Allanblackia: my hypotheses

A few weeks ago, I shared some background information about a project I am working on with the Allanblackia tree species and invited you to make your own hypotheses about how seed dispersal and the tree population might change over time if there are fewer seeds in the forest.

I have two main hypotheses about what will happen to seed dispersal:

1) Allanblackia seeds will be carried further by rodents if there are fewer seeds.

2) Seeds moved by rodents are more likely to get eaten before they are able to germinate.

I think the seeds will be moved further because the rodents want to reduce the risk of other rodents finding "their" seeds and eating them. If there are lots of seeds around, then they can be a bit lazy and just hide them nearby. If there aren't many seeds though, they carry them farther away so other rodents going to the source are less likely to find them.

Any individual seed has a chance of getting eaten or being forgotten by a rodent. If it's forgotten, then the seed might germinate and sprout into a seedling. I think that if there are fewer seeds around, the chance of any one seed getting eaten is much higher. The rats have to eat!

In order to test my hypotheses, I'm putting groups of 16 seeds in different places in the forest, but I need to come up with a way to:

1) Find where the seeds are being moved and how far they are going

2) Revisit the seed over several weeks or months to see if it germinates.

What would you do? How would you track these seeds in the forest? They are roughly the size of a walnut. How would you know if the seed you find is one from the experiment?

Soon I'll let you know how I'm tracking the seeds, but I would love to hear your ideas!

Mystery photo #3 revealed

The last mystery photo was a close up of a caterpillar covered in parasitoid wasp cocoons! Here's the full size photo.

This is one caterpillar that won't ever be a butterfly (or moth). Why not? And what is a parasitoid wasp? The adult female wasps search for particular species of caterpillars and deposit the eggs inside the caterpillars' body. Then the wasp live inside the caterpillar and slowly eat it from the inside out. When the little buggers are finished, they make cocoons on the caterpillars' back and pupate. Then the next generation of wasps will emerge from the cocoons on the back! The caterpillar will die before it is able to pupate, and so it will never reach adulthood or reproduce.

Some insects like parasitoid wasps can be very beneficial for farmers if they lay eggs on caterpillar species that damage crops. You don't have to go to Africa to see parasitoid wasps! You can find them if you grow tomatoes in Chicago! Large, green caterpillars called tomato hornworms eat tomato plants, but also have their own parasitoid wasp species. The cocoons are very similar to these and will appear on the parasitized caterpillars (from a distance they look like they would be white oblong eggs, but if you look closely you can see the little threads of the cocoon).

One of the reasons I love studying biology is because I get to learn about fascinating relationships between different organisms. Would you ever have guessed that some wasps grow up inside a caterpillar!?

Mystery photo #3

This week's photo has nothing to do with seeds! There are two different animals in this photo. Can you describe them? Do you know what they are?

If I see something interesting in the forest, I try to take a photo and write a note about it even if it isn't directly related to my research, which is the case with this photo. Maybe my observation will help someone else with their research!

Mystery photo #2 revealed

Last week's mystery photo was a picture of a giant pouched rat. These large rats have cheek pouches like hamsters, which distinguishes them from many other rats (including the rats that are common in cities). The rat in the photo has really stuffed his cheeks full of seeds! Then they hide the seeds somewhere else in the forest (like squirrels with acorns) or bring it back to their burrow.

Here is another photo of a giant rat with his cheek pouches empty. He looks a bit more rat-like in this pose.

These rats are hunted and eaten in many places in Africa, but some people in the U.S. and Europe keep this species as pets. Unfortunately, some have escaped in Florida and they are now an invasive species. But here in Tanzania, they play an important role as seed dispersers.

Ms. Carrie's response to our questions!

Carrie Seltzer said...

Ms. Kruger's class,
I am so excited to answer your questions!

As far as I know, the area of Tanzania where I work does not have problems with illegal monkey collection. Some other animals like snakes and chameleons are legally collected for the pet trade from the forest outside of the nature reserve. There are international agreements that limit how many of each species can be sent to other countries.

Scientists can learn a great deal from observing animals, but we can't always observe them directly. Most primate are active during the day in relatively open areas (trees) where it can be possible to watch them, and many scientists have been able to accustom primates to their presence. Bats and rats are active at night which makes them much harder to see. I am using motion-sensitive cameras to observe rats. For bats my method is even less direct- I observe what bats eat by looking for the scraps they leave behind. Watching ANY kind of animal in whatever friendly way you can is great practice for a young scientist.

Protecting animals' habitats is the most important way to protect them. The Amani Nature Reserve, where I work, was created in 1997 to protect thousands of acres of rainforest from being logged. The forest is home to many species of plants and animals that are very rare! Even just since 1997, much of the forest outside of the nature reserve has been cleared for small farms so it is important that the reserve exists.

Questions related to The Monkey Thief

Hi Ms. Carrie!

We had a few questions we wanted to ask you. We know you have a lot of experience studying wildlife and their habitats, and we were hoping these questions would help us better understand our novel (The Monkey Thief). Thank you so much--we are loving the website and can't wait to hear more about your work!

-Ms. Kruger's class

1. In our novel The Monkey Thief, we have a problem in the rainforest with monkeys being stolen from the wild to use as pets. Do you have any similar problems in Tanzania?


2. In our novel, the main character (Steve) is trying to better understand monkeys by observing them. He tries to act normally around them so they get used to him being around. What kinds of animals have you observed, and how do you observe them?


3. In our story Steve’s uncle is trying to preserve part of the rainforest to have a habitat for the monkeys. Do you know of similar things being done in Tanzania to help monkeys (or other animals)? Are these successful?

Mystery photo #2

Since Ms. Kruger's class asked me how I observe animals, I thought this picture would be especially appropriate!

This photograph was taken with a motion-sensitive camera that I attached to a tree in the forest. What kind of animal is it and why do you think it's that kind of animal? What is it doing?

Clicking on the photo should enlarge it so you can get a better look.

The Allanblackia Project

Scientists make hypotheses based on observations and/or background information. Then they design experiments to test their hypotheses. I'm going to provide some background information, then let you try to come up with your hypotheses.

Background information:

Allanblackia is the name of a tall canopy tree that produces big fruits with many seeds inside. People collect the seeds because they can be pressed for vegetable oil (you've probably heard of corn oil, olive oil, or canola oil which all come from seeds, too). However, when people collect the seeds from the forest, then there are fewer seeds left for the animals to eat. This isn't a big problem if only a few people are collecting seeds, but many people are collecting seeds all around the Amani Nature Reserve.

What do you think the animals will do if there are fewer Allanblackia seeds? What do you think will happen to Allanblackia over time in the nature reserve?

To answer the first question, think about the answer to mystery photo #1. For the second question, think about why seeds are important in a plant's life cycle.

Juggling different projects

Scientists almost always have more than one project that they are working on at a time. It's kind of like studying different subjects in school, except for scientists the projects are usually related. All of the projects that I am working on are somehow related to plants, rats, and bats in the Tanzanian rainforest.

Over the next few weeks I will introduce some of the different projects that I am working on and give each one a name so that you can keep track of which is which.

Mystery photo #1 revealed!

Here's an uncropped version of the same photo:

Can you tell what it is yet?

That's my hand in the background. I'm holding two large seeds that have been chewed on by a rat! You can see the teeth marks on the seeds.

After seeds fall to the ground from the trees, rodents often carry them away. Sometimes they eat them right away, but often they hide them somewhere else to eat later. Many of the seeds will probably get eaten, but the ones that are forgotten can then sprout into seedlings.

Have you seen squirrels hiding acorns in the fall? They're doing the same thing as the rodents here in Tanzania.

Mystery photo #1

What do you see in this photo? What is it a picture of? Be as specific as you can.

I'll post the answer next Sunday. Maybe I'll post some clues during the week if you need them!

What's this about plants, rats, and bats?

I am a biologist. I study how plants, rats and bats are interconnected in the rainforest of Tanzania. I've created this blog especially for Ms. Kruger's class to see what the life of a field scientist is like, but anyone is welcome to follow along.

Let's start with the basics: Who, What, When, Where, Why, How?

Who? My name is Carrie Seltzer. I am a Ph.D. student at the University of Illinois at Chicago (UIC). This means that I have already finished college and have a Bachelor's degree in Biology. Now I am back in school for a Ph.D. When I'm finished, you can call me Dr. Seltzer, but for now you can just call me Ms. Seltzer (or Carrie).

What? I use the scientific method to learn about the relationships between plants and animals. I am especially interested in how rats and fruit bats disperse seeds.

When? I will be in Tanzania for 3 months this spring, and plan to post to the blog 2-3 times per week while I am here.

Where? Tanzania is in Africa along the coast of the Indian Ocean. The rainforest where I work is the Amani Nature Reserve in a mountain range called the East Usambara Mountains. The area is rural- about 20 miles from a paved road. Although some of the rainforest is protected, many people also live in the area. They speak Swahili and most of them are farmers. Tea, cloves, black pepper, cinnamon, corn, beans, bananas, and mangos are some of the things people typically grow on their farms.

View Larger Map

If you go to this link, you can compare Tanzania to the United States!

Why? I study biology because I find the natural world fascinating, and science offers a way for us to understand how the world works. I care deeply about plants, animals, and people. I am studying the relationships between plants and animals so that we can better understand how to preserve those relationships when humans alter the environment.

How? You're probably wondering how scientists go about studying plant-animal relationships. Over the next several weeks, I'll introduce you to some of the questions I am trying to answer, the species plant and animal species involved, some of the dilemmas of research, and some of the people I work with. I'll ask for your advice for some of the problems I face!

I hope you enjoy following along. I look forward to hearing your thoughts and answering your questions!