February 10, 2012 : Stuart Altmann. Abstract: Optimal foraging theory (“OFT”) was born in 1966 with the simultaneous publication--in the same issue of American Naturalist, vol. 100--of two article on this topic, one by Robert MacArthur and Eric Pianka, another by John Emlen. Both articles took maximizing energy intake rate (e/t) as the central issue in foraging. These two complementary articles by three outstanding ecologists set off a flurry of research, both empirical and model-based. During the next few decades, the number of publications per year on optimal foraging theory grew exponentially, making foraging probably the most intensively studied mode of animal behavior.
The rise and fall of optimal foraging theory.
Curiously, about two decades later, the OFT publication rate began a precipitous decline, one still underway despite the continued growth in foraging behavior’s overall publication rate (Perry & Pianka 1997). I suggest several reasons for this decline, including (i) the almost universally poor fit of data to OFT models, (ii) “the fast-food fallacy,” (iii) lack of a method for maximizing the objective function such as e/t, of a linear optimization problem in which both numerator and denominator are random variables, (iv) regarding OFT models as descriptive rather than normative, that is, as predictions of what foraging animals do rather than predicting the consequences of deviations of their behavior from its optimum, and (v) development of ever more recondite OFT models.
February 24, 2012 : Noam Miller. Abstract: Members of groups that can combine their individual information when making collective decisions can sometimes solve problems in ways that solitary individuals cannot. This is sometimes called ‘swarm intelligence’ (SI). I will present some data demonstrating SI in groups of Golden shiners (Notemigonus crysoleucas). Using the trajectories of the fish we can show how information is combined in these groups and find who the most influential fish are.
Mechanisms of Collective Decision-making.
March 2, 2012 : Julia Pilowsky. Abstract: Song is an important mode of communication that mediates many social behaviors in birds, including territorial defense, dominance interactions, and coordination of nesting activities. Male bird song can be complex and it is often used during reproduction for territorial defense or mate attraction. Female song, however, is generally less complex and used less frequently than in males, and its function in most species is poorly understood. In cooperatively breeding species where both males and females compete intensively for mates, social rank, or other resources, female song may be as complex as in males. We examined in Kenyan male and female cooperatively breeding superb starlings (Lamprotornis superbus) to determine the degree of elaboration of this secondary sexual character in males and females. Consistent with predictions about enhanced selection on female traits due to intrasexual competition, we found high complexity in both male and female song, and that repertoire composition changed with age in both sexes. Although components of the song were similar between the sexes, there were some differences, as female song was lower-pitched than male song. These findings suggest that like male song, female song can develop and change over time, and it may be an important signal in many social species where intrasexual competition is generally high.
Female Song as a Secondary Sexual Character in a Cooperatively Breeding Starling.
March 16, 2012 : Ruthie Birger & Molly Schumer. Abstract: Four ant species form mutualistic relationships with the obligate myrmecophyte Acacia drepanolobium. Dominance structure in competitive ability (Crematogaster sjostedi > C. mimosae > C. nigriceps > T. penzigi) results in more dominant species inhabiting older A. drepanolobium trees. However, the most dominant species against other ants is one of the poorest defenders of the tree from herbivores. Recent research has suggested that all three Crematogaster species inflict substantial costs on their host and reduce investment in tree defense when herbivores are absent. We investigate the distribution of a species of parasitic midges targeting A. drepanolobium. We find that trees inhabited by C. nigriceps are significantly less likely to be infested with parasitic midges, and that this is may be due to behavioral differences between species. We show that while C. mimosae responds more vigorously to simulations of a large mammalian herbivore, C. nigriceps is more aggressive towards insect herbivores. In addition, trees inhabited by C. nigriceps had significantly fewer insect residents than trees inhabited by other species. This suggests that the behavioral response of C. nigriceps may be responsible for the correlation between this species and protection of A. drepanolobium from parasitic midges.
Parasitism, Mutualism, and Defensive Behavior in an Ant-Plant System.
April 13, 2012 : Emma Fuller.
Extracting animal behavior from camera traps: can it work?
Abstract: Wildlife/cattle interactions are a constant source of strife for conservationists and rangeland managers. Historically these interactions are assumed to be negative, resulting in a trade off between cattle and wildlife use of habitat. More recently the heterogeneity in landscape caused by cattle (namely glades derived from temporary predator exclosures) has been shown to be beneficial for wildlife and cattle, through increased nutrient levels in forage.
These glades typically last for decades, and there's evidence that wildlife input through dung and urine maintain the high nutrient levels. I'll present novel methodology for testing the mechanisms behind the glade maintenance: extracting animal behavior from camera traps. These pictures present more detail of animals' habitat use, and allow us to make comparisons across soil types and herbivore communities to understand whether palatably of grasses or predator avoidance may drive glade maintenance and under what conditions they do so.
April 20, 2012 : Carl Zimmer.
A Planet of Viruses : Exploring the True Diversity of Life on Earth.
Special IBRG. 1:30pm. Guyot 10.
April 27, 2012 : Henry Horn.
Searching for Sex and the Ivory-billed Woodpecker.
Abstract: I shall Show&Tell a modified NetLogo Procedure that I originally wrote to examine mate-finding behavior in Butterflies, specifically the Inornate Ringlet (Coenonympha tullia), whose males fly seemingly at random "looking for" females, while the females tend to sit tight after eclosion but before mating. The very few successful encounters that colleague Diane Weirnasz and I witnessed were all initiated by the female launching to meet an approaching male. More about that when I publish the book "Social Butterflies" that I have been working on off-and-on for the past quarter of a century.
On April Fool's Day in 2012, while reading Tim Gallagher's enthralling "The Grail Bird," I suddenly realized that my Butterfly model could be used to explore strategies for discovering the Ivory-billed Woodpecker, if it still survives. The basic question addressed is: Given that the Ivory-bill can traverse its territory far faster, and with massively less discomfort and energy expenditure than an Ornithological Searcher, what balance should the Searcher adopt between slogging through the swamp versus sitting tight in an easily accessible part of the right habitat?
Mind you, neither agent, Bird nor Human, moves at random and with equal probability of visiting each unit of land. So it is likely worthwhile to slog through the swamp to map out places that might have a higher probability than average of being visited by an Ivory-bill, e.g., roost holes, recent diggings and bark-peelings, nest holes, and trees infested with large wood-boring insects that are the prospective food of the Ivory-bill. And those are prime sites to spend a lot of time, ... but even then, how much should the Searcher explore their vicinity in active movement?
The technical result may not surprise technical folk, but the model may have heuristic and/or rhetorical value for others. I shall also speculate about what natural history and biomechanics may say about where to look for Ivory-bills before they get there (cf. Pooh, Piglet, and the Heffalump Trap).
May 4, 2012 : Tim Linksvayer.
How do social interactions affect social insect trait expression and evolution?
Abstract: Individuals within insect societies are so tightly knit together by social interactions that social insect colonies are often described as “superorganisms”, with colony-level properties that are analogous to organism-level properties. For example, group-level activity patterns are regulated via chemical communication among individuals, analogous to endocrine regulation of tissue activity within organisms. I will discuss ongoing ant and honey bee research that seeks to understand how social interactions affect the expression and evolution of individual- and group-level traits.
May 11, 2012 : Stuart Altmann.
How to Evaluate Binoculars.
Abstract: Binoculars are one of the universal tools of those who study animals in the field or are just casual birders. In choosing which binoculars to buy, many important characteristics of binoculars can be compared in the store without access to any specialized equipment, e.g., magnifying power, central focusing with independent adjustment of one ocular, width of field of view, flatness of field, spherical aberration, chromatic aberration, collimation, interocular distance, minimal focal distance, eye-cups that are soft and retractable, low mass, good grip, whether the binoculars are humidity-proof and rain-proof, and of course, price. Some of this information can be obtained from websites that provide technical reviews of binoculars, e.g., www.birds.cornell.edu/Publications, LivingBirds/Winter2005/ Age.Binos.html, and www.birdwatching.optics/2010. Some is provided by manufacturers.
Bring a pair of binoculars to this IBRG meeting to get some practice at these tests.