Oviposition specificity in single vs. cluster egg-laying butterflies: a discrimination phase in Colias eurytheme?

Summary Oviposition preferences and rates of the pierid butterfly Colias eurytheme were examined in laboratory tests. Oviposition rates with only a non-preferred host plant present were not lower than rates observed when both preferred and non-preferred hosts were present. There was no correlation between strength of preference in simultaneous choice tests and the extent to which oviposition rate declined when the preferred host was absent. The results are consistent with the hypothesis that butterflies which lay their eggs singly will accept non-preferred hosts for oviposition more readily than cluster egg-layers.     

Limbs vs. Jaws: Can They Be Compared?

Current experimental research on mammalian limb muscle structureand function is compared to that on mammalian jaw muscles. Twomajor areas of comparison are stressed: structural and functional.Comparisons of limbs and jaws are made from the point of viewof the impact of recent studies on simple mechanical modelsof limb/jaw muscle function. Limb muscle structure is comparedto jaw muscles at the level of muscle architecture, muscle histochemicaland motor unit properties, and the organization of motor unitsinto neuromuscular compartments. Such comparisons reveal thatalthough limb muscles and jaw muscles might be organized insimilar ways, fundamental differences exist, both in terms ofmuscle structure and the functional conclusions which have beenbased on studies of muscle structure. The comparisons also demonstratethat much recent evidence from structural studies have had littledirect impact on simple models of muscle function but a muchlarger influence on the assumptions of the models. Comparisonsof limb/jaw muscle function from kinematic and EMG studies,indicate that many masticatory strategies are used by differentmammals but the basic problems of posture and locomotion havebeen met with essentially similar solutions, even among diversemammalian groups. The results of such comparisons demonstratethat both limb and jaw muscle function are sufficiently complexthat new or re-vitalized models are needed if the relationshipbetween structure and function are ever to be understood.     

Collections‐based systematics and biogeography in the 21st century: A tribute to Dr. Vicki Funk

This special issue honors Dr. Vicki Ann Funk (26 November 1947 – 22 October 2019), who passed away after a battle with an aggressive cancer (Fig. 1). Dr. Funk was a Botanist at the Smithsonian Institution in 1981–2019.     

Sewall Wright’s adaptive landscapes: 1932 vs. 1988

Sewall Wright introduced the metaphor of evolution on “adaptive landscapes” in a pair of papers published in 1931 and 1932. The metaphor has been one of the most influential in modern evolutionary biology, although recent theoretical advancements show that it is deeply flawed and may have actually created research questions that are not, in fact, fecund. In this paper I examine in detail what Wright actually said in the 1932 paper, as well as what he thought of the matter at the very end of his career, in 1988. While the metaphor is flawed, some of the problems which Wright was attempting to address are still with us today, and are in the process of being reformulated as part of a forthcoming Extended Evolutionary Synthesis.

Thiosugars. XII. Synthesis of New 3′‐O‐Substituted 2′,5′‐Anhydro‐2′‐thio‐α‐d‐pentofuranosyl Nucleoside Analogues

Methyl 2,5‐anhydro‐3‐O‐(2‐methoxyethyl)‐2‐thio‐β‐d‐arabinofuranoside and methyl 2,5‐anhydro‐3‐O‐(2‐fluorobenzyl)‐2‐thio‐α‐d‐lyxofuranoside were transformed into the corresponding uridine, thymidine, cytidine and adenosine analogues, which exclusively exhibited the α‐configuration irrespective of the anomeric configuration of the donor. The structure, configuration, and conformation of the products was elucidated by X‐ray structure analyses. The nucleoside analogues were tested for antiviral activities.     

Training vs. body image: does training improve subjective appearance ratings?

The purpose of this study was to determine if a short-term exercise program (6 weeks) could improve subjective physical appearance ratings. Twenty-five previously sedentary adult men (aged 18-40 years) were randomly assigned to one of 3 training groups: cardiovascular, strength, or control. Subjects participating in an exercise group trained for an average of 34 minutes, 3 times per week. All subjects were pre- and posttested to determine body composition, strength, and cardiovascular fitness. Subjects were also digitally photographed from 4 angles. The photographs were rated by the subjects and by a panel of 6 judges using an analog scale. There was no significant difference in the groups by trials interaction effect for pre- and post-Vo(2)max, percent fat, total lean tissue, percent limb fat, percent trunk fat, lean trunk tissue, or lean limb tissue. The subjects rated themselves higher than the panel, with average scores of 4.74 vs. 3.46, 4.26 vs. 3.10, and 4.61 vs. 3.49 for the cardiovascular, strength, and control groups, respectively (p < 0.05). The men of the panel rated the subjects significantly higher than did the women, with average scores of 4.61 vs. 2.31, 4.13 vs. 2.06, and 4.53 vs. 2.18 for the cardiovascular, resistance, and control groups, respectively (p < 0.05). This study showed that a 6-week training program did not change self-rated or panel-rated appearance scores.     

Pavlov vs. K?hler. Pavlov's little-known primate research

During the 1920s, I. P. Pavlov's scholarly interests broadened to consider problem-solving. Distrusting Wolfgang K?hler's Gestalt explanation of the problem-solving process and its interspecies aspects, Pavlov performed, from 1933 to 1936, a number of experiments, including a replication of K?hler's building experiment, using chimpanzees as subjects. Confirming K?hler's findings, Pavlov explained the problem-solving process in terms of unconditional reflexes and the establishment, by Pavlovian conditioning and the Thorndikian method of trial and error, of temporary neural connections identical, on the psychological level, to associations. In contrast to K?hler's "structural" explanation, Pavlov emphasized the processes of analysis and synthesis. According to Pavlov insight is achieved progressively--as the result of the organism's problem-solving behavior--contradicting K?hler's thesis of a sudden subjective reorganization of the environmental situation. Pavlov explained interspecies differences among higher organisms in terms of the range of a species behavior, with the second signal system as the main distinguishing characteristic between human and nonhuman species.     

Cutaneous photobiology. The melanocyte vs. the sun: who will win the final round?

Solar ultraviolet radiation (UV) is a major environmental factor that dramatically alters the homeostasis of the skin as an organ by affecting the survival, proliferation and differentiation of various cutaneous cell types. The effects of UV on the skin include direct damage to DNA, apoptosis, growth arrest, and stimulation of melanogenesis. Long-term effects of UV include photoaging and photocarcinogenesis. Epidermal melanocytes synthesize two main types of melanin: eumelanin and pheomelanin. Melanin, particularly eumelanin, represents the major photoprotective mechanism in the skin. Melanin limits the extent of UV penetration through the epidermal layers, and scavenges reactive oxygen radicals that may lead to oxidative DNA damage. The extent of UV-induced DNA damage and the incidence of skin cancer are inversely correlated with total melanin content of the skin. Given the importance of the melanocyte in guarding against the adverse effects of UV and the fact that the melanocyte has a low self-renewal capacity, it is critical to maintain its survival and genomic integrity in order to prevent malignant transformation to melanoma, the most fatal form of skin cancer. Melanocyte transformation to melanoma involves the activation of certain oncogenes and the inactivation of specific tumor suppressor genes. This review summarizes the current state of knowledge about the role of melanin and the melanocyte in photoprotection, the responses of melanocytes to UV, the signaling pathways that mediate the biological effects of UV on melanocytes, and the most common genetic alterations that lead to melanoma.     

Corimbatichnus fernandezi: A cluster of fossil bee cells from the late cretaceous‐early tertiary of Uruguay

Corimbatichnus fernandezi n.igen, n. isp. is a cluster of fossil bee cells from the Uruguayan Late Cretaceous‐early Tertiary Asencio Formation. It is composed of rows of small excavated cells contained in paleosol peds. Cells have inner surfaces somewhat rough and are closed with loose material. Separation among cells is very thin, and the cells are orientated uniformly, showing a great economy of space as in some halictine constructions. Corimbatichnus can be distinguished from Rosellichnus and Uruguay by its convex face, excavated cells and the spatial arrangement of them.     

Cutaneous Photobiology. The Melanocyte vs. the Sun: Who Will Win the Final Round?

Solar ultraviolet radiation (UV) is a major environmental factor that dramatically alters the homeostasis of the skin as an organ by affecting the survival, proliferation and differentiation of various cutaneous cell types. The effects of UV on the skin include direct damage to DNA, apoptosis, growth arrest, and stimulation of melanogenesis. Long‐term effects of UV include photoaging and photocarcinogenesis. Epidermal melanocytes synthesize two main types of melanin: eumelanin and pheomelanin. Melanin, particularly eumelanin, represents the major photoprotective mechanism in the skin. Melanin limits the extent of UV penetration through the epidermal layers, and scavenges reactive oxygen radicals that may lead to oxidative DNA damage. The extent of UV‐induced DNA damage and the incidence of skin cancer are inversely correlated with total melanin content of the skin. Given the importance of the melanocyte in guarding against the adverse effects of UV and the fact that the melanocyte has a low self‐renewal capacity, it is critical to maintain its survival and genomic integrity in order to prevent malignant transformation to melanoma, the most fatal form of skin cancer. Melanocyte transformation to melanoma involves the activation of certain oncogenes and the inactivation of specific tumor suppressor genes. This review summarizes the current state of knowledge about the role of melanin and the melanocyte in photoprotection, the responses of melanocytes to UV, the signaling pathways that mediate the biological effects of UV on melanocytes, and the most common genetic alterations that lead to melanoma.     

Can isotropy vs. anisotropy in the spatial association of plant species reveal physical vs. biotic facilitation?

In dryland ecosystems and other harsh environments, a large part of the vegetation is often clustered, appearing as ‘islands’. If ‘independent’ species, usually colonizers, can be distinguished from species which are ‘dependent’ on the presence of the colonizing species for successful establishment and/or persistence, the type of spatial pattern of the association ‐ isotropic (spatially symmetric) or anisotropic (spatially asymmetric) ‐ can give information on the underlying environmental factors driving the process of association. Modified spatial pattern analysis based on Ripley's K‐function can be applied to bivariate clustered patterns by cardinal direction in order to detect possible anisotropy in the pattern of association. The method was applied to mapped distribution patterns of two types of semi‐arid shrubland in southeastern Spain. In shrubland of Retama sphaerocarpa, low shrubs of Artemisia barrelieri were significantly clustered under the canopy of the Retama shrubs in all four cardinal directions, suggesting an isotropic facilitation effect. In low shrubland dominated by Anthyllis cytisoides and Artemisia barrelieri, Anthyllis shrubs occurred more frequently than expected on the eastern side (and downslope) of an Artemisia shrub. The possible environmental factors driving the two association patterns are discussed and recommendations for further applications of the analytical method are given.     

Overweight and obesity among foreign‐born and U.S.‐born Hispanics

Abstract

In this study, data from the New Immigrant Survey and the National Health and Nutrition Examination Survey are combined to examine patterns of overweight and obesity among U.S.‐born and foreign‐born Hispanics. Results indicate that, after using height and weight measures adjusted for self‐reporting bias, foreign‐born Hispanic men and women have substantially lower likelihoods of being overweight and obese than the U.S.‐born. However, both likelihoods increase as years in the U.S. accumulate for the foreign‐born. Controls for smoking behavior, physical activity, and the degree of dietary change do not reduce the strength of the positive relationship between years in the U.S. and overweight/obesity.     

Recycling‐mediated facilitation and coexistence based on plant size

We introduce nutrient recycling into a model where competitors differ in the scale at which they perceive their environment. In a two-resource system with both external nutrient inputs and recycling, larger consumers ("integrators") often generate resource distributions that favor their smaller ("nonintegrator") competitors, and vice versa. This occurs because recycling of integrator biomass reduces between-patch resource heterogeneity, whereas recycling of nonintegrator biomass does not. Combined, recycling and throughput can allow coexistence when it is not possible with either alone. With recycling, the presence of an integrator also may facilitate higher biomass of a co-occurring nonintegrator. Our model provides a context where recycling can generate negative feedback between competitors that differ in size and so promote coexistence. This is opposite to the positive recycling-mediated feedback commonly expected on the basis of litter chemistry differences between competitors. Effects of recycling and homogenization on nonintegrators may also be negative in our model, depending on the conformation of the system's resource supply points and the species' relative resource requirements. Our model suggests that the effects of plant size on competitive outcomes may depend critically on the degree of resource recycling found in the system and, reciprocally, that the effects of recycling may depend on plant size.