The significance of major pheromone components and interspecific signals as expressed by receptor neurons in the oriental tobacco budworm moth, Helicoverpa assulta

Abstract

Receptor neuron specificities for intra-and interspecific chemical signals were determined in males of Helicoverpa assulta, by testing single neurons for twelve heliothine produced compounds and two chemical analogues. Three types of receptor neurons were identified in the male specific sensilla trichodea type 1. 1. One large group of neurons (29 out of 63) was tuned to the major pheromone component (Z)-9-hexadecenal, in contrast to results obtained previously in a related species, where the information from this compound seems to be mediated via neurons tuned to (Z)-9-tetradecenal. 2. Another group of neurons (28/63) was tuned to (Z)-9-tetradecenal which is not produced by the conspecific females. These neurons and those tuned to the major pheromone component, always appearing together, are probably located in the same sensillum. Their large number suggests that (Z)-9-tetradecenal mediates an important message in this species, probably causing interspecific interruption. 3. The third group of neurons (6/63) was tuned to the second principal pheromone component (Z)-ll-hexadecenal. These neurons showed similar specificities as the corresponding type of neurons in related species, indicating a conservation of their membrane receptors through evolution. In contrast, the (Z)-9-tetradecenal receptor neurons in H. assulta showed a different specificity than their counterparts in the related species, suggesting that their receptor proteins have evolved differently.Abbreviations Z9-16:AL (Z)-9-hexadecenal Zll-16.AL (Z)-I 1-hexadecenal Z9-14:AL (Z)-9-tetradecenal ZT-16:AL (Z)-7-hexadecenal -16:AL hexadecanal 14:AL tetradecanal 9 Z9-16:AC (Z)-9-tetradecenyl acetate 9 Zll-16:AC (Z)-I 1-hexadecenyl acetate ZT-16:A C (Z)-7-hexadecenyl acetate 16:AC hexadecanyl acetate 9 Z9-16.'OH (Z)-9-hexadecenol 9 Zll-16.OH (Z)-I 1-hexadecenol 16:OH hexadecanol 9

Projections of male-specific receptor neurons in the antennal lobe of the oriental tobacco budworm moth,Helicoverpa assulta: A unique glomerular organization among related species

“…2C). The identification of the neuron types was confirmed by the concordance between the data presented here and those previously reported by Berg and Mustaparta (1995). The large-amplitude Z9-16:AL neurons responded, in addition to the key compound, weakly to the highest concentration of Z9-14:AL (n ϭ 142) ( Fig.…”

“…The second, infrequently occurring sensillum type of H. assulta, the A-type, housing the receptor neurons detecting Z11-16:AL also corresponds with a similar, but abundant type in other heliothine moths, including H. zea, H. armigera, H. virescens, and H. subflexa (Almaas and Mustaparta, 1990;Hansson et al, 1995;Berg et al, 1995;Mustaparta, 1997Mustaparta, , 1998Cossé et al, 1998;Skiri, 1999;Baker et al, 2004). The occasional appearance of a nonresponding, small-amplitude neuron, as shown in Figure 4, is in accordance with the data from H. virescens (Berg et al, 1998).…”

Representation of pheromones, interspecific signals, and plant odors in higher olfactory centers; mapping physiologically identified antennal-lobe projection neurons in the male heliothine moth

“…For example, males of H. vires c ens possess two types of pheromone sensory neurons tuned to cis -11-hexadecenal (Z11-16:AL) and cis -9-tetrdecenal (Z9-14:AL), respectively, whereas two additional neuron populations are tuned to substances produced by females of sympatric species, one to cis -11-hexadecenyl acetate (Z11-16:AC) and the other to cis -11- hexadecenol (Z11-16:OH; Almaas et al, 1991; Berg et al, 1995, 1998; Hansson et al, 1995). In males of the Oriental tobacco moth, H. assulta , two types of pheromone sensory neurons are tuned to cis -9-hexadecenal (Z9-16:AL) and Z11-16:AL, respectively, whereas a population of Z9-14:AL-responding neurons carries interspecific information (Berg and Mustaparta, 1995; Berg et al, 2005). …”

(Z)-9-tetradecenal: a potent inhibitor of pheromone-mediated communication in the oriental tobacco budworm moth, Helicoverpa assulta

“…The interrupting effect of this compound was also seen at a relatively low amount, 2%, when it was added to a 1:20 blend of Zll-16:AL and Z9-16:AL (Cork et al 1992). It is, therefore, interesting that out of all the heliothine pheromone components tested, the receptor neurons tuned to Z9-14:AL in H. assulta also responded to Z9-16:OH (Berg and Mustaparta, 1995). It seems, therefore, that the Z9-14:AL neurons could mediate information from more than one interspecific signal that can interrupt pheromone mediated attraction.…”

“…Electrophysiological studies of receptor neuron specificities for compounds identified in the female pheromone glands of heliothine moths were conducted on male H. assulta from Korea (Berg and Mustaparta 1995). In that study, recordings from sensilla trichodea type I revealed three types of receptor neurons, each type was found to be tuned to one compound.…”