Species concepts and the determination of historic gene flow patterns in the Eulemur fulvus (Brown Lemur) complex

Eulmur fulvus , a complex comprising six subspecies, is a classic example of species status conferred through evolutionary taxonomy. We used the phylogcnctic species concept as an alternative method to the biological species concept for determining historic patterns of gene flow between the various E. julvus subspecies and for conferring species status. In this paper, we used population aggregation analysis to determine the proper species partitions and cladistic analysis to reconstruct the evolutionary relationships of the different populations in the Eulemur fulvus complex. We sequenced three mtDNA gene regions (d-loop, 12S, and cyt-b) and one nuclear region, casein kinase, for a total of 1247 bases. Through population aggregation analysis, we determined that the E. fulvus complex should be split into three units; one unit supported by six diagnostic sites comprising E.f. albocollans , one unit supported by three diagnostic sites comprising E.f. collaris , and one unit supported by two diagnostic sites comprising the four other subspecies. Although all six subspecies in the E. julvus complex share a common ancestor, we found in our cladistic analysis that E. J. collaris and E. j. albocollans share a common ancestor that more recently split off from the common ancestor of the four other E. fulvus subspecies.     

The structure of the apical meristem of Isoetes engelmannii, I. riparia and I. macrospora (Isoetales)

The shoot apex in three species of Isoetes (I. engelmannii, I. macrospora and I. riparia ) is differentiated into a cap-like initiation layer of somewhat columnar meristematic cells which divide most frequently anticlinally and a subadjacent central core of cells which divide irregularly, but with periclinal divisions predominating. The conflicting views of apical organization in Isoetes are discussed.     

Comparative mortalities of the brown-tail moth, Euproctis chrysorrhoea (L.) (Lepidoptera: Lymantriidae), in south-east England

STERLING, P. H. & SPEIGHT, M. R., 1989. Comparative mortalities of the brown-tail moth, Euproctis chrysorrhoea (L.) (Lepidoptera: Lymantriidae), in south-east England . The mortalities within natural infestations of the brown-tail moth were investigated from 1982–1984 in four sites in south-east England. Mortality agents were quantified from field and laboratory assessments. Microsporidial disease was the most important factor, causing 91.9% mortality in large larvae in one population; cytoplasmic and nuclear polyhedrosis viruses were present, but not significant. Many species of parasitoid were recorded, particularly at the end of the larval and in the pupal stages; however, combined parasitoid mortality was low. Predators were also of little importance, although cuckoos were found to take up to 19.3% of pupae at one site. Changes in density of larvae in the spring were more strongly influenced by dispersal following defoliation than by any particular mortality agent in most cases. In terms of biological control, diseases offer the greatest potential for development.