Multiple sex expressions in Cimicifuga simplex: dichogamy destabilizes hermaphroditism

Cimicifuga simplex (Ranunculaceae) has four types of individuals, differing in their sex expression: there are individuals with hermaphroditic, hermaphroditic and male (andromonoecious), only male, or only female flowers. Purely female individuals appear during the early part of the flowering period of the population, and males during the later part. Strong protandry in hermaphroditic flowers causes a shift in functional sex ratio in the population over time. This facilitates the evolution and maintenance of small proportions of unisexual individuals in the population. A hypothesis developed from this case of multiple sex expression predicts dichogamy as a near-universal feature of andro-and gynomonoecious, androdioecious, and gynodioecious species, and also specific temporal distributions for each sex form depending upon the form of dichogamy. Results of tests on large sets of species strongly support the relevance of this hypothesis.     

Effects of Frost Hardening and Dehardening on Photosynthetic Electron Transport and Fluorescence Properties in Isolated Chloroplasts of Pinus silvestris

Photosynthetic electron transport and low-temperature fluorescence emission properties have been analyzed in isolated chloroplasts during the course of frost hardening and dehardening of Pinus silvestris L. Both the partial electron-transport reactions (H₂O DPIP and Asc./DPIP NADP) and the overall electron transport (H₂O — NAPD) showed decreasing capacities during the course of hardening. Upon exposing the plants to ?5°C and high irradiance a block in the electron-transport chain between the two photosystems developed, whereas the partial reactions still showed activities. The decrease in activity of PSl was accompanied by a decrease in P700 content, as determined by light oxidation of P700, which indicates a correlation between the two changes. Hardening also induced changes in the in vivo chlorophyll organization. During the course of hardening the fluorescence emission bands F692 and F726 decreased relative to F680. These changes were more pronounced if the plants were treated in high than in low irradiance. This suggests a greater destruction of the chlorophyll antennae in close association with the two photoreactions than in the so-called light-harvesting chlorophyll a/b antenna. During dehardening basically the reverse of the changes observed during hardening occurred. The recovery of secondary needles was complete, whereas primary needles only partly recovered.     

Fine needle aspiration in nodular fasciitis of the face

Nodular fasciitis (NF) appears typically as a rapidly growing solitary mass which is most commonly located on the extremities, followed by the trunk and then the head and neck. NF is often suitable for fine needle aspiration (FNA), but few reports of NF diagnosed cytologically have been published. The purpose of this paper is to describe FNA cytology in three cases of nodular fasciitis. All three cases were located on the face.     

THE ANATOMY OF PACHYDERMIA LAEVIS (ARCHAEOGASTROPODA: 'PELTOSPIRIDAE')

The anatomy of Pachydermia laevis Warén & Bouchet,1989 is investigated. It is a deep-sea gastropod and restrictedto hydrothermal vents of the East Pacific Rise. Its anatomyresembles that of Melanodrymia aurantiaca Hickman, 1984 (Melanodrymiidae)in most respects, except that its gonopericardial duct opensinto the renopericardial duct, not into the peri-cardial chamber,and that it lacks a copulatory organ. Examination of M. aurantiacamain confirms earlier work. The two species have a cerebralbuccal connective fused with the cerebral ganglion (not freefrom it), a synapomorphy that has not been described for anyother archaeogastropod. The investigation suggests that Melanodrymiaand Pachydermia are closely related and together with Cyathermiidaeand Neomphalidae form a monophyletic group within the Neomphalina.No evidence was found to support earlier speculations aboutclose relations of Neomphalina to Viviparoidea. (Received 10 January 1996; accepted 3 April 1997)     

Phylogenetic relationships in brown argus butterflies (Lepidoptera: Lycaenidae: Aricia) from northwestern Europe

Lycaenid butterflies of the Aricia agestisartaxerxes complex pose an unresolved taxonomic and conservation problem in northwestern Europe. Two key issues require resolution: (i) how many species of Aricia occur in northwestern Europe and what are their distributions?; (ii) how is the morphological variation observed in northwestern Europe best explained? We investigated phylogenetic relationships and phylogeographic patterns in this species group using mitochondrial and nuclear markers in comparison with morphological variation. A 325 bp fragment of the mitochondrial cytochromeb gene was sequenced from 179 individuals representing 18 populations from the UK and Scandinavia. Seventeen enzymecoding loci were analysed from 538 individuals from the same populations. Highly congruent phylogenies between mitochondrial and allozyme markers demonstrate that the sample is composed of two closely related species, A. agestis and A. artaxerxes. Both marker types also suggest that Scottish and northern Scandinavian A. artaxerxes populations are conspecific, and consequently do not support the endemic status of A. artaxerxes in the UK. The subspecies division of British populations of A. artaxerxes is also not supported by phylogenetic analyses. Allozyme and mitochondrial analyses cluster two populations from the Peak District, UK, differently. The former suggests that they are A. artaxerxes whilst the latter suggests they are A. agestis. Further research is required to find the reason for this disagreement, which could be associated with the different dynamics of nuclear and mitochondrial genes across a hybrid zone between the two species. © 2002 The Linnean Society of London, Biological Journal of the Linnean Society, 2002, 75 , 27–37.     

Defective Gene Product in <Emphasis Type="Italic">dna</Emphasis>F Mutant of <Emphasis Type="Italic">Escherichia coli</Emphasis>

The dnaF mutant of Escherichia coli has been shown to contain very low ribonucleoside diphosphate reductase activity. The B1 sub unit of the reductase is heat-sensitive in the mutant.     

The evolutionary ecology of cheating: does superficial oviposition facilitate the evolution of a cheater yucca moth?

Abstract 1. A major question in the study of mutualism is to understand how mutualists may revert to antagonists that exploit the mutualism (i.e. switch to cheating). In the classic pollination mutualism between yuccas and yucca moths, the cheater moth Tegeticula intermedia is sister to the pollinator moth T. cassandra. These moth species have similar ovipositor morphology, but T. intermedia emerges later, oviposits into fruit rather than flowers, and does not pollinate. 2. We tested if the pollinator, T. cassandra, was pre‐adapted to evolve a cheater lineage by comparing its emergence and oviposition behaviour on yucca fruit to a distantly related pollinator, T. yuccasella, that differs in ovipositor morphology and oviposition behaviour. We predicted that if T. cassandra was pre‐adapted to cheat, then these pollinators would emerge later and be able to oviposit into fruit in contrast to T. yuccasella. 3. Contrary to expectations, a common garden‐rearing experiment demonstrated that emergence of T. cassandra was not significantly delayed relative to T. yuccasella. Moth emergence patterns overlapped broadly. 4. No choice oviposition experiments with female moths demonstrated that both pollinator species attempted to oviposit into fruit, but only T. cassandra was successful. Four out of 84 T. cassandra successfully oviposited into older fruit, whereas zero out of 79 T. yuccasella oviposited into older fruit. The rarity of the cheating behaviour in pollinators, however, meant that no significant difference in oviposition ability was detected. 5. The results suggest that a shift in emergence phenology is likely not a pre‐adaptation to the evolution of cheating, but that the ability to successfully lay eggs into fruit may be. The results also demonstrate that cheating attempts are rare in these pollinator species and, hence, the evolutionary transition rate from pollinator to cheater is likely to be low.     

Seasonal Effects on Photosynthetic Electron Transport and Fluorescence Properties in Isolated Chloroplasts of Pinus silvestris

Chloroplasts were isolated from primary needles of 1-year-old seedlings and from secondary needles of a 20-year-old pine tree in a natural stand. In autumn the electron transport capacities of PSII, PSI and PS (II + I) decreased and the electron transport between PSII and PSI became inhibited in October in the 20-year-old tree. This inhibition lasted until May the following year. The partial reactions of PSI and PSII still showed low but fairly constant rates during the whole winter seedlings. Seasonal changes in the electron transport properties of 1-year-old showed the same general trends as observed in the 20-year-old tree, but the changes were less pronounced. However, in snow-covered seedlings the PSI-mediated electron transport and the electron transport from H₂O to NADP increased during the late winter when the seedlings were still covered by snow. The total chlorophyll content of the needles decreased in autumn and winter. Low temperature fluorescence ratios of F692/F680 and F726/F680 indicated more severe destruction of the chlorophyll a antennae closely associated with the two photosystems than of the light harvesting chlorophyll a/b complex. In this case, too, the changes were more pronounced in the 20-year-old tree than in the 1-year-old seedlings. The chlorophyll/P700 ratios indicated a more marked reduction in the reaction centre molecules during autumn than in the antennae chlorophyll molecules. The changes in electron transport and low temperature fluorescence properties which occurred during autumn and winter were mainly reversed during spring.     

Gallery construction and oviposition of the bark beetle Ips typographus (Coleoptera: Scolytidae) at different breeding densities

Abstract. 1. The bole of a Norway spruce, Picea abies (L.) Karst., was cut in 25 cm sections and infested in the laboratory with 2 or 8 females/dm² of Ips typographus (L.) and an equal number of males.
2. One log of each beetle density was dissected every second day, beginning 2 days after female introduction.
3. The oviposition rate was highest at the beginning of the breeding period for both densities and then declined, especially at the high density. Residence time is a useful approximation for the number of laid eggs in the beginning of the oviposition period or when the density is low.
4. Final gallery length and egg number per gallery were on average significantly smaller at density 8 than at density 2.
5. Linear relationships between total gallery length and number of egg niches were found to be similar for the two densities.
6. An estimate of the egg to adult mortality at different densities was found by using data from a field study that related gallery length to breeding density in attacked living trees, together with published relationships between density and egg niches or emergence of new adults.
7. It was concluded that both decreased oviposition rate and earlier re-emergence at higher densities contribute to a declining oviposition with increasing density. The final offspring production is futher reduced by lower survival due to larval competition as density increases.