Monthly Archives: September 2009

Aggressive mimicry

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I just ran across an interesting New Scientist article on an Australian katydid that is an acoustic aggressive mimic.

Aggressive mimicry is a form of mimicry where predators, parasites or parasitoids share similar signals with a harmless model, allowing them to avoid being correctly identified by their prey or host. *

The Spotted Predatory Katydid, Chlorobalius leucoviridis, imitates a female cicada’s reply to the male’s song.

Marshall_katydid

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By 2008, Marshall and Hill had recorded more than 30 minutes of cicada-katydid duets. The songs varied from very simple with just one sort of cue to the virtuoso, with long introductory passages followed by complex cueing sections. Cues ranged from a simple isolated “tick” to a passage lasting nearly 2 seconds (see diagram). None of this seemed to faze the katydids. They could respond correctly to 22 of the 26 species tested, and for 18 of these, they got it right more than 90 per cent of the time (PloS ONE, DOI: 10.1371/journal.pone.0004185). *

And once again (flipping the bird in passing to a truly stupid idea) we see the dance of predator and prey driving evolutionary changes:

Marshall and Hill suspect that in the case of Cicadettini cicadas, predation could be one of the forces driving change, as they engage in a sort of musical arms race to outwit spotted katydids. “Some songs are very complex with short phrases that look like cues. Katydids click after them – but female cicadas never do,” says Hill. “These could be false cues to trick the katydid into giving itself away.” As katydids cotton on to the false cues, then the cicadas must lay more traps to keep one step ahead of their predators, speeding the rate of song evolution and perhaps explaining why some songs are so extraordinarily complex. *

For more aggressive mimicry fun, let me recommend, once again, Bruce Sterling’s saga of Photinus vs. Photuris: Luciferase (link is via the Wayback Machine, so formatting may leave something to be desired).

Teckelmania II – The Puppening

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On the way back from an open house the NH Falconers Assoc. put on for National Hunting and Fishing Day, I stopped by to see Lotte. The litter is 16 days old – eyes and ears are open and they are starting to explore a bit. Mom is feeling a bit needy – fine by me – I don’t mind giving her some pats.

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Her call name will (obviously) be Lotte; short for Lotte Feist or Löttë Ümlaüt – as the fancy strikes me.  A side note, revealing either what a dog person I am or how clueless I am (or both): a year or so ago I heard a song on the radio I liked quite a bit (My Moon My Man). When I found out the name of the band/artist (still clueless) – Feist – I thought it was interesting but a little dissonant – the music didn’t match the big attitude I associate with feists. Oops.

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A shot from the open house – a gyr taking advantage of an alternative perch, with a sakeret and a line of peregrines behind her.

A year from now

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microcosm

“Tree Walkers International is proud to present Microcosm, a celebration of life under glass.  Microcosm is a new kind of event that brings enthusiasts together through the common bond of nurturing life within glass enclosures, from aquaria to vivaria, greenhouses and Wardian cases.

The theme of Microcosm is conservation.  Just as species combine to form healthy, functioning ecosystems, Microcosm seeks to form a coalition of partners who apply their skills in cooperation to safeguard the planet’s biodiversity.

Microcosm is a two-day event that includes field trips, lectures, workshops, and a sale.  All proceeds benefit Tree Walkers International to support amphibian conservation efforts.”

September 3-4, 2010, Lynnwood WA. More info here.

Atlatls and Flint-knapping

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Boy, I wish I could scoot off to this:

September 19: Fourteenth Annual Northeastern Open Atlatl Championship & Chimney Point Knap-In and Festival of Nations
Participate in or watch this annual championship, part of the Festival of Nations with the Crown Point, NY, State Historic Site. The sport of atlatl throwing is based on the ancient hunting technique of using the atlatl or spear thrower. Flint knapping and other Native American life and craft demonstrations. Festival of Nations. Top Ten Vermont Fall Event. Co-sponsored by Vermont Archaeological Society. Vermont Archaeology Month program. Camping available at DAR State Park. 10:30 – 4:30 PM.
Where: Chimney Point State Historic Site, Addison directions
Contact: ChimneyPoint@HistoricVermont.org

September 20: ISAC Atlatl Championship
Second day of atlatl International Standard Accuracy Competition. The Knap-in and Festival of Nations continues. After ISAC, master class/coaching for boys and girls. 10:00 AM.
Where: Chimney Point State Historic Site, Addison directions
Contact: ChimneyPoint@HistoricVermont.org

Info from here.

Take me to the river

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Via Bruce S comes this very nice ubicomp project.

Amphibious Architecture submerges ubiquitous computing into the water—that 90% of the Earth’s inhabitable volume that envelops New York City but remains under-explored and under-engaged. Two networks of floating interactive tubes, installed at sites in the East River and the Bronx River, house a range of sensors below water and an array of lights above water. The sensors monitor water quality, presence of fish, and human interest in the river ecosystem. The lights respond to the sensors and create feedback loops between humans, fish, and their shared environment. An SMS interface allows citizens to text-message the fish, to receive real-time information about the river, and to contribute to a display of collective interest in the environment. *

AMPHIBIOUS_2-web

Fish Sensor from xDesign Project on Vimeo.

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Also – augmented reality seems poised for a big takeoff – at least buzz-wise. I’ve been seeing AR posts everywhere (especially on Bruce S’s blog); like ubicomp, AR makes info in one’s surroundings more accessible. Maybe spoken word:writing::5 senses:augmented reality?

Pelvicachromis

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I’d mentioned in an earlier post that I had a (presumed) pair of Pelvicachromis sacrimontis in my West African streambank tank. Well, I think I was wrong on both counts. I lost one of the fish to aggression; my guess is that I had two males. Off I went to see if I couldn’t do better on gender selection – this time I brought home three fish, both to improve my chances and to diffuse the aggression. I put the resident male into the filter (one of the nice things about the filter set-ups on the tanks – they provide nice spaces to isolate fish in) and, after a short quarantine, popped the three noobs into the tank. Today was the day I reintroduced the original and what fireworks! Two of the new fish went into full fledged courtship mode – clearly female – and the male responded. The dominant female and the male are house hunting while the sub-dominant female is trying to play homewrecker. The fourth fish (possible male) is just trying not to be noticed. The second count I think I was wrong on was species. Though they were sold to me as sacrimontis, the spots on the dorsal and caudal fins make me think pulcher – the good ol’ krib (Dan, you were right). I’m not complaining – they’re very pretty and quite entertaining.

The male.

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Dominant female.

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The females, sparring.