Fossils that Change Everything We Know About Human Evolution (...Or Not)

Dramatic headlines touting new fossil discoveries often proclaim that our view of human evolution has been revolutionized. While this is occasionally the case, it is more often true that new fossils enrich our understanding of our own ancestry or answer scientific questions that could not be resolved with previous data. Even spectacular new discoveries, such as the now famous “hobbit” skeleton (Homo floresiensis), can usually be included in the human family tree without any significant change in the inferences about the phylogenetic relationships or taxonomic status of the rest of its members. It is a testament to the power of evolutionary theory and the careful comparative study of human and other fossils that what we know about human evolution changes so little, even when spectacular new discoveries are announced.     

Why Are There Still Monkeys?

The question “If humans evolved from monkeys, why are there still monkeys?” reveals a widespread and persistent misconception about the process and pattern of evolution. The concept of “cousins” is central to understanding and overcoming this particular obstacle to evolution education.     

Stimulation of bone resorption in vitro by a non-prostanoid factor released by human monocytes in culture

Cultured human monocytes produce a non-prostanoid factor which stimulates bone resorption in vitro. Production of the factor is not dependent on prostaglandin synthesis, but stimulation of resorption by the factor does involve prostaglandin production by bone. Salmon calcitonin inhibits the stimulatory activity by up to 80%. Production of the factor is not increased by the presence of lymphocytes in the monocyte cultures. Partial purification of the bone-resorbing activity by Ultrogel ACA 54 chromatography shows that it has an apparent molecular weight between 12 000 and 20 000. We suggest that the resorptive activity is due to an interleukin 1-like factor rather than an osteoclast activating factor.     

Pseudomonas contamination of a fungus-based biopesticide: Implications for honey bee (Hymenoptera: Apidae) health and Varroa mite (Acari: Varroidae) control

The ectoparasitic mite Varroa destructor is a major honey bee pest, and its control using pathogen-based biopesticides would resolve many of the problems, such as contamination and pesticide resistance, experienced with chemical control. A biopesticide, formulated with commercially-prepared conidia of a strain of Beauveria bassiana isolated from V. destructor was tested against the mites in bee colonies in southern France. The impact of treatment on hive survivorship, weight and mite infestation levels were very different from those of previous experiments using laboratory-prepared conidia: bee hives treated with the biopesticide died at a higher rate, lost more weight, and had higher mite densities at the end of the study than control hives. The biopesticide was subsequently found to be contaminated with bacteria. Two strains of bacteria were identified, by biotyping and sequencing data of the 16S rRNA and rpoB regions, and while the strains were distinct both were Pseudomonas sp. belonging to the P. fluorescens group. In dual cultures B. bassiana growth was slowed or suppressed when bacterial cfu density was about equal or greater than that of B. bassiana. Experiments using caged adult bees showed that bees ingesting diet and sugar solution treated with B. bassiana and kept at 30 °C had significantly lower survival times than those treated with one of the bacterial strains, but the opposite was true at 33 °C. Because one arthropod (honey bees) was treated for infestation by another (V. destructor), the impact of bacterial contamination was likely more noticeable than in most uses of biopesticides, such as treating plants against phytophagous insects. To reduce such risk in biopesticide development, a systematic screening for bacterial contamination prior to field application is recommended.     

Cortisol secretion after adrenocorticotrophin (ACTH) and Dexamethasone tests in healthy female and male dogs

Background  

For the conclusive diagnosis of Cushing's Syndrome, a stimulating ACTH test or a low suppressive Dexamethasone test is used. Reports in other species than the dog indicate that plasma cortisol concentration after ACTH administration is affected by gender. We investigated the effect of gender on the cortisol response to ACTH and Dexamethasone tests in dogs.     

Annual changes in structural complexity of understory vegetation and relative abundance ofPeromyscus leucopus in fragmented habitats

Greater structural complexity of understory vegetation may be one factor that contributes to the negative relation ship between density of generalist rodents (eg,Peromyscus leucopus Rafinesque, 1818) and forest patch area; however, this hypothesis is difficult to test. We removed the problem of multicollinearity among variables by analyzing changes in structural complexity and relative abundance ofP. leucopus in 15 forest patches (1.3–200 ha) over a 3-yr period. We found that an in crease in the relative abundance ofP. leucopus was associated with an increase in structural complexity of understory vegetation in the same patches between years. Structural complexity of the understory was greater in smaller forest patches which we speculate may be influenced by moisture. It is possible that understory vegetation provides greater food availability and/or cover from some predators in small patches, but the specific mechanism(s) remains unclear. Multiple factors can potentially influence populations ofP. leucopus, but our results provide strong evidence that structural complexity of understory vegetation positively in fluences relative abundance ofP. leucopus in fragmented habitats.