Plant-derived visual signals may protect beetle herbivores from bird predators

Insect herbivores often use chemical signals obtained from their food plants to deter enemies and/or attract sexual partners. Do plant-based visual signals act similarly, i.e., repel consumers' enemies and appeal to potential mates? We explored this question using the pollen-feeding beetle Pygopleurus israelitus (Glaphyridae), a specialized pollinator of Anemone coronaria's chemically defended red-morph flowers. We presented dead beetles, which had fed either on anemones or on cat food, to young domestic chicks on a red (anemone-like) or a green (leaf-like) background. We determined whether the beetles' background color and diet affected the chicks' feeding. Cuticle surface extracts from anemone-fed beetles, but not from cat food-fed beetles, contained a secondary metabolite characteristic of anemones. Latencies to the first picking up and consuming of beetles from green backgrounds were shorter than of beetles from red backgrounds. The picking up order of beetles also indicated that prey from the green background was preferred. The chicks retained this preference when re-tested, 3 days later. Handling times of anemone-fed beetles were longer than of cat food-fed beetles. A previous study showed that glaphyrids improve their mate-finding prospects by orienting to large red anemone flowers. Here, female beetles preferred cat food-fed to anemone-fed males in mate-choice assays, thus anemone-derived chemicals did not increase mating success. Instead, the combined results indicate that A. coronaria's red flowers provide a visual signal that may both deter its herbivore's predators and attract its mates. To our knowledge, this is the first experimental evidence for a potential protective role of plant-derived visual signals for insect herbivores/pollinators.     

Mimicry of queen Dufour's gland secretions by workers of Apis mellifera scutellata and A. m. capensis

The development of the Dufour's gland of workers of the two honey bee races Apis mellifera scutellata and A. m. capensis was measured. The Dufour's glands of A. m. capensis workers were longer and increased in length more rapidly than the glands of workers of A. m. scutellata at comparable ages. Analysis of the Dufour's gland secretions of workers and queens of both races revealed that there were caste and racial differences. Secretions of queenright A. m. scutellata workers were dominated by a series of long-chain hydrocarbons. In contrast the secretions of the A. m. capensis workers both under queenright and queenless conditions were a mixture of hydrocarbons and wax-type esters, as were those of queens. Multivariate analysis of the secretion profiles indicated that laying workers of both races mimic queens. The secretions of the A. m. capensis laying workers mimicked queen secretions most closely, enabling them to act as successful social parasites.     

Relationship Between Inactivation and Genome Damage of Human Enteroviruses Upon Treatment by UV254, Free Chlorine,and Ozone

Food and Environmental Virology - Quantitative PCR (qPCR) is a convenient tool for monitoring virus concentrations in water and wastewater treatment trains, though it only informs about virus...     

Ultrastructural and chemical characterization of egg surface of honeybee worker and queen-laid eggs

Summary. Worker policing in honeybees predicts the evolution of a mechanism to discriminate between queenand worker-born eggs. Although it has been postulated that this discrimination is based on an egg recognition pheromone, neither the chemistry nor the glandular source were elucidated. To verify whether egg discrimination might be based on structural differences, we compared the ultrastructure surface of queen-laid diploid and haploid eggs to that of worker-laid eggs using SEM. Only small differences between the different types of eggs were found. Thus, at least based on the fine structure of the egg surface, queen eggs are indistinguishable from worker-laid eggs.To explore the chemosensory hypothesis for egg discrimination, we conducted a detailed comparative chemical analysis of the different egg types. The coating of all egg types was dominated by linear alkanes, but queen eggs, diploid and haploid, differed from those of workers on two accounts: 1. The diversity of compounds found on queenlaid eggs was much greater than found on worker-laid eggs, mainly due to the number of hydrocarbons. 2. Acetates of some fatty alcohols, alkenes and especially monomethylalkanes were characteristic to queen eggs. The origin of the two latter substances and the acetates is still unknown. Whether these compounds constitute the signal that enables police workers to discriminate between queen- and workerborn eggs remains to be investigated.     

如何在教学中做到“到位而不越位”——针对中年段语文教学的研讨

<正>中年级的语文阅读教学,既要完成本学段的学习目标,又要为高年级的阅读教学作准备,起着承上启下的作用,是学生语文学习的一个重要阶段。但是纵观中年段的语文课文安排,我们不难发现:有一些是原老教材的高年级课文,移到了中年级,如《太阳》《小英雄雨来》《西门豹》《一个中国孩子的呼声》等。这些文章篇幅长、内容深,对于中年级孩