Tag / insects

by Roslyn

Innovative, naturally

bluegill sunfish field work

Chandra Rodgers sampling bluegill sunfish on Lake Opinicon.

This spring I had the opportunity to write a feature article on the Queen’s University Biological Station, a site just north of Kingston where researchers have a long history of major scientific breakthroughs involving modest Ontario wildlife. Several of these discoveries have proved to be as useful as they are compelling. The story was published in the Kingston Whig Standard, and on the web through the Queen’s Alumni Review and InnovationCanada.ca. Funding for photography was provided by the CFI’s 2011 Emerging Science Journalists Award.

Talking to scientists about their research was by far the best part of this project – much more fun than I expected! And even the toughest interviews were a gold mine of ideas. Thanks to everyone who participated. The full story is posted below…

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by Roslyn

A case of mistaken celebrity

They all look the same to us. Celebrities, that is. And by us, I mean academics.

The proof starts with peacocks. Last fall, I was working on some measurements I took of the crest ornament in these birds. Peafowl have this funky little fan of feathers on top of their heads, and though it’s not that small in the grand scheme of fancy bird plumage ornaments, the peacock’s five centimetre crest looks a bit ridiculous next to the metre-and-a-half long train.

Why bother having a crest when you also have a big train? And why do females wear crests too? In this species, the crest appears to be the only plumage ornament shared by both sexes. Here are some of my pictures from the field, taken on the cusp of the breeding season:

Crest ornaments of male and female peafowl

Crests of (a) male and (b-c) female peafowl. Scale bars are 10 cm. Photos by Roslyn Dakin.

Over the years, I’ve measured the crests of close to 150 birds. These data lend some support to the idea that the crest is a signal of health in both males and females, although it might work in slightly different ways for the two sexes1. As you can see from the picture above, there is a lot of variation in how the crests look – and it’s mostly on the female side of the equation. Almost all adult males have tidy looking crests like the one shown in (a), but females often have crests with a lot of new feathers growing in (c). It turns out that males in better condition tend to have fuller, wider crests. The healthiest females, on the other hand, have crests that look most like those of males, with all feathers grown out to the top level (b).

The extreme variability among females leads to an additional hypothesis, and it’s one that I can’t rule out at this time. Perhaps the crest is a signal of individual identity that the birds use to sort out who’s who in their social groups – just as faces do for us. A clue that this could potentially work for peahens is that my field assistants and I can do it. Once you spend enough time hanging around with these birds, you find yourself recognizing certain females that haven’t been captured yet (and that therefore lack identifying leg bands). Your first clue? Usually a unique pattern of crest feathers.

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by Roslyn

Groupthink

Which animal would use Facebook most, if it could?

My poll in class last week was a popular one – a fact that I couldn’t properly enjoy, since Charlie came up with it for me in a fit of brain-dead incapacity. Charlie’s Facebook question elicited chirps of excitement, compliments and even a few drawings on the response sheets. Here are the results, ranked by favour among the students:

  • Chimpanzees: So they have opposable thumbs, and can “use the spacebar” (is this actually important in Facebook?). A number of students gave bonobos special mention, since they would probably want to keep track of all their casual sexual relationships.
  • Dolphins: Highly intelligent, social, and they might also be interested in monitoring multiple sexual conquests. Dolphins and migratory whales could use Facebook to keep in touch while roaming widely over the oceans – the long-distance relationships of the animal kingdom. For some reason, students in different tutorial groups who chose dolphins were inspired to draw them for me as well. Coincidence?
  • Parrots and other birds: Especially in species that have high levels of extra-pair paternity, birds could use Facebook as a form of mate-guarding to keep tabs on their social partner1,2. There are other reasons to think that songbirds might easily make the transition to internet gossip. Female black-capped chickadees, for instance, eavesdrop on the outcome of song contests between rival males, and use this information when deciding on a mate3.
  • Eusocial animals: Like ants or naked mole rats (the only known eusocial mammal). A couple of students also mentioned highly social meerkats, since living in groups of 10-40 individuals would require them to keep track of a lot of social information.
  • Other yappy follower-types: hyenas, seals, lemmings, and Yorkshire terriers all got a mention.

Charlie and I discussed it over dinner at the Iron Duke. My first thought went to ants, for their extreme group lifestyle. The problem is that ants don’t really care about what other ants do or think about each other. Insect sociality is all about the greater good: worker ants toil away for the colony despite having no hope of reproducing on their own. Ok, so maybe the internet isn’t conducive to real reproduction either, but ants just don’t have the ego required. Plus, as one clever student pointed out, a colony of eusocial animals are all very close genetic relatives of one another – and she tends to block family members from Facebook.

Charlie mentioned peacocks for spending so much time on courtship and preening, but I rejected that one too.

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by Roslyn

Super indelible flower colours

How do you fire a pollinator?

That was the question in last week’s Ecology, Evolution and Behaviour departmental seminar. The speaker was James Thomson, an evolutionary ecologist from the University of Toronto who specializes in the interactions between plants and their animal pollinators. His research shows that nectar-addled hummingbirds are like corporate ladder climbers. Bees, on the other hand, are always getting canned.

Pollination syndromes have been a major focus of Thomson’s work1. These are not garden ailments. “Syndrome” here refers to a suite of traits that tend to be found together, in this case because they help a plant attract a certain kind of pollinator.

Bird-pollinated flowers tend to be red and tube-shaped, producing lots of nectar but relatively little scent. Birds have sharp vision, and do not depend much on their sense of smell. Honeysuckle is an example of this type of flower – or anything that looks like a hummingbird feeder. Bee-pollinated flowers come in shades of yellow, blue, and purple, because bees cannot see the colour red. Familiar examples are sunflowers, snapdragons and wild pansies. These often have petals modified into special bee landing platforms. Flowers that specialize on birds and bees are common, but there are many other pollination syndromes. If a flower is orange-brown and smells like rot, it probably depends on carrion flies. Mammal-pollinated flowers often smell fruity, like synthetic grape flavouring.

In his talk, James Thomson reviewed a decade’s worth of work on beardtongue flowers from the genus Penstemon2. In 2007, Thomson and his collaborators used genetic analyses to build the evolutionary tree for close to 200 of the species in this group3. When flower traits were mapped on to the Penstemon family tree, interesting patterns were revealed.

First, the bird and bee pollinated species were distributed broadly throughout, implying frequent transitions between these two syndromes in the history of the Penstemon group. Like an evolutionary magnet, pollination by one type of animal or another exerts a strong pull on multiple flower traits in concert. Evolving species are drawn rapidly towards a new form, so you almost never find intermediates.

This lability or changeable nature of floral traits was not much of a surprise, but the Penstemon tree also suggested something incredible. Floral evolution was directional.

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by Roslyn

How to raise a science major

The newspapers have been abuzz lately about a controversial book: Battle Hymn of the Tiger Mother, by Amy Chua, is a memoir on the rewards and perils of stereotypically strict Asian-American parenting. This week I asked students in my 4th-year biology class to tell me about their earliest memory of being fascinated with something biological, information that could be useful for parents hoping to form their children into university science majors.

And so, some lessons learned:

1. Worms work. Let your kids get close to the ground, outside. At least two students listed earthworms appearing after the rain as their most important early memory. A large portion of the class described similar encounters with tadpoles, snails, caterpillars, ants, spiders and their webs, and other minutiae found on the lawn. Larger examples of charismatic megafauna barely got a mention. Perhaps opportunity plays a role. For instance, one student remembers being particularly enamoured with deer in the backyard.

2. Pain. A wise teacher once told me that “learning hurts”. The converse might also be true: harmful organisms can be educational. An encounter with razor-sharp zebra mussels was particularly salient for one student. Another recounted a family vacation in the New Mexico desert, where a first-hand experience with cacti led to an early lesson in adaptation.

Well-armed cacti

Hidden Valley, Joshua Tree National Park, California.

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by Roslyn

Reaching the other side, in synchrony

It’s a familiar site on campus here during the first week of class: packs of jaywalkers moving in tight co-ordination, in sync with the flow of oncoming cars. From traffic lights and power grids to stereo sound and cinema, synchrony is so common in our environment that we usually only notice it when it fails. Not so with nature: the examples of synchrony in living things tend to be much more surprising to people studying animal behaviour.

Group courtship displays are a classic example. Think of chorusing songbirds in the morning or calling frogs gathered around a pool of water at night. Readers of my blog on peacock field work might be familiar with lek-mating birds gathered around a clearing to wait for females. Peacock train displays also tend to happen in sync. One traditional explanation for these co-ordinated displays is that, by synchronizing their most conspicuous behaviour, animals might gain some protection from predation1. Another possibility is constructive interference: co-ordinated timing might allow a pair of animals to spread the message farther than either one could on its own2. Two innovative new studies on animal courtship have added to this list. The first, on firefly displays, shows that synchrony might help insects recognize members of their own species by getting rid of visual clutter.

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