Clutch size in the swallowtail butterfly,Battus philenor: the role of host quality and egg load within and among seasonal flights in California

Summary Clutch size in the pipevine swallowtail of California (Battus philenor hirsuta) varies widely within and among two seasonal flights, early and late spring. Pilson and Rausher (1988) proposed that variation in clutch size in a Texan B. philenor population is due to assessment of host quality with subsequent adjustment of clutch size and to differences in motivational state. The assessment hypothesis and a nonexclusive alternative that clutch size is determined by mature egg load were tested for populations in Sacramento, California. Weak and sporadic correlations between host quality and clutch size were found, suggesting that host assessment with adjustment of clutch size is not a strong factor in this population. Clutch size was highly correlated to mature egg load in the early but not in the late spring flight. Yet, females from both flights had similar loads of mature eggs. It is proposed that females lay clutch sizes proportional to egg load, up to a maximum threshold. The threshold may be lowered in the late spring flight in response to changes in overall host quality or to increased egg predation, reducing both the mean clutch size and the correlation between clutch size and egg load. Potential mechanisms for the change in behavior among flights, based on changes in the threshold, are discussed.     

The importance of temperature in assessing iron pipe corrosion in water distribution systems

Temperature is expected to play a significant role in the corrosion of iron pipes in drinking water distribution systems. Temperature impacts many parameters that are critical to pipe corrosion including biological activity, physical properties of the solution, thermodynamic and physical properties of corrosion scale, and chemical rates. Moreover, variations in temperature and temperature gradients may give rise to new corrosion phenomena worthy of consideration by water treatment personnel.     

The evolutionary position of turtles revised

Consensus on the evolutionary position of turtles within the amniote phylogeny has eluded evolutionary biologists for more than a century. This phylogenetic problem has remained unsolved partly because turtles have such a unique morphology that only few characters can be used to link them with any other group of amniotes. Among the many alternative hypotheses that have been postulated to explain the origin and phylogenetic relationships of turtles, a general agreement among paleontologists emerged in favoring the placement of turtles as the only living survivors of the anapsid reptiles (those that lack temporal fenestrae in the skull). However, recent morphological and molecular studies have radically changed our view of amniote phylogenetic relationships, and evidence is accumulating that supports the diapsid affinities of turtles. Molecular studies favor archosaurs (crocodiles and birds) as the living sister group of turtles, whereas morphological studies support lepidosaurs (tuatara, lizards, and snakes) as the closest living relatives of turtles. Accepting these hypotheses implies that turtles cannot be viewed any longer as primitive reptiles, and that they might have lost the temporal holes in the skull secondarily rather than never having had them.     

Fluid Mechanics of Biological Surfaces and their Technological Application

 A survey is given on fluid-dynamic effects caused by the structure and properties of biological surfaces. It is demonstrated that the results of investigations aiming at technological applications can also provide insights into biophysical phenomena. Techniques are described both for reducing wall shear stresses and for controlling boundary-layer separation. (a) Wall shear stress reduction was investigated experimentally for various riblet surfaces including a shark skin replica. The latter consists of 800 plastic model scales with compliant anchoring. Hairy surfaces are also considered, and surfaces in which the no-slip condition is modified. Self-cleaning surfaces such as that of lotus leaves represent an interesting option to avoid fluid-dynamic deterioration by the agglomeration of dirt. An example of technological implementation is discussed for riblets in long-range commercial aircraft. (b) Separation control is also an important issue in biology. After a few brief comments on vortex generators, the mechanism of separation control by bird feathers is described in detail. Self-activated movable flaps (=artificial bird feathers) represent a high-lift system enhancing the maximum lift of airfoils by about 20%. This is achieved without perceivable deleterious effects under cruise conditions. Finally, flight experiments on an aircraft with laminar wing and movable flaps are presented.     

Meckel-Gruber syndrome: Prenatal diagnosis at 10 menstrual weeks using embryoscopy

A case of Meckel—Gruber syndrome was diagnosed by embryoscopy at 10 menstrual weeks, allowing for early termination of pregnancy. Post-mortem examination confirmed the presence of polydactyly and bilateral cystic lesions of the mesonephros and metanephros. Both the forming nephrons and the collecting ducts were involved in the formation of renal cysts.     

Sulfate as tridentate ligand

Dedicated to Professor H. J. Berthold, Hannover, on the occasion of his 65th birthday.     

Toward a psychological and cultural model of downsizing

Organizational downsizing is often counterproductive and applied irrespective of past financial performance. The popularity of this tactic leads to the question of whether an executive's propensity to downsize is linked to characteristics such as uncertainty avoidance and risk tolerance, which can be examined at either an individual or societal level. Copyright © 2005 John Wiley & Sons, Ltd.     

Sustainable Human Resources in a Protected Area in Southwestern Gabon

Abstract: In central Africa, where governments and funding agencies cover only a fraction of the recurrent expenditures needed to effectively manage the protected-areas network, it is essential to invest in the people who will be called on to participate in conservation efforts over the long term. In the Gamba Protected Areas Complex in southwestern Gabon, we analyzed the perseverance of all those who participated in training sessions, held since 1996, in ecological survey techniques and in participatory rural appraisal (socioeconomic studies). Of government agents who attended the respective training sessions, 7.7% continued ecological surveys and 0% continued participatory rural appraisal 2 years after training. However, 76.2% and 60.0% of the members of local communities who received training were still active in ecological surveys and participatory rural appraisal respectively after 2 years. Definitive conclusions regarding the participation of nongovernmental organization members cannot be drawn because of the low number of initial participants in the training programs. Based on our results, village collaborators seem to be a more "sustainable" human resource than government agents or of nongovernmental organizations members. Even though local communities cannot be solely responsible for managing protected areas, today's conservation professionals must acknowledge the strengths and limitations of village collaborators. Implementing a process involving the participation and the emulation of community members is a demanding task because protected-area managers must be based in the field to identify key individuals and to organize intensive training sessions. Also, constant support must be provided during the first years, and then the most capable and motivated collaborators will be able to pursue further training and work their way up through the ranks of the protected area's organizational structure.