(Press-News.org) Brown widow spiders are relatively new to North America, where they were first documented in Florida in 1935, and even newer to southern California, where they were only recently discovered in 2003. However, in the last decade they have been so successful that they may be displacing native black widow spiders. If so, the overall danger to homeowners may decrease because brown widow spider bites are less toxic than those of native western black widow spiders.
In "The Prevalence of Brown Widow and Black Widow Spiders (Araneae: Theridiidae) in Urban Southern California," (DOI: http://dx.doi.org/10.1603/ME11285) a soon-to-be-released article in the July issue of the Journal of Medical Entomology, the authors describe the results of their efforts to document the presence of brown widows in southern California by performing timed searches in various habitats, such as urban properties, agricultural lands, developed parks, and undeveloped natural areas. They also included the native western black widow spider to compare the abundance and habitat selection of the two species.
"The brown widows really burst on to the scene in a very short time, and we found brown widows in many habitats where we expected to find black widows," said corresponding author Richard Vetter (University of California, Riverside). "There may be some competition where brown widows are displacing black widows because there is some habitat overlap. There are also places where only brown widows were able to make homes, but in other habitats the black widows still predominate."
After collecting data at 72 sites, which involved 96.8 hours of collecting, the authors found 20 times as many brown widows than black widows outside homes, especially under outdoor tables and chairs, and in tiny spaces in walls, fences and other objects. Neither spider is found in the living space of houses.
"Homeowners would benefit to know about the hiding places of brown widows, displaying care when placing their hands in nooks and crannies," the authors conclude. However, they should also keep in mind that even if the chances of being bitten do increase, the dangers are lessened because the brown widow bite is less toxic than that of the black widow.
###
Members of the media who would like the full report should write to pubs@entsoc.org or call 301-731-4535, ext. 3009.
The Journal of Medical Entomology is published by the Entomological Society of America, the largest organization in the world serving the professional and scientific needs of entomologists and people in related disciplines. Founded in 1889, ESA today has more than 6,000 members affiliated with educational institutions, health agencies, private industry, and government. For more information, visit http://www.entsoc.org.
CONTACT:
Richard Vetter
University of California, Riverside
rick.vetter@ucr.edu
END
A new species of phorid fly from Thailand is the smallest fly ever discovered. At just 0.40 millimeters in length, it is 15 times smaller than a house fly and five times smaller than a fruit fly.
The tiny fly, Euryplatea nanaknihali, is also the first of its genus to be discovered in Asia, and it belongs to a fly family (Phoridae) that is known for "decapitating" ants.
Some species in the Phoridae fly family lay eggs in the bodies of ants, and the resulting larvae feed in the ants' heads, eventually causing decapitation. In fact, some of these phorid flies are being ...
MINNEAPOLIS – Botulinum toxin may help prevent shaking or tremor in the arms and hands of people with multiple sclerosis (MS), according to new research published in the July 3, 2012, print issue of Neurology®, the medical journal of the American Academy of Neurology.
"Treatments in use for tremor in MS are not sufficiently effective and new alternatives are needed," said study author Anneke van der Walt, MD, consultant neurologist at The Royal Melbourne Hospital and research fellow with the University of Melbourne in Australia.
For the study 23 people with MS were ...
Fruit flies on dietary restriction (DR) need to be physically active in order to get the lifespan extending benefits that come from their Spartan diet. If the same axiom holds true in humans, those practicing caloric restriction in hopes of living longer need to make sure they eat enough to avoid fatigue.
According to research at the Buck Institute, flies on DR shift their metabolism toward increasing fatty acid synthesis and breakdown, specifically in muscle tissue. "Dietary restriction is known to enhance spontaneous movement in a variety of species including primates, ...
Tree ring and oxygen isotope data from the U.S. Pacific Northwest do not provide the same information on past precipitation, but rather than causing a problem, the differing results are a good thing, according to a team of geologists.
The researchers are trying to understand the larger spatial patterns and timing of drought in the arid and semiarid areas of the American West.
"We generally understand that the Medieval Climate Anomaly, a warm period in much of the northern hemisphere that occurred about 950 to 1250 was a dry period in the American West," said Byron ...
High levels of low-density lipoprotein (LDL) cholesterol increases the risk for coronary heart disease. A variant in the human gene encoding the protein sortilin is associated with reduced plasma LDL levels and a decreased risk of heart attack. This variant results in markedly higher sortilin protein expression in liver. Dr. Daniel Rader and colleagues at the University of Pennsylvania in Philadelphia have uncovered a two-pronged mechanism for the change in LDL observed. Using a mouse model system, the Rader team found that increased liver sortilin is responsible for reducing ...
CARDIOVASCULAR DISEASE
Gene variant reduces cholesterol by two mechanisms
High levels of low-density lipoprotein (LDL) cholesterol increases the risk for coronary heart disease. A variant in the human gene encoding the protein sortilin is associated with reduced plasma LDL levels and a decreased risk of heart attack. This variant results in markedly higher sortilin protein expression in liver. Dr. Daniel Rader and colleagues at the University of Pennsylvania in Philadelphia have uncovered a two-pronged mechanism for the change in LDL observed. Using a mouse model system, ...
In Parkinson's disease, the loss of dopamine-producing cells in the midbrain causes well-characterized motor symptoms. Though embryonic stem cells could potentially be used to replace dopaminergic (DA) neurons in Parkinson's disease patients, such cell therapy options must still overcome technical obstacles before the approach is ready for the clinic. Embryonic stem cell-based transplantation regimens carry a risk of introducing inappropriate cells or even cancer-prone cells. To develop cell purification strategies to minimize these risks, Dr. Lorenza Studer and colleagues ...
The influence of aerosols (small particles less than 1 micrometre in diameter) and clouds (liquid droplets 1 – 1000 micrometres diameter) represents one of the largest uncertainties in our understanding of trends in past global climate and predicting future climate change, as recognised by the 2007 report of the Intergovernmental Panel on Climate Change.
One of the most significant 'known unknowns' is how quickly water can condense on the small aerosol particles to grow and become cloud droplets, influencing the albedo (reflectivity) of clouds and cloud lifetime (precipitation). ...
Nearly two-thirds of U.S. adolescents have experienced an anger attack that involved threatening violence, destroying property or engaging in violence toward others at some point in their lives. These severe attacks of uncontrollable anger are much more common among adolescents than previously recognized, a new study led by researchers from Harvard Medical School finds.
The study, based on the National Comorbidity Survey Replication Adolescent Supplement, a national face-to-face household survey of 10,148 U.S. adolescents, found that nearly two-thirds of adolescents in ...
CHICAGO – A study of students at seven public high schools in Texas suggests that "sexting" was prevalent and may be linked to teens' sexual behaviors, according to a report published Online First by Archives of Pediatrics & Adolescent Medicine, a JAMA Network publication.
Sexting (a combination of the words sex and texting) is the practice of electronically sending sexually explicit images or messages from one person to another. The study background suggests pediatricians, policy makers, schools and parents have insufficient information about the nature and importance ...
