Geographical variation in cone volatile composition among populations of the African cycad Encephalartos villosus

Variation in traits across species distribution ranges is often indicative of diversifying evolution that can lead to speciation. Of particular interest is whether traits vary clinally or abruptly because the latter pattern can be indicative of incipient speciation. Understanding of intraspecific variation in chemical traits is still in its infancy because studies of population variation have tended to focus on morphology or neutral genetic markers. To address these issues, the composition of cone volatile odours was examined in ten populations of the South African cycad Encephalartos villosus across its range in the Eastern Cape and KwaZulu Natal using headspace sampling and analysis by gas chromatography‐mass spectrometry. Because volatiles play a key role in attracting pollinators to cones of Encephalartos cycads and may thus reflect local adaptation to pollinators, pollinator assemblages were also investigated in the ten populations of E. villosus. Volatile compounds from populations in the north of the distribution range were dominated by unsaturated hydrocarbons, whereas, in the southern populations, nitrogen‐containing compound and terpenoids were the major compounds. A shift between southern and northern populations appeared to occur at the Umtamvuna River, where populations had odour profiles with components of both the northern and southern populations. However, one population in the north (Vernon Crookes Nature Reserve) had a quantitatively similar odour profile to the populations in the extreme south of the range. These results reveal strong interpopulation variation in the cone scent of E. villosus, including variation in the relative emission of dominant compounds that may play key functional role in this pollination system. However, pollinator assemblages did not differ across the different populations, which suggest that these patterns were produced by co‐evolution or drift, rather than by pollinator shifts. © 2012 The Linnean Society of London, Biological Journal of the Linnean Society, 2012, 106 , 514–527.     

Segment number,body length,and latitude in geophilomorph centipedes: a ‘converse‐Bergmann’ pattern

There is a negative relationship between trunk segment number and latitude among geophilomorph centipedes in general. A similar relationship is known to exist within the most intensively‐studied geophilomorph species, Strigamia maritima, and also within several other species from this group. Previously, it was considered that this relationship did not involve body length; instead, individuals of S. maritima with more segments were considered to be more finely subdivided (not longer) than those with fewer segments. This incorrect interpretation arose from the difficulty of reliably separating post‐embryonic stages and thus of making a simple and direct comparison. In the present study, we build on recent work that facilitates such comparisons; and we show conclusively that individuals with more segments are longer. Our finding means that it is now possible to connect the work on S. maritima in particular, and on geophilomorph centipedes in general, with the debate about Bergmann's ‘rule’: the proposal that body size increases with increasing latitude. There is a clear ‘converse‐Bergmann’ pattern, as has been found in several other taxa. We propose an adaptive hypothesis that may explain why geophilomorphs show this pattern. © 2012 The Linnean Society of London, Biological Journal of the Linnean Society, 2012, ?? , ??–??.     

Pyrethroid resistance in Australian field populations of the sheep body louse, Bovicola (Damalinia) ovis

Abstract. Synthetic pyrethroid (SP) resistance has developed in Australian field populations of the sheep body louse, Bovicola ( Damalinia ) ovis. Laboratory bioassays were used to measure the susceptibility of lice to cypermethrin and the other registered SPs. Results of these bioassays indicated resistance to cypermethrin, deltamethrin, cyhalothrin and alphacypermethrin. So far, high-level resistance has been diagnosed in only a few strains. The toxicological responses of these strains were clearly separated from those of the majority of louse strains tested. Furthermore, these strains had survived immersion in commercial SP dips. The level of resistance described in some strains was sufficient to cause pour-on products to fail despite the fact that the LC50s of these strains fell within the normal range of field responses.     

Guidelines for anal cytology—to make cytological diagnosis and follow up much more reliable

scholefield j. h., johnson j., hitchcock a., kocjan g., smith j. h. f., smith p. a., ferryman s. and byass p . (1998) Cytopathology 9, 15–22
Guidelines for anal cytology—to make cytological diagnosis and follow up much more reliable     

A select panel of polymorphic microsatellite loci for individual identification of snow leopards (Panthera uncia)

Snow leopards (Panthera uncia) are elusive endangered carnivores found in remote mountain regions of Central Asia. New methods for identifying and counting snow leopards are needed for conservation and management efforts. To develop molecular genetic tools for individual identification of hair and faecal samples, we screened 50 microsatellite loci developed for the domestic cat (Felis catus) in 19 captive snow leopards. Forty‐eight loci were polymorphic with numbers of alleles per locus ranging from two to 11. The probability of observing matching genotypes for unrelated individuals (2.1 × 10^?11) and siblings (7.5 × 10^?5) using the 10 most polymorphic loci was low, suggesting that this panel would easily discriminate among individuals in the wild.     

Disturbance, rainfall and contrasting species responses mediated aboveground biomass response to 11 years of CO2 enrichment in a Florida scrub-oak ecosystem

This study reports the aboveground biomass response of a fire-regenerated Florida scrub-oak ecosystem exposed to elevated CO₂ (1996–2007), from emergence after fire through canopy closure. Eleven years exposure to elevated CO₂ caused a 67% increase in aboveground shoot biomass. Growth stimulation was sustained throughout the experiment; although there was significant variability between years. The absolute stimulation of aboveground biomass generally declined over time, reflecting increasing environmental limitations to long-term growth response. Extensive defoliation caused by hurricanes in September 2004 was followed by a strong increase in shoot density in 2005 that may have resulted from reopening the canopy and relocating nitrogen from leaves to the nutrient-poor soil. Biomass response to elevated CO₂ was driven primarily by stimulation of growth of the dominant species, Quercus myrtifolia , while Quercus geminata , the other co-dominant oak, displayed no significant CO₂ response. Aboveground growth also displayed interannual variation, which was correlated with total annual rainfall. The rainfall × CO₂ interaction was partially masked at the community level by species-specific responses: elevated CO₂ had an ameliorating effect on Q. myrtifolia growth under water stress. The results of this long-term study not only show that atmospheric CO₂ concentration had a consistent stimulating effect on aboveground biomass production, but also showed that available water is the primary driver of interannual variation in shoot growth and that the long-term response to elevated CO₂ may have been caused by other factors such as nutrient limitation and disturbance.