Some Environmental and Nutritional Factors Affecting Growth and Sporulation of Aspergillus sydowi

Aspergillus sydowi (Bain. & Start.) Thom & Church grew and sporulated best at 30°C. The best pH for growth and sporulation was 5.5. Light was stimulatory to sporulation but inhibitory to growth. Among the carbon sources employed, sucrose supported the best growth and sporulation. Nitrate, ammonium and asparagine were good nitrogen sources for growth and sporulation. During utilization of sucrose, the carbohydrates found in the mycelium included dulcitol, inositol, mannitol, arabinose, trehalose and galactose.     

Flight regulation in the green spruce aphid (Elatobium abietinum)

In Britain the flight of alate parthenogenetic viviparae of Elatobium abietinum was found to occur only in early summer. Data for this study were extracted from suction trap catches and weather records obtained from meteorological stations adjacent to the traps. The duration of the flight period increased with latitude. At 51° N 95 % of the trap catch was taken in 24 days and at 55° N in 32 days. A flight threshold temperature of 12–13°C was deduced from trap catches taken within the forest crop. Displacements in median flight days at various sites in Britain could be related to values of accumulated day-degrees but not to differences in photoperiod. The median flight day can be predicted empirically by accumulating day-degree values over 8°C from 1 January up to a total of 115 day-degrees. The implications of seasonal flight activity on crop reinvasion is discussed.     

Protonemal Morphogenesis of the Moss Tetraphis pellucida Hedw. in Culture and in the Wild

In axenic culture, the protonemal filaments of Tetraphis pellucidaderived from either spores and gemmae, or excised stems andleaves, share a mixture of attributes of chloronemata and caulonemata.Indirect immunofluorescence reveals that the tip cells containcortical and endoplasmic arrays of microtubules at interphase,and phragmoplasts associated with cell plate formation, butpre-prophase bands are absent. Protonemal plates originate fromthe same sites as filamentous protonemal side branches or directlyfrom young gemmae or excised stem fragments. These plates havea cylindrical base, the latter producing a single gametophorebud, and a unistratose lamina. The gametophores produce gemmacups in culture with the vegetative life cycle taking approximately28 d. Gibberellic acid (GA₃) has no visible effect on protonemal morphogenesiswhereas the auxin naphthalene acetic acid (NAA) suppresses plateand side branch formation. In the presence of kinetin the platesare callus-like and produce supernumerary buds. Abscisic acid(ABA) induces malformed plates and filaments with swollen cells,similar to those found in ageing cultures. Rhizoids are produced in abundance from gametophores and protonemalplates in nature but were never seen in culture. In the wild,rhizoids produce numerous protonemal plates and occasional gametophorebuds. The former are the main source of new shoots. The filamentousprotonemal phase in nature mainly comprises upright filamentscontaining one or more abscission cells. The protonemal plates in Tetraphis are homologous with thosein the allied genus Tetrodontium but are very different fromthose in Diphyscium and Sphagnum. Differences between cultureand nature are attributed to lower nutrient levels and irradiancesin the wild. Tetraphis pellucida, protonema, moss, morphogenesis, immunocytochemistry, gemmae, tip growth, vegetative reproduction     

Evolution of host- and habitat association in the wood-feeding cockroach, Cryptocercus

Members of the cockroach genus Cryptocercus are subsocial insects that live in temperate forests and feed on decomposing logs. At present, seven species are recognized worldwide: four in the eastern USA, one in the western USA, and one each in Russia and China. Genetic variation within and among the Nearctic species has been characterized extensively in previous studies. However, whether there has been a corresponding divergence in the host and habitat association of Cryptocercus species is not known. Here, we report on differences in host and habitat association among six of the seven Cryptocercus species, estimated from field observations, elevation data, and land cover data. Our results indicated that the eastern and western USA species differ from one another in their distribution patterns, abundance, and habitat association. The eastern USA species are associated largely with deciduous forests, whereas the western USA and the Russian species are associated with evergreen forests. Thus, the eastern USA species, which are evolutionarily the most recent ones, have adapted to a different set of tree species relative to the basal species. There were also differences in the habitat association of the various species. Specifically, in the eastern USA, Cryptocercus darwini , evolutionarily the most recent species, occupied a habitat that is predominantly at low elevation [<400 m above sea level (ASL)] while all the other Nearctic species and the Russian species occupied a habitat that is at relatively higher elevations (>400 m ASL). Mapping of the above traits on a phylogenetic tree revealed that the evolutionary trend in Cryptocercus with regard to host and habitat association has been toward the utilization of low elevation habitats dominated by deciduous forests. © 2002 The Linnean Society of London, Biological Journal of the Linnean Society , 2002, 75 , 163–172.