n Introduction to the ProjectThe Social Behavior of Polistine Wasps Project is based on data collected on six nests located in Texas' Brazos Bend State Park with the permission of Texas Parks and Wildlife (Permits 36-93, 60-95) in May 1994 for Polistes bellicosus and March and April 1995 for P. carolina.
The nests of Polistes bellicosus were videotaped over a four day period shortly after worker emergence. Before videotaping the nests, nearly every wasp was marked using spots of various colors of paint in order to distinguish individuals. In the first half of the videotaping period, nests were left undisturbed. After three days, the queen was removed and the nests were again videotaped.
The nests of P. carolina were videotaped before worker emergence when the nests had just eggs or eggs and larvae. The tapes cover periods before and after we removed some of the eggs from the nest.
After recording the behavioral videotape, all wasps still on the nest were collected (missing wasps died between video and collection). Each of the marked wasps was assigned a number, photographed, and later dissected. Before dissection, the head size of each of the wasps was measured. Upon dissection, the ovaries of each of the wasps were removed and photographed. Following dissection, microsatellites were used to determine maternity and genetic relatedness.
In the following projects, you will be expected to use components of all of the collected data in order to determine the social structure of the colony, the importance of variation among the wasps, and, if you have the videotapes of the nest, the effect of the social structure on individual behavior. Throughout the project, you should attempt to make connections between the various types of data. Scientists must continuously interpret data and be able to make connections between the results of different data, projects, and experiments. Once they make these connections, they are then expected to be able to coherently and precisely present their results. As science researchers, you should look at the questions as a stimulus for conducting your own research based on the data provided. Your assignment will ask you to test a specific hypothesis, but exactly how you use the data to test it is up to you. You must also decide what specific predictions to test, and when to reject your test of a prediction as being inadequate and when to reject the prediction and maybe the whole hypothesis. Do not assume the hypothesis is true and just explain away any problems with your test.
ssignmentsBelow, you will see several different projects in which students have participated. The first assignments are various versions that have been used by Professor Joan Strassmann in her Animal Behavior (Bios321) class at Rice University. The project was an application of the ideas covered in class and was first used in 1994. The project emphasizes a student's ability to work in a group to test hypotheses.
The next assignment, presented to eleventh and twelfth graders at the South Texas Science Academy in Mercedes, Texas, focuses on developing observation and analysis skills. Students were asked to select three questions which they wished to explore. This choice encouraged them to individually chose the research path they would follow and to focus on a particular problem, giving them a sense of responsibility for the ultimate outcome of the project.
The final set of questions were given to fifth graders participating in Take Your Daughters to Work Day at Rice University. The questions are designed to develop observation skills.
Rice University Animal Behavior (Bios321)
Reproductive Skew in Polistes
In this paper I would like you to test the hypothesis of reproductive skew. This theory offers an explanation for how reproduction is partitioned in small societies of individuals who might each reproduce on their own. It assumes that there is a dominant individual that is in control, and that she offers some reproduction to other group members in order to both keep them from leaving (staying incentives) and keep them from challenging her too much (peace incentives). The size of these incentives is predicted from kin selection theory and is based on several factors. If individuals are more closely related, the incentive can be smaller because they can pass on genes through the dominant. If the dominant is a lot larger than the subordinates the incentive can be smaller because they won't win if they challenge her. If it is hard to nest alone, the incentive can be smaller since the subordinates won't have other options. You may come up with other testable predictions of the theory from the readings, or your own discussions. More details on the theory and examples of the tests are in the readings provided to you. You can gather data to test this hypothesis from the videotapes and at the website. You have three nests of two species and so can compare them and see if the hypothesis is supported or rejected in both species and why. Use the following papers for background on skew theory, examples of skew tests and natural history of Polistes.
Keller, Laurent & Reeve, H. Kern (1994) Partitioning of reproduction in animal societies. Trends in Ecology and Evolution 9:99-102.
Reeve, H. Kern (1991) Polistes in: The social biology of wasps (Kenneth G. Ross and Robert W. Matthews, eds.) pp. 99-148.
Jamieson, Ian G. (199?) Testing reproductive skew models in a communally breeding bird, the pukeko, Porphyrio porphyrio. Proceedings of the Royal Society of London: Biological Sciences ?:335-340.
Scott, Michelle P. (1997) Reproductive dominance and differential ovicide in the communally breeding burying beetle Nicrophorus tomentosus. Behavioral Ecology and Sociobiology 40:313-320.
Since P. carolina nests in dark boxes and hollow trees and P. bellicosus nests on brambles, bushes and grasses in prairies, other opportunities for nesting are much greater for P. bellicosus than they are for P. carolina. Thus you should treat ecological constraints as high in P. carolina and low in P. bellicosus. Remember that in a test of a hypothesis you may find support for it or you may reject it. You may also support some parts and not others. When you reject a hypothesis, it is good to try to come up with an alternative hypothesis that seems more reasonable, though this one is not necessarily tested since you may not have gathered the data for it. This is presented in the discussion section.
To test the skew hypothesis you will need to figure out a number of things including the following.
1. What is genetic relatedness among foundresses on a colony? Does it vary among colonies? What is average genetic relatedness among foundresses in a colony for each species?
2. How is reproduction divided up in the group of foundresses?
3. How is the work of the colony divided up? Foraging, especially for caterpillar is a very risky job.
4. What kind of social conflict is there? Is it greater where you would expected it to be greater according to skew theory?
Put the honor code on the assignment. Work with your study group, divide up work, share data, figures and tables within the group. Don't share text or outlines of the results, though discussions by email are ok. Share only discussion with members of different study groups. It is part of the honor code to tell in a paragraph at the beginning how you divided up the work, and to attribute each figure or table to its authors. Please put a more realistic honor code for this assignment than that you gave no aid, maybe no unauthorized aid...
Data sources:
This project involves testing hypotheses using data from the videotapes on reserve at the library and at the website http://www.rice.edu/wasps. There are images of the heads and ovaries and DNA microsatellites of wasps from three nests of Polistes bellicosus and Polistes carolina. These data were collected in the spring of 1994 and 1995 at Brazos Bend State Park. On the P. bellicosus nests, there are two types of wasps, foundresses who have mated and overwintered, and the first generation of progeny, generally workers. On the P. carolina nests there are only foundresses. To do the relatedness estimations you will need the background frequencies of alleles. These are given in a table in the relatedness section. For the alleles of the wasps in the study, score the autorad images of DNA microsatellites. Again, everything should be explained in the web site. Use the bulletin board for questions.
Behavior: On reserve at the library are 3 videotapes from P. carolina colonies 14, 35, and 39. On the tapes are behaviors before and after we removed some eggs from the nest, but we will not be using this particular difference in this work. There are also 6 videotapes from P. bellicosus colonies 64, 114, and 155. The first three are before we removed the queen and the second, set with later dates are after we removed the queen. You do not need to use the ones from after we removed the queen. The P. carolina nests are taped earlier in the season before there were any workers while the P. bellicosus nests were taped after the first workers hatched out. These workers are the first brood of the colonies, and are analogous to the oldest brood or larvae in the P. carolina nests.
Genotypes: You have genotypes for all the foundresses and workers of P. bellicosus, and for the foundresses, larvae and eggs for P. carolina. These genotypes can be used to assess genetic relatedness among individuals. They can also be used to determine which of the foundresses produced which of the young. We have computer programs which help with both tasks, and they can be done by hand.
Head sizes: Head size can be used as an overall indicator of size. Head sizes are available for all foundresses on the website for P. bellicosus. I will give you the head sizes of P. carolina. At the website are the pictures of the marks on P. carolina so you can tell them apart.
Ovaries: Images of the ovaries are available at the website too. Unlaid eggs are clearly visible in some of the ovaries. Obviously these were taken at the end of the study, and so may not reflect their earlier condition. All of the foundresses have mated. Though the workers on the P. bellicosus nests have not, they can do so should they become queen.
Nest sizes: The number of cells in the nest can be used as an overall indicator of reproductive success of the group. Of course the nests will grow more later in the season, and some will be predated or otherwise die which will reduce their fitness. The adult wasps can rebuild a predated nest since the adults are rarely killed, but of course it sets them back at least a month since that is about how long the brood take to develop.
Order of arrival: We do not know which wasp began the nest for P. bellicosus. In P. carolina, the first ones at the nest site were wasps 7 on nest 14, 28 on nest 35, and 33 on nest 39. The others came later and at close to the same time.
Sperm:We do not have data from the spermathecae of the queens
of P. bellicosus. We do know that each queen only mated once, and that most
of the workers were produced by a single queen, so the sperm allele can
be inferred from the workers.
Presentation of your work:
Your work should be presented in the form of a scientific paper addressing a specific set of hypotheses, and prepared in a standard way. You had practice doing this in the first assignment where you wrote everything but the methods and results.
Title: (2 points) This should be a concise, complete description of the study. It should not be too vague or general.
Abstract: (6 points) This should be concise and well-worded. It should make clear what question you addressed and what you found. This paragraph should include a little bit of everything: background, summary of the experiment, results, and discussion. It should NOT include details of the experiment. It shouldn't be more than 6 or 8 sentences long. Many people will read nothing but the abstract, obtaining it on line. It is your chance to hook people into reading the whole paper.
Introduction: (10 points) The introduction should give some background that lets the reader know why the results are important and relevant. It is here that you present the specific hypothesis being tested and what predictions from the hypothesis will be most critically evaluated. You should not summarize methods here. The introduction should provide context, with the briefesp experimental description, so the reader knows how this study fits in with other work. The background should be sufficient, however, to make the reader understand why the different aspects of the study were necessary.
Methods: (7 points) In this section you should be clear about how you analyzed your data to test the hypotheses. You do not need to cover the part actually done in the field or DNA laboratory.
Results: (55 points) Here you present your results as clearly and concisely as possible. Results have the tests of the predictions of the hypothesis. This is not the place for interpretation. If the tests are carefully constructed, the results can be very brief and straightforward. Tables and figures should document all the most important points. Lots of people reading papers look first at the figures. You should not have tons and tons of figures and tables however. Extra data or tables or figures can be put in an appendix, a section that is not required.
Discussion: (20 points) The discussion should create a complete story relating all of the results. You should spend a paragraph, at most, summarizing results, then go on to discuss the significance of the results. It is here that the reader learns what you think your results have to say about the hypothesis being tested. The discussion section is the researcher's chance to shine and be interesting. If you end up rejecting your hypothesis, or a portion of it, or changing your mind about the relationship between the general hypothesis and the specific predictions, this is the place to tell us. Speculation is good, but be sure the distinction between speculation and results is clear.
General recommendations for writing a successful paper: Read journal articles. This is the best way to get a feel for what is appropriate where. Anthropomorphizing is never acceptable. Don't compare animals to humans; they are too evolutionarily divergent to make these comparisons useful. Be concise. There's no room in journals for lines like "this experiment was carefully planned." The reader will assume that you were careful. Just say what you have to say in the most succinct way possible.
Alternative assignment from 1996:
Paper Wasps as a Model System
After the recordings you have already seen of Polistes
bellicosus, we removed a dominant female from each of the three colonies
and again recorded behaviors. These tapes are available in the library.
This assignment is based on these videotapes, the comments on your previous
assignment, and on your reading for this class.
1. How does the behavior of Polistes bellicosus change after the
removal of a dominant female? Are females more or less active? Is there
more or less aggression? Is the dominance hierarchy more or less well defined?
Is there more or less foraging for food? Do other behaviors associated with
bearing or caring change? Are there great differences among the colonies,
and why or why not?
2. Who becomes the new dominant female? How can you tell? In whose interests
is this? Were your predictions supported? Why or why not? Take into account
any comments your instructors made on the first assignment, if this is appropriate.
3. A model system in biology is a system in which important conceptual issues
can be tested and the results generalized to other systems. A model system
is usually particularly amenable to the study of an important general phenomenon.
This might be the case because it involves an animal with short lifespans,
or that is easily reared, observed or experimented on, or because it has
been thoroughly studied previously. A model system should be simple and
general enough that important concepts can be easily explored and understood.
This project has used Polistes bellicosus as a model system for kin
selection. What are its strengths and weaknesses as a model system? In answering
consider similarities and differences of kin selection in wasps and other
animals where kin selection has been studied, such as other social insects,
dwarf mongooses, naked mole rats, Florida scrub jays, or other animals from
your class reading.
Honor code: You are strongly encouraged to work in groups on many aspects
of this assignment. You may watch videos, look at data and brainstorm together.
You can develop a list of behaviors together. You may generate figures,
tables and graphs as a group, or share them within a group only if you have
participated in the data analysis that supports each figure, table or graph.
Clearly label which figures, tables or graphs you did independently, and
which you got from the group. Write a few sentences describing to me how
your group worked. Sign the honor code on this assignment. The final text
of the report must be done independently!
Alternative assignment from 1994
Three colonies of Polistes bellicosus were videotaped in the wild at Brazos Bend State Park for a number of hours. After videotaping, the colonies were collected and the females were measured and genotyped. These videotapes are available from the reserve desk in the library. I also put one set of videotapes in the biosciences computer classroom, where several VCRs are available. These data are available to you over owlnet in a Netscape format in the form of images of the heads (an indicator of size), the ovaries (an indicator of reproductive status) and DNA microsatellites (used to partition reproduction among females and to assess genetic relatedness). This assignment is based on your analysis and interpretation of these data.
1. What do Polistes bellicosus females do? Make a complete list of
all the behaviors you see performed. This list should be organized by general
type of behavior and should have a brief name followed by a longer description.
Give a specific place on a tape which you feel is a good example of the
behavior. (5 points)
Partial example (from mockingbirds):
etc.
2. How do Polistes bellicosus females partition their efforts between
reproducing and caring for young? Why? Support your view with appropriate
behavioral, ovarian, size or genetic data. You may cite specific locations
on the tapes. You may illustrate your answer with figures, tables and graphs.
(5 points)
3. How is reproduction divided up in the group of Polistes bellicosus
females? Why? Support your view with appropriate behavioral, ovarian, size,
or genetic data. You may illustrate your answer with figures, tables and
graphs. (5 points)
4. If the dominant female is removed who would the foundresses prefer to
have assume the role of dominant female? If the dominant female is removed
who would the workers prefer to have assume the role of dominant female?
Why? Support your view with appropriate behavioral, ovarian, size or genetic
data. You may illustrate your answer with figures, tables and graphs. (5
points)
5. Who do you think will actually take over? Why? In whose interests is
this? Support your view with appropriate behavioral, ovarian, size or genetic
data. You may illustrate your answer with figures, tables and graphs. (5
points)
Honor code: You are strongly encouraged to work in groups on many aspects
of this assignment. You may watch videos, look at data and brainstorm together.
You can develop a list of behaviors together. You may generate figures,
tables and graphs as a group, or share them within a group only if you have
participated in the data analysis that supports each figure, table or graph.
Clearly label which figures, tables or graphs you did independently, and
which you got from the group. Write a few sentences describing to me how
your group worked. Sign the honor code on this assignment. The final text
of the report must be done independently!
South Texas Science Academy (High school)
Exploring Social Wasp Behavior
I. Questions based only on videotapes of behavior.
II. Questions based only on material available at
the website.
III. Questions based on website material and videotapes.
BRING OUR DAUGHTERS TO WORK ON WASPS (middle school)
Electronic Studio Project
[Home Page] [Introduction] [Assignment] [Behavior]
[Head Size] [Ovaries]
[DNA Microsatellites] [Relatedness]