SIERRA DOME SPIDER
I thank the late Dr. Allen Stokes for getting me started on my decades of sierra dome spider research. I took his 8-week field course in animal behavior at Flathead Lake Biological Station in the summer of 1980. Dr. Stokes' intelligence, indefatigable curiosity, love of nature and observation, and his unwavering encouragement, got me started on a project that continues to profoundly influence my personal and professional life.
The complex life of the sierra dome spider, the Darwinian algorithms natural selection has programmed into its tiny nervous system to deal with so many challenges to its survival and reproduction, has given me a fantastic window, so wide open, straight into the heart of nature. Throw open that window for yourself. Deeply get to know the evolutionary behavioral ecology of some wild yet observable creature, in nature. While you work, scientifically, take time to ponder as well, and let the purifying breeze that flows through your mind gradually clarify your view of what it means to be a product of natural selection. Get sober. I dare you, go taste the "awesomeness" of the real.
There are so many other extraordinary individuals to thank for enabling me to become a naturalist and a Darwinian, but my doctoral and postdoctoral mentors (see above) are the most important. Teachers I encountered in the Gurdjieff Work also have been vital to my development. Without these people, I cannot even imagine what my my inner and outer life would consist of - probably little. Special thanks also to J.A. Baker, for his amazing book, "The Peregrine," and Shunryu Suzuki, for "Zen Mind, Beginner's Mind," which were especially important in irreversibly activating my thirst, early in life, for views from the real world.
The over arching interest in my animal research is intersexual conflict, and understanding the complimentary behavioral, morphological, and physiological products of antagonistic intersexual arms races over control of the opposite sex as a reproductive resource. I perform interdisciplinary studies of invertebrates designed to reveal the information content of sexual signals, and thus the adaptive significance of decision rules based on these sexual signals (1) in choosing mates and, (2) as a separate issue specific to female choice of sires, in determining which mates actually fertilize eggs, and so contribute genetically to offspring. Another major research focus is the adaptive significance of multi-male mating by females. A third emphasis has been to study the rules and information processing that informs decisions by males concerning how hard to fight over access to specific females. Methodologically, my research is rooted deeply in observation and experimentation in nature. However, it also includes laboratory components involving carbon dioxide and oxygen respirometry to measure individual variation in metabolic capacities and rates of aging, as well as morphometric analysis to quantify variation in developmental competence via measures of fluctuating asymmetry. These aspects of my research help me to understand how sexual signals convey information about fundamental aspects of individual viability that, genetically and epigenetically, impact the reproductive success of offspring.
More specifically, my ongoing sierra dome spider studies seek to elucidate: (1) the information content of male and female courtship signals and cues, (2) the conditionality of choice mechanisms and sexual preferences, (3) trade-offs amongst sexual preferences, (4) the importance of antagonistic coevolution with diseases in its effect on the evolutionary dynamics of mate choice, (5) the use of polyandry as a tactic to mitigate problems of intersexual competition, harassment, and mate selection, and (6) the multivariate decision rules males use to modulate their fighting behavior and intersexual courtship intensity. I continue this work primarily at the University of Montana's Flathead Lake Biological Station.
In my research on the metabolic capacities demonstrated by male sierra dome spiders during their elaborate strenuous copulatory courtship, I have found that both metabolic efficiency (microwatts consumed per unit of courtship performance) and maximum metabolic rate (sustainable aerobic capacity) are positively selected by females. Two overt male traits independently predict fertilization success, body mass and copulatory vigor (measured as intromission rate - the number of separate genitalic connections made by the male per unit time during copulatory courtship). Metabolic efficiency is correlated with male body mass (even after compensating for the expected allometric relationship) and aerobic capacity with copulatory vigor.
Interestingly, due to some fundamental physiological trade-off (maybe to do with accelerating rates of oxygen free-radicals with increasing metabolic rates) efficiency and maximum metabolic rate are negatively correlated in the general male population. By simultaneously selecting positively for both of these traits, females are effectively shopping for the least negative trade-off between these two viability-enhancing physiological traits. In other words, by cross-referencing body mass and courtship performance, females are sexually selecting for metabolic power: the maximum rate at which the male can perform useful metabolic work (as opposed, for example, to "work" wasting calories in the production of heat or unnecessary movement.
My respirometric studies also suggest that males sierra domes that are more sexually competitive early in life, have more rapid rates of physiological senescence (as measured by their resting and active metabolic rates). Rates of aging of prospective sires may be a major issue for female sierra dome spiders. In my study population, variable proportions (up to 85 percent!) of gravid females die each year just before they are able to oviposit. They apparently succumb just a bit too early to a rickettsial disease, but their susceptibility may be related to their level of senescence.
While a given female's sons can hope to reproduce early in adult life, and so not have their reproductive fitness threatened by the sexual competitiveness/senescence rate trade-off, daughters may be reproductively crippled by genes received from of a rapidly aging father because females always need to live long to have a chance to yolk up a sizeable clutch of eggs. Early reproduction is not an option for females, so they cannot easily escape the competitiveness/senescence rate trade-off. Thus, to protect their daughters, female sierra dome spiders may need to resist always mating with only the most sexually impressive males in the population, especially early in the mating season before the ravages of aging have taken their toll on the super studs of the population.
Shorter term insect studies include environmentally determined mate choice criteria and the energetics of intersexual conflict in Mormon crickets and water striders, the energetics of feeding preferences in a seed-eating bug, sensory and behavioral adaptations for facultative hematophagy in a sap-sucking plant bug, and the ecological and life history correlates of ritualized versus injurious competitive sexual displays in microlepidopteran moths.
I also have a long-standing interest in human evolutionary psychology. Here is a an excellent introduction to evolutionary psychology specifically geared to understanding the evolution of violence in humans and other animals, including especially intraspecific violence. Humans are built to be intensely curious about the workings of the minds of others. We instinctively hunger for insights into "what makes others tick," so to say, that allow us to predict and influence (manage) the operation of the minds and hence behaviors of fellow humans. Whether the relationship is loving or ruthlessly exploitative, our biological fitness depends on turning members of our social group, as much as possible, into components of our "extended phenotype" (sensu Dawkins, 1999). Less commonly, people also are non-superficially curious about their own minds, and the hyper-subjective self-models and world-models our minds create "for us." Behavioral ecology is essentially the analysis of animal and human mental design from the combined perspectives of ecology and evolutionary biology. The analyses conducted by evolutionarily-oriented students of behavior often include efforts to elucidate the functional design of a specific component of the subject species' mind (i.e., how it gathers and processes information relevant to a specific fitness-related opportunity or threat, and why it responds, contingently, with certain behavioral outputs), as well as the fitness consequences and phylogenetic history of mental design.
I am a member of the University of New Mexico's Human Evolutionary Behavioral Sciences faculty. Generally, I am interested in developing evolutionarily principled conceptual models of human intrapsychic organization. I am especially fascinated by the adaptive function(s) of conscious experience. I seek fuller understanding of how unconscious information processing and regulatory mechanisms dynamically and "transparently," on a moment-to-moment basis, influence the cocktail of subjective and objective content and emotional colorings of our conscious experience. As a window into the organization and regulation of subjective experience, and as a fascinating phenomenon in and of itself, the evolution of religiosity is a longstanding special interest of mine.
I continue to work up accumulated data from many years of field and lab studies of the sierra dome spider for publication. Most of the work remaining to be published concerns the energetics of copulatory courtship and what it suggests about the female sierra dome's strategy for selecting sires for their offspring offering good genes for high metabolic and developmental competence. This summer (July 2014) I will be in Montana collecting data on a male behavior that often may have been missed during earlier work, entailing quick departures from the webs of non-virgin females in the middle of the day, even sometimes when the female is showing sexual receptivity. Another project left to be done would use morphometric techniques examine male sierra dome facial features, documented in hundreds of photos, related to mating and fertilization success in the field. And there is much more to be done - I am looking for an heir to this study system. If you are looking for a wonderfully observable and fascinating creature to study for a a PhD or Post doc, and possibly a whole career, let me know. I'll give you a personal introduction to sierra domes and get you massively kick started!
