| |
Le Compte Ory - Lizards Got There First
By Dmitri Dergun
08 March 2009
In Rossini's opera, the Count and his men infiltrate a nunnery dressed as nuns.
Now it seems that this would be no news to lizards.
The male Augrabies Flat Lizard is a highly territorial animal: fully grown
adult males dominate their territories, which contain multiple females - harems
- by attacking and driving off younger males.
The adult males are highly coloured whereas females are a dull brown colour.
A team of South African and Australian researchers has discovered that some
young male lizards protect themselves from older males by pretending to be females,
gaining access both to a territory and its resident females, where they are probably a lot more welcome than the Count and his men were.
As juveniles, all males look like females before gradually developing their
extravagant adult male coloration at the onset of sexual maturity. Young males
are most vulnerable to aggressive adult male rivals when these first signs of
masculinity develop. Experienced males will chase and bite their young rivals.
"Young males purposefully only develop colours on their belly, so they
reach sexual maturity by still looking like a female," says co-author Associate
Professor Scott Keogh, of the School of Biological Sciences at the Australian
National University. Professor Keogh says that the young transvestite males
appear to have a dual advantage: “They can avoid potentially dangerous
bouts with dominant males and still have access to normally inaccessible females.”
“By delaying the onset of colour to a more convenient period, these males
(termed she-males) are making the best of a bad situation,” said team
member Associate Professor Martin Whiting of the University of the Witwatersrand.
An immediate advantage of this phenomenon is freedom of movement in the normally
treacherous zones which make up the territories of highly aggressive males that
already have fighting experience. At the same time, the female mimics are able
to court the myriad of females that share the territorial male’s residence.
The researchers also tested whether she-males are able to mimic the chemical
‘signature’ of females. In a clever experiment performed in the
wild, they removed all pheromones and skin lipids that might signal gender and
relabelled a group of females and she-males with either male or female scent,
before presenting them to typical adult males. Males use their tongues to sample
chemical scent and responded by courting she-males labelled as females, but
not she-males labelled as males. “Males are fooled by looks, but not by
scent” said researcher Dr Jonathan Webb of the University of Sydney. “She-males
are able to maintain this deception by staying one step ahead of a prying male,
and thereby avoiding a nosey tongue that might give the game away.”
Question: at what level do the young transvestite males 'know' that they are
deceiving the older males? Clearly a lizard can tell a male from a female both
by sight and by smell. A she-male is aware at some level that it doesn't look
like an older male - it has to, or its behaviour would be a give-away on the
older male's territory. It has to walk and behave like a female, or it would
immediately be spotted and attacked by the reisdent tyrant male. The lizard
is not 'conscious' of course, in the sense of being self-aware in the way that
humans are. But some part of its brain knows that it looks like a girl. An early
component of intentionality.
Emotions And Trade Aren't A Good Match
by Michael Bell
02 November 2008
After 3,000 hours of observing grooming behaviour in chimpanzees, Cristina
Gomes, a behavioural ecologist at the Max Planck Institute for Evolutionary
Anthropology in Leipzig, Germany, has demonstrated that the chimps keep an accurate
balance sheet of their interactions with other individuals in the troop which
results in a tit-for-tat match over periods of a week or more.
The team used rules to exclude effects that might have resulted from sex, hierarchy,
age, and friendship: "Everything I could come up with," Gomes says.
She concludes that the only way to explain the symmetry of grooming exchanges
between pairs over time is through reciprocity. "If you don't have a set
price, then you're susceptible to being cheated and cooperation would probably
break down."
So far, so good, and so classical, but Gomes goes on to say that the accuracy
of the exchanges is more likely to be driven by an emotional agenda than a cognitive
social calculus. "It does not necessarily have to be a cognitive process,"
she says, "it could be emotional." Gomes hypothesizes that chimpanzees
- and by extension, humans - use fine adjustments to levels of endorphins to
associate particular levels of generosity or meanness with individuals, and
it's then hormonal motivation that causes the tit-for-tat behaviour.
While not excluding a major affective element in relationships, which indisputably
exists, this view seems to deny the very adaptive advance which made human group
social life possible, that being the evolution of a cognitively and cortically
based social calculus. The vast enlargement of the neo-cortex in primates and
then in humans cannot be adequately accounted for other than by the need to
store enormous volumes of data about the historical relationships between members
of the group, and as much between other members of the group as about one's
own relationships. Think soap operas. Your endorphins may help you assess the
state of things between you and your mates, but they won't help you much when
it comes to understanding why Joe dumped Jane in favour of Chardonnay.
As well as enabling the matrix of extended group relationships, cognitive reciprocity
led to exchange in goods, ie trade, the other key building block, after the
group itself, of the society of which we are all members. The notions of fairness,
value and trust that originally developed and expressed themselves through behaviours
such as grooming and food-sharing underlie all types of trading activity: it
seems intuitively implausible, even unworkable, that they could be successfully
underpinned by a hormonal mechanism rather than a cognitive one.
Wasps Remember Who Not To Sting
by Dmitri Dergun
19 October 2008
Research carried out at the University of Michigan has demonstrated that the
social insect Polistes fuscatus (the paper wasp) has long-term memory for individual
conspecifics even after meeting and interacting with many other wasps in the
meantime.
The research, by graduate student Michael Sheehan and assistant professor of
ecology and evolutionary biology Elizabeth Tibbetts, suggests that the wasps'
social interactions are based on memories of past encounters rather than on
rote adherence to simple rules.
Until now it was assumed that all social insects had very limited memories.
Honeybees can remember where they've found nectar, "But those memories
are pretty fleeting," Sheehan said. "There seems to be a limit to
the number of things they can juggle in their head at one time."
Tibbetts had previously showed that the wasps recognize individuals by variations
in their facial markings and that they behave more aggressively toward wasps
with unfamiliar faces. In the new research, Sheehan measured aggression between
50 wasp queens in four different encounters over eight days. On the first day,
two wasps that never had met were placed in an observation chamber for a day
and their initial interactions videotaped. Then the pair was separated, and
each wasp was put in a communal cage with 10 other wasps. A week later, the
pair met again, and again their behavior was videotaped.
It was clear from teh results that the wasps treated each other better during
their second encounter than when they were strangers, suggesting they remembered
each other. "Instead of trying to bite each other and really have a rough-and-tumble
encounter, they just sort of hung out next to each other when they met the second
time," Sheehan said.
Recognition matters to the wasps because Polistes fuscatus females often share
nests, so that it is adaptive for them to be able to recognize nest-partners.
Most social insects use smell to identify nest-partners; separate research by
Wulfila Gronenberg, associate professor of neurobiology and ecology and evolutionary
biology at the University of Arizona, and who had previously worked with Tibbetts,
has shown that in the paper wasp, the antennal lobe (used for smell recognition)
is smaller than in other wasps, while the so-called mushroom body subcompartments,
which integrate information from the senses and help control learning and memory,
were not any larger than usual.
Sheehan points out that the findings of the Michigan research challenge assumptions
about social cognition, which is generally thought to require a large and advanced
brain.
Calmly Considered, I Would Say Your Bottom Is Tops
by Michael Bell
04 October 2008
Did Jack Lemmon say it to Shirley MacLaine in The Apartment? Research with chimpanzees has shown that they can identify other members of
their group from pictures of their bottoms. Humans are really good at that:
at an office picnic once in Moscow I noticed that almost everyone was wearing
black jeans, so bored by the Russian chit-chat I could barely understand, I
took photos of ten of their derrieres, deliberately using strange angles, and
set a competition back in the office next day to see how many people could identify.
The average score was seven, and one person got all ten.
Primatologists Frans de Waal and Jennifer Pokorny of the Yerkes National Primate
Research Centre at Emory University in Atlanta, Georgia, asked six adult chimpanzees
to link pictures of male and female chimpanzee behinds with photos of their
comrades' faces. The chimpanzees scored well above chance, but only if they
knew the individuals concerned - that's not too surprising, though.
The researchers say the test shows that chimpanzees use a 'whole body' method
of storage and recognition, something that has been also demonstrated in humans
(and in my office game).
In a further test, the researchers established that chimpanzees could identify
the sex of a chimp face (no lipstick, promise!), but again only if they knew
the individual, which shows, de Waal speculates, that the chimps recognise the
sex of other chimps based, not just on physical attributes, but on other information
from their previous experience with those individuals, such as their roles in
the larger group.
If you think about how you identify the males and females you come across in
non-gender-specific situations, I think you'll agree that we are not so different.
Well, how would we be different?
Now for the interesting part: recognition of conspecifics should surely have
origins way back in the phylogenetic tree? But how far back? Presumably recognition
of known individuals is a given in any group setting. Dogs, birds, whales, for
a start. Would they not then use the 'whole body' method? What about cockroaches?
Intuitively you'll say not; but cockroaches have been shown to exhibit group
behaviour. A cockroach has to be able to identify another one, and can presumably
tell a male from a female - or is it done by pheronomes? Perhaps it's both -
cockroaches live in the dark, a lot.
There are not many answers to be had. But time and time again it turns out
that an ability we thought was special to us can in fact be demonstrated in
quite remote species. 'Whole body' recognition is perhaps just such a case.
Human Or Animal?
by Michael Bell
07 September 2008
Well, are we like animals or aren't we? Of course, we are animals, anyway,
but everyone intuitively accepts that we humans are somehow 'special', so that
the question is readily understood. The last 150 years has seen a gradual reduction
of the list of differences between humans and other animals, and every day now
seems to bring a new discovery of some feature of the brain or the body which,
sometimes surprisingly, we find we have in common with some other species, or
many of them.
But the argument between the 'likes' and the 'unlikes' (I almost want to call
them dualists) will not go away, and is well illustrated by two pieces of research
which were published this week.
'What is it that distinguishes humans from other mammals? The answer to this
question lies in the neocortex – the part of the brain responsible for
sensory perceptions, conscious thought, and language. Humans have a considerably
larger neocortex than other mammals, making it an ideal subject for the research
of higher cognition.' Thus speaks a dualist in Science Daily, reporting on research
on the functioning of cortical 'chandelier' cells (Molnár G, Oláh
S, Komlósi G, Füle M, Szabadics J, et al. (2008) Complex events
initiated by individual spikes in the human cerebral cortex. PLoS Biol 6(9):
e222. doi:10.1371/journal.pbio.0060222).
The authors triggered specific chandelier cells, causing a sequence of electrical
events in the neocortex. They found that the synaptic pathways between chandeliers
and pyramidal cells are extremely strong – much stronger than has been
recorded previously in other mammals. This, say the authors, suggests that humans
do possess different types of cells, and that our higher cognition isn't due
to having larger cells.
Meanwhile, at the Great Ape Trust, a peer-reviewed paper by Janni Pedersen,
an Iowa State University Ph.D. candidate from Denmark, analyzed a videotaped
conversation between the bonobo Panbanisha and Dr. Sue Savage-Rumbaugh, now
a scientist with special standing at Great Ape Trust, but a researcher at Georgia
State University's Language Research Center when the video was made about 15
years ago.
Language-competent bonobos use lexigrams, which are made up of arbitrary symbols
that represent words, as the basis for conversations with humans. In the video,
Panbanisha was in the forest with Savage-Rumbaugh and an assistant, who had
a dog in tow that Panbanisha didn't like. Panbanisha repeatedly used the lexigrams
to ask to be carried by the assistant. Savage-Rumbaugh offered other resolutions,
but Panbanisha remained firm.
Pedersen said linguistic aspects of the conversation included turn taking,
negotiation, pauses and repetition, and went far beyond information sharing
made possible through the use of lexigrams symbols. "She was using language
to get at what she wanted," Pedersen said. "She is very, very clever
and is fully capable of following the conversation the same way a human does.
This tells me that Panbanisha's knowledge of language is far beyond understanding
the words, to understanding how to use them in a conversation to get what she
wants."
William M. Fields, director of bonobo research at Great Ape Trust, says the
publication opens an important new chapter in the debate about the linguistic
capabilities of apes. "The resistance to this in the scientific community
is enormous," he said. "For the first time, we have a student who
is using linguistic tools that have normally been applied to humans now being
applied to non-humans. This is a move toward using the kinds of methodology
that are appropriate in ape language, based on Savage-Rumbaugh's 1993 monograph,
Language Comprehension in Ape and Child."
"One of the things Janni has affirmed, and affirmed in a way the lay person
can understand, is the aspect of turn-taking. If there is anything universal
in human language, it's turn of talk," Fields said. "The fact that
Panbanisha has done this, and it's accessible even to an untrained reviewer,
I think is an important aspect of her paper. She has looked at the whole social
action, and the meaning. Ideational flow – going back and forth –
is obvious.
"Originally, repetition was thought of as something that happens normally
in human language," he said. "Traditionally, repetition in ape communicative
behaviors is assumed to be proof that they don't have language. It's a kind
of dichotomy or unfairness."
I'd like to know about Panbanisha's chandelier cells . . .
Older
posts:
- Sharing Nurture And Nature
- Arise, Sir Gordon!
- The Female Of The (Social) Species . . .
- How Do You Program A Group Of Robots?
- Exploring The Brain: Intentionality
- Oh What A Tangled Web We Weave, When First We Practice To Deceive
- Girls On Top!
- Will Your Grandchild Talk To A Raven?
- At Last, A Use For Cats
- Anyone For World Of Statecraft?
- Another Glass Of Wine, Sir?
- Just How Nasty Should We Be?
- Your New, Improved President
- Are Mirror Neurons Racist?
- Conferences Are Groups, Too
- Brains For Washing Machines: Silicon Or Hydrocarbons?
- Altruism And Xenophobia May Be Bedfellows
- Pensions For Immortals
- Private - Good; Public - Bad
- Robot Cockroach Can Change Roach Group Behaviour
- Altruism And Xenophobia May Be Bedfellows
- Elephants Can Classify Humans
- On-Line Gaming Helps To Form Social Groups, Says Study
- 'Baby-Talk' Used In Social Settings By Rhesus Monkeys
- Group Behaviour in Birds Triggered By Rainfall Patterns
- Apes Play Charades To Get Preferred Food
- Mirror Neurons Influenced By Cultural Spin
|
|