slide1
Download
Skip this Video
Download Presentation
Measuring Communication Signals in Lizards: How and Why

Loading in 2 Seconds...

play fullscreen
1 / 48

Measuring Communication Signals in Lizards:How and Why - PowerPoint PPT Presentation


  • 378 Views
  • Uploaded on

Measuring Communication Signals in Lizards: How and Why Rich Glor, Losos Lab, WUSTL I. Introduction to communication A. Definition B. Brief history (Marler 1967) C. My approach/outlook II. Communication in lizards A. Anolis carolinensis display description (DeCourcy

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about 'Measuring Communication Signals in Lizards:How and Why' - jacob


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
slide1

Measuring Communication Signals in Lizards:

How and Why

Rich Glor, Losos Lab, WUSTL

slide2

I. Introduction to communication

A. Definition

B. Brief history (Marler 1967)

C. My approach/outlook

II. Communication in lizards

A. Anolis carolinensis display description (DeCourcy

& Jenssen 1994)

1. Function

2. Ontogeny

3. Causation

4. Evolution

slide3

A. Definition

“Evolution hates definitions;

for every tidy definition a biologist constructs, evolution will have

provided some exception.”

Bradbury & Vehrencamp 1998

Proposed Definition:

Information transfer from sender to receiver

slide4

Wayne Lynch

National Wildlife Federation

e.g., Tuttle & Ryan 1981

slide5

Nature 2004

Nature 2004

slide6

Starring Greg Pryor, University of Florida

(more specifically, his toe), & an unidentified

male Anolis sagrei

slide7

Revised Definition:

Communication is the phenomenon of one organism producing a

signal that, when responded to by another organism, confers some

advantage (or the statistical probability of it) to the signaler

Burghardt 1970

Signal

Sender Receiver

Environment

Decision

&

Response

slide8

Signal

Sender Receiver

Environment

Decision

&

Response

Signals vs. Cues

Receivers vs. Eavesdroppers

slide9

B. Brief history

*Animal communication as a scientific discipline has a recent past

Lorenz Ethologists

1940’s-60’s Tinbergen NATURE/Instinct

Von Frisch Umvelt

slide10

*In contrast to

PavlovBehaviorists

1890’s-1960’sWatson NURTURE/Learning

Skinner Experimental Control

slide11

Definitions of communication:

1950’s-60’s  For the “survival of the species”

*Signaler/receiver cooperation

1960’s-80’s  Individual benefit

*Signaler/receiver competition

1980’s-present  Synthesis

*Honest and dishonest signals

*Context-dependent decision making at the

individual level

slide12

Dugatkin 2004

*Structure/Function relationships between signal mode

and environment

slide14

C. My approach/outlook

Tinbergen’s four questions

(Tinbergen 1963)

*Function

*Ontogeny

*Causation

*Evolution

N. Tinbergen

1907-1988

slide16

Anolis carolinensis range (U.S.)

Modified from Conant & Collins, 1998

  • Huge genus; only species endemic to North America
  • Polygynous social organization
  • Seasonal breeders (~ April-July)
  • Females lay single-egg clutches at ~ weekly intervals
  • No parental care
  • Communication via “headbobbing displays”
  • Excellent field and laboratory model
slide18

Anolis Communication(Jenssen, 1977, 1978)

Headbobbing displays are body movements which raise and

lower the head and dewlap

Headbobbing displays can be divided into core and modifier

components

The core component is the display type; a species-specific

headbobbing pattern that is performed predictably across all

displays of the same type

Display modifiers are postures or movements added to the

display type, but they are neither species-specific nor predictably

associated with any particular display type

slide20

Display Action Pattern (DAP-)Graphing

Charles C. Carpenter

(e.g., Carpenter & Grubitz 1961)

slide21

Anolis carolinensis DAP-graph

A

B

C

1 2 3 4 5 6 7 8 9 10

HEAD AMPLITUDE

1 2 5 6 7 8 9 10

5 6 7 8 9 10

0.0 0.5 1.0 1.5 2.0

DISPLAY DURATION (s)

slide22

The problem of function-labeling

*Longstanding concern; widespread problem

*Similar to problem of anthropomorphism

One behavior  many functions

One function  many behaviors

Anolis carolinensis signaling repertoire good cautionary tale;

 Don’t name the behavior by the context in which it

occurs!

slide24

An overview of subsequent A. carolinensis display

work, via Tinbergen’s four questions:

*Function – examination of sex differences in structure and use

*Ontogeny – display description through development

*Causation – proximate mediators, in this case, steroids (T)

*Evolution – population-level analysis of structure

slide25

1. Function

  • Adult males and females use the same three stereotyped

display types

Jenssen, Orrell, Lovern 2000

slide26

Sex Differences in Adult Display Use

Nunez, Jenssen, Ersland, 1997 Jenssen, Orrell, Lovern, 2000

slide27

More Sex Differences in Adult Display Use

Males Females

Advertisement Displays YES NO

Territory Patrol Displays YES NO

Ritualized Aggression YES NO

Dewlap in Courtship YES NO

Type C in Courtship YES NO

Display Modifiers YES FEW

Nunez, Jenssen, Ersland 1997, Jenssen, Orrell, Lovern 2000, Orrell & Jenssen 2003

slide28

Also: Jenssen, Greenberg, Hovde 1995

Jenssen & Nunez 1998

Jenssen, Lovern, Congdon 2001

slide30

Juvenile Display Structure

  • Juvenile males and females can display at hatching
  • Juvenile display structure does not differ by sex
  • Juvenile and adult display structure are the same
      • BUT stereotypy differs…

Lovern & Jenssen 2003

slide31

Juvenile Display Use

N=60 juveniles, 515 displays

Size class: H = 15.7, P = 0.001

*

N=30 each sex

Lovern & Jenssen, 2001

slide32

Juvenile Display Use -- Continued

Unlike Adults:

  • Social context has no effect on display type use
  • No advertisement displays, patrolling displays,

ritualized aggression, courtship

Lovern & Jenssen, 2001, 2003

slide34

Background on Steroids

  • Major class of hormones; highly evolutionarily conserved
  • Primarily synthesized by the gonads and adrenal glands
  • Circulate in bloodstream; affect target tissues throughout

body via binding to steroid-specific receptors and

subsequent modification of gene activity

  • Very small (0.5-1.0 pg) quantities can be reliably measured --

from a variety of tissue types -- by radioimmunoassay (RIA)

  • Sex steroids (androgens and estrogens) play major roles

in sexual differentiation and adult reproductive function

slide35

Juvenile and Adult T Comparison

*P < 0.001

*

ADULTS

JUVENILES

*

N = 8 50 21 44

Lovern, McNabb, Jenssen, 2001

slide36

Juvenile T-Implant Study

P < 0.001

BLANK IMPLANTS

T IMPLANTS

a

a

b

c

N = 6 6 8 6

Lovern, McNabb, Jenssen, 2001

slide37

T Implant Study: Results

Lovern, McNabb, Jenssen, 2001

slide38

Causation:

Sexual dimorphisms in adult behavior likely arise through

underlying physiological differences between males and

females that mediate the expression of behavior, rather than

through fundamental sex differences in the ability to perform

sexually dimorphic behaviors.

slide39

4. Evolution

Comparisons of Temporal Display Structure across Contexts and Populations in Male Anolis carolinensis:Signal Stability or Lability?

Lovern, Jenssen, Orrell, Tuchak 1999

slide41

Objectives

*To determine if males from three geographically distinct populations possess the same display types

*To determine if males vary the temporal structure of display types (i.e., intra-display structure) across contexts, populations

  • Hypothesis:Due to recent founding of Hawaii population

(ca. 1950), and dramatic climatic differences found there,

we expected males in this population to express the highest

degree of display type variability, potentially due to founder

effects, genetic drift, and/or unique selective pressures of a

tropical environment

slide43

Results I:Do Male Anolis carolinensis from Different Populations

Possess the Same Display Types?YES

Nearest Neighbor

Discriminant Analysis

GA: 100% (96%)

FL: 99.5% (92%)

HI: 100% (100%)

slide44

Results II:Do Male Anolis carolinensis Vary Display Type Structure across Populations?MAYBE...

Intra-display structure

Among GA, FL, and HI populations, totaldisplay duration was not significantly different for any display type

However, 18/24 display units were significantly different:

Display Type A: 6/10

Display Type B: 7/8

Display Type C: 5/6

slide47

Conclusions

*Male Anolis carolinensis useall display types (A, B, C) in the field and lab, and in all contexts; display type structure is unaffected by these parameters

*Males from three distinct populations (GA, FL, HI) possess the same three highly stereotyped -- but statistically distinguishable -- display types in their repertoires

*Within relatively small total variance, among- and within-individual differences account for more of the existing variance than does population or context

*Overall, male Anolis carolinensis show display type stability; males from HI show no evidence of increased display lability resulting from potential genetic and/or environmental influences from recent colonization of a novel habitat

ad