FINE STRUCTURE OF ANNELLOPHORES. I. SCOPULARIOPSIS BREVICAULIS AND S. KONINGII

Fine-structure observations of annelloconidium production in filamentous Hyphomycetes are reported for the first time. The difference in conidium morphology between Scopulariopsis brevicaulis and S. koningii was quite distinct. In S. brevicaulis, verrucosities appeared early in conidium ontogeny and formed an integral part of the primary wall layer of mature conidia. In S. koningii, verrucosities were absent. In S. brevicaulis, annellations did not invariably result on conidiophore necks with the production of each conidium in the basipetal sequence, but alternatively could be left on subapical regions of subsequently formed conidia. In S. koningii, annellations were more distinct, and the position of a conidium-delimiting septum was variable. If a septum were formed at a position proximal to previous septa, a portion of the annellophore neck remained attached to the base f the seceding conidium. In both species, a spherical electron-dense body, perhaps analogous to septal pore plugs in vegetative hyphae, plugged the pore between conidia and conidiophores and remained embedded in the base of seceded conidia.     

Seed transmission of turnip yellow mosaic virus in winter turnip and winter oilseed rapes

This is the first record of seed transmission of turnip yellow mosaic virus (TYMV) in oilseed and turnip rapes. The seed transmission of TYMV in a naturally infected winter turnip rape (Brassica napus var. silvestris) cultivar Perko PVH was investigated. By ELISA 1.6%, 3.2% and 8.3% seed transmission of the virus was found in seed of plants from three localities. The proportion of infected seeds produced by artificially infected plants of winter oilseed rape (Brassica napus ssp. oleifera) and winter turnip rape cultivars was determined. The virus transmission rate, expressed as the proportion of virus-infected plants which germinated from the seed was for the oilseed rape cvs Jet Neuf 0.1%, Solida 0.4%, Silesia 0.8%, Darmor 1.2%, SL-507 0.2%, SL-509 0.0% and for the winter turnip rape cv. Perko 1.5%. ELISA cannot be used in direct tests on bulk seed lots to estimate proportion of infected seed, but must be used on germinated seedlings.     

ESTIMATING PUP PRODUCTION OF HARP SEALS, PAGOPHILUS GROENLANDICUS, IN THE NORTHWEST ATLANTIC

Photographic and visual aerial surveys to determine current pup production of Northwest Atlantic harp seals were conducted off Newfoundland and in the Gulf of St. Lawrence during March 1999-Photographic surveys were conducted on all whelping concentrations between 14 and 24 March, whereas a visual survey was made of the southern Gulf concentrations on 14 March. Pup production was estimated to be 739,100 (SE = 96,300, CV = 13.0%) at the Front, 82,600 (SE = 22,500, CV = 27.2%) in the northern Gulf, and 176,200 (SE = 25,400, CV = 14.4%) in the southern Gulf (Magdalen Island) for a total of 997,900 (SE = 102,100, 10.2%). Changes in aerial survey estimates indicate that pup production has increased since 1994. A new method to correct for the temporal change in the proportion of pups present on the ice was examined by fitting the percentage of pups observed in three age-dependent stages to a Normal distribution. The results were compared to those obtained from a more complex model used previously. The Simple model produced slightly higher, and hence more conservative, estimates of the proportion of births that had occurred before the time of the survey than the Complex model. When using the Simple model fewer assumptions regarding the start date of pupping and the proportion of older pups remaining on the ice were required, the herd had to be followed for a shorter period, and a more convenient means of calculating confidence limits was available.     

Aspects of hadrosaurian cranial anatomy

Supraorbital bones in Saurolophus angustirostris are described, and their presence in all hadrosaurs is suggested. Frontal-nasal and premaxillar-nasal fontanellae are distinguished in hadrosaurs; their presence is explained as connected with growth and considered to he responsible for the variability of crest structures. New data indicating the presence of a cartilaginous diverticulum nasi within the circumnarial depression in Saurobphus ongustirostris are presented. A physiological (respiratory and/or thermoregulatory) function of the nasal diverticulum is proposed.     

Seasonal movements of hooded seals tagged in the Gulf of St. Lawrence,Canada

Hooded seals were tagged as pups (N = 1186) in the Gulf of St. Lawrence between 1975 and 1984. A total of 76 tags have been recovered or resighted. These recoveries indicate a dispersal from the Gulf in the spring to Greenland waters during the summer, and confirm that some seals marked as pups in the Gulf return as adults to this area during the whelping season.     

华西银腊梅挥发油化学成分的研究

用水蒸气蒸馏法提取华西银腊梅挥发油,并用气相色谱-质谱(GC-MS)联用技术对其挥发油的化学成分进行分析,结果共鉴定了其中的39种成分,所鉴定成分含量约占总检出量的87.83%。其化学成分主要为(Z,Z)-9,12-十八碳二烯酸甲酯(9.00%),壬醛(5.83%),二十一烷(5.69%),二十烷(5.08%),辛炔酸(4.50%),2,6,10,15-四甲基十七烷(3.93%),(Z)-6-十八烯酸甲酯(3.65%),3,8-二甲基十一烷(3.52%),1-十六碳炔(3.31%),肉豆蔻酸(2.86%),月桂醛(2.81%),壬酸(2.23%),5,6,7,7α-四氢-4,4,7α三甲基-2(4H)-苯并呋喃酮(2.18%)等。     

European checkerspots (Melitaeini: Lepidoptera,Nymphalidae) are not aposematic – the point of view of great tits (Parus major)

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Fear in the dark? Community‐level effects of non‐lethal predators change with light regime

The total effect of predators on prey is a combination of direct consumption, and non‐consumptive effects (NCEs), such as predator‐induced changes to prey morphology, behaviour and life history. Past research into NCEs has tended to focus on pair‐wise interactions between predators and prey, while in natural ecosystems, species exist in complex communities with several trophic levels made up of multiple autotrophic and heterotropic species. To address how predator NCEs alter the photosynthetic and heterotrophic components of communities, we exposed microbial microcosms to one of three predator treatments: live predators (full predator effect), freeze‐killed predators (NCEs only) or no predators (control), and incubated them under either 12 h:12 h light:dark conditions or continual darkness. Under 12 h:12 h light:dark conditions, NCEs‐only communities never differed from predator‐free communities, but differed from live predator communities. Under conditions of continual darkness, the structure of NCEs‐only communities differed from predator‐free controls, but not from live predator communities, suggesting NCEs can be strong enough to structure communities. Predation threat may cause certain prey to induce defences, such as reductions in movement, which make them less competitive in a community setting. This reduction in competitive ability could lead to these species being driven to extinction through interspecific competition, resulting in similar communities to those in which live predators are present. Heterotrophic species whose rates of resource acquisition depend on movement rates may be affected to a greater extent than autotrophs by predator‐induced reductions in movement, accounting for our observed differences in predator NCEs in ‘dark’ and ‘light’ communities. Our results suggest that the community‐level consequences of fear are greater in the dark. Synthesis Predators affect prey through consumptive and non‐consumptive effects (NCEs) such as alterations to prey behaviour, morphology, and life history. However, predators and prey do not exist in isolated pairs, but in complex communities where they interact with many other species. Using a long term study (>10 predator generations), we show that predator NCEs alone can alter community structure under conditions of darkness, but not in a 12h:12h light:dark cycle. Our results demonstrate for the first time that although the community‐level consequences of predator NCEs may be dramatic, they depend upon the abiotic conditions of the ecosystem.     

Towards a Better Understanding of the Effects of UV on Atlantic Walruses,Odobenus rosmarus rosmarus: A Study Combining Histological Data with Local Ecological Knowledge

Walruses, Odobenus rosmarus, play a key role in the Arctic ecosystem, including northern Indigenous communities, which are reliant upon walruses for aspects of their diet and culture. However, walruses face varied environmental threats including rising sea-water temperatures and decreasing ice cover. An underappreciated threat may be the large amount of solar ultraviolet radiation (UV) that continues to reach the Arctic as a result of ozone loss. UV has been shown to negatively affect whales. Like whales, walrus skin is unprotected by fur, but in contrast, walruses spend long periods of time hauled-out on land. In this study, we combined the results of histological analyses of skin sections from five Atlantic walruses, Odobenus rosmarus rosmarus, collected in Nunavik (Northern Quebec, Canada) with qualitative data obtained through the interviews of 33 local walrus hunters and Inuit Elders. Histological analyses allowed us to explore UV-induced cellular lesions and interviews with experienced walrus hunters and Elders helped us to study the incidences and temporal changes of UV-induced gross lesions in walruses. At the microscopic scale, we detected a range of skin abnormalities consistent with UV damage. However, currently such UV effects do not seem to be widely observed at the whole-animal level (i.e., absence of skin blistering, erythema, eye cataract) by individuals interviewed. Although walruses may experience skin damage under normal everyday UV exposure, the long-term data from local walrus hunters and Inuit Elders did not report a relation between the increased sun radiation secondary to ozone loss and walrus health.