A large‐scale latitudinal pattern of life‐history traits in a strictly univoltine damselfly

1. Variation in thermal conditions and season length along latitudinal gradients affect body size‐related traits over different life stages. Selection is expected to optimise these size traits in response to the costs and benefits. 2. Egg, hatchling, larval and adult size in males and females were estimated along a latitudinal gradient of 2730 km across Europe in the univoltine damselfly Lestes sponsa, using a combination of field‐collection and laboratory‐rearing experiments. In the laboratory, individuals were grown in temperatures and photoperiod simulating those at the latitude of origin, and in common‐garden conditions. 3. The size of adults sampled in nature was negatively correlated with latitude. In all populations the females were larger than the males. Results from simulated and common‐garden rearing experiments supported this pattern of size difference across latitudes and between sexes, suggesting a genetic component for the latitudinal size trend and female‐biased size dimorphism. In contrast, hatchling size showed a positive relationship with latitude, but egg size, although differing between latitudes, showed no such relationship. 4. The results support a converse Bergmann cline, i.e. a negative body size cline towards the north. This negative cline in body size is probably driven by progressively stronger seasonal time and temperature constraints towards the higher latitudes and by the obligate univoltine life cycle of L. sponsa. As egg size showed no relationship with latitude, other environmental factors besides temperature, such as desiccation risk, probably affect this trait.     

The Immunochemical Relationships of Prolamins of Temperate Meadow Grasses and Cereals

The immunochemical relationships between the aqueous alcohol-solubleprolamin storage proteins of temperate cereals (wheat, barley,rye and oats) and five species of Festucoid meadow grasses (Loliumperenne, Festuca rubra, F. arundinacea, Dactylis glomerata andPhleum pratense) were studied by "Western Blot" analyses usingantisera raised against C hordein of barley, -gliadin of wheatand avenins of oats. In addition, the reaction between the Chordein antiserum and the grass prolamins was studied usinga quantitative laser nephelometer assay. The results confirmedthe previously reported structural relationship between theprolamins of Festuca and Lolium and members of the Triticeae(barley, wheat, rye). They also showed a strong antigenic relationshipbetween the prolamins of Dactylis and Phleum and avenins ofoats, and this is consistent with their molecular weights andamino acid compositions. The results indicate that similar immunochemicalstudies may be of value in clarifying the taxonomic relationshipsof Festucoid meadow grasses. Key words: Cereals, grasses, prolamins, homology, evolution, immunochemistry     

Propagation and Purification of Rat Pneumocystis carinii in Short-Term Cell Culture

ABSTRACT. A short-term cell culture is used to propagate and purify rat-derived Pneumocystis carinii (Pc). An aliquot of pelleted material washed out of the lungs of rats with moderate to severe Pc pneumonia is cultured for 7 to 10 days on the adherent mink lung cell line Mv I Lu, and the rest of the material is frozen down in medium with 10% glycerol. Although it has not been established that substantial multiplication of Pc occurs in culture, the Pc organisms harvested from the supernatant at the end of the culture period are relatively free of both host and feeder cells. This is in marked contrast with the lung wash inoculum in which the Pc organisms are heavily contaminated with rat cells and enmeshed in a highly sticky material. Lung wash preparations frozen down in glycerol and stored at −70° C for as long as 6 months or more can be successfully cultured upon thawing with no apparent loss of viability of the Pc organisms.     

Surface Labeling of Pneumocystis carinii from in Vitro Culture

Pneumocystis carinii is an opportunistic pathogen of man, carried as a commensal in healthy subjects. It frequently causes a fatal pneumonia in the immunosupprcssed host. It is a major complication of HIV-1 infection in man (AIDS). Using surface radioiodination of rat-denved P. carinii trophozoites obtained from in vitro culture, a major surface glycoprotein (gp120) has been identified. The glycoprotein exhibits adherent behavior similar to that of the intact organism. Purification of gp120 by conventional methods was unsuccessful as the glycoprotein irreversibly bound lo numerous column matrices. A combination of gel chromatography and hydroxyapatile chromatography in sodium dodecylsulfaie v. as utilized to purify the glycoprotein. Some preliminary characterization of the glycoprotein is presented.     

Characterization of the T, L, I, S, M and P Cell Surface (Immobilization) Antigens of Tetrahymena thermophila: Molecular Weights, Isoforms, and Cross-Reactivity of Antisera

ABSTRACT. In the ciliate protist Tetrahymena thermophila the L, H, T, I, S, M and P cell surface proteins (immobilization antigens) are expressed under different conditions of temperature (L, H, T), culture media (I, S), and mutant genotype (M, P). Immunoblot and autoradiographic studies using antisera to purified protein show that the molecular weights of these proteins range from 25,000 to 59,000. The H, T, S, M and P antigens are recognized as single polypeptides, whereas L, I, and one allelic form of T each appear to consist of a family of polypeptides. Although antisera are specific in immobilization and immunofluorescence assays of surface protein in living cells, cross-reactivity is seen with denatured protein on immunoblots. It is hypothesized that the surface protein genes are organized into families of evolutionarily related isoloci.     

The influence of fish on leaf breakdown in a Virginia pond

1. To find if fish affect leaf breakdown, sugar maple leaves ( Acer sacchrum March) were placed in a soft-water, farm pond at a depth of 1 m for up to 3 months in four treatment groups: (1) enclosure with sunfish (Lepomis macrochirus Rafinesque) (SUNFISH treatment); (2) enclosure with catfish ( Ictalurus punctatus Rafinesque) (CATFISH treatment); (3) enclosure without fish (NO FISH treatment); and (4) no enclosure (OPEN treatment). The study was conducted in spring and autumn.
2. The leaf breakdown rates, k ±95% CL, for SUNFISH (0.0082± 0.00059 and 0.0111±0.00162 d⁻¹) and CATFISH (0.0072±0.00096 and 0.0103±0.00077 d⁻¹) were greater in spring and summer, respectively, than in the OPEN treatments (0.0065 ±0.00048 and 0.0105± 0.00141 d⁻¹) and NO FISH (0.0067±0.00039 and 0.0088±0.00099 d⁻¹). However, only k for SUNFISH was significantly different from NO FISH and OPEN treatments.
3. Fish in the pond did not appear to affect breakdown rates of OPEN leaf packs in the first replicate but k approached that of the fish treatments in the second replicate.
4. Fish may have promoted leaf breakdown directly by fragmentation of leaves while foraging for food and, indirectly, by agitation of leaves, leading to increased microbial activity.     

The ecology and evolution of male reproductive behaviour in the bees and wasps

Males of aculeate Hymenoptera differ in the behavioural adaptations employed to locate and secure mates. The ecological and evolutionary bases of these differences are explored in this paper. Male bees and wasps search for females by patrolling widely within emergence-nesting areas or within patches of flowers attractive to conspecific females, or by waiting at landmarks, at specific emergence sites, or at nests. Nest dispersion, flower distribution, the type of female mating system and the nature of male-male competition appear to be key factors in determining the mate-locating behaviour of males. Of special interest in multiple-mating by females, which may be an evolutionary response to the costs of attempting to resist copulation in certain situations. When polyandry occurs, males are under selection pressure to be the last male to copulate with a female prior to oviposition if sperm precedence occurs. In species in which females mate just once, a selective premium is placed on being the first male to reach a virgin female. In either case, because receptive females are a limited resource, there is intense competition among males for access to the resource. The density of competitor males may play an important role in determining whether holding a relatively restricted territory is preferable to the strategy of patrolling widely at various sites which may have females. Territoriality is practiced by males of several species of aculeate Hymenoptera when the number of male competitors is relatively few in number and the distribution of emergence sites or foraging areas of females is clumped in space.     

Effects of Natural Barriers and Habitat on the Western Spread of Raccoon Rabies in Alabama

Abstract: Although domestic animal transmission of rabies has largely been mitigated, the disease remains a concern in both Europe and North America where wildlife transmission has caused epizootics. Raccoon (Procyon lotor) rabies was established in Alabama, USA, in 1975, primarily in the southeastern corner of the state. However, with the exception of isolated events, rabies has not continued to spread westward across the Alabama River. We monitored movements of 100 radiocollared raccoons on 2 sites within hardwood and agriculture habitats in a rabies enzootic area east of the Alabama River, in managed pine habitat area west of the river where rabies sporadically occurs, and in a mixed pine hardwood area outside of the known rabies enzootic area to determine if raccoon movements and habitat use in certain habitat types and the presence of a river may serve as natural barriers preventing the western spread of rabies in Alabama. We also examined raccoon contact rates to determine if they influence disease transmission through static and dynamic interactions. Raccoons in mixed pine-hardwood forest habitats had smaller home ranges and less overlap of ranges compared to the other 3 habitats. However, static interactions between habitats in the use of overlap areas did not differ (F_11,129 = 1.63, P = 0.09). Rabies antibody titers were highest in the managed pine habitat (28%) even prior to oral vaccine bait distributions in spring of 2004 and 2005. Biomarker data from radiocollared and additional raccoons captured after the bait distribution west of the Alabama River demonstrated a low efficacy of the vaccine reaching the small southern raccoons. The combination of the river as a partial barrier, the high percentage of pine forested habitat west of the river, and limited spatial movements of raccoons within these forested habitats appears to have reduced the likelihood of rabies establishing west of the river. Understanding different host-habitat- disease systems is important for successful management of diseases. Based on our results, we recommend that the oral vaccine program continue to use the Alabama River as a partial barrier and baiting be concentrated in the fragmented bottomland hardwood forests and around larger bodies of water where raccoon densities are highest. Success of baiting strategies designed to take advantage of northern raccoon dynamics and habitat use may not be applicable to southern populations.