Epicuticular lipids induce aggregation in Chagas disease vectors
Open Access
- 27 January 2009
- journal article
- Published by Springer Science and Business Media LLC in Parasites & Vectors
- Vol. 2 (1), 8
- https://doi.org/10.1186/1756-3305-2-8
Abstract
The triatomine bugs are vectors of the protozoan parasite Trypanosoma cruzi, the causative agent of Chagas disease. Aggregation behavior plays an important role in their survival by facilitating the location of refuges and cohesion of aggregates, helping to keep them safely assembled into shelters during daylight time, when they are vulnerable to predators. There are evidences that aggregation is mediated by thigmotaxis, by volatile cues from their faeces, and by hexane-extractable contact chemoreceptive signals from their cuticle surface. The epicuticular lipids of Triatoma infestans include a complex mixture of hydrocarbons, free and esterified fatty acids, alcohols, and sterols. We analyzed the response of T. infestans fifth instar nymphs after exposure to different amounts either of total epicuticular lipid extracts or individual lipid fractions. Assays were performed in a circular arena, employing a binary choice test with filter papers acting as aggregation attractive sites; papers were either impregnated with a hexane-extract of the total lipids, or lipid fraction; or with the solvent. Insects were significantly aggregated around papers impregnated with the epicuticular lipid extracts. Among the lipid fractions separately tested, only the free fatty acid fraction promoted significant bug aggregation. We also investigated the response to different amounts of selected fatty acid components of this fraction; receptiveness varied with the fatty acid chain length. No response was elicited by hexadecanoic acid (C16:0), the major fatty acid component. Octadecanoic acid (C18:0) showed a significant assembling effect in the concentration range tested (0.1 to 2 insect equivalents). The very long chain hexacosanoic acid (C26:0) was significantly attractant at low doses (≤ 1 equivalent), although a repellent effect was observed at higher doses. The detection of contact aggregation pheromones has practical application in Chagas disease vector control. These data may be used to help design new tools against triatomine bugs.Keywords
This publication has 35 references indexed in Scilit:
- Antimicrobial activity of terpenoids from Trichodesma amplexicaule Roth.Phytotherapy Research, 2003
- Aggregation in the haematophagous bug Triatoma infestans: a novel assembling factorPhysiological Entomology, 1998
- Aggregation pheromone system of nymphal gregarious desert locust,Schistocerca gregaria (forskål)Journal of Chemical Ecology, 1996
- Inhibition of cuticular lipid synthesis and its effect on insect survivalArchives of Insect Biochemistry and Physiology, 1994
- Aggregation pheromone in five species of Triatominae (Hemiptera: Reduviidae)Memórias do Instituto Oswaldo Cruz, 1993
- Aggregated oviposition inDelia antiqua (Meigen): A case for mediation by semiochemicalsJournal of Chemical Ecology, 1992
- Chemical camouflage of the death's head hawkmoth (Acherontia atropos L.) in honeybee coloniesThe Science of Nature, 1991
- Identification of a brood pheromone in honeybeesThe Science of Nature, 1990
- Attraction of the Parasitic Mite Varroa to the Drone Larvae of Honey Bees by Simple Aliphatic EstersScience, 1989
- RESPONSE OF THE FEMALES OF TROGODERMA GRANARIUM (COLEOPTERA, DERMESTIDAE) TO CUTICULAR FREE FATTY ACIDSEntomologia Experimentalis et Applicata, 1971