Relationship between floral tube length and nectar robbing in Duranta erecta L. (Verbenaceae)

Although nectar robbing is a common phenomenon in plant species with tubular flowers or flowers with nectar spurs, the potential effect of this illegitimate interaction on plant reproductive success has not received the deserved attention. In the present study, we analysed the functional relationship between flower morphology and nectar robbing, and examined the reproductive consequences of the interaction in a population of Duranta erecta (Verbenaceae) on the island of Cuba. The results show that nectar robbing is conducted by the carpenter bees Xylocopa cubaecola and affects up to 44% of flowers in the studied population. However, not all the flowers have the same probability of being robbed. The chance of flowers being robbed increases with flower length and flower diameter. Moreover, nectar robbing significantly decreases the chance that flowers will set fruit. Also, the impact of nectar robbing on the probability of flowers to set fruits is dependent on the plant. We suggest that nectar robbing may represent an opposite selective force that balances the selection for longer corollas often imposed by pollinators specializing in visiting tubular flowers. Such a relationship with nectar robbers would have obvious implications for the evolution of tubular or closed flowers. This preliminary finding deserves further research in light of the ecological and evolutionary consequences of nectar robbing in tubular flowers.  © 2009 The Linnean Society of London, Biological Journal of the Linnean Society , 2009, 96 , 392–398.     

Comparative morphology,biology and phylogeny of terminal‐instar larvae of the European species of Toryminae (Hym., Chalcidoidea,Torymidae) parasitoids of gall wasps (Hym. Cynipidae)

We present a phylogenetic and taxonomic study of the morphology and biology of the terminal‐instar larval stage of 19 species representing all the genera of Torymidae parasitoids of gall wasps in Europe, with the single exception of Megastigmus. The genera studied include Adontomerus Nikol'skaya, Idiomacromerus Crawford, Chalcimerus Steffan & Andriescu, Glyphomerus Förster, Pseudotorymus Masi and Torymus Dalman. We primarily used chaetotaxy and some head structures. The terminal‐instar larvae of all studied species are thoroughly described for the first time and illustrated with SEM images. We provide diagnostic characters for the family and the genera studied, and keys to genera and species for the identification of torymid larvae associated with cynipid galls. The majority of the torymid larvae studied are solitary monophagous parasitoids. Finally, to assess the potential use of larval characters in systematic studies of the family, a phylogenetic analysis of the studied taxa based on 42 larval morphological characters is proposed and compared with the current taxonomy of Torymidae. Our results suggest that body chaetotaxy, and characters of the head and mouthparts could be used for genera and species discrimination. © 2008 The Linnean Society of London, Zoological Journal of the Linnean Society, 2008, 154 , 676–721.     

Ferricrocin synthesis in Magnaporthe grisea and its role in pathogenicity in rice

Iron is an essential element for the growth of nearly all organisms. In order to overcome the problem of its low bioavailability, microorganisms (including fungi) secrete siderophores, high-affinity iron chelators. As the acquisition of iron is also a key step in infection processes, siderophores have been considered as potential virulence factors in several host–pathogen interactions. Most fungi produce siderophores of the hydroxamate-type, which are synthesized by non-ribosomal peptide synthetases (NRPSs). Magnaporthe grisea , the causal agent of rice blast disease, produces ferricrocin as intracellular storage siderophore and excretes coprogens. In the M. grisea genome we identified SSM1 , an NRPS gene, and a gene encoding an l -ornithine N5-monooxygenase ( OMO1 ) that is clustered with SSM1 and responsible for catalysing the first step in siderophore biosynthesis, the N⁵ hydroxylation of ornithine. Disruption of SSM1 confirmed that the gene encodes ferricrocin synthetase. Pathogenicity of these mutants towards rice was reduced, suggesting a role of this siderophore in pathogenicity of M. grisea .     

Strategies and counterstrategies to infanticide in mammals

I analyse and summarize the empirical evidence in mammals supporting alternative benefits that individuals may accrue when committing nonparental infanticide. Nonparental infanticide may provide the perpetrator with nutritional benefits, increased access to limited resources, increased reproductive opportunities, or it may prevent misdirecting parental care to unrelated offspring. The possibility that infanticide is either a neutral or maladaptive behaviour also is considered. I devote the second half of this article to reviewing potential mechanisms that individuals may use to prevent infanticide. These counterstrategies include the early termination of pregnancy, direct aggression by the mother against intruders, the formation of coalitions for group defence, the avoidance of infanticidal conspecifics, female promiscuity, and territoriality. I evaluate the support for each benefit and counterstrategy across different groups of mammals and make suggestions for future research.     

Plant species variation in bottom‐up effects across three trophic levels: a test of traits and mechanisms

1. An increasing number of studies have addressed the mechanisms by which plant inter‐specific variation influence interactions at higher trophic levels, but little is known about the underlying plant traits driving these dynamics. 2. Here we investigated the effects of host plant species on herbivore‐parasitoid interactions and the underlying traits driving such effects. For this, we measured the abundance of seed‐eating bruchids and their parasitoids across seven sympatric populations of the bean species Phaseolus coccineus and Phaseolus vulgaris in Central Mexico. To investigate the mechanisms underlying differences between bean species in bruchid‐parasitoid interactions, we carried out two laboratory experiments to test whether bruchid and parasitoid performance differed between plant species. We also measured seed size and phenolic compounds to investigate if seed traits mediate bruchid‐parasitoid interactions by influencing herbivore susceptibility or resistance to parasitoids. 3. Field surveys revealed that the rate of parasitoid recruitment to bruchids was significantly higher on P. vulgaris than on P. coccineus. Subsequent laboratory bioassays indicated that bruchids developed more slowly and exhibited lower fitness on P. vulgaris seeds than on P. coccineus seeds. Accordingly, we found that bean species differed in seed size, with P. vulgaris having smaller (less nutritious) seeds, which explains why bruchid development was slower on this plant species. 4. These results provide a mechanism for why bruchids exhibited higher parasitism rates on seeds of P. vulgaris in the field which could be due to Slow‐Growth/High‐Mortality effects, a smaller physical refuge provided by the seed, or both factors. The roles of these mechanisms remain inconclusive without further study.     

Karyosystematic study of Potentilla L. subgen. Potentilla (Rosaceae) in the Iberian Peninsula

Chromosome numbers in 80 populations belonging to 18 species of Potentilla L. subgen. Potentilla from the Iberian Peninsula and two of P. maura, a North African endemic taxon, have been counted. The basic number of chromosomes is always x = 7 and these chromosomes are small (between 1 and 2 μm). For three species, the number of chromosomes is reported for the first time and, for another six, this number has been established in Iberian representatives. Moreover, new ploidy levels have been obtained for P. hispanica and P. crantzii with regard to their entire distribution area, and in P. cinerea and P. neumanniana for the Iberian Peninsula. Some taxonomic, phylogenetic and phytogeographic comments are made for several species or groups of species from the West Mediterranean region. In 13 species only one ploidy level has been found, but six species have several ploidy levels. Seven ploidy levels occur in the investigated taxa. The frequency of each ploidy level represented within Iberian Potentilla is analysed and the data are compared with those available for taxa from the rest of the distribution area of the genus.     

High European sauropod dinosaur diversity during Jurassic–Cretaceous transition in Riodeva (Teruel, Spain)

Abstract:  Up to now, more than 40 dinosaur sites have been found in the latest Jurassic – earliest Cretaceous sedimentary outcrops (Villar del Arzobispo Formation) of Riodeva (Iberian Range, Spain). Those already excavated, as well as other findings, provide a large and diverse number of sauropod remains, suggesting a great diversity for this group in the Iberian Peninsula during this time. Vertebrae and ischial remains from Riodevan site RD-13 are assigned to Turiasaurus riodevensis (a species described in RD-10, Barrihonda site), which is part of the Turiasauria clade. This is the first time that a taxon is attributed to Turiasaurus genus out of its type site. A Neosauropod caudal vertebra from the RD-11 site has been classified as Diplodocinae indet., supporting the previous attribution on an ilion also found in Riodeva (CPT-1074) referring to the Diplodocidae clade. New remains from the RD-28, RD-41 and RD-43 sites, of the same age, among which there are caudal vertebrae, are assigned to Macronaria. New sauropod footprints from the Villar del Arzobispo Formation complete the extraordinary sauropod record coming to light in the area. The inclusion of other sauropods from different contemporaneous exposures in Teruel within the Turiasauria clade adds new evidence of a great diversity of sauropods in Iberia during the Jurassic–Cretaceous transition. Turiasauria distribution contributes to the understanding of European and global palaeobiogeography.     

Skolithos pipe rock and associated ichnofabrics from the southern Rocky Mountains,Canada: colonization trends and environmental controls in an early Cambrian sand‐sheet complex

Desjardins, P.R., Mángano, M.G., Buatois, L.A. & Pratt, B.R. 2010: Skolithos pipe rock and associated ichnofabrics from the southern Rocky Mountains, Canada: colonization trends and environmental controls in an early Cambrian sand‐sheet complex. Lethaia, 10.1111/j.1502‐3931.2009.00214.x The Lower Cambrian Gog Group of the southern Rocky Mountains of western Canada offers an opportunity to explore animal–sediment relationships in a high‐energy setting, during the early phase of Phanerozoic diversification. Its strata record a sand‐sheet complex on the broad pericontinental shelf of West Laurentia. Six ichnofabrics are recognized: Skolithos IF‐1 characterized by Skolithos linearis in planar cross‐stratified sandstone; Skolithos IF‐2 with Skolithos linearis and accessory Diplocraterion parallelum in ripple cross‐laminated, and planar and trough cross‐stratified sandstone; Skolithos IF‐3 with S. linearis and Planolites montanus in wavy‐ and flaser‐bedded sandstone, interfingering with bioturbated mudstone exhibiting P. montanus and Teichichnus rectus; Skolithos IF‐4, characterized by abundant Skolithos linearis in planar and trough cross‐stratified sandstone; Rosselia IF‐1 consisting of Rosselia isp. in planar cross‐stratified sandstone; and Rosselia IF‐2 consisting of scattered small Rosselia isp. in hummocky, cross‐stratified sandstone. The presence of contrasting ichnofabrics within a single early Cambrian sand‐sheet complex illuminates how the colonization trends of suspension and detritus feeders were controlled by factors specific to the various sub‐environments. □Gog Group, Ichnofabric, Lower Cambrian, Pipe Rock, Rosselia, Skolithos.