## Anurag Agrawal: Summer in the milkweed patch

Anurag Agrawal is a professor in the Department of Ecology and Evolutionary Biology and the Department of Entomology at Cornell University. He lives in Ithaca, New York. His latest book, Monarchs and Milkweed, is available now.

It’s peak season for milkweed and the village of insects that make milkweed its home.  In my book on Monarchs and Milkweed, I devote an entire chapter to these diverse and fascinating other milkweed insects.  Below are photos from two days last week (July 6 and 7th), one set from my front yard and the other from Shawangunk National Grassland Preserve, both in NY State. All but two of the 11 specialized milkweed herbivores was seen on these four species of milkweed. Do you know which two species are missing?

## Oscar Fernandez: A Healthier You is Just a Few Equations Away

This post appears concurrently on the Wellesley College Summer blog.

How many calories should you eat each day? What proportion should come from carbohydrates, or protein? How can we improve our health through diets based on research findings?

You might be surprised to find that we can answer all of these questions using math.  Indeed, mathematics is at the heart of nutrition and health research. Scientists in these fields often use math to analyze the results from their experiments and clinical trials.  Based on decades of research (and yes, math), scientists have developed a handful of formulas that have been proven to improve your health (and even help you lose weight!).

So, back to our first question: How many calories should we eat each day?  Let’s find out…

Each of us has a “total daily energy expenditure” (TDEE), the total number of calories your body burns each day. Theoretically, if you consume more calories than your TDEE, you will gain weight. If you consume less, you will lose weight. Eat exactly your TDEE in calories and you won’t gain or lose weight.

“Great! So how do I calculate my TDEE?” I hear you saying. Good question. Here’s a preliminary answer:

TDEE = RMR + CBE + DIT         (1)

Here’s what the acronyms on the right-hand side of the equation mean.

• RMR: Your resting metabolic rate, roughly defined as the number of calories your body burns while awake and at rest
• CBE: The calories you burned during the day exercising (including walking)
• DIT: Your diet’s diet-induced thermogenesis, which quantifies what percentage of calories from dietary fat, protein, and carbohydrates are left over for your body to use after you ingest those calories

So, in order to calculate TDEE, we need to calculate each of these three components. This requires very precise knowledge of your daily activities, for example: what exercises you did, how many minutes you spent doing them, what foods you ate, and how much protein, carbohydrates, and dietary fat these foods contained. Luckily, nutrition scientists have developed a simpler formula that takes all of these factors into account:

TDEE = RMR(Activity Factor) + 0.1C.         (2)

Here C is how many calories you eat each day, and the “Activity Factor” (below) estimates the calories you burn through exercise:

 Level of Activity Activity Factor Little to no physical activity 1.2 Light-intensity exercise 1-3 days/week 1.4 Moderate-intensity exercise 3-5 days/week 1.5 Moderate- to vigorous-intensity exercise 6-7 days/week 1.7 Vigorous daily training 1.9

As an example, picture a tall young man named Alberto. Suppose his RMR is 2,000 calories, that he eats 2,100 calories a day, and that his Activity Factor is 1.2. Alberto’s TDEE estimate from (2) would then be

TDEE = 2,000(1.2) + 0.1(2,100) = 2,610.

Since Alberto’s caloric intake (2,100) is lower than his TDEE, in theory, Alberto would lose weight if he kept eating and exercising as he is currently doing.

Formula (2) is certainly more user-friendly than formula (1). But in either case we still need to know the RMR number. Luckily, RMR is one of the most studied components of TDEE, and there are several fairly accurate equations for it that only require your weight, height, age, and sex as inputs. I’ve created a free online RMR calculator to make the calculation easier: Resting Metabolic Heart Rate. In addition, I’ve also created a TDEE calculator (based on equation (2)) to help you estimate your TDEE: Total Daily Energy Expenditure.

I hope this short tour of nutrition science has helped you see that mathematics can be empowering, life-changing, and personally relevant. I encourage you to continue exploring the subject and discovering the hidden math all around you.

Oscar E. Fernandez is assistant professor of mathematics at Wellesley College. He is the author of Everyday Calculus: Discovering the Hidden Math All around Us and The Calculus of Happiness: How a Mathematical Approach to Life Adds Up to Health, Wealth, and Love. He also writes about mathematics for the Huffington Post and on his website, surroundedbymath.com.

## Presenting the new trailer for Silent Sparks

Fireflies are beloved insects, conjurers of summer magic, but have you ever wondered exactly what is behind their flashing?  Check out the stunning trailer for our new book by biologist Sara Lewis, Silent Sparks: The Wondrous World of Fireflies.

## Firefly Fact Friday

In honor of the publication of Silent Sparks by Sara Lewis, we are going to suspend Bird Fact Friday for the next few weeks and replace it with Firefly Fact Friday. Silent Sparks is filled with a wealth of fascinating information on fireflies, and we’re excited to share it with you!

From page 17 of Silent Sparks:

Fireflies begin life as larvae, living underground and dedicated to eating and growth. They can subdue and consume prey several times their size, including earthworms and snails. Fireflies only live as adults for a few weeks, compared with the one to three years that make up their juvenile stage.

For centuries, the beauty of fireflies has evoked wonder and delight. Yet for most of us, fireflies remain shrouded in mystery: How do fireflies make their light? What are they saying with their flashing? And what do fireflies look for in a mate? In Silent Sparks, noted biologist and firefly expert Sara Lewis dives into the fascinating world of fireflies and reveals the most up-to-date discoveries about these beloved insects. From the meadows of New England and the hills of the Great Smoky Mountains, to the rivers of Japan and mangrove forests of Malaysia, this beautifully illustrated and accessible book uncovers the remarkable, dramatic stories of birth, courtship, romance, sex, deceit, poison, and death among fireflies.

The nearly two thousand species of fireflies worldwide have evolved in different ways—and while most mate through the aerial language of blinking lights, not all do. Lewis introduces us to fireflies that don’t light up at all, relying on wind-borne perfumes to find mates, and we encounter glow-worm fireflies, whose plump, wingless females never fly. We go behind the scenes to meet inquisitive scientists who have dedicated their lives to understanding fireflies, and we learn about various modern threats including light pollution and habitat destruction. In the last section of the book, Lewis provides a field guide for North American fireflies, enabling us to identify them in our own backyards and neighborhoods. This concise, handy guide includes distinguishing features, habits, and range maps for the most commonly encountered fireflies, as well as a gear list.

A passionate exploration of one of the world’s most charismatic and admired insects, Silent Sparks will inspire us to reconnect with the natural world.

## Bird Fact Friday – When is the best time to go bird watching in Botswana?

From page 17 of Birds of Botswana:

The best time to bird watch in Botswana is during the wet summer months. In addition to the 595 bird species currently on record, numerous migrants boost the population. Many of these birds breed during the summer and are conspicuous in their nuptial finery. A birder’s paradise!

Birds of Botswana
Peter Hancock & Ingrid Weiersbye
Sample Entry

Here is the ultimate field guide to Botswana’s stunningly diverse birdlife. Covering all 597 species recorded to date, Birds of Botswana features more than 1,200 superb color illustrations, detailed species accounts, seasonality and breeding bars, and a color distribution map for each species. Drawing on the latest regional and national data, the book highlights the best birding areas in Botswana, provides helpful tips on where and when to see key species, and depicts special races and morphs specific to Botswana. This is the first birding guide written by a Botswana-based ornithologist and the only one dedicated specifically to Botswana.

Portable and easy to use, Birds of Botswana is the essential travel companion for anyone visiting this remarkable country.

## Princeton University Press Books Dominate on Popular Reading Lists!

If you’re looking for the perfect book to compliment your vacation or leisure time, here are some standouts to check out.

Roy Christopher‘s Summer Reading List featured four Princeton University Press books including: Michael Nelson‘s Reinventing Discovery, Lisa McGirr‘s Suburban Warriors: The Origins of the New American Right, Jürgen Osterhammel‘s The Transformation of the World: A Global History of the Nineteenth Century, and Steven F. Railsback and Volker Grimm‘s Agent-Based and Individual-Based Modeling: A Practical Introduction.

Check out Roy Christopher’s entire Summer Reading List 2015 here.

Award-winning journalist Frann Briggs also released a list, The Best of Spring Reading 2015 Part 1, featuring Princeton University Press publication Create Dangerously: The Immigrant Artist at Work by Edwidge Danticat.

Explore the list in its entirety here.