Multiple origins of viviparity,or reversal from viviparity to oviparity? The European common lizard (Zootoca vivipara,Lacertidae) and the evolution of parity

The evolution of viviparity in squamates has been the focus of much scientific attention in previous years. In particular, the possibility of the transition from viviparity back to oviparity has been the subject of a vigorous debate. Some studies have suggested this reversal is more frequent than previously thought. However, none of them provide conclusive evidence. We investigated this problem by studying the phylogenetic relationships between oviparous and viviparous lineages of the reproductively bimodal lizard species Zootoca vivipara . Our results show that viviparous populations are not monophyletic, and that several evolutionary transitions in parity mode have occurred. The most parsimonious scenario involves a single origin of viviparity followed by a reversal back to oviparity. This is the first study with a strongly supported phylogenetic framework supporting a transition from viviparity to oviparity.  © 2006 The Linnean Society of London, Biological Journal of the Linnean Society , 2006, 87 , 1–11.     

Pair Formation in California Condors

SYNOPSIS. Pair formation is a prerequisite for reproductionin California condors and exploring the process has been centralto the captive breeding program for this endangered species.Observations show that once birds reach sexual maturity theycan form pairs within a matter of months; even birds who havelost or been separated from their mates will successfully bondwith others. However, some adults who are housed together showlittle indication of pairing. When such birds are placed withother potential mates they frequently successfully pair andproduce young, suggesting that individual differences play arole in pair formation. We recommend that adults who have notbonded within two years be housed with different potential mates. Condors raised together may or may not form pair bonds uponreaching sexual maturity; unfamiliar condors introduced at fouryears of age or older will form pair bonds. In the four caseswhere pairings have been successful the male initiates moreintrapair interactions with aggressive behavior than does thefemale. Unpaired condors housed in groups do show courtshipand the most dominant birds, usually males, are the most activein giving wings-out/head-down displays. Displays may be directedto males or females and may signal dominance and/or interest.Displays may be followed by mounts and one female may crowdin front of the bird to whom a male is displaying, increasingthe chances that she will receive the display and be mounted.Displaying and the response to displaying birds may be mechanismswhich influence mate selection.     

Where do Sardinian orchids come from: a putative African origin for the insular population of Platanthera bifolia var. kuenkelei?

Because of the complex geoclimatic dynamics of the Mediterranean basin, resulting from a combination of Tertiary geological processes and Quaternary climatic oscillations, the current species composition of the main continental islands is a mosaic resulting from relative contribution of vicariance, geodispersal and long‐distance dispersal by seed. To help distinguish among the contributions of these different dispersal modes to the orchid species richness on the island of Sardinia, we investigated the genetic structure and phylogeographic relationship of the only Platanthera bifolia var. kuenkelei population on the island. By using plastid DNA sequence variation, we show that this recently discovered population is more closely related to the Tunisian P. bifolia var. kuenkelei than to the geographically closer P. bifolia populations from peninsular Italy. Results from haplotype network construction support the hypothesis that the current distribution of P. bifolia var. kuenkelei (Sardinia and Tunisia) is most likely explained by over‐sea dispersal. However, haplotype diversity and mismatch analysis of this unique Sardinian population suggest that, if a long‐distance dispersal event did occur, it was not recent. More likely, temporarily favourable climatic conditions generated a suitable habitat on the island (also in terms of suitable mycorrhizas and pollinators) and thus a transient opportunity for seedling growth and population establishment of P. bifolia var. kuenkelei from North Africa. © 2011 The Linnean Society of London, Botanical Journal of the Linnean Society, 2011, 167 , 466–475.     

Phosphate Relations of Acetabularia: Phosphate Pools, Adenylate Phosphates and 32P Influx Kinetics

Steady state phosphate relations are determined for the marinealga Acetabularia mediterranea with respect to cellular phosphatepools and phosphate transport. About 20% of the cellular acid-labilephosphate is found in the cell wall fraction (low speed sediment).By the use of cytoplasm-depleted cell segments, it isa establishedthat only about 10% of the total intracellular phosphate islocalized in the vacuole when cells are bathed in normal phosphateconcentration (<30 µM). Measurements of ATP, ADP, AMPand inorganic phosphate (Pj) in the entire cytoplasm and inisolated chloroplasts has enabled the calculation of the cytosolicadenylate energy charge (0.7–0.9) and phosphate potential(110–170 mV). Influx of ³²P, displays complex kinetics.Four components for uptake (approximate time constants: (A)1 s, (B) 20 s, (C) 300 s and (D) 3000 s) are tentatively identified.Focusing on the faster components, B and C, and possibly evenA, appear to be metabolically-linked, as judged by their sensitivityto temperature and to the inhibitor 2, 4-dinitrophenol. Thesethree components of influx are proportional to the externalP, concentration for values <30 µM, but B and C tendto saturate at higher concentrations. The results are discussedwith respect to the energetics of transport at the plasmalemmaof Acetabularia, especially the activity of the electrogenicCI-ATPase. Key words: Acetabularia, Energy charge, Phosphate pools, Phosphate potential, Phosphate uptake kinetics     

Intraspecific chromosomal and genetic polymorphism in Brassica napus L. detected by cytogenetic and molecular markers

The application of DNA intercalator 9-aminoacridine allowed us to increase the resolution of chromosome C-banding and DAPI-banding patterns and to investigate chromosomal polymorphism in karyotypes of seven spring and six winter rape varieties. It was shown that the pericentromeric and intercalary C-bands of most of the chromosomes in spring rape were smaller in size and less polymorphic than those of winter rape. More 26S and 5S rDNA sites were found in the winter rape karyotypes than the spring varieties. Separate or colocalized 26S and 5S rDNA sites were revealed on chromosomes 4, 5, 6, 8, 10, 14, 15, 16 and 18. Intervarietal and intravarietal polymorphism of the number and chromosomal localization of rDNA sites were detected. The generalized idiogram of chromosomes of 13 Brassica napus varieties with account of all possibilities of C-banding patterns as well as localization of 26S and 5S rDNA sites were constructed. Polymorphism of the examined molecular and cytogenetic markers as well as the heterozygosis level of FAE1.1 gene controlling erucic acid synthesis in rapeseed was higher in the winter varieties than in the spring ones. The obtained data were in a satisfactory agreement with increased tolerance to environmental stress conditions of winter rape.     

Protein Synthetic Activities during Spermiogenesis in the Sea Urchin: An high Resolution Autoradiographic Study of 3H-Leucine Incorporation

Protein synthetic activity has been studied during spermiogenesis of Paracentrotus lividus by high-resolution autoradiography using ³H-leucine as a labeled precursor. Under the adopted experimental conditions ³H-leucine is incorporated during the whole spermiogenesis period. The early spermatid is the most active stage and it shows labeling over the nucleus, the cytosol and the mitochondria. Nuclear ³H-leucine incorporation progressively decreases as spermiogenesis proceeds. Cytosol labeling shows similar values at early and intermediate spermatid and it undergoes a considerable decreases at late spermatid. Mitochondrial grain density increases from early to intermediate spermatid and it remains almost constant at late spermatid.
Our results are compared with the data reported for other animal groups and possible functions of the observed protein synthesis are discussed.     

Molecular phylogeny of the Mediterranean species of Philaenus (Hemiptera: Auchenorrhyncha: Aphrophoridae) using mitochondrial and nuclear DNA sequences

The phylogenies of all eight European species of Philaenus were estimated from cytochrome oxidase subunit I, cytochrome B and internal transcribed spacer 2 (ITS2) fragments of DNA using phylogenetic reconstruction methods: maximum parsimony (MP), maximum likelihood (ML) and Bayesian inference (BI) analyses. Based on the topologies of all obtained phylogenetic trees, the monophyly of Philaenus is well supported, being congruent with morphological, ecological and chromosomal data. Three phylogenetic lineages were distinguished in the mitochondrial and combined (mtDNA with ITS2) trees. The first lineage is represented by only one species, Philaenus maghresignus, which inhabits Maghreb and southern Spain. Clade A includes three species: P. tarifa (Southern Iberia), P. italosignus (Sicily and Southern Italy) and P. signatus (the Balkans and Middle East). In clade B two subclades were recognized: B1 represented by P. loukasi (Southern Balkans) and P. arslani (Middle East), and B2 comprising P. spumarus (the most widespread Palaearctic species) and P. tesselatus (from Southern Iberia and Maghreb). These clades were also retrieved in trees reconstructed from nuclear sequences. However, four species (P. maghresignus, P. tarifa, P. italosignus and P. signatus) showed unresolved polytomy at the base of the nuclear tree. Clade A together with P. maghresignus clustered with the ‘signatus’ group defined from morphology, and clade B with the ‘spumarius’ group; these might be considered separate subgenera. Genetic distances in mitochondrial DNA between ingroup species ranged from 14.0% between P. signatus and P. spumarius to 2.4% between P. tesselatus and P. spumarius. By contrast, genetic divergence of ITS2 between ingroup species was very low, at most 2.1%. The divergence of Philaenus species is estimated to have occcurred between 7.9 and 0.6 Ma. Possibly three main speciation events occurred: the first at the Miocene/Pliocene boundary (c. 5.5 Ma) for deeper splits; the second between 4.2 and 2.5 Ma in the Pliocene, when pairs of more closely related species diverged; and the most recent during the Pleistocene glaciations, when the separation of P. tesselatus and P. spumarius took place. The species status of all Philaenus species is confirmed except for P. tesselatus.     

Direct and indirect effects of weather variability in a specialist butterfly

1. Climate change poses serious threats to the long‐term persistence of many animal and plant populations. Species having specific niche requirements, or characterised by highly co‐evolved interactions, will face the greatest challenges. An example is represented by Maculinea alcon (Denis & Schiffermüller), a monophagous and univoltine butterfly species, which lays eggs only on larval host plants which occur inparticular phenological conditions. 2. The present 2‐year study focused on two M. alcon populations, both located at the southern boundaries of the species, but facing different climatic conditions (360 m, low altitude versus 860 m, high altitude). Population vulnerability with respect to direct and indirect effects of climate change was analysed, focusing on two important aspects of butterfly biology, i.e. the flight activity of adults and the degree of synchrony in the larval plant–insect interactions. 3. It was observed that, when positive temperature anomalies are reached, the temperature can exert detrimental effects on adults' activity. At a low altitude, in a hotter than usual year, a temperature threshold was recorded (around 32 °C), above which the activity of butterflies is inhibited. In contrast, at a high altitude, temperature increases maintain the opportunity to enhance butterfly activity. Altitudinal differences were also observed in the phenology of the two interacting species, which generate stronger asynchrony at low altitudes. 4. High‐ and low‐altitude populations represent different conservation units: a global increase in temperature would pose a serious threat to the lowland populations, whereas high‐altitude populations would gain a greater role in assuring the persistence of M. alcon at its southern boundaries.     

Reversal of Electrogenic Cl- Pump in Acetabularia Increases Level and 32P Labelling of ATP

In order to test the prediction that the Cl^– ATPase inthe plasmalemma of Acetabularia is reversible, the content and³²P labelling of ATP in centrifuged, cytoplasm-depleted stalksegments has been measured upon incubation in ³²P containingmedia with normal (c. 500 mM) and zero Cl^–concentration.Increases in content and labelling of ATP could be demonstratedwhen the preparations were exposed to zero external Cl^–(1.1 M sorbitol, isotonic with the control medium–emdashErdschreiber solution). These effects are reduced in 1: 1 mixturesof 1.1 M sorbitol with 0.55 M Nal or Na-benzenesulphonate, thelatter two of which are known to diminish the number of activeCl^– pumps. Increased ATP content upon exposure to sorbitolis not observed at 5 °C, when the Cl- pump is known to bestrongly inhibited. These results provide strong evidence forthe hypothesis that the electrogenic Cl^– pump is a reversible,primary Cl^– transporting ATPase. The relationship of theseresults to the transmembrane potential difference measured underthe same conditions is not yet clear. Key words: Acetabularia, Electrogenic Cl^– pump, Cl^– ATPase, Cl^– gradient driven ATP synthesis, Reversible ATPase     

Phylogeography of Parnassius apollo: hints on taxonomy and conservation of a vulnerable glacial butterfly invader

Parnassius apollo (Linnaeus, 1758) is probably the most renowned Eurasian montane butterfly. Its specialized ecology makes it very sensitive to habitat and climate changes, so that it is now experiencing range contraction and local extinction across most of its range. We sequenced 869 bp of the mitochondrial DNA (mtDNA) cytochrome oxidase I gene in 78 P. apollo populations (201 individuals) in order to: (1) assess the phylogeographic pattern of the species; (2) shed light on the historical biogeographic processes that shaped the distribution of the species; and (3) identify geographic population units of special value for the conservation of the species' genetic diversity. Our analyses revealed a very strong phylogeographic structure in P. apollo, which displays a number of distinctive mtDNA lineages populating geographically distinct areas. Overall sequence divergence is relatively shallow, and is consistent with a recent (late Pleistocene) colonization of most of the range. We propose that P. apollo is best viewed as an atypical glacial invader in southern and western Europe, the isolated, montane populations of which, threatened by climate warming, retain a large fraction of the species evolutionary heritage. © 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2010, 101 , 169–183.