Bucimex chilensis Usinger (Hemiptera: Cimicidae) is recorded for the first time in La Pampa province, Argentina, representing the second record of the species in the country and extending its known distribution 635 km northwards. The specimens were collected inside a cave alongside Myotis dinellii Thomas (Chiroptera: Vespertilionidae). This study expands the geographic range of B. chilensis and contributes to the knowledge of bat-parasite interactions in southern South America.
In the Quebrada de Humahuaca, Cactoblastis bucyrus Dyar and Cactoblastis doddi Heinrich (Lepidoptera: Pyralidae) are considered to be among the causes affecting negatively their respective host plants, Trichocereus atacamensis (Phil.) W.T. Marshall & T.M. Bock and Opuntia sulphurea G.Don in Loudon (Cactaceae). However, these interactions are endemic, so it is necessary to review whether these lepidopteran species are a significant factor in the deterioration of the cacti. The objectives were to quantify and analyze the presence of both lepidoptera species on their host cacti at six sites in the Quebrada de Humahuaca, between 2000 and 3360 masl. The study was conducted in September 2018. Thirty cardons of two heights per sampling site were evaluated in 200 m2 quadrants for C. bucyrus (180 cardons) and 1 m2 quadrants for O. sulphurea. Cactoblastis bucyrus was more evident in plants taller than 1 m (40-100 %), with Pinchayoc being the site with the highest presence. The incidence of C. doddi on O. sulphurea was low (4-21 %), with no significant differences between sites. Herbivory may not be a determining factor in the deterioration of cacti. Quantitative baseline information was generated to deepen our current understanding of two endemic interactions and to contribute to the improvement of environmental protection policies.
The mosquito Aedes aegypti L. (Diptera: Culicidae) is the primary vector of arboviruses such as dengue, posing a significant global health challenge that is exacerbated by resistance to synthetic insecticides. This study evaluated the efficacy of Piper amalago L. (Piperaceae) essential oil as an ecofriendly, bio-rational control agent against A. aegypti. A total of 69 volatile compounds were identified, with (-)-spathulenol (10.08 %), (+/-)-trans-nerolidol (8.68 %), and cubebol (5.44 %) being the predominant constituents. The results demonstrated that the essential oil exhibits significant ovicidal activity, achieving 100 % inhibition at concentrations of 400 ppm and above. Additionally, the oil induced significant concentration-and time-dependent larval mortality. Exposure to 800 ppm resulted in 100 % cumulative mortality of second-instar larvae within 72 h. Probit analysis revealed a progressive decrease in the median lethal concentration (LC50) from 603.71 ppm at 24 h to 211.15 ppm by the end of the experiment. Surviving larvae showed significant relative growth inhibition and reduced adult emergence. These findings provide the first toxicological baseline for P. amalago, highlighting its ovicidal, larvicidal, and growth-regulating properties. This botanical resource represents an alternative for integrated mosquito control strategies.
The objective of this study was to determine the chemical profile of Aloysia citrodora (Verbenaceae) essential oil using gas chromatography-mass spectrometry (GC-MS), and to evaluate its insecticidal activity and repellent effect against Sitophilus zeamais (Coleoptera: Curculionidae) adults. A total of 31 compounds were identified, accounting for 99.18 % of the essential oil composition; the major constituents were D-limonene (50.61 %), chrysanthenone (17.85 %), and beta-myrcene (6.59 %). Bioassays were conducted at concentrations of 100, 200, 400, 600, and 800 ppm. Insect mortality increased significantly as a function of both concentration and exposure time. Concentrations of 600 and 800 ppm caused 100 % mortality after 48 h of exposure, yielding lethal concentrations LC50 and LC90 of 254.94 +/- 15.40 ppm and 463.34 +/- 27.18 ppm, respectively. Furthermore, the essential oil exhibited high repellent activity against S. zeamais at all tested concentrations. These findings indicate that A. citrodora essential oil has strong potential for inclusion in integrated pest management programs against this species, serving as a safer alternative for human health and the environment.
Syllimnophora variceps Malloch, 1934 is a single female-based muscid species described from Buenos Aires province, Argentina, whose male counterpart remains unknown. In this study we present the description of S. variceps male for the first time and the redescription of the female, including the description of the terminalia of both sexes with their ultrastructural morphology. We used molecular identification to find the male counterpart of this species. Moreover, we observed that females present specific sensilla at the distal end of their ovipositor, which might be related to an adaptation used to evaluate substrates before egg-laying.
