matias garcia

10 p.-2 fig.-2 tab.[EN] We focused our study on the effects of Larrea cuneifolia phenolic resin on leaf-cutting ants from two populations (Sierra de las Quijadas National Park and San Roque) of Acromyrmex lobicornis in San Luis, Argentina. We conducted two bioassays of food choice (fi eld and laboratory) to compare the effects of phenolic resin on ant workers from these two populations. Results of the fi eld experiment indicated that there were no differences in preference for either leaves treated with resin or untreated leaves among colonies from both localities. However, results of the laboratory experiments with individual ants indicated a signifi cant effect of population and treatment on the time spent in different treatments. While leaf-cutting individual workers from Quijadas preferred the phenolic resin, workers from San Roque avoided it. These results evidence that ants respond according to time of exposure to chemicals from plants (presence or absence) and that the effect...

s ABSTRACT. In order to evaluate the allelochemical activity of some sesqui-terpenes isolated from the native plant Tessaria absinthioides (Hook. et Arn.) DC, and some semi synthetic derivatives against Tenebrio molitor L. larvae, we have developed bioassays directed to quantify repellency, larval mortality, and its effects on the development. Although costic aldehyde caused the ma-ximum repellent effect, all the compounds showed a significant effect at some dose or time, indicating behavioral avoidance. The topical application of cos-tic aldehyde produced the largest increase on the duration of the pupal stage. Tessaric acid exhibited the highest toxicity by topical application at the experi-ment closure. Both eremophilane–1(10),2,11(13)–triene–12–oic, and γ-costic acids induced some morphological deformities. KEY WORDS. Sesquiterpenes. Tenebrio molitor. Repellency. Development. Mortality. s RESUMEN. Efectos de algunos sesquiterpenos sobre el insecto de produc-tos almacenados, Tene...

ABSTRACT. Duration of the pupal stage, toxic activity and nutritional indices induced by oleanolic acid (I), maslinic acid (II), and daucosterol (III) isolated from the native plant Junellia aspera and chemical derivatives, were determinated on larvae, and adults of Tribolium castaneum ( ...

RESUMEN En la presente nota se realizo un relevamiento de las hormigas del Parque Nacional de las Quijadas (32° 22` a 32°47`S y 67°10` a 66°58`W), San Luis, Argentina. Los resultados arrojaron 10 registros nuevos para esta provincia: Acromyrmex striatus Roger 1863, Crematogaster jheringi Emery 1908, Pogonomyrmex odoratus Kusnezov 1949; P. abdominalis Santschi 1929; P. lobatus Santschi 1921; Solenopsis saevissima (Fr.Smith 1855); S. interrupta Santschi 1916; Forelius breviscapus Forel 1931; Dorymyrmex wolffhuegeli Forel 1911 y Linephitema humile Mayr 1868

Allelochemical effects were observed when Tribolium castaneum (Herbst) adults were treated with Baccharis salicifolia (Ruiz & Pavon) Pers essential oil. The main biological activities were toxicity and repellence. Terpenes present in the essential oil were identified by GC-MS, and some authentic samples were tested to assess their activity individually. The most acutely toxic compounds after 3 days were β-pinene and pulegone. Most of the monoterpenes elicited symptoms indicative of neurotoxicity. The most repellent compound was α-terpineol. Toxic and repellent effects of chemical derivatives of the major sesquiterpene present in B salicifolia essential oil, as well as a series of monoterpenes, were evaluated in order to investigate structure-activity relationships. The reduced derivatives of the monoterpenes and sesquiterpenes were more repellent that their carbonyl analogues. In addition, unsaturation in the germacrane skeleton enhanced repellent activity. Copyright © 2005 Society of Chemical Industry

Eight eudesmane and eremophilane sesquiterpenes administered to Tribolium castaneum larvae caused different allelochemical effects. Topical application of 3-oxo-γ-costic acid produced the greatest lengthening in the duration of the pupal stage. Morphological deformities were found, specifically when ilicic, costic, and γ-costic acids and costic aldehyde were used. Ilicic acid exhibited the major toxicity 72 hr following topical application. All compounds were significantly toxic at the end point of the experiment (60 days). Treated surface toxicity was lower than when topical assays were carried out. Responses to tessaric acid in choice bioassays had the highest attractive effect. Maximum repellency was caused by the 3-oxo-γ-costic acid. However, experimental series carried out using γ-costic acid, eremophilan-1(10),2,11(13)-trien-12-oic acid, costic aldehyde, and ilicic aldehyde showed no clear response.