The fallacy of the average: on the ubiquity, utility and continuing novelty of Jensen's inequality

Denny, Mark W.

doi:10.1242/jeb.140368

Cited by 151 publications

(164 citation statements)

References 26 publications

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“…Jensen's inequality (Denny, 2017) means that highly variable temperatures in the autumn and spring can lead to disproportionately high lipid Most overwintering insects appear to fuel their metabolism over winter with lipid. RQ, respiratory quotient (the ratio between oxygen consumption and carbon dioxide production; conventionally a value of approximately 0.7 indicates lipid metabolism).…”

Section: Fat As Fuel In Overwintering Insectsmentioning

confidence: 99%

The many roles of fats in overwintering insects

Sinclair

Marshall

2018

Journal of Experimental Biology

119

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Temperate, polar and alpine insects generally do not feed over winter and hence must manage their energy stores to fuel their metabolism over winter and to meet the energetic demands of development and reproduction in the spring. In this Review, we give an overview of the accumulation, use and conservation of fat reserves in overwintering insects and discuss the ways insects modify fats to facilitate their selective consumption or conservation. Many insects are in diapause and have depressed metabolic rates over winter; together with low temperatures, this means that lipid stores are likely to be consumed predominantly in the autumn and spring, when temperatures are higher but insects remain dormant. Although there is ample evidence for a shift towards less-saturated lipids in overwintering insects, switches between the use of carbohydrate and lipid stores during winter have not been well-explored. Insects usually accumulate cryoprotectants over winter, and the resulting increase in haemolymph viscosity is likely to reduce lipid transport. For freezetolerant insects (which withstand internal ice), we speculate that impaired oxygen delivery limits lipid oxidation when frozen. Acetylated triacylglycerols remain liquid at low temperatures and interact with water molecules, providing intriguing possibilities for a role in cryoprotection. Similarly, antifreeze glycolipids may play an important role in structuring water and ice during overwintering. We also touch on the uncertain role of non-esterified fatty acids in insect overwintering. In conclusion, lipids are an important component of insect overwintering energetics, but there remain many uncertainties ripe for detailed exploration.

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Section: Fat As Fuel In Overwintering Insectsmentioning

confidence: 99%

The many roles of fats in overwintering insects

Sinclair

Marshall

2018

Journal of Experimental Biology

119

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“…Such an irregular pattern of producing seeds has strong consequences in ecosystems, leading to cascading effects throughout the food web (Ostfeld and Keesing, 2000;Bogdziewicz et al, 2016). The mechanisms behind this intriguing behavior have puzzled ecologists for decades (Norton and Kelly, 1988;Sork et al, 1993;Espelta et al, 2008;Fernández-Martínez et al, 2012, 2017Crone and Rapp, 2014;Pearse et al, 2016), leading to the formulation of several hypotheses about ultimate and proximate causes of this bizarre reproductive behavior.…”

Section: Introductionmentioning

confidence: 99%

“…Hypotheses accounting for proximate causes, though, are focussed on the mechanisms by which plants produce fruits (Norton and Kelly, 1988;Kelly and Sork, 2002). These hypotheses are being intensely debated, and many studies have investigated the potential causes of the high interannual variability of fruit production: stored carbohydrates (Hoch et al, 2013;Ichie et al, 2013), reproductive costs (Sala et al, 2012), availability of nutrients (Crone et al, 2009;Fernández-Martínez et al, 2016), pollination efficiency Bogdziewicz et al, 2017a,b), or weather, either as a cue prompting reproduction (Kelly et al, 2013;Pearse et al, 2014;Bogdziewicz et al, 2017b) or by its effect on plant productivity either by enhancing photosynthesis (Fernández-Martínez et al, 2015, 2017 or by its interaction with nutrient availability (Smaill et al, 2011). Amongst proximate causes, meteorological variability may be an inseparable component of variable seed production , because weather is the most evident source of interannual variability that can affect plant productivity.…”

Section: Introductionmentioning

confidence: 99%

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Nature beyond Linearity: Meteorological Variability and Jensen's Inequality Can Explain Mast Seeding Behavior

et al. 2017

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Mast seeding, the extremely variable and synchronized production of fruits, is a common reproductive behavior in plants. Weather is centrally involved in driving masting. Yet, it is often claimed that it cannot be the sole proximate cause of masting because weather is less variable than fruit production and because the shape of their distributions differ. We used computer simulations to demonstrate that the assumption that weather cannot be the main driver of masting was only valid for linear relationships between weather and fruit production. Non-linear relationships between interannual variability in weather and crop size, however, can account for the differences in their variability and the shape of their distributions because of Jensen's inequality. Exponential relationships with weather can increase the variability of fruit production, and sigmoidal relationships can produce bimodal distributions. These results challenge the idea that meteorological variability cannot be the main proximate driver of mast seeding, returning meteorological variability to the forefront of masting research.

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“…Examinations for industrialization by mimic spider silk of the drag line have been an actively challenged cause of the outstanding properties on strength. 1,2 Most studies concerning analyses of the secondary molecular structure of proteins in the drag line have proposed that the silk consists of highly oriented crystalline β-sheets embedded in a matrix of disordered amorphous structures. [3][4][5][6] On the other hand, the capture threads of an orb-web have important roles, such as being a trap for flying insects for their feed.…”

Section: Introductionmentioning

confidence: 99%