Lactic acid-sensitive receptors on the antennae of the mosquito,Aedes aegypti

Abstract

Summary. 1. A pair of chemoreceptor neurons sensitive to lactic acid (LA) was identified in the grooved-peg (A3) sensilla on the antennae of the mosquito, Aedes aegypti.2. One chemoreceptor responded to LA with an increase in spike frequency, whereas the other chemoreceptor exhibited a decrease in spike frequency when presented with LA.3. CO2, either alone or in combination with LA, elicited no change in spike frequency of either LA-sensitive neuron, indicating that the behavioral synergism of CO2 and LA occurs centrally and not at the primary receptor level.4. Water vapor induced such a weak excitatory response in both LAsensitive neurons that their involvement in the detection of water vapor is questioned.5. The insect repellent, DEET, inhibited both LA-sensitive neurons. DEET plus LA was additive in the LA-inhibited cell, whereas the LA response of the LA-excited cell was attenuated by DEET.6. The reaction spectra of the LA-sensitive neurons were determined using pure compounds (Table 1).7. The importance of LA in the host-finding behavior of the mosquito is discussed.

Ultrastructure and receptor cell responses of the antennal grooved peg sensilla of Triatoma infestans (Hemiptera: Reduviidae)

“…This hypothesis is supported by the responses of the receptor cells in the sw-wp basiconic sensilla on the antenna of T. infestans which are sensitive to long-chain aldehydes and terpenes (Guerenstein, 1999;Guerenstein and Guerin, 2001) whereas the dw-wp GP sensilla receptor cells are sensitive to more polar products such as NH 3 , short-chain carboxylic acids and short-chain amines (this paper). This is comparable to the results reported from the dw sensilla in Aedes responding to lactic acid (Davis, 1977;Davis and Sokolove, 1976), in Locusta to green leaf volatiles such as hexenal, hexanol and aliphatic organic acids with a chain length of 3-8 carbons (Boeckh, 1967;Kafka, 1970), and in Periplaneta to acids with a chain length up to six carbons and to amines (Altner et al, 1977;Altner and Prillinger, 1980). In addition, most receptor cells in the dw-wp sensilla coeloconica from Bombyx responded best to acids and aldehydes (Pophof, 1997).…”

Olfaction in vector-host interactions

“…The function of ORNs in ST with various shapes was reported for several species of culicines (Bentley et al 1979, Bowen 1990, Davis 1976, Klowden and Blackmer 1987, Kuthiala et al 1992, Lacher 1967 (Table 2). A recent study by Ghaninia et al (2007) classified 11 functional groups within ST using a panel of 16 compounds from six different chemical groups (Table 2).…”

“…Similar as for anophelines, grooved peg sensilla in culicine mosquitoes have also been found responding to short-chain carboxylic acids but hardly to plant and oviposition site-associated volatiles (Davis 1988, Davis andSokolove 1976). However, the responses of the GP sensilla in Ae.…”

“…ORNs in the short sharptipped ST respond strongly to indole, 4-methylcyclohexanol and esters of short-chain carboxylic acids; these compounds stimulate oviposition by gravid culicine mosquitoes (Allan and Kline 1995, Beehler et al 1994b, Bentley et al 1982, Perry and Fay 1967, whereas indole is also a major component of aged human sweat (Meijerink et al 2000). Short blunt-tipped ST contain neurons sensitive to esters of short-chain carboxylic acids, 4-methylphenol and alcohols, the former two types of compounds were reported to attract gravid mosquitoes and considered to be oviposition stimulants (Bentley et al 1979, Davis 1976, Klowden and Blackmer 1987). An ORN strongly tuned to the plant volatile, α-thujone, is also found in the short blunt-tipped ST (Ghaninia et al 2007).…”

“…Gillies and Wilkes (1968) demonstrated that mosquitoes could also be manipulated with host odours, and it was soon found that synthetic blends of odorants could be used to manipulate mosquito populations . These behavioural studies were gradually augmented with physiological studies to reveal the sensory processes that made the insects respond to the odorants (Cork 1996, Davis andSokolove 1976). The advent of molecular genetics has allowed for detailed insight in the genetics and molecular regulation of insect olfaction, which provides fundamental knowledge on the regulation of insect behaviour (Jacquin Joly and Merlin 2004, Lessing and Carlson 1999, Touhara and Vosshall 2009).…”