花冠对紫茉莉繁殖适合度的影响

以授粉后具花闭合特性的紫茉莉为研究材料,通过在不同天气状况下作去花冠和存留花冠处理,观察花冠对花粉活力、柱头可授性及结实率等繁殖特性的影响。结果表明:紫茉莉自然存留花冠比去花冠的花粉活力、柱头可授性、柱头上的花粉数及柱头上花粉萌发率各指标达最高值的时间重叠性更强,并以阴天存留花冠的最强。存留花冠通过这种时间的重叠性来保证花粉在柱头上的萌发,产生了有利的繁殖适合度。越晚去花冠结实率越高,结实率呈现花闭合自然存留花冠>花冠闭合期去花冠>散粉初期去花冠>花冠展开期去花冠的规律。因此,花冠对紫茉莉繁殖适合度具有利影响。紫茉莉花冠的存留提高了繁殖适合度,增强了对环境的适应能力。     

Improving foliar applications of entomopathogenic nematodes by selecting adjuvants and spray nozzles

This study explores the influence of a selection of adjuvants and of three different nozzle sizes on the foliar application of entomopathogenic nematodes (EPNs). Two EPN species were studied: Steinernema feltiae and Steinernema carpocapsae. A viability test of EPNs suspended in different solutions of adjuvants showed that all selected alcohol ethoxylates and an alkyl polysaccharide have an immobilising effect on the selected nematode species. In a sedimentation test, xanthan gum proved to be the only adjuvant in a broad selection, capable of delaying sedimentation of EPNs in suspension. Without xanthan gum, sedimentation of S. carpocapsae and S. feltiae was noticeable after 20 and 10 minutes, respectively. When xanthan gum (0.3 g/L) was added to the suspension, no signs of sedimentation were noticed after 20 minutes with both EPN species. An ISO 02 flat fan nozzle can clog when spraying S. carpocapsae. A deposition test determined that an ISO 04 standard flat fan nozzle provides a higher relative deposition on cauliflower leaves and is therefore a better nozzle choice than the bigger ISO 08 standard flat fan nozzle for spraying S. carpocapsae. The addition of a spreading agent improved the deposition of S. carpocapsae. Adding xanthan gum to the EPN-spreading agent mixtures did not further improve deposition.     

The relative importance of reproduction and survival for the conservation of two dolphin populations

It has been proposed that in slow‐growing vertebrate populations survival generally has a greater influence on population growth than reproduction. Despite many studies cautioning against such generalizations for conservation, wildlife management for slow‐growing populations still often focuses on perturbing survival without careful evaluation as to whether those changes are likely or feasible. Here, we evaluate the relative importance of reproduction and survival for the conservation of two bottlenose dolphin (Tursiops cf aduncus) populations: a large, apparently stable population and a smaller one that is forecast to decline. We also assessed the feasibility and effectiveness of wildlife management objectives aimed at boosting either reproduction or survival. Consistent with other analytically based elasticity studies, survival had the greatest effect on population trajectories when altering vital rates by equal proportions. However, the findings of our alternative analytical approaches are in stark contrast to commonly used proportional sensitivity analyses and suggest that reproduction is considerably more important. We show that

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Temporal variation in selection on male and female traits in wild tree crickets

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Bumble bee colony dynamics: quantifying the importance of land use and floral resources for colony growth and queen production

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Role of long non‐coding RNA MIAT in proliferation,apoptosis and migration of lens epithelial cells: a clinical and in vitro study

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Hydroxylated chalcones with dual properties: Xanthine oxidase inhibitors and radical scavengers

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Strong sexual selection in males against a mutation load that reduces offspring production in seed beetles

Theory predicts that sexual reproduction can increase population viability relative to asexual reproduction by allowing sexual selection in males to remove deleterious mutations from the population without large demographic costs. This requires that selection acts more strongly in males than females and that mutations affecting male reproductive success have pleiotropic effects on population productivity, but empirical support for these assumptions is mixed. We used the seed beetle Callosobruchus maculatus to implement a three‐generation breeding design where we induced mutations via ionizing radiation (IR) in the F₀ generation and measured mutational effects (relative to nonirradiated controls) on an estimate of population productivity in the F₁ and effects on sex‐specific competitive lifetime reproductive success (LRS) in the F₂. Regardless of whether mutations were induced via F₀ males or females, they had strong negative effects on male LRS, but a nonsignificant influence on female LRS, suggesting that selection is more efficient in removing deleterious alleles in males. Moreover, mutations had seemingly shared effects on population productivity and competitive LRS in both sexes. Thus, our results lend support to the hypothesis that strong sexual selection on males can act to remove the mutation load on population viability, thereby offering a benefit to sexual reproduction.