Withdrawn food rate for larvae of Siberian moth on conifers of Siberia

Experimental evaluation of the mass of food withdrawn by larvae of the Siberian moth during their development on larch, cedar pine, fir, spruce, and common pine was carried out. The obtained dependences between the masses of larvae and food withdrawn by them can be directly used to determine the withdrawn food rate of Siberian moth on each of the Siberian conifer species.     

The structure and function of phytochrome A: the roles of the entire molecule and of its various parts

Phytochrome A is readily cleavable by proteolytic agents to yield an amino-terminal fragment of 66 kilodalton (kDa), which consists of residues 1 to approximately 600, and a dimer of the carboxy-terminal 55-kDa fragment, from residue 600 or so to the carboxyl terminus. The former domain, carrying the tetrapyrrole chromophore, has been studied extensively because of its photoactivity, while less attention has been paid to the non-chromophoric portion until quite recently. However, the evidence gathered to date suggests that this domain is also of great improtance. We present here a review of the structure and the biochemical and physiological functions of the two domains, of parts of these domains, and of the cooperation between them.     

Hybridization and the evolution of invasiveness in plants and other organisms

Less than a decade ago, we proposed that hybridization could serve as a stimulus for the evolution of invasiveness in plants (Ellstrand and Schierenbeck Proc Nat Acad Sci USA 97:7043–7050, 2000). A substantial amount of research has taken place on that topic since the publication of that paper, stimulating the symposium that makes up this special issue. Here we present an update of this emergent field, based both on the papers in this volume and on the relevant literature. We reevaluate the lists that we presented in our earlier paper of reports in which hybridization has preceded the evolution of invasiveness. We discard a few cases that were found to be in error, published only as abstracts, or based on personal communication. Then we augment the list from examples in this volume and a supplementary literature search. Despite the omissions, the total number of cases has increased. Many have been strengthened. We add a list of cases in which there has been evidence that intra-taxon hybridization has preceded the evolution of invasiveness. We also provide a number of examples from organisms other than plants. We consider how our examples suggest mechanisms whereby hybridization may act to stimulate the evolution of invasiveness. Hybridization does not represent the only evolutionary pathway to invasiveness, but it is one that can explain why the appearance of invasiveness often involves a long lag time and/or multiple introductions of exotics.     

Pollination ofDianthus gratianopolitanus (Caryophyllaceae)

Pollination ofDianthus gratianopolitanus was studied in a population of the Swiss Jura mountains. Pollinators of this plant species are reported here for the first time. The flowers were not only visited by butterflies as postulated in the literature, but also by diurnal hawkmoths (Macroglossum stellatarum) and by diurnal and nocturnal noctuid moths. — Nectar is sucrose-dominant, the sugar concentration is moderate but the amino acid concentration is high. Nectar characteristics correspond well with the syndrome ofLepidoptera-pollinated flowers. — Field observations and flower characters (colour, range of the calyx length) suggest thatDianthus gratianopolitanus is an intermediate species in the transition of butterfly to moth pollination. — Lack of reproductive success inDianthus gratianopolitanus can not be attributed to lack of suitable pollinators.     

Nectar bacteria stimulate pollen germination and bursting to enhance microbial fitness

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Note Floristiche Valdarnesi

Abstract

The involvement of cellulase (endo-b-l,4-glucanase, EC 3.2.1.4) in a number of different cell separation events which occur in higher plants has been well established. Besides their significance for the plant growth and differentiation, these events can be economically important since they also comprise softening of fleshy fruits and abscission of fruits, flowers and leaves. In higher plants cellulase is present in a number of different biochemical isoforms which are encoded by different genes. This finding is in accordance with the wide range of physiological events which require the intervention of cellulase activity, and whose peculiarities and amplitudes can be quite various.     

Tempo and mode of evolutionary radiation in Diabroticina beetles (genera Acalymma,Cerotoma, and Diabrotica)

Adaptive radiation is an aspect of evolutionary biology encompassing microevolution and macroevolution, for explaining the principles of lineage divergence. There are intrinsic as well as extrinsic factors that can be postulated to explain that adaptive radiation has taken place in specific lineages. The Diabroticina beetles are a prominent example of differential diversity that could be examined in detail to explain the diverse paradigms of adaptive radiation. Macroevolutionary analyses must present the differential diversity patterns in a chronological framework. The current study reviews the processes that shaped the differential diversity of some Diabroticina lineages (i.e. genera Acalymma, Cerotoma, and Diabrotica). These diversity patterns and the putative processes that produced them are discussed within a statistically reliable estimate of time. This was achieved by performing phylogenetic and coalescent analyses for 44 species of chrysomelid beetles. The data set encompassed a total of 2,718 nucleotide positions from three mitochondrial and two nuclear loci. Pharmacophagy, host plant coevolution, competitive exclusion, and geomorphological complexity are discussed as putative factors that might have influenced the observed diversity patterns. The coalescent analysis concluded that the main radiation within Diabroticina beetles occurred between middle Oligocene and middle Miocene. Therefore, the radiation observed in these beetles is not recent (i.e. post-Panamanian uplift, 4 Mya). Only a few speciation events in the genus Diabrotica might be the result of the Pleistocene climatic oscillations.