758) i Tribolium confusum (du Val, 1863) su česte i &scaron;tetne vrste skladi&scaron;nih insekata. Svake godine nanose vrlo velike ekonomske kvalitativne i kvantitativne gubitke u industriji hrane. Zbog toga je veoma važno da se sprovodi adekvatna za&scaron;tita uskladi&scaron;tenih proizvoda, kao skup mera čijim izvođenjem se gubici u toku skladi&scaron;tenja proizvoda svode na minimum. U doktorskoj disertaciji je ispitano delovanje različitih koncentracija etarskih ulja sledećih biljnih vrsta: mirođija- Anethum graveolens (Linnaeus), kim - Carum carvi (Linnaeus) i zvezdasti anis - Illicium verum (Hook) na ispoljvanje mortaliteta malog i velikog bra&scaron;nara u različitim vremenima ekspozicije (24, 48 i 72h). Na osnovu dobijenih rezultata, Probit analizom određene su LC50 i LC95 vrednosti za svaku vrstu i svako vreme ekspozicije. LC50 koncentracija nakon 48h izabrana je dalja ispitivanja koja su imala zadatak da odrede uticaj na životne parametre velikog i malog bra&scaron;nara, među kojima su: brojnost položenih jaja i brojnost ispiljenih larvi, broj formiranih lutaka, brojnost i odnos polova eklodiranih imaga, mortalitet u toku embrionalnog, postembrionalnog razvića i u toku celokupnog trajanja razvića. Hromatografska analiza etarskih ulja je urađena snimanjem masenih spektara detektovanih komponenti gasnom hromatografijom sa masenom spektrometrijom (Agilent 7890AC opremljen inertnim 5975 XL masenim<br />spektometrom), a zatim i njihova kvantifikacija gasnom hromatografijom sa plameno-jonizacionim detektorom (GC-FID). Takođe, u disertaciji su urađena i sledeća biohemijska ispitivanja insekata:, aktivnost katalaze CAT, superoksid dizmutaze SOD, određivanje sadržaja redukovanog glutationa GSH, aktivnost glutation-S-transferaze GST, intenzitet lipidne peroksidacije kao i određivanje ukupnih proteina<br />Analizom dobijenih rezultata je ustanovljeno da etarska ulja mirođije, kima i zvezdastog anisa značajno skraćuju život imaga malog i velikog bra&scaron;nara, ali ne i život potomstva onih odraslih jedinki koje su preživele uticaj etarskih ulja. Od svih primenjenih etarskih ulja, najjači letalni efekat ima etarsko ulje kima, pri trajanju od 48h. Izračunata LC50 koncentracija za etarsko ulje kima je bila ista za obe vrste 22,18&mu;l/L, pa se ovo ulje izdvaja kao najpogodniji kandidat za kontrolu pojave malog i velikog bra&scaron;nara.<br />Etarska ulja su značajno uticala na smanjenje dužine života mužjaka velikog bra&scaron;nara. Najkraći životni vek utvrđen je nakon ekspozicije LC50 koncentraciji etarskog ulja kima (7,40 dana), dok je najduži zabeležen nakon ekspozicije etarskom ulju mirođije (13,00 dana). Ženke velikog bra&scaron;nara su se izdvojile kao osetljivi pol, po&scaron;to su zabeležene vrednosti bile približne onim kod mužjaka, ali ipak manje (7,32 za etarsko ulje kima, 7,87 za etarsko ulje zvezdastog anisa i 11,15 za etarsko ulje mirođije).<br />Etarska ulja su uticala na dužinu života mužjaka malog bra&scaron;nara. Najkraći život je zabeležen nakon izlaganja etarskom ulju zvezdastog anisa (5,72), dok je najduži, kao i kod velikog bra&scaron;nara, zabeležen nakon ekspozicije etarskom ulju mirođije (13,22). Suprotno mužjacima, ženke malog bra&scaron;nara su najkraće živele nakon izlaganja etarskom ulju kima (9,32), dok su nakon izlaganja etarskim uljima mirođije i zvezdastog anisa imale približno iste srednje vrednosti (14,72 i 14,35).<br />Aktivnost antioksidativnih parametara se menjala pod uticajem vremena izlaganja i vrste etarskih ulja. Superoksid-dizmutaza se izdvojila kao osetljiv parametar, po&scaron;to je u slučaju obe vrste primećena statistički značajna promena aktivnosti, bez obzira na vreme izlaganja. Nakon 48h u slučaju sva tri etarska ulja je primećeno značajno povećanje aktivnosti kod malog bra&scaron;nara, dok je ova pojava kod velikog bra&scaron;nara primećena u slučaju etarskog ulja mirođije. Aktivnost Glutation S-transferaze se može uporediti sa aktivnosti SOD, po&scaron;to se kod malog bra&scaron;nara ovaj parametar u većini<br />slučajeva statistički značajno razlikovao. Kod velikog bra&scaron;nara ova pojava je uočena u slučaju etarskog ulja mirođije, dok je u druga dva slučaja primećena nakon 48h. Sadržaj glutationa statistički je vi&scaron;e varirao u slučaju malog bra&scaron;nara, naročito u slučaju etarskog ulja kima i mirođije, gde je zapaženo statistički značajno smanjenje sadržaja. U slučaju T. molitor smanjen sadržaj je primećen nakon 48h izlaganja etarskom ulju zvezdastog anisa. Obe ispitane insekatske vrste su bile podložne promenama u antioksidativnom sistemu za&scaron;tite, &scaron;to govori o mogućem oksidativnom stresu.</p>

<p>Tenebrio molitor (Linnaeus, 1758) and Tribolium confusum (du Val, 1863) are common and harmful species of storage insects. Every year they inflict very large economic qualitative and quantitative losses in the food industry. Therefore, it is very important to implement adequate protection of stored products, as a set of measures whose implementation minimize losses during storage of products. In the doctoral dissertation, the effects of various concentrations of essential oils of the following plant species was examined: dill - Anethum graveolens (Linnaeus), caraway - Carum carvi (Linnaeus) and star anise - Illicium verum (Hook) on expression of mortality of confused flour beetle and yellow mealworm. Based on the results, Probit analysis was conducted to obtain LC50 and LC95 concentrations. Finally LC50 concentrations after 48h for all three essential oils weres chosen for the further experiments which were conducted in order to examine the influence on the the life parameters of mealworm beetle and confused flour beetle, among which were: the number of layed eggs and number of hatched larvae, number of formed pupae, number and sex ratio of eclosed imagos, mortality during embryonic, postembryonic development and during the entire duration of development. Chromatographic analysis of essential oils was performed by recording the mass spectra of the detected components by gas chromatography with mass spectrometry (Agilent 7890AC equipped with an inert 5975 XL mass spectrometer),<br />followed by their quantification using gas chromatography with flame ionization detector (G). The following biochemical tests of insects were performed in the dissertation, as well: determination of total proteins, CAT catalase activity, SOD superoxide dismutase, determination of reduced glutathione GSH content, glutathione-S-transferase GST activity, as well as, lipid peroxidation intensity.<br />The analysis of the obtained results established that the essential oils of dill, caraway and star anise significantly shorten the life of adults of mealworm beetle and confused flour beetle, but not the life of the offspring of those adult individuals that survived the influence of essential oils. Of all the essential oils used, caraway essential oil has the strongest lethal effect, lasting 48 hours. The calculated LC50 concentration for caraway essential oil of 22.18&mu;l/L, was the same for both insect types, so this oil stands out as the most suitable candidate for controlling the appearance of mealworm beetle and confused flour beetle.<br />Essential oils significantly reduced the life expectancy of confused flour beetle. The shortest lifespan was determined after LC50 exposure to caraway essential oil concentration (7.40 days), while the longest was recorded after exposure to dill essential oil (13.00 days). Females of confused flour beetle were singled out as the sensitive sex, as the recorded values were close to those of males, but still less (7.32 for caraway essential oil, 7.87 for star anise essential oil and 11.15 for dill essential oil).<br />Essential oils have affected the life expectancy of male mealworm beetle. The shortest life was recorded after exposure to the essential oil of star anise (5.72), while the longest, as it was in the case of confused flour beetle, was recorded after exposure to the essential oil of dill (13.22). In contrast to males, females of mealworm beetle lived the shortest after exposure to essential oil of caraway (9.32), while after exposure to essential oils of dill and star anise had approximately the same mean values (14.72 and 14.35).<br />The activity of antioxidant parameters changed under the influence of exposure time and type of essential oils. Superoxide dismutase was singled out as a sensitive parameter, since in both cases a statistically significant change in activity was observed, regardless of the time of exposure. After 48 hours, in the case of all three essential oils, a significant increase in activity was observed in mealworm beetle, while this<br />phenomenon was observed in confused flour beetle in the case of dill essential oil. Glutathione S-transferase activity can be compared with SOD activity, since in mealworm beetle this parameter differed statistically significantly in most cases. In confused flour beetle, this phenomenon was observed in the case of dill essential oil, while in the other two cases it was noticed after 48 hours. The content of glutathione was statistically more varied in the case of mealworm beetle, especially in the case of caraway and dill essential oils, where a statistically significant decrease in content was observed. In the case of T. molitor, a reduced content was observed after 48h of exposure to star anise essential oil. Both examined insect species were subject to changes in the antioxidant protection system, which indicates possible oxidative stress.<br />Accepted on</p>