HAWAII 2009: Happy-Faced HAWAII 2009: Happy-Faced Spiders, Insects of Hawaii, Spiders, Insects of Hawaii,

andand“Javametrics”“Javametrics”

Presented byPresented by

Dr. Sean D. PuckettDr. Sean D. Puckett

Dr. Maureen MurphyDr. Maureen Murphy

HAWAII 2009: “HIJ” of HHAWAII 2009: “HIJ” of Hawaiiawaii

Please get used to this scene. Once you fly Please get used to this scene. Once you fly away from the U.S. coast, heading to Hawaii, away from the U.S. coast, heading to Hawaii, this is what you see out the airplane window this is what you see out the airplane window

for 2500 miles.for 2500 miles.

HAPPY-FACE SPIDERSHAPPY-FACE SPIDERS

HAPPY-FACE SPIDERSHAPPY-FACE SPIDERS

The happy-face spider exhibits an array of color patterns on the back The happy-face spider exhibits an array of color patterns on the back of its abdomen, sometimes resembles a smiling face. These spiders of its abdomen, sometimes resembles a smiling face. These spiders blend in with the undersides of leaves where they build their flimsy blend in with the undersides of leaves where they build their flimsy webs and catch prey. webs and catch prey.

The happy-face spider is The happy-face spider is endemicendemic to the Hawaiian to the Hawaiian archipelagoarchipelago but is but is only found on four of the islands: Oahu, Molokai, Maui, and Hawaii. only found on four of the islands: Oahu, Molokai, Maui, and Hawaii. The spider populations on these four islands show off a variety of The spider populations on these four islands show off a variety of

happy-face patterns.happy-face patterns. Such a variation in form is Such a variation in form is referred to as a polymorphism — many referred to as a polymorphism — many forms (also known as morphs).forms (also known as morphs).

HAPPY-FACE SPIDERSHAPPY-FACE SPIDERS

Different smiles, single speciesDifferent smiles, single species Despite the variation in colors (and underlying Despite the variation in colors (and underlying

gene versions), all of the happy-face spiders: gene versions), all of the happy-face spiders:

have the same anatomical features, have the same anatomical features,

interact in the same ways with their environment interact in the same ways with their environment and with other organisms, and with other organisms,

share the same reproductive behaviors and share the same reproductive behaviors and methods of catching insect prey, and methods of catching insect prey, and

freely mate with one another. freely mate with one another.

HAPPY-FACE SPIDERSHAPPY-FACE SPIDERS

HAPPY-FACE SPIDERSHAPPY-FACE SPIDERS

For these reasons, researchers consider happy-face spiders to be one species, even though individuals have different color patterns.Intrigued by their variation, Drs. Rosemary Gillespie, Geoff Oxford, and Bruce Tabashnik, all then working at the University of Hawaii, set out to study the morphology, ecology, and behavior of these spiders. Let's follow their investigation as they learn more about the evolution of "smiling."

A MYSTERIOUS RATIO on A MYSTERIOUS RATIO on the Island of Mauithe Island of Maui

WHY?WHY?

The "other" patterns included plain red, plain The "other" patterns included plain red, plain white, red smiles, and red frowns. There white, red smiles, and red frowns. There was no consistency within the occurrence of was no consistency within the occurrence of the "other" patterns, but the two yellow to the "other" patterns, but the two yellow to one "other" occurred generation after one "other" occurred generation after generation. The researchers always found generation. The researchers always found about two yellow morphs for every one non-about two yellow morphs for every one non-yellow morph. yellow morph.

How about on the other islands?How about on the other islands?

When Gillespie and Oxford went on to study When Gillespie and Oxford went on to study the happy-face spiders on the other islands, the happy-face spiders on the other islands, they were surprised by their results. Not they were surprised by their results. Not only did each island harbor the same sorts only did each island harbor the same sorts of morphs, but the different morphs also of morphs, but the different morphs also occurred at almost exactly the same occurred at almost exactly the same frequency in each population. Just as in frequency in each population. Just as in Maui, the frequency of yellow morph spiders Maui, the frequency of yellow morph spiders to those with other patterns was 2:1. to those with other patterns was 2:1.

Is this surprising?Is this surprising?

Why is that so surprising? Well, if you rolled a pair Why is that so surprising? Well, if you rolled a pair of dice and got a two and a one you wouldn't be of dice and got a two and a one you wouldn't be surprised. But if you rolled the same dice again surprised. But if you rolled the same dice again and got a two and a one, and again and got a two and got a two and a one, and again and got a two and a one, and again and got a two and a one, and a one, and again and got a two and a one, you'd start to wonder what was going on! Gillespie you'd start to wonder what was going on! Gillespie and Oxford were similarly surprised. Why were the and Oxford were similarly surprised. Why were the same color patterns found at the same frequency same color patterns found at the same frequency on each of the four islands? What was going on? on each of the four islands? What was going on?

MARVIN GAYE: “What’s Goin’ MARVIN GAYE: “What’s Goin’ On?”On?”

Listen to Marvin and think about Listen to Marvin and think about the happy-face spidersthe happy-face spiders

Exploring the Color-Pattern Exploring the Color-Pattern Frequency on the IslandsFrequency on the Islands

Why did each island have a 2:1 ratio of yellow to Why did each island have a 2:1 ratio of yellow to other morphs? A first hypothesis involved other morphs? A first hypothesis involved dispersal. As an example, imagine that we start dispersal. As an example, imagine that we start out with two populations with different ratios of out with two populations with different ratios of blue to orange individuals. One population is half blue to orange individuals. One population is half blue spiders and half orange, and the other is blue spiders and half orange, and the other is heavily biased towards orange individuals. What heavily biased towards orange individuals. What would happen to the populations if there were no would happen to the populations if there were no movement between them, in other words, if there movement between them, in other words, if there were no dispersal? were no dispersal?

What happens?What happens?The ratios in each population change The ratios in each population change

independently and remain quite different independently and remain quite different from each other. But what would happen if from each other. But what would happen if individuals were allowed to individuals were allowed to move between move between populations, in other words, if dispersal populations, in other words, if dispersal between populations were common?between populations were common?

http://evolution.berkeley.edu/evolibrary/article/_0_0/happyface_05http://evolution.berkeley.edu/evolibrary/article/_0_0/happyface_05

The Happy Face Spider “Dispersal” The Happy Face Spider “Dispersal” TheoryTheory

Because some genes are being exchanged Because some genes are being exchanged every generation, each population ends up every generation, each population ends up with the same ratio of blue to orange! with the same ratio of blue to orange! Gillespie and Oxford thought that this Gillespie and Oxford thought that this mechanism might explain the consistent 2:1 mechanism might explain the consistent 2:1 ratio they found among the happy-face ratio they found among the happy-face spiders. They based a first hypothesis on spiders. They based a first hypothesis on this idea.this idea.

DISPERSAL HYPOTHESISDISPERSAL HYPOTHESIS

Dispersal of spiders between islands Dispersal of spiders between islands has caused a consistent ratio of has caused a consistent ratio of 2 2

yellowyellow: 1 "other": 1 "other" on all four islands. on all four islands.

Molecular Data to the RescueMolecular Data to the Rescue

Gillespie and Oxford turned to molecular Gillespie and Oxford turned to molecular data to test this hypothesis.data to test this hypothesis.

Two types of molecular data used:Two types of molecular data used:

PROTEIN DATA andPROTEIN DATA and

DNADNA

DATA SET #1:ProteinsDATA SET #1:Proteins

Individuals normally vary in the exact structure of Individuals normally vary in the exact structure of their proteins, a set of molecules essential to all their proteins, a set of molecules essential to all living things. You and your mom, for example, living things. You and your mom, for example, might carry Version A of a particular protein, while might carry Version A of a particular protein, while your cousin carries Version B of that protein. your cousin carries Version B of that protein. Furthermore, different populations have different Furthermore, different populations have different protein versions and different frequencies of these protein versions and different frequencies of these versions. So perhaps in Thailand, there are six versions. So perhaps in Thailand, there are six common versions of the protein (a high variation common versions of the protein (a high variation population), but in Peru, only one protein version population), but in Peru, only one protein version is common (a low variation population). is common (a low variation population).

DATA SET #1:Evaluating the DATA SET #1:Evaluating the Evidence from Proteins in the Evidence from Proteins in the

Happy-Face SpidersHappy-Face Spiders

Evaluating the evidence from proteinsEvaluating the evidence from proteinsThe scientists' study of proteins in the The scientists' study of proteins in the happy-face spiders revealed that different happy-face spiders revealed that different islands had very different levels of variation. islands had very different levels of variation. This suggests that dispersal between the This suggests that dispersal between the islands is not very common. islands is not very common.

DATA SET #2: DNADATA SET #2: DNA

DNA is a molecule that carries genetic information DNA is a molecule that carries genetic information from generation to generation in the form of a from generation to generation in the form of a code. By comparing differences in the code's code. By comparing differences in the code's sequence between individuals, it is possible to sequence between individuals, it is possible to determine "who is more closely related to whom" determine "who is more closely related to whom" — in general, the more similar the DNA — in general, the more similar the DNA sequences, the more closely related any two sequences, the more closely related any two individuals or populations are and the less time individuals or populations are and the less time they have been isolated. Gillespie and Oxford they have been isolated. Gillespie and Oxford sampled DNA from different morphs on different sampled DNA from different morphs on different islands and compared their sequences. islands and compared their sequences.

Evaluating the DNA EvidenceEvaluating the DNA Evidence

The DNA evidence suggested that the spider The DNA evidence suggested that the spider populations were related as this tree shows. All of populations were related as this tree shows. All of the color morphs in one island population are the color morphs in one island population are more closely related to each other than they are to more closely related to each other than they are to the color morphs from populations on other the color morphs from populations on other islands. For example, yellow morphs from a islands. For example, yellow morphs from a population on Hawaii are almost identical in DNA population on Hawaii are almost identical in DNA sequence to red front morphs from the same sequence to red front morphs from the same island, but are quite different from a yellow morph island, but are quite different from a yellow morph on Maui or Oahu.on Maui or Oahu.

TreeTree

And the Tree shows??And the Tree shows??

All of the color morphs in one island All of the color morphs in one island population are more closely related to each population are more closely related to each other than they are to the color morphs from other than they are to the color morphs from populations on other islands. For example, populations on other islands. For example, yellow morphs from a population on Hawaii yellow morphs from a population on Hawaii are almost identical in DNA sequence to red are almost identical in DNA sequence to red front morphs from the same island, but are front morphs from the same island, but are quite different from a yellow morph on Maui quite different from a yellow morph on Maui or Oahu. or Oahu.

The Tree Suggests…The Tree Suggests…

The tree suggests that the populations of The tree suggests that the populations of spiders on different islands have been spiders on different islands have been isolated from one another — in other words, isolated from one another — in other words, that dispersal between islands is not very that dispersal between islands is not very common. After all, if dispersal between common. After all, if dispersal between islands were common, we would expect to islands were common, we would expect to find some spiders on Maui that were more find some spiders on Maui that were more closely related to some spiders on Hawaii closely related to some spiders on Hawaii than to other spiders on Maui. than to other spiders on Maui.

What do YOU think the Protein and What do YOU think the Protein and DNA evidence say about the DNA evidence say about the “DISPERSAL” hypothesis?“DISPERSAL” hypothesis?

Well, both lines of evidence point to the same Well, both lines of evidence point to the same answer: dispersal is not common, so the Dispersal answer: dispersal is not common, so the Dispersal Hypothesis is probably not a good one.Hypothesis is probably not a good one.

Gillespie and her colleagues needed to come up Gillespie and her colleagues needed to come up with an alternative hypothesis to explain the with an alternative hypothesis to explain the mysterious 2:1 ratio — but meanwhile, they mysterious 2:1 ratio — but meanwhile, they noticed something striking about the tree they had noticed something striking about the tree they had produced.produced.

Do you notice anything STRIKING Do you notice anything STRIKING about the Tree and the ORDER of about the Tree and the ORDER of

the Islands?the Islands?

A SURPRISE!A SURPRISE!

The physical order of the islands and the tree's branching The physical order of the islands and the tree's branching pattern match up! That's a bit like drawing numbers out of pattern match up! That's a bit like drawing numbers out of a hat one at a time and getting the numbers 1 through 4 in a hat one at a time and getting the numbers 1 through 4 in the exact correct order — it might happen by chance, but the exact correct order — it might happen by chance, but not very often. Is this correspondence between island not very often. Is this correspondence between island geography and the evolutionary tree a coincidence, or is geography and the evolutionary tree a coincidence, or is there some other explanation?there some other explanation?

The correspondence is not a coincidence, but in order to The correspondence is not a coincidence, but in order to understand why, you need to know a little bit about the understand why, you need to know a little bit about the formation of these islands. The islands in the Hawaiian formation of these islands. The islands in the Hawaiian archipelago are arranged linearly from oldest to youngest. archipelago are arranged linearly from oldest to youngest. Kauai is the oldest island, Oahu the next oldest, and the Kauai is the oldest island, Oahu the next oldest, and the large island of Hawaii is the youngest.large island of Hawaii is the youngest.

Age of the Hawaiian IslandsAge of the Hawaiian Islands

EVOLUTIONARY TREE EVOLUTIONARY TREE SUGGESTSSUGGESTS

The evolutionary tree suggests that the "oldest" (original) group of The evolutionary tree suggests that the "oldest" (original) group of spiders evolved on the oldest island of Oahu. spiders evolved on the oldest island of Oahu.

As new islands formed, individuals from this original population As new islands formed, individuals from this original population colonized subsequent islands in a "hopscotch" manner. The youngest colonized subsequent islands in a "hopscotch" manner. The youngest islands of Maui and Hawaii were colonized last and harbor the islands of Maui and Hawaii were colonized last and harbor the "youngest" populations of spiders. "youngest" populations of spiders.

TO SEE THIS IN ACTION, GO TO:TO SEE THIS IN ACTION, GO TO:

http://evolution.berkeley.edu/evolibrary/article/_0_0/happyface_07http://evolution.berkeley.edu/evolibrary/article/_0_0/happyface_07

STUDYING GENES: More MysterySTUDYING GENES: More Mystery

Now Gillespie and her colleagues understood a Now Gillespie and her colleagues understood a little more about the evolutionary history of the little more about the evolutionary history of the happy-face spiders, but they still didn't understand happy-face spiders, but they still didn't understand the 2:1 ratio. The proteins and DNA sequences the 2:1 ratio. The proteins and DNA sequences together demonstrated that very few spiders together demonstrated that very few spiders moved between populations on different islands. moved between populations on different islands. This ruled out dispersal as an explanation for the This ruled out dispersal as an explanation for the similar morphs and morph frequencies on different similar morphs and morph frequencies on different islands. What else might explain the consistent islands. What else might explain the consistent ratio? Perhaps learning more about the genetics of ratio? Perhaps learning more about the genetics of these happy-face patterns would reveal these happy-face patterns would reveal something. something.

HAPPY-FACE SPIDER GENETICSHAPPY-FACE SPIDER GENETICS

Gillespie and Oxford turned to breeding experiments to identify the Gillespie and Oxford turned to breeding experiments to identify the genetic mechanism behind color pattern formation.genetic mechanism behind color pattern formation.

They started with spiders from Maui, bred individuals of known They started with spiders from Maui, bred individuals of known parentage, and counted the number of offspring of each morph. This parentage, and counted the number of offspring of each morph. This type of breeding experiment is a common method used to figure out type of breeding experiment is a common method used to figure out how genes produce a particular trait such as color morphhow genes produce a particular trait such as color morph

Selective breeding between individuals of known parentage should Selective breeding between individuals of known parentage should result in predictable patterns of color morphs in the offspring. And in result in predictable patterns of color morphs in the offspring. And in fact, that was the case for the Maui spiders. The frequency of color fact, that was the case for the Maui spiders. The frequency of color patterns in both male and female offspring was consistent with what patterns in both male and female offspring was consistent with what you would expect if color pattern were passed from parent to offspring you would expect if color pattern were passed from parent to offspring at a single gene on a chromosome.at a single gene on a chromosome.

GENETICS on MAUI GENETICS on MAUI

On the Big Island (HAWAII), things On the Big Island (HAWAII), things were different!were different!

GENETICS on HAWAIIGENETICS on HAWAII

On HawaiiOn Hawaii, when a yellow female is mated with a , when a yellow female is mated with a "red front" male, the cross produces 50% yellow "red front" male, the cross produces 50% yellow females, 0 yellow males, 0 red front females, and females, 0 yellow males, 0 red front females, and 50% red front males. These results are typical of 50% red front males. These results are typical of this cross. this cross.

The genetic mechanisms were different between The genetic mechanisms were different between the spider populations on Maui and Hawaii. The the spider populations on Maui and Hawaii. The spider populations had evolved the same color spider populations had evolved the same color patterns and the same color pattern frequencies, patterns and the same color pattern frequencies, but they'd done it in totally different ways! Why did but they'd done it in totally different ways! Why did all the islands independently evolve the same set all the islands independently evolve the same set of color pattern traits?of color pattern traits?

Does SEXUAL SELECTION have Does SEXUAL SELECTION have anything to do with it?anything to do with it?

Listen to Marvin Gaye’s “Sexual Listen to Marvin Gaye’s “Sexual Healing” and think about SEXUAL Healing” and think about SEXUAL SELECTION and the HAPPY-SELECTION and the HAPPY-FACE SPIDERS….FACE SPIDERS….

STRANGERS in the NIGHT…STRANGERS in the NIGHT…

Gillespie and Oxford also rejected this Gillespie and Oxford also rejected this hypothesis based on two pieces of hypothesis based on two pieces of evidence: (1) the spiders cannot see color, evidence: (1) the spiders cannot see color, and (2) they are nocturnal. Color blind and (2) they are nocturnal. Color blind spiders finding each other in the dark are spiders finding each other in the dark are unlikely to choose a mate based on a unlikely to choose a mate based on a smiling red abdomen! So sexual selection smiling red abdomen! So sexual selection probably doesn't have much to do with it. probably doesn't have much to do with it.

Does it pay to mate blind and Does it pay to mate blind and nocturnal?nocturnal?

THE PREDATOR-SEARCH THE PREDATOR-SEARCH HYpothesisHYpothesis

Based upon research with blue jays.Based upon research with blue jays. Gillespie and colleagues currently hypothesize that Gillespie and colleagues currently hypothesize that

predators searching for happy-face spiders maintain the predators searching for happy-face spiders maintain the 2:1 ratio on the islands. On each island, predators are 2:1 ratio on the islands. On each island, predators are efficiently searching for the most common morph, the efficiently searching for the most common morph, the yellow morph, or inefficiently searching for several morphs. yellow morph, or inefficiently searching for several morphs. This gives an advantage to non-yellow morphs, since they This gives an advantage to non-yellow morphs, since they escape predation more often. But anytime other morphs escape predation more often. But anytime other morphs get very common, predators start looking for them instead, get very common, predators start looking for them instead, which drives their frequencies back down. This mechanism which drives their frequencies back down. This mechanism could help explain why each island has evolved a variety of could help explain why each island has evolved a variety of morphs and why we consistently observe a 2:1 ratio of morphs and why we consistently observe a 2:1 ratio of yellow to other spiders. yellow to other spiders.

TIME FOR A TIME FOR A HAPPY-FACE SPIDERHAPPY-FACE SPIDERCUPCAKE!CUPCAKE!

It’s Hawaiian cocktail time (pineapple juice/ It’s Hawaiian cocktail time (pineapple juice/ Kona coffee, snacks) to mingle and meet Kona coffee, snacks) to mingle and meet your classmates and hear some authentic your classmates and hear some authentic Hawaiian music….return in about 15 Hawaiian music….return in about 15 minutes for Kona Coffee and Hawaiian minutes for Kona Coffee and Hawaiian Javametrics!Javametrics!