Behavioural Thermoregulation by High Arctic Butterflies

Reports summer 1967-68 observations and experimental temperature measurements made at Hazen and Gilman Camps, northern Ellesmere Island, on Colias helca, Boloria chariclea and B. polaris, Lycaena feildeni and Plebius aquilo. In order to utilize direct isolation to increase their body temperatures, they selected basking substrates and precisely oriented their wings with respect to the sun. High arctic butterflies are most often found in a warm, relatively windless, sheltered places where on sunny days they fly in the warmest air close to the ground. Their wing morphology, venation, color, hairiness and physiology are briefly discussed.Comportement thermo-régulatoire des papillons du haut Arctique. Chez cinq espèces de papillons trouvés au lac Hazen (81º49'N, 71º18'W), île d'Ellesmere, Territoires du Nord-Ouest, le comportement thermo-régulatoire est une importante adaptation. Ces papillons arctiques se servent de l'insolation directe pour augmenter la température de leur corps : ils choisissent des sous-strates réchauffantes et orientent leurs ailes de façon précise par rapport au soleil. Quelques expériences ont confirmé l'importance de ce fait. On discute brièvement de la morphologie alaire, de la couleur, de la pilosité et de la physiologie de ces insectes

Microbial diversity across a Canadian sub-Arctic, isostatically rebounding, soil transect

AbstractSeacoast to inland soil transects of 1 and 2km were researched over 2years to understand the microbial diversity in a post ice age, isostatically, rebounding, soil environment. Community level substrate utilization analysis and 16S rDNA eubacterial diversity were employed. The community level substrate analysis demonstrated that regardless of the location along the transect from seacoast to forest, sandy or peat soil, the microbial diversity (Shannon diversity index about 3) was virtually the same. Shannon diversity indexes based on PCR-DGGE analysis yielded values between about 0.6 and about 2 depending on the sand or peat soil type and the year the samples were collected and analyzed (2002 and 2003). Regardless of the genetic diversity, the soils exhibited similar metabolic capabilities. This is a good example of redundant, functional, physiology regardless of the species present at each location along the transects

Light and Life: Exotic Photosynthesis in Binary Star Systems

The potential for hosting photosynthetic life on Earth-like planets within binary/multiple stellar systems was evaluated by modelling the levels of photosynthetically active radiation (PAR) such planets receive. Combinations of M and G stars in: (i) close-binary systems; (ii) wide-binary systems and (iii) three-star systems were investigated and a range of stable radiation environments found to be possible. These environmental conditions allow for the possibility of familiar, but also more exotic forms of photosynthetic life, such as infrared photosynthesisers and organisms specialised for specific spectral niches.Comment: Accepted for publication in: Astrobiolog

Control of Mediterranean fruit fly Ceratitis capitata (Diptera: Tephritidae) with the parasitoid Muscidifurax raptor (Hymenoptera: Pteromalidae) in vineyards

The control of Ceratitis capitata (Diptera: Tephritidae) has been mostly done with chemical insecticides and some selected natural enemies. However, these control methods are not popular because of the adverse effects of chemical controls and the unreliability of some natural enemies (Spalangia sp. and Pachycrepoideus sp.: Hymenoptera: Pteromalidae). The generalist parasitoid, Muscidifurax raptor (Hymenoptera: Pteromalidae), has been used successfully for biological control of the house fly [Musca domestica (Diptera: Muscidae)] pupae in poultry houses. Our study investigated the use of this parasitoid to control C. capitata in a vineyard. Parasitoids were released at rate of 5, 10, and 20 per m2 in a vineyard and in laboratory cages to parasitize pupae of C. capitata and M. domestica, respectively, for 2 days. The number of killed pupae of both host pests increased with the number of released parasitoids in the field. The highest rate of 20 released M. raptor resulted in 23.52% (±0.30 SE) killed pupae, respectively, for house fly and fruit fly. M. raptor parasitized indiscriminately host species of pupae and the daily oviposition rate was 4.9 (±0.07 SE) eggs per female. The parasitoid laid the same number of eggs as when released in poultry houses for the control of M. domestica. We conclude that M. raptor constitutes a promising biocontrol agent for the control of C. capitata in vineyards.Articl

Bimodal pollination system in rare endemic Oncocyclus irises (Iridaceae) of Lebanon

Pollination systems based on indirect rewards, such as heat and shelter, have seldom been studied. Plant-pollinator interactions were characterized in Iris cedretii Dinsmore ex Chaudhary and Iris sofarana subsp. kasruwana Dinsmore ex Chaudhary, rare endemic Lebanese Oncocyclus irises exhibiting potential adaptation to shelter pollination. Despite a diversity of floral visitors (47 species), only two groups of Anthophoridae male bees (Xylocopa spp. and Eucera spp.) could be considered as efficient pollinators on the basis of frequency of visits, visiting behaviour, and pollen load. Lebanese Oncocyclus irises showed a bimodal pollination system with (1) diurnal visits at low rates but with potentially large pollen transfers by Xylocopa bees, exhibiting a foraging-like behaviour, principally during warm periods of the day and (2) sheltering, especially Eucera male bees, during night and day when the weather is changeable. Refuge occurrence in flowers was more important during the night (27%) than during the day (12%) and, for daytime, during cloudy or windy than sunny conditions. It also varied depending on the exposure of floral tunnels. Visitation rates of both day-visiting Xylocopa and night-sheltering Eucera were negatively associated with an increase of the number of flowers per clump. No experimental evidence was found showing that the principal advantage for male bees to shelter in Iris flowers was to fly earlier in the morning