Bayesian hierarchical models suggest oldest known plant-visiting bat was omnivorous

The earliest record of plant visiting in bats dates to the Middle Miocene of La Venta, the world''s most diverse tropical palaeocommunity. Palynephyllum antimaster is known from molars that indicate nectarivory. Skull length, an important indicator of key traits such as body size, bite force and trophic specialization, remains unknown. We developed Bayesian models to infer skull length based on dental measurements. These models account for variation within and between species, variation between clades, and phylogenetic error structure. Models relating skull length to trophic level for nectarivorous bats were then used to infer the diet of the fossil. The skull length estimate for Palynephyllum places it among the larger lonchophylline bats. The inferred diet suggests Palynephyllum fed on nectar and insects, similar to its living relatives. Omnivory has persisted since the mid-Miocene. This is the first study to corroborate with fossil data that highly specialized nectarivory in bats requires an omnivorous transition.     

Insights into the Witheringia solanacea (Solanaceae) Complex in Costa Rica. II. Insect Visitors and Pollination Biology of W. asterotricha and W. meiantha1

Isolating mechanisms are important in maintaining the taxonomic integrity of closely related sympatric taxa. A previous study found strong post‐zygotic isolating barriers between two species, Witheringia asterotricha and W. meiantha, of the W. solanacea (Solanaceae) species complex in Costa Rica. This study examines the presence of pre‐zygotic barriers between the two species at La Selva Biological Station in Costa Rica. Both species offer pollen and nectar as floral rewards and are visited primarily by solitary or semi‐social bees, some of which sonicate (“buzz”) the anthers to discharge pollen. No evidence was found for phenological differences in flowering time between W. asterotricha and W meiantha, but pre‐zygotic factors, such as ethological isolation and possibly fine‐scale ecological or geographic barriers, may be responsible for restricting gene flow between the two species.     

Life‐history traits of Encarsia guadeloupae,a natural enemy of the invasive spiralling whitefly Aleurodicus dispersus

On south‐west Indian Ocean islands, many crops and ornamental plants are threatened by the spiralling whitefly Aleurodicus dispersus (Hemiptera: Aleyrodidae), which is a polyphagous pest that is native to the Caribbean region. Aleurodicus dispersus causes economic damage to various crops on all the islands in the south‐west Indian Ocean. The hymenopteran parasitoid Encarsia guadeloupae (Hymenoptera: Aphelinidae) is a natural enemy of A. dispersus on the Caribbean islands. In this study, we assessed the geographical distribution of the parasitoid in La Réunion, an island in the south‐west Indian Ocean where the parasitoid was first observed in 2004. We also investigated its main life‐history traits. Field surveys indicated that the parasitoid is widespread in most of the low‐lying areas of the island and exhibits high parasitism rates on A. dispersus populations. At 25°C, E. guadeloupae adults had a mean longevity of 33.6 days, and its pre‐imaginal development required 23 days. The lower temperature threshold and thermal constant were estimated to be 7.9°C and 132 degree‐days, respectively. Females of E. guadeloupae preferred to deposit eggs in early rather than in late instars of A. dispersus, and oviposition rates were highest in the second larval instar. Females of E. guadeloupae were able to oviposit in larvae of other species of whiteflies found in La Réunion (Bemisia tabaci and Dialeurolonga simplex), although subsequent development of the parasitoid was not monitored. Finally, we discuss the potential use of E. guadeloupae for the control of whitefly populations on islands in the south‐west Indian Ocean.     

Hemoglobin Rothschild (β37(C3)Trp → Arg): A high/low affinity hemoglobin mutant

In hemoglobin Rothschild arginine replaces the normal tryptophan at β37(C3), at α₁β₂ contact. Residue β37 is in close proximity to Argα92 (FG4). Substitution of Trp by Arg at β37 results in two positively charged Arg residues at FG4 and C3 facing each other, a situation that would destabilize the subunit constraints essential for the tetrameric integrity of the molecule and for the reduced ligand affinity of unliganded normal HB³ compared to isolated chains.Our studies show liganded HbR is extensively dissociated into dimers and has a high ligand affinity in phosphate buffer and a low ligand affinity in bis-Tris at alkaline pH. Kinetic studies indicate that in the T state HbR has a higher ligand affinity than HbA. This is explained by reduced subunit constraints in the T state and dissociation of the monoliganded species (Hb₄L) into dimers. Kinetic studies also show that R state Hb Rothschild has lower ligand affinity than R state HbA. These results are explained on the basis of extensive dissociation of R state Hb Rothschild into dimers and lower ligand affinity of dimers as compared to triliganded tetramers (α₂β₂(O₂)₃). Kinetic data indicate that the lower ligand affinity of dimers (Hb Rothschild) as compared to that of triliganded tetramers (HbA) is due to the increased ligand dissociation rates in the case of oxyhemoglobin and reduced ligand combination in the case of carboxyderivatives. Both the CO combination reaction time-course around 425 nm and the O₂ dissociation rates at 437.8 nm indicate the presence of large α,β-chain differences in Hb Rothschild.     

Cranial remains of Middle Pleistocene European hominids

Cranial remains of the Middle Pleistocene European hominids are reviewed in a historical context. Swanscombe and Steinheim, the earliest specimens to be discovered, are compared with each other. Following this, the more recently discovered specimens from Vértesszöllös, Petralona and Bilzingsleben are compared. Finally, Riss remains from La Chaise, Biache and Arago are discussed in the context provided by the above specimens. It is suggested that while phyletic evolution may play a role in the observed differences, a marked degree of sexual dimorphism contributes to the variation expressed by these specimens.     

The effect of sulfur-containing nitrogen fertilizers on the elemental composition of celery (Apium graveolens) grown on a polluted marsh soil

Summary In order to investigate elemental composition of celery, and to quantify the influence of sulfur-containing N-fertilizers on the trace element uptake, a field trial with celery was carried out on marsh soil polluted with municipal wastes. The research yielded the following results:Compared to leaves at harvest time, bulbs showed significantly lower concentrations of Mo, S and Sb, but higher contents of B, Br and Cr and Cu. Since the acidifying effect of the fertilizers was suppressed by the free calcium carbonate in the soil, no significant changes in concentrations of cationic trace elements were detected in plants fertilized with ammonium sulfate compared to those which received urea or calcium ammonium nitrate. On the other hand, in these plants the conspicuous increase in total sulfur was accompanied by a significant decrease in concentrations of up to 30% for B, Br and Sb, 50% for As, 60% for Se and 80% for Mo.According to these results, in plant production on contaminated soils certain plant parts may be marketable due to their low tendency to accumulate toxic elements, and furthermore it may be feasible to reduce the contents of some of these elements in plants by the use of sulfur-containing fertilizers.     

Effect of cell size, age and anatomical location on the lipolytic response of adipocytes

Studies were conducted on the norepinephrine (NE) stimulated lipolytic sensitivity of adipocytes from epididymal (Epi), perirenal (PR), subcutaneous (SC) and mesentric (M) depots from young (7–8 wk.) and adult (14–16 wk.) male rats. In the young rats dose response curves to NE were similar for Epi, PR and M depots whereas adipocytes from the SC depot showed a diminished effect over the mid-portion of the curve. This difference could not be ascribed to differences in cell size. In the adult rats glycerol release in the Epi depot in response to NE was identical to the younger rats which was in marked contrast to the other depots in which glycerol release was decreased in comparison to the younger animals. This decreased responsiveness was probably largely a result of age and not changes vn adipocyte size within a given depot. In these older rats, glycerol release was greatest in the Epi cells, least in the SC and M depots, and intermediate in PR. When young rats were subjected to a 72-hour fast, loss of triglyceride per cell was the same in all depots as predicted by the $\text{in vitro}$ data whereas in old rats (610 g), triglyceride loss was proportional to cell size with Epi ≥ PR > SC ≥ M. This was also essentially in agreement with the $\text{in vitro}$ lipolytic data from adult rats. These data demonstrate lipolytic differences between depots that are minimal in young rats and which are accentuated with age.     

Multi locus analysis of Pristionchus pacificus on La Réunion Island reveals an evolutionary history shaped by multiple introductions, constrained dispersal events and rare out-crossing

Pristionchus pacificus, recently established as a model organism in evolutionary biology, is a cosmopolitan nematode that has a necromenic association with scarab beetles. The diverse array of host beetle species and habitat types occupied by P. pacificus make it a good model for investigating local adaptation to novel environments. Presence of P. pacificus on La Réunion Island, a young volcanic island with a dynamic geological history and a wide variety of ecozones, facilitates such investigation in an island biogeographic setting. Microsatellite data from 20 markers and 223 strains and mitochondrial sequence data from 272 strains reveal rich genetic diversity among La Réunion P. pacificus isolates, shaped by differentially timed introductions from diverse sources and in association with different beetle species. Distinctions between volcanic zones and between arid western and wet eastern climatic zones have likely limited westward dispersal of recently colonized lineages and maintained a genetic distinction between eastern and western clades. The highly selfing lifestyle of P. pacificus contributes to the strong fine‐scale population structure detected, with each beetle host harbouring strongly differentiated assemblages of strains. Periodic out‐crossing generates admixture between genetically diverse lineages, creating a diverse array of allelic combinations likely to increase the evolutionary potential of the species and facilitate adaptation to local environments and beetle hosts.