Increase in Levels of Cyclic AMP During Avian Limb Chondrogenesis in vitro

In the present study the level of cAMP was measured during in vitro chondrogenesis of wing mesenchyme of stage 24 chick embryos and was found to increase significantly from 6.3 pmol/mg protein at the end of the first day of culture to 9.7 pmol/mg protein on the second day, when chondrogenic expression is first detected by the appearance of an Alcian blue staining extracellular matrix. Nonchondrogenic cultures derived from wings of stage 19 embryos had a lower level of cAMP (4.4 ± 0.07 pmol/mg protein). The level of CAMP in intact wings was 4.5 ± 0.4 pmol/mg protein and did not change between stages 19 trough 25. The correlation between increased levels of CAMP and the onset of chondrogenesis is consistent with a role of cAMP in the expression of differentiated functions in chondrocytes, as well as in some other cell types.     

Molecular phylogeny reveals the repeated evolution of complex male genital traits in the New Zealand moth genus Izatha (Lepidoptera: Xyloryctidae)

Male genitalia are among the most rapidly evolving and divergent morphological structures and sexual selection is known to drive this phenomenon in many taxa. Because of their diversity, even within a single genus, genital characters are frequently used to infer relationships among closely‐related species. Moths within the genus Izatha (Xyloryctidae) are ideal candidates for investigating the phylogenetic patterns of genital evolution as they display great variation in male genital structure and complexity. We determined the evolutionary relationships among 31 species of Izatha by constructing a molecular phylogeny of the genus based on the mitochondrial cytochrome oxidase subunit I gene and the isocitrate dehydrogenase and carbamoylphosphate synthase domain protein nuclear genes. This allowed estimations of ancestral male genital character states and patterns of male genital diversification using maximum‐likelihood models. The genus is divided into two well‐supported clades and two poorly supported clades at the root of the phylogeny with incomplete phylogenetic resolution within two species groups, likely due to rapid speciation. Izatha display a number of apomorphic phallic traits including cornuti (sclerotized spines) which are either discharged into the female during copulation (deciduous cornuti) or fixed to the male phallus (compound and fish‐hook cornuti). Within the genus, there is a reduction of secondary genital characters – the uncus and gnathos – but an elaboration of another grasping structure, the juxta; the potential origin and functionality of these male genital traits are discussed. Overall, some male genital characters provided a good indication of species relationships; however, several parts of the complex male genitalia of Izatha show evidence of homoplasy and convergence highlighting the problems of using these traits in determining species relationships. Additionally, this convergence has highlighted that complex genital structures may evolve repeatedly and independently within a lineage.     

Adaptation of the BG-Sentinel trap to capture male and female Aedes albopictus mosquitoes

In recent years, the remarkable spread of Aedes albopictus (Skuse) (Diptera: Culicidae) throughout the world has drawn attention to this hitherto poorly studied species, particularly after its role in outbreaks of chikungunya fever in the western Indian Ocean and in Italy. Variants of sterile insect technique (SIT), including the release of transgenic males with a dominant lethal gene (RIDL), have been proposed in the search for new and innovative methods of control. Knowledge of male dispersal, mating behaviour and longevity will be critical to the success of this approach. We present an effective and practical method for trapping both male and female Ae. albopictus using a mouse-baited BG-Sentinel trap.     

Nutritional status and the foraging behaviour of Bactrocera tryoni with particular reference to protein bait spray

Poisoned protein baits comprise a recognized method for controlling tephritid fruit flies in the form of a ‘lure‐and‐kill’ technique. However, little is known about how a fly's internal protein and carbohydrate levels (i.e. nutritional status) might influence the efficacy of this control. In the present study, the relationships between the internal levels of protein (as measured by total body nitrogen) and carbohydrate (as measured by total body carbon) of the fruit fly Bactrocera tryoni (Froggatt) (Diptera: Tephritidae) are investigated, as well as its foraging behaviours in response to protein, fruit and cue‐lure (a male‐specific attractant) baits. Small cage behavioural experiments are conducted using flies from cultures of different nutritional status and wild flies sampled from the field during the fruiting cycle of a guava crop. For female flies, increasing total body nitrogen is correlated with decreased protein foraging and increased oviposition activity; increasing total body carbon levels generate the same behavioural changes except that the oviposition response is not significant. For males, there are no significant correlations between changes in total body nitrogen and total body carbon and protein or cue‐lure foraging. For wild flies from the guava orchard, almost all of them are sexually mature when entering the crop and, over the entire season, total body nitrogen and total body carbon levels are such that protein hunger is unlikely for most flies. The results infer strongly that the requirements of wild, sexually mature flies for protein are minimal and that flies can readily gain sufficient nutrients from wild sources for their physiological needs. The results offer a mechanistic explanation for the poor response of male and mature female fruit flies to protein bait spray.     

Waterlogging duration: Interspecific comparison of Leptospermum scoparium (Forst et Forst.f.), Acacia melanoxylon (R. Br.), Nothofagus cunninghamii (Hook.) and Eucalyptus obliqua (L’Herit)

Abstract The effect of the duration of waterlogging on the pre‐dawn water potential, gas exchange, biomass accumulation and survival was investigated on four species, Leptospermum scoparium (Forst et Forst.f.), Acacia melanoxylon (R. Br.), Eucalyptus obliqua (L’Herit) and Nothofagus cunninghamii (Hook.). These species co‐occur, but are restricted to particular microsites. The three waterlogging treatments applied to potted seedlings were: four cycles of 15 days, two cycles of 30 days or one 60‐day cycle, followed by an equal period in freely drained conditions. Water potential, gas exchange, biomass accumulation and survival were not significantly affected by the duration of waterlogging in L. scoparium or A. melanoxylon. With increased waterlogging duration, N. cunninghamii had progressively decreased survival, had less biomass accumulation in all waterlogging treatments and more negative water potential after the 60‐day waterlogging cycle. In contrast, E. obliqua had low survival under the 15‐day waterlogging cycle treatment, although survival, biomass accumulation and maximum net photosynthesis were decreased by all waterlogging cycle treatments. Water potential was significantly lower (more negative) in E. obliqua than other species after the 30‐ and 60‐day waterlogging cycle treatments only. When exposed to oxygen deficit in hypoxic nutrient culture for 5 days, L. scoparium had 100% survival and maximum net photosynthesis was not affected. Acacia melanoxylon had 80% survival and decreased photosynthesis from 2 days of exposure onwards. Nothofagus cunninghamii and E. obliqua had 70% and 30% survival, respectively, and their photosynthesis was significantly depressed after 1 day of exposure to hypoxic conditions. Relative tolerance of the species examined to waterlogging and hypoxia was consistent with adaptation to conditions of seasonal variation in water table height and soil oxygenation concentration observed at the microsites occupied by the respective species. The results indicate that duration of waterlogging may be a major determinant in the microsite distribution of the co‐occurring species investigated.     

Cell Number and Cell Size in Parthenocarpicvs. Pollinated Blueberry (Vaccinium ashei) Fruits

Gibberellic acid (GA₃) promotes parthenocarpic fruit developmentand is used commercially to increase fruit set in many crops.However, fruit size is usually smaller than that of pollinatedfruit. The purpose of this work was to determine the anatomicalbasis for differences in fruit size between pollinated and GA₃-inducedparthenocarpic blueberry (Vaccinium asheiReade) fruits. Freshweights at ripening averaged 1.6 and 2.5 g for GA₃-treatedvs.pollinated fruits, respectively. In both pollinated and GA₃-treatedfruits, mesocarp cell number comprised about 75% of the totalpericarp cell number, and increased from