253 research outputs found

    Chemical contaminants, pathogen exposure and general health status of live and beach-cast Washington sea otters (Enhydra lutris kenyoni)

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    Analyses of blood and liver samples from live captured sea otters and liver samples from beachcast sea otter carcasses off the remote Washington coast indicate relatively low exposure to contaminants, but suggest that even at the low levels measured, exposure may be indicated by biomarker response. Evidence of pathogen exposure is noteworthy - infectious disease presents a potential risk to Washington sea otters, particularly due to their small population size and limited distribution. During 2001 and 2002, 32 sea otters were captured, of which 28 were implanted with transmitters to track their movements and liver and blood samples were collected to evaluate contaminant and pathogen exposure. In addition, liver samples from fifteen beachcast animals that washed ashore between 1991 and 2002 were analyzed to provide historical information and a basis of reference for values obtained from live otters. The results indicate low levels of metals, butyltins, and organochlorine compounds in the blood samples, with many of the organochlorines not detected except polychlorinated biphenyls (PCBs), and a few aromatic hydrocarbons detected in the liver of the live captured animals. Aliphatic hydrocarbons were measurable in the liver from the live captured animals; however, some of these are likely from biogenic sources. A significant reduction of vitamin A storage in the liver was observed in relation to PCB, dibutyltin and octacosane concentration. A significant and strong positive correlation in vitamin A storage in the liver was observed for cadmium and several of the aliphatic hydrocarbons. Peripheral blood mononuclear cell (PBMC) cytochrome P450 induction was elevated in two of 16 animals and may be potentially related to aliphatic and aromatic hydrocarbon exposure. Mean concentration of total butyltin in the liver of the Washington beach-cast otters was more than 15 times lower than the mean concentration reported by Kannan et al. (1998) for Southern sea otters in California. Organochlorine compounds were evident in the liver of beach-cast animals, despite the lack of large human population centers and development along the Washington coast. Concentrations of PCBs and chlordanes (e.g., transchlordane, cis-chlordane, trans-nonachlor, cis-nonachlor and oxychlordane) in liver of Washington beach-cast sea otters were similar to those measured in Aleutian and California sea otters, excluding those from Monterey Bay, which were higher. Mean concentrations of 1,1,1,- trichloro-2,2-bis(p-chlorophyenyl)ethanes (DDTs) were lower, and mean concentrations of cyclohexanes (HCH, e.g., alpha BHC, beta BHC, delta BHC and gamma BHC) were slightly higher in Washington beach-cast otters versus those from California and the Aleutians. Epidemiologically, blood tests revealed that 80 percent of the otters tested positive for morbillivirus and 60 percent for Toxoplasma, the latter of which has been a significant cause of mortality in Southern sea otters in California. This is the first finding of positive morbillivirus titers in sea otters from the Northeast Pacific. Individual deaths may occur from these diseases, perhaps more so when animals are otherwise immuno-compromised or infected with multiple diseases, but a population-threatening die-off from these diseases singly is unlikely while population immunity remains high. The high frequency of detection of morbillivirus and Toxoplasma in the live otters corresponds well with the cause of death of stranded Washington sea otters reported herein, which has generally been attributable to infectious disease. Washington’s sea otter population continues to grow, with over 1100 animals currently inhabiting Washington waters; however, the rate of growth has slowed over recent years. The population has a limited distribution and has not yet reached its carrying capacity and as such, is still considered at high risk to catastrophic events. (PDF contains 189 pages

    Determination of Helicoverpa armigera (Lepidoptera: Noctuidae) larval instars and age based on head capsule width and larval weight

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    Προνύμφες του Helicoverpa armigera (Lepidoptera: Noctuidae) εκτράφηκαν σε χώρο με 26°C, φωτόφαση 16 ωρών και σχετική υγρασία 60-75%. Μετρήθηκαν, ανά προνυμφικό στάδιο, το πλάτος της κεφαλικής κάψας και το βάρος κάθε προνύμφης 2-3 ημέρες μετά την έκδυση, με σκοπό τον προσδιορισμό του προνυμφικού σταδίου και της ηλικίας. Χρησιμοποιήθηκε επί πλέον το βάρος της προνύμφης γιατί δεν είναι ασφαλής ο προσδιορισμός των προνυμφικών σταδίων μόνο από το πλάτος της κεφαλικής κάψας, καθόσον υπάρχει αλληλεπικάλυψη μεταξύ πλάτους ενός σταδίου και του προηγούμενου και επόμενου του, και ακόμη παρατηρείται διαφορετικός αριθμός σταδίων μεταξύ των προνυμφών. Η ανάπτυξη συμπληρώνεται σε 5 προνυμφικά στάδια στο 75% των προνυμφών, σε 6 στο 24% και σε 7 στο1%. Το πλάτος της κεφαλικής κάψας ήταν αρκετό για τη διάκριση των προνυμφών της Ιου σταδίου μόνο και το μέγιστο πλάτος ήταν 0,4mm. Το βάρος της προνύμφης ήταν ικανό μόνο του να προσδιορίσει προνύμφες 1ης και 2ης ηλικίας. Η διαφορά μεταξύ Ιου και 2ου σταδίου ήταν lmg και μεταξύ 2ου και 3ου σταδίου 5,5mg. Συσχέτιση και ανάλυση παραλλακτικότητας των δύο παραμέτρων μας δίνει τη δυνατότητα προσδιορισμού όλων των προνυμφικών σταδίων μιας προνύμφης με πιθανότητα 96,9%,.καθώς και την ηλικία της σε ημέρες από την εκκόλαψη.Larνae of Helicoverpa armigera (Hubner) (Lepidoptera: Noctuidae) were reared in laboratory conditions (26°C, 16:8 L:D) and measurements of larval head capsule width, and body weight, were used in order to determine the boundaries of larval instars. Larvae of Η. armigera completed development in 5 to 7 instars. Head capsule width could predict the larval instar only for Ll. The upper boundary of head width for L1 was 0.4mm. Body weight could predict both L1 and L2 larval instars. Boundaries between L1-L2 instars were found to be 1 mg and for L2-L3 5,5 mg. Correlation and regression analysis suggest that a combination of head capsule width and body weight can predict both larval instars and chronological age under constant conditions in the laboratory

    Egg parasitoids of the genus Trichogramma (Hymenoptera, Trichogrammatidae) in olive groves of the Mediterranean region

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    A survey of egg parasitoids of the genus Trichogramma (Hymenoptera, Trichogrammatidae) was carried out in olive groves in Portugal, Greece, Egypt, and Tunisia during the years 2002–2004. Parasitoids were obtained either by exposing sentinel eggs (Sitotroga cerealella Olivier or Ephestia kuehniella Zeller) on olive trees or by collecting eggs of lepidopterous olive pests. Parasitized egg samples were reared separately in the laboratory for emergence of parasitoids. These were further reared in separate lines and processed by morphological and molecular biology techniques for species characterization. The recorded fauna of Trichogramma parasitoids in olive groves was species poor and consisted of species mainly known from the Mediterranean region. Trichogramma bourarachae Pintureau and Babault was found in Tunisia and Egypt, T. cordubensis Vargas and Cabello, and T. euproctidis Girault in Egypt, Trichogramma cacoeciae Marchal in Portugal, Greece, Egypt, Tunisia and Trichogramma nerudai Pintureau and Gerding in Portugal. Apart from that, Trichogramma oleae Voegele´ and Pointel was collected in Tunisia. This species is probably not indigenous, but has established after several releases of a French strain were made in recent years. For selected strains, the sequence of the internal transcribed spacer 2 (ITS-2) region of rDNA was determined and deposited in the GenBank database. Differences in important biological attributes were found among collected strains of T. bourarachae, suggesting the existence of biotypes. The results contribute to the limited knowledge on distribution and biodiversity of the genus Trichogramma in the Mediterranean region. They can be helpful for the preservation and use of indigenous Trichogramma species in biological control of lepidopterous pests in olive and other local crops

    Pest categorisation of Thecodiplosis japonensis

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    The EFSA Panel on Plant Health performed a pest categorisation of Thecodiplosis japonensis (Diptera: Cecidomyiidae) for the EU territory. This species is not included in the EU Commission Implementing Regulation 2019/2072. T. japonensis Uchida & Inouye is a well-defined species, native to a large part of Japan, which was introduced to the Republic of Korea and eastern China: Fujian and Shandong. It attacks Pinus densiflora, P. thunbergii and P. luchuensis in Japan; P. densiflora and P. thunbergii in Korea; and P. massoniana in China, and has been observed to attack other two-needle pine species, including species present in the EU. The pest is univoltine and the adults emerge between May and August. The adults live only for 1 day. Each female oviposits in batches on developing needles. The neonate larvae crawl to the base of the needle fascicle and create a gall in which they feed gregariously by sap sucking. The third-instar larvae leave the galls in November, overwinter in a cocoon in the soil and pupate at the end of the winter. Degree day models have been developed to predict adult emergence. Survival of overwintering stages is poor below 15°C and above 30°C. The pest can be detected by its symptoms (stunted or dead needles, galls at the base of infected needle fascicles), and identified using morphological characters or the mitochondrial COI gene. T. japonensis is one of the major forest pests in the Republic of Korea, where 1.7 million trees were cut to control it in 2014–2015. It flies uneasily (a few hundred metres) but can be transported in galls on Pinus plants for planting, including artificially dwarfed plants, or with cut branches. Climate matching and host tree distribution suggest that T. japonensis would be able to establish and have an impact in the EU territory. T. japonensis satisfies all the criteria that are within the remit of EFSA to assess for it to be regarded as a potential Union quarantine pest
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