A comparison of life history traits of sexual and asexual strains of the parasitoid wasp,Lysiphlebus fabarum (Braconidae: Aphidiinae)

1. This study examined biological characteristics of sexual and asexual strains of the parasitoid wasp, Lysiphlebus fabarum (Marshall) (Hymenoptera: Braconidae). 2. Strains were reared in different instar hosts (the black bean aphid, Aphis fabae Scopoli) under identical environmental conditions (21 °C, 65–75% RH, and LD 16:8 h). 3. Results showed that the second instar of the aphid is the most suitable growth stage for both strains, as the wasps that emerged from the second instar hosts were larger, more fecund, and had larger egg size. Trade‐offs between the fitness components of the parasitoid were clearer when the parasitoids were reared in suboptimal instars. 4. According to the results, sexual females emerged around 1 day earlier and lived around 0.5 day less than asexual females. Also, sexual females emerged with a lower initial egg load, although these wasps tend to have larger eggs than asexual females. Asexual females may enjoy greater longevity and higher developmental plasticity which suggests a higher degree of synchronization with pest population dynamism. 5. The results suggest that sexual wasps, in contrast to asexual wasps, invest more in egg size than in egg load. This study suggests strain‐specific adaptations of L. fabarum to different instars of the black bean aphid by which the allocation of nutritional resources to various functions differs between strains. 6. Furthermore, differences in life history traits between strains can greatly influence the population dynamics of each strain, and hence their effectiveness in suppressing pest populations.     

球孢白僵菌对油桐尺蛾的生物效力（英文）

分别在2005年和2006年的5、6月份,在Kamalpur和Hunterpara茶园、孟加拉西部以及印度地区对一种昆虫致病真菌球孢白僵菌对油桐尺蛾Buzura (=Biston) suppressaria Guen.的生物效力进行了评估。以农场主常用的化学杀虫剂40% SP灭多虫和25% EC氯氰菊酯作为标准检测物。试验中球孢白僵菌浓度为1.50 g,2.00 g和2.5 g/lit. of water;灭多虫和氯氰菊酯浓度分别为0.75 mL,1.00 mL和1.50 mL,和0.50 mL,1.00 mL和1.50 mL/lit. of water。在喷洒2.5 g/lit. of water 球孢白僵菌3天后,Kamalpur和Hunterpara茶园中油桐尺蛾种群个体数分别降低了88.00%和84.00%。死的毛虫变成黑色,垂悬在叶片上。并且发现球孢白僵菌的杀虫活性与高剂量的灭多虫和氯氰菊酯的相当。     

Anatomy and ultrastructure of the floral nectary in Peganum harmala L. (Nitrariaceae)

Anatomy and ultrastructure of the floral nectary of Peganum harmala L. were studied using light and transmission electron microscopy. The floral nectary was visible as a glabrous, regularly five‐lobed circular disc encircling the base of the ovary. Anatomically, it comprised a single layered epidermis and 15–20 layers of small, subepidermal secretory cells overlying several layers of large, ground parenchyma cells. The floral nectary was supplied by phloem and both sieve tubes and companion cells were found adjacent to the ground parenchyma. Based on our ultrastructural observations, plastids of secretory cells during the early stages of development were rich in starch grains and/or osmiophilic plastoglobuli, but these disappeared as nectar secretion progressed. The nectar appeared to exude through the modified stomata along symplastic and apoplastic routes. The abundant plastids and mitochondria suggest an eccrine mechanism of nectar secretion in P. harmala.     

A dual role of tobacco hexokinase 1 in primary metabolism and sugar sensing

Hexokinase (HXK) is present in all virtually living organisms and is central to carbohydrate metabolism catalysing the ATP‐dependent phosphorylation of hexoses. In plants, HXKs are supposed to act as sugar sensors and/or to interact with other enzymes directly supplying metabolic pathways such as glycolysis, the nucleotide phosphate monosaccharide (NDP‐glucose) pathway and the pentose phosphate pathway. We identified nine members of the tobacco HXK gene family and observed that among RNAi lines of these nine NtHXKs, only RNAi lines of NtHXK1 showed an altered phenotype, namely stunted growth and leaf chlorosis. NtHXK1 was also the isoform with highest relative expression levels among all NtHXKs. GFP‐tagging and immunolocalization indicated that NtHXK1 is associated with mitochondrial membranes. Overexpression of NtHXK1 resulted in elevated glucose phosphorylation activity in leaf extracts or chloroplasts. Moreover, NtHXK1 was able to complement the glucose‐insensitive Arabidopsis mutant gin2‐1 suggesting that NtHXK1 can take over glucose sensing functions. RNAi lines of NtHXK1 showed severely damaged leaf and chloroplast structure, coinciding with an excess accumulation of starch. We conclude that NtHXK1 is not only essential for maintaining glycolytic activity during respiration but also for regulating starch turnover, especially during the night.     

Molecular phylogenetics of Erebidae (Lepidoptera,Noctuoidea)

As a step towards understanding the higher‐level phylogeny and evolutionary affinities of quadrifid noctuoid moths, we have undertaken the first large‐scale molecular phylogenetic analysis of the moth family Erebidae, including almost all subfamilies, as well as most tribes and subtribes. DNA sequence data for one mitochondrial gene (COI) and seven nuclear genes (EF‐1α, wingless, RpS5, IDH, MDH, GAPDH and CAD) were analysed for a total of 237 taxa, principally type genera of higher taxa. Data matrices (6407 bp in total) were analysed by parsimony with equal weighting and model‐based evolutionary methods (maximum likelihood), which revealed a well‐resolved skeleton phylogenetic hypothesis with 18 major lineages, which we treat here as subfamilies of Erebidae. We thus present a new phylogeny for Erebidae consisting of 18 moderate to strongly supported subfamilies: Scoliopteryginae, Rivulinae, Anobinae, Hypeninae, Lymantriinae, Pangraptinae, Herminiinae, Aganainae, Arctiinae, Calpinae, Hypocalinae, Eulepidotinae, Toxocampinae, Tinoliinae, Scolecocampinae, Hypenodinae, Boletobiinae and Erebinae. Where possible, each monophyletic lineage is diagnosed by autapomorphic morphological character states, and within each subfamily, monophyletic tribes and subtribes can be circumscribed, most of which can also be diagnosed by morphological apomorphies. All additional taxa sampled fell within one of the four previously recognized quadrifid families (mostly into Erebidae), which are now found to include two unusual monobasic taxa from New Guinea: Cocytiinae (now in Erebidae: Erebinae) and Eucocytiinae (now in Noctuidae: Pantheinae).     

A taxonomic revision of Centaurea section Acrocentron (Asteraceae) in Iran

The taxonomic status of Centaurea section Acrocentron in Iran is briefly reviewed. A critical study of 251 herbarium specimens, and an additional 37 accessions collected specifically for this research, led to the discovery of a new variety, Centaurea irritans var. longispinosa Montazerolghaem , and the revival of another, C. persica var. subinermis, a taxon previously treated as a synonym for about 25 years. A key to all Iranian species of Centaurea section Acrocentron is provided. © 2010 The Linnean Society of London, Botanical Journal of the Linnean Society, 2010, 163 , 99–106.