George Middendorf

Canid elicitation of blood-squirting in a horned lizard (Phrynosoma cornutum)

In staged, predator-prey encounters between Texas horned lizards, Phrynosoma cornutum, and a canid, Canis familiaris, 47 of 55 lizards (85%) squirted blood from orbital sinuses. The probability of blood-squirting was not significantly affected by either (1) lizard body temperature (low, 85% vs high, 100%) or (2) time of day (diurnal, 70% vs nocturnal, 70%). A canid was more likely to elicit blood-squirting (100%) than a canid-mimicking human (20%). When the canid was restrained from direct contact, blood-squirting did not occur, but when lizards were simultaneously subjected to human tactile stimulation, 20% squirted blood. Lizards responded similarly to canid saliva and distilled water, implying that saliva does not provide cues used in the discrimination of canids. Overall, tactile cues appear to play a significant role in the elicitation of blood-squirting. Because roadrunners and grasshopper mice are known to not elicit blood-squirting in predator-prey encounters, these data support the canid antipredator defense hypothesis as an explanation of this unique behavior. Blood-squirting appears to be a context-dependent reptilian antipredator display in which elicitation of the squirting response is determined by predator type.

Responses of Kit Foxes (Vulpes macrotis) to Antipredator Blood-Squirting and Blood of Texas Horned Lizards (Phrynosoma cornutum)

Abstract Six related studies were conducted with four captive juvenile Kit Foxes (Vulpes macrotis) to test the hypothesis that blood-squirting from eye-socket tissues by Texas Horned Lizards (Phrynosoma cornutum) is a canid antipredator defense. In 16 trials, naive “hungry” foxes killed and ate adult Yarrows Spiny Lizards (Sceloporus jarrovii; eight of eight trials) slightly more frequently than adult P. cornutum (six of eight trials). Adverse responses by foxes (head shaking) were seen in five of six trials in which Phrynosoma squirted blood. Later these experienced foxes, fed ad libitum, killed and ate mice (eight of eight trials) while largely ignoring P. cornutum (one killed and eaten in eight trials), suggesting a learned aversion to horned lizards as prey. During attacks on mice smeared with horned-lizard blood, foxes displayed behaviors typical of predatory encounters with horned lizard prey (head shaking and prey tearing). These prey-handling behaviors were in striking contrast to those elicited by untreated mice and by mice treated with mouse blood, demonstrating that horned-lizard blood (and its chemical constituents) altered normal behaviors toward mouse prey. Prey-handling times for mice treated with horned lizard blood were significantly longer than mouse-only treatments. Responses of foxes to mice coated with horned lizard Harderian- and lacrimal-gland tissues coupled with responses to mice coated with systemic horned-lizard blood, mouse blood, and untreated mice suggest that (1) no defensive chemicals are added to the blood by orbital glands before blood ejection, and (2) active antipredator chemicals are carried in the circulating blood as well as in squirted blood. In four trials, foxes attacked “de-horned” horned lizards; a role for cranial horns in facilitating predator hesitancy prior to blood squirting is proposed. Evidence is presented that horned lizards visually identify and categorize foxes as appropriate predators for a blood-squirting defense. We conclude that, in many predator-prey encounters with wild canids, blood-squirting by Texas Horned Lizards is an effective chemical defense. We propose a scenario for the evolution of this unique defense and suggest that the defensive compounds found in the blood may be sequestered from the seed-harvester ant prey of horned lizards.

Blood-Squirting Variability in Horned Lizards (Phrynosoma)

Abstract Variability within the genus Phrynosoma in the occurrence of ocular-sinus blood-squirting, reportedly a defense used in canid encounters, is reviewed from the literature. Six species have been reported to squirt blood, and seven species remain unreported. Five of the latter species were tested in dog trials; one exhibited blood-squirting (Phrynosoma hernandesi), one exhibited precursor behaviors but failed to squirt blood (Phrynosoma ditmarsi), and three yielded negative results (Phrynosoma mcallii, Phrynosoma modestum, and Phrynosoma platyrhinos). Instances of blood-squirting in response to human encounters were collected and largely support the negative results for the three species P. mcallii, P. modestum, and P. platyrhinos. A phylogeny of blood-squirting and nonblood-squirting species is presented with blood-squirting being plesiomorphic in the genus and the synapomorphic condition of nonsquirting species being restricted to a single clade of P. mcallii-modestum-platyrhinos. The possibility of P. douglasii independently evolving an autapomorphic condition remains unresolved. Dog trials with 40 adult Phrynosoma cornutum were conducted to determine influences of body size and sex on squirt frequency and blood mass expelled, as well as to examine aspects of the potential physiological cost of the defense. In 153 trials, 85% of all lizards squirted in at least one trial, 82% squirted in more than one trial, and two lizards squirted daily over the seven-day trial period. Initial body mass positively correlated with the total number of squirts/individual (r2 = 0.28; P < 0.001) and the number of days a lizard continued squirting (r2 = 0.63; P < 0.01). Number of squirts/individual/day declined over the seven-day trial period (r2 = 0.20; P < 0.05). Cumulative mass loss for individual lizards attributable to blood-squirting averaged 0.7 ± 0.8 g (2.0 ± 2.0% body mass), with a high of 2.8 g (6.8% body mass). In addition, juvenile P. cornutum and P. hernandesi were shown to squirt blood in dog trials, illustrating the early developmental onset of the behavior.

Responses to snake odors by laboratory mice

Male and female laboratory mice (Mus musculus ; Harlan Sprague Dawley) were tested for reactions to snake odors. In the first experiment, mice were presented with untreated paper on the floor of one side of a test tank and snake-scented or control (water misted) paper on the other side. The scented papers were obtained from rough earth snakes (Virginia striatula ), which were fed earthworms, and a rat snake (Elaphe obsoleta ), which ate mice. Male mice exhibited no differences in response to the three conditions. Female mice showed no response to the control or earth snake odor, but they deposited significantly more fecal boli on the side of the tank with the rat snake odor than on the blank side. No significant differences in other behaviors, e.g. ambulation, were detected. In the second experiment, female mice were offered food pellets treated with the shed skin extract of the rat snake or with a solvent alone. Less material was bit off and consumed from the snake-scented pellets. The results of both experiments indicate that female mice detect the odors of rat snakes.

Introducing Survival Ethics into Engineering Education and Practice

Given the possibilities of synthetic biology, weapons of mass destruction and global climate change, humans may achieve the capacity globally to alter life. This crisis calls for an ethics that furnishes effective motives to take global action necessary for survival. We propose a research program for understanding why ethical principles change across time and culture. We also propose provisional motives and methods for reaching global consensus on engineering field ethics. Current interdisciplinary research in ethics, psychology, neuroscience and evolutionary theory grounds these proposals. Experimental ethics, the application of scientific principles to ethical studies, provides a model for developing policies to advance solutions. A growing literature proposes evolutionary explanations for moral development. Connecting these approaches necessitates an experimental or scientific ethics that deliberately examines theories of morality for reliability. To illustrate how such an approach works, we cover three areas. The first section analyzes cross-cultural ethical systems in light of evolutionary theory. While such research is in its early stages, its assumptions entail consequences for engineering education. The second section discusses Howard University and University of Puerto Rico/Mayagüez (UPRM) courses that bring ethicists together with scientists and engineers to unite ethical theory and practice. We include a syllabus for engineering and STEM (Science, Technology, Engineering and Mathematics) ethics courses and a checklist model for translating educational theory and practice into community action. The model is based on aviation, medicine and engineering practice. The third and concluding section illustrates Howard University and UPRM efforts to translate engineering educational theory into community action. Multidisciplinary teams of engineering students and instructors take their expertise from the classroom to global communities to examine further the ethicality of prospective technologies and the decision-making processes that lead to them.

Survival Ethics in the Real World: The Research University and Sustainable Development

We discuss how academically-based interdisciplinary teams can address the extreme challenges of the world’s poorest by increasing access to the basic necessities of life. The essay’s first part illustrates the evolving commitment of research universities to develop ethical solutions for populations whose survival is at risk and whose quality of life is deeply impaired. The second part proposes a rationale for university responsibility to solve the problems of impoverished populations at a geographical remove. It also presents a framework for integrating science, engineering and ethics in the efforts of multidisciplinary teams dedicated to this task. The essay’s third part illustrates the efforts of Howard University researchers to join forces with African university colleagues in fleshing out a model for sustainable and ethical global development.

Maturation characteristics of Rubus pennsylvanicus fruit: are black and red the same?

SummaryFruit of the blackberry, Rubus pennsylvanicus Poir. (Rosaceae), were examined to determine variation in maturation characteristics. Maturation timing and rate varied greatly among individual fruits, resulting in a bi-colored fruiting display comprised largely of two maturation stages, pre-ripe (salmon and scarlet) and ripe (dark brown and black). While ripe fruit were generally larger and heavier than pre-ripe fruit, exhibiting greater fresh and dry fruit weight, diameter, water content, and total seed weight, no significant differences were found in energy content, i.e. numbers of calories per gram pulp, or in pulp:seed ratio. The differences between ripe and pre-ripe fruit appear to be due largely to an increase in water content and seed weight with maturity. The fact that little energetic benefit accrues to the preferential selection of ripe fruit suggests that bi-colored Rubus displays may be considered to be unicolored.

Add ecology to the pre-medical curriculum.

In their Letter “Competencies: A cure for pre-med curriculum” (11 November 2011, p. [760][1]), W. A. Anderson and colleagues endorse a proposed shift in pre-medical education toward core competencies. We believe that the specific competencies proposed by the Association of American Medical

African philosophy: a key to African innovation and development

This essay demonstrates how African philosophy can be a key to African innovation and development. Its first section illustrates how philosophy as a discipline drives innovation in science and technology. The second part proposes a new discipline linking science, engineering and technology to sustainable, ethical development. The third section proposes an ethics core derived from ancient Egyptian and Ethiopian thought. It addresses the fact that non-African principles and personnel have in some measure directed African development, resulting in unsustainable and sometimes destructive outcomes. The conclusion argues that the primary instrument for African development must be a Pan-African curriculum developed through research funded by the African Union. The curriculums dissemination will depend on widespread broadband internet access throughout Africa. The essays method is philosophical, deploying conceptual analysis of key terms as well as generalized descriptions of the intersections of science, technology, innovation and development. The essay proposes prescriptions for developing relations among these fields for the theory and policy of African development. This study is empirical in the sense that philosophy offers broad generalizations about experience. However, it does not examine data-sets characteristic of more specifically targeted scientific descriptions.

NOCTURNAL ACTIVITY BY DIURNAL LIZARDS (SCELOPORUS JARROVI, S. VIRGATUS) EATEN BY SMALL OWLS (GLAUCIDIUM GNOMA, OTUS TRICHOPSIS)

Abstract Whiskered screech-owls (Otus trichopsis) and northern pygmy-owls (Glaucidium gnoma) delivered freshly caught Yarrows spiny lizards (Sceloporus jarrovi) and striped plateau lizards (S. virgatus) to nestlings from dusk to dark in southeastern Arizona. This observation stimulated studies of the prey deliveries by the owls and lizard activity patterns, because the lizards are not known to be nocturnal. Lizards were more frequent prey of both owls than endothermic vertebrates but infrequent compared to arthropods, a pattern in the pygmy-owl that differs from its northern populations. Yarrows spiny lizard, the most abundant and frequently captured lizard, was most active in the morning but also active in the evening. Striped plateau lizard, the second most abundant and depredated species, had morning and evening peaks of activity. Few lizards, including S. clarki and Urosaurus ornatus, but not Cnemidophorus exsanguis and C. sonorae, were active at or after dark, when relatively few were captured by the owls.