Field bands of marching locust juveniles show carbohydrate, not protein, limitation

Locusts are grasshoppers that migrate en masse and devastate food security, yet little is known about the nutritional needs of marching bands in nature. While it has been hypothesized that protein limitation promotes locust marching behavior, migration is fueled by dietary carbohydrates. We studied South American Locust (Schistocerca cancellata) bands at eight sites across Argentina, Bolivia, and Paraguay. Bands ate most frequently from dishes containing carbohydrate artificial diets and minimally from balanced, protein, or control (vitamins and salts) dishes-indicating carbohydrate hunger. This hunger for carbohydrates is likely explained by the observation that local vegetation was generally protein-biased relative to locusts' preferred protein to carbohydrate ratio. This study highlights the importance of studying the nutritional ecology of animals in their environment and suggests that carbohydrate limitation may be a common pattern for migrating insect herbivores.

Plant carbohydrate content limits performance and lipid accumulation of an outbreaking herbivore

Locusts are major intermittent threats to food security and the ecological factors determining where and when these occur remain poorly understood. For many herbivores, obtaining adequate protein from plants is a key challenge. We tested how the dietary protein : non-structural carbohydrate ratio (p : c) affects the developmental and physiological performance of 4th-5th instar nymphs of the South American locust, Schistocerca cancellata, which has recently resurged in Argentina, Bolivia and Paraguay. Field marching locusts preferred to feed on high carbohydrate foods. Field-collected juveniles transferred to the laboratory selected artificial diets or local plants with low p : c. On single artificial diets, survival rate increased as foods became more carbohydrate-biased. On single local plants, growth only occurred on the plant with the lowest p : c. Most local plants had p : c ratios substantially higher than optimal, demonstrating that field marching locusts must search for adequate carbohydrate or their survival and growth will be carbohydrate-limited. Total body lipids increased as dietary p : c decreased on both artificial and plant diets, and the low lipid contents of field-collected nymphs suggest that obtaining adequate carbohydrate may pose a strong limitation on migration for S. cancellata. Anthropogenic influences such as conversions of forests to pastures, may increase carbohydrate availability and promote outbreaks and migration of some locusts.

[Effectiveness of Bacillus sphaericus strain 2362 on larvae of Anopheles nuñeztovari]

A study, under laboratory and field conditions, was conducted to evaluate the effectiveness, persistence in the time and some factors that can affect the larvicidal action of the Griselef formulation of the sporogenous bacteria Bacillus sphaericus strain 2362, on the larvae population of the Anopheles nuñeztovari Gabaldón, the main malaria vector in western Venezuela. The degree of susceptibility of this species to the Bacillus sphaericus was determined to be at a LD50 in 0.07 ppm a LD95 in 0.69 ppm. The pH ranges of the water, as tested in the laboratory, showed that values between 7.0 and 9.0 did not affect the action of the larvicide, producing more than 95% of mortality after 72 hours of observation. Under controlled field conditions, the high susceptibility of the An. nuñeztovari larvae to the larvicidal action of the product was demonstrated. With a dose of 5 ml/m2, a 100% mortality was obtained after 72 hours of exposure. In the field, it was determined that after 12 hours, solar radiation decreased the effectiveness of the B. sphaericus in 30% and that the presence of vegetation reduced the biolarvicidal effect between 5 and 12%. Under natural field conditions, it was shown that the larvicide was effective, since a 100% larval mortality was obtained in the two treated breeding places. This effect persisted up to 4 months of observation, with more than 85% of larvae reduction, showing that it is capable or remaining in the natural environment.

Biliary sludge: a well defined sonographic entity

OBJECTIVES

Identify the present of biliary sludge (BS) in our patients, since different authors have concluded that this entity may be an etiologic agent of biliary colic, gallbladder stones and some complications such as acute pancreatitis and acalculous cholecystitis.

METHODS

We reviewed retrospectively the abdominal sonographic reports of 2802 patients of our gastroenterologic unit, with an average age of 40.5 years. The variables of the protocol were: gallbladder stones, BS and acute and chronic gallbladder inflammation.

RESULTS

Considering the mentioned criteria, we entered to the study 2682 patients, 17.8% (n = 479) had lithiasis, 13.2% (n = 356) had BS, 2% (n = 54) had acute gallbladder inflammation and 2.3% (n = 64) had chronic gallbladder inflammation. Of the group of patients with BS 42.7% (n = 152) were female and 57.3% (n = 204) were males. 52% of the patients with BS were between the ages of 26 to 45 years.

CONCLUSIONS

In our study we found an important prevalence of BS that was over 13% which is higher than the results reported by additional series. Its early sonographic detection, follow-up, removal of precipitating factors and treatment are all adequate measures in order to achieve its elimination.

[Esophageal squamous papilloma: a case report and review of the literature]

We report a case of an esophagic squamous papilloma (SP) in a 90 year old patient. This pathology is benign and its diagnosis is generally a finding during an upper digestive endoscopy. Only 150 cases have been reported in the world's medical literature. Treatment consists in an endoscopic resection with diathermic snare or a conservative approach with periodical endoscopic control and observation depending of the type of patient.

Syphilitic rectal ulcer associated with perforation of the hard palate: case report

We report a case of a patient that presented with a perforated hard palate as a late complication due to an unsuspected syphilis. This disease first presented as a rectal ulcer which was misdiagnosed as an amebic proctitis. The patient received antiamebic treatment with a satisfactory outcome. He did not return for late control of the latter treatment and returned seeking medical advice six years later with the former complication. He tested positive for syphilis and appropriate treatment was performed. In addition, the ORL department recommended a palate prosthesis.