The impact of habitat fragmentation and the success of habitat restoration were studied through a multi-taxonomic approach. The response to landscape structure and/or habitat quality of three taxonomic groups was explored, in (semi-)natural habitats. The three taxonomic groups were complementary, both in terms of their specific life history traits and their place in the food chain. We considered autotrophic species (vascular plants), herbivores (butterflies) and predators (spiders). Life-history traits and species specialization for target habitat were used to refine the analysis. Target habitat was a complex of wet heathlands, poor fens and bogs. Patches of this complex of habitats were sampled on two high plateaus in the Belgian Ardenne, the Plateau de Saint-Hubert and the Plateau des Tailles. Over the last 250 years, two jointly acting habitat dynamics were observed in these areas: a loss of area (and connectivity) on the one hand but also the creation of new habitat patches. It is precisely this double dynamics that enabled us to analyze and develop concepts linked to the response of species faced with spatio-temporal modifications of their habitat. Specifically, in this work we focused on the comprehension of two unbalanced situations, affecting the relationships between species richness and patch characteristics. A first unbalanced situation, the extinction debt, was observed for vascular plant communities. On the opposite, a colonization credit, the second unbalanced situation, was noted for butterflies and seemed to mainly affect specialist species. Specialist species of the three taxonomic groups showed relatively contrasted responses compared to generalist species. However, the life-history traits we studied only slightly influenced the response of species at the community level, excepted for pioneer communities in habitat patches less than 5 years old.

For many years, primates have been considered to be animals with a poorly developed sense of smell. However, in recent years several studies have shown that at least some primate species have a high olfactory sensitivity for a variety of odorants. The present study used a two-choice instrumental conditioning paradigm to test the olfactory sensitivity for six aromatic aldehydes in four spider monkeys (Ateles geoffroyi). With helional, cyclamal,canthoxal and lilial all animals discriminated concentrations below 1 ppm from the odorless solvent, with single individuals even scoring better. With 3-phenyl-propionic aldehyde all animals detected concentrations below 2 ppb, and with bourgeonal even below 0.3 ppb. The detection thresholds of the odorants changed systematically with molecular structure. Addition of a dioxo or methoxy group to the benzene ring led to an increase in threshold values,while the absence of a methyl group close to the aldehyde moiety was linked to a low threshold value for the odorant. The study shows that spider monkeys have a well developed olfactory sensitivity for aromatic aldehydes.

The shake and wash technique (samples placed in a jar with alcohol added and shaken to remove the mites) was effective in removing 100% of the predator mites, and adult spruce spider mites from Douglas-fir foliage and 98% of the spruce spider mite nymphs. Eighty-eight percent of the spruce spider mite eggs was removed. This technique was considered efficient for removal of spruce spider mite and its predators from Douglas-fir foliage. Sodium hypochlorite (0.84%) added to the alcohol did not increase the number of spruce spider mites or phytoseiid mites removed from the foliage. The intracanopy distribution of spruce spider mite and its predator mites was studied on Douglas-fir Christmas trees in the Willamette Valley, Oregon. When overwintering spruce spider mite egg densities populations were low (<5 eggs/19 cm of stem), significantly more eggs were found on the current season's growth. No significant differences were found between top and bottom halves of the tree or between compass directions. Differences between current and previous season's growth were not found when egg densities were high (>40 eggs/19 cm of stem), but significant differences were found between levels for current season's growth with more eggs found in the upper portion of the canopy. Quadri-directional differences did not exist with either low or high mite populations. Sampling tip or basal stem-halves with low overwintering egg populations did not bias population estimates. Heavy spring rainfall appeared to reduce mite populations as has been reported elsewhere by washing them off the tree and causing increased mortality. Spruce spider mite disperse to the current season's growth shortly after budbreak. Population density rapidly increased in late May and then abruptly declined in mid-July. / Graduation date: 1991

Sexual selection drives the evolution of male morphology, life history, physiology, and behaviour across taxa. Here I examine the mechanisms of sexual selection that arise at various stages in mating interactions to identify congruence or conflict between the traits selected by choice and competition. I first examine plasticity of developing male Australian redback spiders (Latrodectus hasselti) and show that male metabolic rates vary adaptively to facilitate the scramble to reach virgins. Next, I show that females cease sex pheromone production after mating and re-advertise receptivity later in their reproductive season effectively creating two windows in which males may compete. I show that females discriminate against males that do not meet a threshold courtship duration suggesting that courtship is the trait selected through choice. However, male-male competition leads to reductions in courtship effort provided to females. During the first window paternity is split equally if rival males mate in quick succession with a virgin female. However, if the second mating is delayed, there is a strong bias in the paternity of the second male. A delay in the second mating is beneficial to females as it reduces longevity costs of polyandry. However, delays in the initial mating decrease female longevity, likely because of elevated metabolic rates of virgins. My research shows that the trait favoured by female choice is in opposition to selection via male-male competition. Females’ sex pheromone production yields windows during which mating will optimize female, but not male, fitness. Studies that isolate the mechanisms of sexual selection are valuable in that they can identify the traits under selection. However, my research shows that considering these processes in isolation can lead to incorrect inferences about the net effect of sexual selection.

Sexual selection drives the evolution of male morphology, life history, physiology, and behaviour across taxa. Here I examine the mechanisms of sexual selection that arise at various stages in mating interactions to identify congruence or conflict between the traits selected by choice and competition. I first examine plasticity of developing male Australian redback spiders (Latrodectus hasselti) and show that male metabolic rates vary adaptively to facilitate the scramble to reach virgins. Next, I show that females cease sex pheromone production after mating and re-advertise receptivity later in their reproductive season effectively creating two windows in which males may compete. I show that females discriminate against males that do not meet a threshold courtship duration suggesting that courtship is the trait selected through choice. However, male-male competition leads to reductions in courtship effort provided to females. During the first window paternity is split equally if rival males mate in quick succession with a virgin female. However, if the second mating is delayed, there is a strong bias in the paternity of the second male. A delay in the second mating is beneficial to females as it reduces longevity costs of polyandry. However, delays in the initial mating decrease female longevity, likely because of elevated metabolic rates of virgins. My research shows that the trait favoured by female choice is in opposition to selection via male-male competition. Females’ sex pheromone production yields windows during which mating will optimize female, but not male, fitness. Studies that isolate the mechanisms of sexual selection are valuable in that they can identify the traits under selection. However, my research shows that considering these processes in isolation can lead to incorrect inferences about the net effect of sexual selection.

Vår tids syn på teknik ser vi tydliga spår av i dagens filmer, och kanske framförallt superhjältefilmer. Där använder sig både hjältar och skurkar av avancerad teknik i sin kamp mot varandra. Men även synen på biologi avspeglas i dessa filmer, och det mest intressanta är när dessa ställs mot varandra. Vi har jämfört två av vår tids största hjältar, en som använder sig av teknik och en som har biologiska krafter, för att se vilka likheter och skillnader som finns. Hjältarna det rör sig om är Spider-Man och Batman.

Cyro-EM and three-dimensional reconstruction have become important research tools for virus structure. These techniques have benefit of fast and keep samples in native folding. Simulated prefer orientation images of DGNNV, PaV and TBSV were reconstructed by SPIDER or PurdueEM, with projection matching with. SPIDER prefers 3-fold and 5-fold view fields, and PurdueEM prefers 2-fold view fields. SPIDER could reconstruction images which have more noise than PurdueEM can successfully reconstruct. Reconstruction of RNA-cages has some relationship with the symmetry of capsid protein. Prefer orientation, noise and RNA-cages are the factors that can effect reconstruction.

No description available.

Cyrba algerina is a salticid (Salticidae) spider that lives on the undersides of stones. Two populations were studied, Sintra and Algarve (Portugal), and shown to have similar phenology but different dominant prey. Life cycle in the laboratory was similar for the two populations, but Sintra matured at larger size than Algarve individuals, with these differences potentially having a genetic basis. Sintra individuals used prey-specific prey-capture behaviour against allopatric (Oecobius amboseli) and sympatric (O. machadoi, Trachyzelotes bardiae) spider and insect (bristletails) species. In contrast, Algarve C. algerina only adopted specialised capture behaviour against bristletails. Sintra, but not Algarve, individuals responded to the odour of O. machadoi and T. bardiae, and showed preference for T. bardiae over O. machadoi. Interpopulation variation in the use of specific prey-capture behaviour and in sensitivity to odour cues from prey is directly related to the prey available to individuals from each population, suggesting local adaptation to local prey. Preference for oecobiids seems to be controlled by an experiencetriggered developmental switch. The optics and histology of C. algerina’s principal eye suggest that living in a microhabitat with dim ambient light has favoured sensitivity at the expense of spatial acuity. Short focal length, reduced power of the eye’s diverging lens, and wide, contiguous rhabdomeres, seem to minimise the visual constraints imposed by the low light levels in C. algerina’s microhabitat. While relying solely on vision, C. algerina can detect, identify and capture prey in dim-light conditions under which other salticids perform poorly. C. algerina’s behaviour suggest use of temporal summation to improve its visual performance in dim light.

Mannheim, Univ., Diplomarbeit, 2006.