Sex differences in telomeres and lifespan in Soay sheep: From the beginning to the end

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/137314/1/mec14129_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/137314/2/mec14129.pd

Yield benefits of additional pollination to faba bean vary with cultivar, scale, yield parameter and experimental method

The benefits of insect pollination to crop yield are used to justify management decisions across agricultural landscapes but current methods for assessing these benefits may underestimate the importance of context. We quantify how the effects of simulated insect pollination vary between five faba bean cultivars, and to what extent this changes between years, scales, yield parameters, and experimental methods. We do this by measuring responses to standardised hand pollination treatments in controlled experiments in flight cages and in the field. Pollination treatments generally improved yield, but in some cases yield was lower with additional pollination. Pollination dependence varied with cultivar, ranging from 58% (loss in yield mass per plant without pollination) in one cultivar, to a lower yield with pollination in another (-51%). Pollination dependence also varied between flight cage and field experiments (-10% to 37% in the same cultivar and year), year (4 to 33%; same cultivar and yield parameter), and yield parameter (-4% to 46%; same cultivar and year). This variability highlights that to be robust, assessments of pollination benefits need to focus upon marketable crop outputs at a whole-plant or larger scale while including and accounting for the effects of different years, sites, methodologies and cultivars

Life history evolution, reproduction, and the origins of sex‐dependent aging and longevity

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/136319/1/nyas13302.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/136319/2/nyas13302_am.pd

Perceived threats of infanticide reduce maternal allocation during lactation and lead to elevated oxidative damage in offspring

Maternal investment is costly to the mother but essential to offspring survival in altrical species. Infanticide by novel males results in loss of maternal investment, and maternal strategies have evolved to mitigate these losses. One such maternal strategy, the Bruce effect, involves spontaneous abortion by females of some mammal species when exposed to a novel male during pregnancy.In mice, the Bruce effect only occurs during early pregnancy, but we have previously found that female mice exposed to a novel male’s scent in late pregnancy weaned smaller offspring. Here, we replicate that manipulation to resolve the cause of the reduced weaning weight and subsequent effects on offspring fitness.Females exposed to an unfamiliar male’s scent in late pregnancy spent significantly less time nursing their pups during lactation, suggesting that reduced maternal allocation contributes to slower offspring growth. The offspring with a reduced weaning weight exhibited catch‐up growth and reached a normal weight at adulthood. These offspring, however, were found to bear oxidative damage in adulthood, revealing long‐term effects on offspring condition.We conclude that female mice strategically alter their investment in lactation in relation to the likelihood of infanticide, but that this results in long‐term fitness costs to their offspring.A plain language summary is available for this article.Plain Language SummaryPeer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/145500/1/fec13146_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/145500/2/fec13146.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/145500/3/fec13146-sup-0001-Summary.pd

Integrated crop pollination to buffer spatial and temporal variability in pollinator activity

Insect pollination improves the yield and quality of many crops, yet there is increasing evidence of insufficient insect pollinators limiting crop production. Effective Integrated Crop Pollination (ICP) involves adaptable, targeted and cost effective management of crop pollination and encourages the use of both wild and managed pollinators where appropriate. In this study we investigate how the addition of honeybee hives affects the community of insects visiting oilseed rape, and if hive number and location affect pollinator foraging and oilseed rape pollination in order to provide evidence for effective ICP. We found that introducing hives increased overall flower visitor numbers and altered the pollinator community, which became dominated by honeybees. Furthermore a greater number of hives did not increase bee numbers significantly but did result in honeybees foraging further into fields. The timing of surveys and proximity to the field edge influenced different pollinators in different ways and represents an example of spatial and temporal complementarity. For example dipteran flower visitor numbers declined away from the field edge whereas honeybees peaked at intermediate distances into the field. Furthermore, no significant effects of survey round on wild bees overall was observed but honeybee numbers were relatively lower during peak flowering and dipteran abundance was greater in later survey rounds. Thus combining diverse wild pollinators and managed species for crop pollination buffers spatial and temporal variation in flower visitation. However we found no effect of insect pollination on seed set or yield of oilseed rape in our trial, highlighting the critical need to understand crop demand for insect pollination before investments are made in managing pollination services

Economic valuation of natural pest control of the summer grain aphid in wheat in South East England

Wheat (Triticum spp.) is the most important arable crop grown in the UK, and the grain aphid (Sitobion avenae) is one of the key pests of this crop. Natural enemies could help suppress grain aphid and reduce unnecessary insecticide inputs, but few studies have estimated the economic value of natural pest control in this crop-pest system, which could help inform effective integrated pest management strategies. Based on a natural enemy exclusion experiment carried out in South East England, this study used an economic surplus model to estimate the value of predators and parasitoids to control summer grain aphid in wheat in this region. Incorporating three levels of spray intensity and three levels of pest infestation, the annual economic value of natural pest control service was conservatively estimated to be £0-2.3 Million. Under the medium pest infestation level, a 10% increase in the proportion of wheat fields using economic threshold-based spray method would increase this value by 23% (£0.4 Million). 71% of the value would benefit wheat growers. A potential rise in insecticide costs due to resistance development would also enhance the value of natural pest control. These findings support growing efforts from policy-makers to promote this ecosystem service in agriculture

The benefits of hedgerows for pollinators and natural enemies depends on hedge quality and landscape context

Ecological intensification advocates the harnessing of regulating and supporting ecosystem services to promote more sustainable food production, and this relies on effective management of non-cropped habitats. Hedgerows are an important component of the landscape in many farming systems across the world, management of which provides a potential mechanism to enhance ecological intensification. Here we investigate the value of hedgerows in Southern England as a source of functionally important taxa, and how hedgerow quality and local landscape composition impact on their potential contribution to sustainable agriculture in arable landscapes. We show that hedgerows are a source habitat for many natural enemies which spill over into neighbouring fields, and that hedgerows provide a valuable forage resource and corridor for movement of pollinators. Hedgerow quality affects these benefits and continuous unbroken hedgerows, with a high diversity of woody species, are more valuable for the provision of bumblebees and Linyphiid spiders, while the presence of trees within the hedgerow supports Lycosid spiders. Floral resources, beyond the woody hedgerow species themselves, are also a key forage resource for hoverflies. The impact of these hedgerows on invertebrate abundance is moderated by local landscape, and hedgerows are a more valuable forage resource for pollinators in more intensely managed landscapes. Our study shows that in order to support abundant and a broad range of natural enemies and pollinators in agricultural landscapes, both hedgerows and local semi-natural habitats need to be protected and managed. The benefit of hedgerows, as a habitat for functionally important taxa depends on hedgerow quality and management practices such as avoiding gaps, high hedge species diversity and maintaining an abundant understory of plants, can improve their value for ecological intensification

Male lifespan extension with 17â α estradiol is linked to a sexâ specific metabolomic response modulated by gonadal hormones in mice

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/145263/1/acel12786.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/145263/2/acel12786_am.pd

Going beyond Lifespan in Comparative Biology of Aging

International audienceOver the last few decades, comparative biology of aging has aimed toidentify factors responsible for the huge variability in lifespan observedacross the animal kingdom. While these studies have undeniablyimproved our understanding of the complex processes that shape lifespan,we argue that time has now come to focus on specific aging metrics (e.g.,age at the onset of aging, rate of aging) rather than on lifespan. Such a shiftin research programs would help decipher the fine-scale mechanismsshaping age-specific mortality profiles across the tree of lif