Kissinella-Christiania Associations in the early Ashgill Foliomena brachiopod fauna of South China

A new ecological unit within the well-documented late Ordovician brachiopod Foliomena fauna is defined on the basis of assemblages from Northern Cuizhou and southern Sichuan. Southwest China. The Kassinella-Chrisriania Association, from the lower Ashgill Linhsiang and Chientsaokou formations, is dominated by the eponymous genera together with species of mainly Dedzetina, Sericoidea and Kozlowskites Foliomena is rare or absent. To date, the Foliomena fauna has been documented only from deep-water environments however, the new association apparently occupied shallower depths, probably in lowermost Benthic Assemblage Zone 3 and uppermost Benthic Assemblage Zone 4, presumably at the shallow end of the depth range of the Foliomere fauna. The incursion of the Foliomena fauna into relatively shallow-water environments may have been encouraged by abnormally low oxygen levels and sparse nutrients together with persistent soft substrates across this part of the Yangtze Platform during the early Ashgill. *** Ordovician, Ashgill, China, brachiopods. F oliomena fauna.     

Analysis of museum specimens suggests extreme genetic drift in the adonis blue butterfly (Polyommatus bellargus)

We amplified microsatellite DNA from museum specimens over 100 years old of the adonis blue butterfly, Polyommatus bellargus. These results were compared with butterfly samples taken from the same site near Folkestone in southern UK in 1998/9, 200 generations later, and with samples from other extant UK populations. Dramatic changes in allele frequencies have occurred over time, which is indicative of substantial genetic drift or extinction/recolonization. Patterns of heterozygosity in the 1998/9 sample are indicative of a past bottleneck, and one was known to have occurred in the late 1970s in this and many other UK populations. One allele present at high frequency in 1896 was not detected in any extant UK population, suggesting that it may have been lost from the UK (a 'ghost' allele), although the allele may well persist elsewhere within the range of the species. Although the present study is relatively small in scale (20 museum specimens from one site), it serves to reinforce the enormous potential of museum specimens in well represented taxa such as butterflies for examining the effects of demographic events spanning many years.  © 2006 The Linnean Society of London, Biological Journal of the Linnean Society , 2006, 88 , 447–452.     

Between‐species facilitation by male fig wasps in shared figs

1. Facilitation is recorded from diverse plant–insect interactions, including pollination and herbivory. 2. The significance of facilitation resulting from the behavior of males of multiple fig wasp species inside figs was investigated. Female fig wasps emerge from natal figs via exit holes dug by males, especially male pollinators. When no males are present, the females struggle to escape and may die. 3. Ficus microcarpa L. is a widely‐established invasive fig tree from Southeast Asia. Its pollinator is absent in South Africa, so the tree cannot reproduce, but two Asian non‐pollinating fig wasps (NPFW) Walkerella microcarpae and Odontofroggatia galili occupy its figs. Abundance patterns of the two NPFW and the proportion of male‐free figs in South Africa, Spain (where the pollinator is introduced), and in China, where the native fig wasp community is diverse, were compared to determine the consequences of reduced species richness for insect survival. 4. Female fig wasps in male‐free figs were found to be trapped, and small clutch sizes contributed to the absence of males in both species. The presence of pollinators in Spain allowed most NPFW to develop in figs containing males. Far more male‐free figs were present in South Africa, elevating mortality rates among female NPFW. Facilitation of female release by males of other NPFW species nonetheless benefitted the rarer species. 5. Selection pressures in South Africa currently favour greater aggregation of NPFW offspring and/or less female biased sex ratios.     

Can an increased copper requirement in copper-tolerant Mimulus guttatus explain the cost of tolerance? II. Reproductive phase

Circumstantial evidence suggests that plants that have evolved metal tolerance are at a disadvantage on normal soil, i.e. there is a cost of tolerance. One hypothesis for the cause of this cost is that individuals have a greater requirement for copper, and so suffer micronutrient deficiency on normal soils, as a result of a reduced uptake, distribution and/or utilization of copper. We provided highly and less copper-tolerant plants of Mimulus guttatus Fischer ex DC. (the common monkey flower) with sub-optimal copper, and demonstrated the importance of copper as an essential micronutrient during the reproductive phase, both in the production of viable pollen and in seed set. We also looked at the effect of sub-optimal copper supply on the growth of the microgametophyte, and the efficiency with which seed was set. No evidence was found that highly tolerant plants have an increased copper requirement during the reproductive phase. This is in agreement with earlier work on Mimulus guttatus , which investigated the copper requirement of highly tolerant plants during vegetative growth and found that any differences in copper requirement were small. The 'metal requirement hypothesis' is, therefore, not the sole explanation for the cost of copper tolerance in M. guttatus .     

Assessing the heritability of body condition in birds: a challenge exemplified by the great tit Parus major L. (Aves)

The definition and measurement of body condition are central to many ecological and evolutionary studies, yet the fundamental issue of whether variation in condition is inherited genetically remains unresolved. Furthermore, confusion has been caused through diverse uses of the word 'condition' itself. In this paper, we introduce the terms 'broad-sense condition' and 'narrow-sense condition' in an attempt to reduce this confusion. Because of the difficulty of measuring condition, field biologists use the mass relative to body size as a convenient index of condition. Such indices have also been used to estimate die heritability of condition. Using data from a wild great tit Parus major population, we demonstrate that a condition index may still contain residual variance that is due to body size. Hence, using a condition index to study the heritability of condition can give misleading results because that residual variance may itself be heritable. To avoid this problem, direct measures of condition, such as reserve tissues, should be used. We provide the first heritability estimates of direct measures of condition of full-grown birds in a wild population by the regression of mean offspring (both in winter, and when breeding) on mean parent (when breeding) values of two reserve tissues, fat and pectoral muscle, which are independent of body-size. A great tit's fat and muscle reserves in winter were significandy correlated with their respective values when the birds bred. However there was no evidence that the level of fat reserves in winter resembled those of the parents (when breeding), more than expected by chance. Slight resemblances between parents and offspring were detected for muscle in winter and for fat reserves when breeding. Muscle size in the breeding season provided stronger evidence for the inheritance of condition.     

Effects of short- and long-term water-level drawdown on the populations and activity of aerobic decomposers in a boreal peatland

We analysed the response of microbial communities, characterized by phospholipid fatty acids (PLFAs), to changing hydrological conditions at sites with different nutrient levels in a southern boreal peatland. Although PLFAs of Gram‐negative bacteria were characteristic of the peatland complex, microbial communities differed among sites (ombrotrophic bog, oligotrophic fen, mesotrophic fen) and sampling depths (0–5, 5–10, 10–20, 20–30 cm). The microbial communities in each site changed significantly following water‐level drawdown. The patterns of change varied among sites and sampling depths. The relative proportion of Gram‐negative bacteria decreased in the upper 10 cm but increased in deeper layers of the fen sites. Fungi benefited from water‐level drawdown in the upper 5 cm of the mesotrophic fen, but suffered in the drier surfaces of the ombrotrophic bog, especially in the 5–10 cm layer. In contrast, actinobacteria suffered from water‐level drawdown in the mesotrophic fen, but benefited in the drier surfaces of the ombrotrophic bog. Basal respiration rate correlated positively with pH and fungal PLFA, and negatively with depth. We suggest that the changes in microbial community structure after persistent water‐level drawdown follow not only the hydrological conditions but also the patterns of vegetation change. Our results imply that changes in structure and activity of the microbial community in response to climate change will be strongly dependent on the type of peatland.