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Heliothis zea and H. virescens: Moth Activity as Measured by Blacklight and Pheromone Traps
Abstract
Activity of adult bollworms, Heliothis zea (Boddie) and tobacco budworms, H. virescens (F.), was monitored with BL and pheromone traps. Light traps captured far more of both sexes of bollworms than of tobacco budworms; pheromone traps seemed more effective in early season when populations were low. When both species were combined as attractants in the same pheromone traps, significantly fewer moths of each species were captured than when traps contained only 1 species.
... Some field trapping studies have suggested that one species can recognize sex pheromone component of other sympatric species. A specific pheromone component of H. virescens, Z9-14:Ald, played an intraspecific role in sexual communication, and also served as behavioral antagonist for H. zea to avoid the cross-attraction (Haile et al., 1973;Roach, 1975;Carpenter et al., 1984;Hansson et al., 1986;Grant et al., 1987;Christensen et al., 1990). As a minor component of the sex pheromone in Chilo suppressalis, Z11-16:OH did not increase the attractiveness of the pheromone for conspecific males in the field, but did increase the sex pheromone specificity (Chen et al., 2018). ...
Spodoptera exigua and S. litura are two sympatric species in China and many other countries. Both moths employ a multiple component sex pheromone blend, including a common component Z9,E12-14:OAc, and two specific components Z9-14:OH and Z11-16:OAc for S. exigua, and one specific component Z9,E11-14:OAc for S. litura. For the two species, it has been well documented that males are able to recognize and behaviorally attracted by their species-specific sex pheromone, which functions as a means of reproductive isolation, but whether males could mutually recognize pheromone components of its sympatric species is unknown. In the present study, the electroantennogram (EAG) and field evaluation were conducted to address this topic. The EAG recordings revealed that males of each species could significantly respond to specific components of its sympatric species, although the response values were lower than that to its own major component. In field tests, the specific components Z9-14:OH and Z11-16:OAc of S. exigua strongly inhibited the male catches of S. litura to its conspecific sex pheromone, while specific component Z9,E11-14:OAc of S. litura significantly reduced the male catches of S. exigua to its sex pheromone. Furthermore, the combined lure of the two species completely inhibited male catches of S. litura, and significantly decreased the male catches of S. exigua, compared to the species-specific lure alone. The results demonstrated that males of the two sibling species could perceive the specific components of its counterpart, suggesting that mutual recognition of pheromone components may function to strengthen the behavioral isolation between the two species. Our study has added new knowledge to the reproductive isolation via sex pheromone communication system in sympatric moth species, and provided a base for designing of mating disruption tactics targeting multispecies by using insect sex pheromones.
... bees and ants) are known to release alarm pheromones that warn others of impending dangers (Regnier and Law, 1968). Insect pheromones may be detected across large distances with moth pheromones being detected by other moths at distances in excess of five miles (Roach, 1975). Whilst it is apparent that animals use chemo-signalling, this form of vestigial olfactory communication for communicating stress, alarm or fear, is little known in humans (Ackerl et al., 2002). ...
Individuals trying to conceal knowledge from interrogators are likely to experience raised levels of stress that can manifest itself across biological, physiological, psychological and behavioural factors, providing an opportunity for detection. Using established research paradigms an innovative scalable interrogation was designed in which participants were given a ‘token’ that represented information they had to conceal from interviewers. A control group did not receive a token and therefore did not have to deceive the investigators. The aim of this investigation was to examine differences between deceivers and truth-tellers across the four factors by collecting data for cortisol levels, sweat samples, heart-rate, respiration, skin temperature, subjective stress ratings and video and audio recordings. The results provided an integrated understanding of responses to interrogation by those actively concealing information and those acting innocently. Of particular importance, the results also suggest, for the first time in an interrogation setting, that stressed individuals may secrete a volatile steroid based marker that could be used for stand-off detection. The findings are discussed in relation to developing a scalable interrogation protocol for future research in this area.
... Several group of researchers made the comparison of indexing populations of Helicoverpa spp. in light traps versus pheromone traps. There results revealed that light trap catches may index seasonal fluctuation of populations more accurately than pheromone traps, however, pheromone traps are more sensitive to low populations early in the season and decline in efficiency with high populations late in the season [69]. ...
... Compared to blacklight traps, there were more moths trapped with pheromone in the spring flight and consistently smaller numbers of moths trapped with pheromone later in the summer. Similar differential responses to pheromone vs. blacklight, with greater responses to pheromone earlier and greater responses to blacklight later in the season, were reported for codling moth, Cydia pomonella (L.), by Howell (1981) and for corn earworm, Helicoverpa zea (Boddie), by Roach (1975). Possible explanations for this disparity in trapping the spotted cutworm relate to differential environmental conditions or genetic strains. ...
Traps baited with the sex pheromone blend of (Z7)- and (Z5)-tetradecenyl acetate captured significant numbers of male spotted cutworm moths, Xestia c-nigrum (L.) compared to unbaited traps. Nearly no males were captured in traps baited with (Z7)-tetradecenyl acetate, the major pheromone component. Antennae of spotted cutworm males responded to (Z7)-, (E7)-, (Z5)- and (E5)-tetradecenyl acetate in the laboratory; however there was no response by moths in the field to the E isomers when presented in traps as major and minor components respectively of a binary blend or to the (E7) isomer as a single component. These findings clarify the makeup of a sex attractant that can be used for monitoring X. c-nigrum on agricultural crops in Washington. However, multi-year season-long monitoring of spotted cutworm moths in Yakima Valley apple orchards revealed differential responses to pheromone and blacklight traps. A spring flight period showed a strong moth response to the pheromone compared to blacklight, while a later summer flight period showed a weak moth response to the pheromone relative to blacklight. At this time, we do not know which trap type might best indicate spotted cutworm abundance and risk to crops.
... Studies of receptor neurons (Almaas et a1 1991) as well as antenna1 lobe projection neurons (Christensen et a1 I989 ;Christensen et a1 1991) in H zea males have suggested that Z9-14:AL at low concentrations might be able to replace Z9-16:AL in the H zea pheromone blend Nevertheless, when flight tunnel behavioral experiments (Tables 2-4) confirmed that these compounds were indeed somewhat mutually replaceable in their ability to evoke upwind flight, the results were surprising, since all previous reports have supported the idea that Z9-14 : AL exclusively acts antagonistically to H zea pheromone-mediated behavior (Haile et a1 1973;Roach 1975;Shaver et a1 1982;Carpenter et a1 1984;Lopez and Witz 1988) The ability to replace Z9-16: AL with Z9-14: AL in H zea males, both at the behavioral and receptor cell level, has major evolutionary importance We hypothesize that such low-specificity receptors can readily accept and respond to molecules formed as a result of a mutation affecting the emitted blend In contrast to previous evolutionary models (cf Roelofs and Comeau 1969;Lanier and Burkholder 1974), even a major mutation affecting the pheromone biosynthetic pathway need not be lost due to the lack of a simultaneous similar mutation in the receiver Rather, receptor neurons would allow for adequate levels of mate-finding to continue among mutant senders and normal receivers, despite the altered blend Given appropriate selection pressures, communication among mutant senders and normal receivers could even be favored, and we believe that this type of change may have shaped the current H zea communication system ...
1.
Helicoverpa zea males flew upwind and successfully contacted the source when presented with 2-component blends consisting of their principal conspecific sex pheromone component, (Z)-11-hexadecenal, plus small amounts of (Z)-9-tetradecenal, a key secondary component in the Heliothis virescens blend which has heretofore been considered antagonistic to H. zea pheromone-mediated behavior. Neurophysiological studies of H. zea antennal receptor neurons and central interneurons had suggested that this unexpected antagonistic effect on behavior might occur.
2.
When the amount of (Z)-9-tetradecenal in the blend reached 15% relative to the principal component its effect did become antagonistic with significantly more H. zea males remaining quiescent. Five-to-fifteen percent (Z)-9-tetradecenal is emitted by H. virescens in its pheromone blend, levels that evoked optimal upwind flight and source contact in H. virescens males.
3.
As suggested by studies of H. virescens antennal receptor neurons, H. virescens males were unresponsive to the reciprocal inter-specific blend, comprised of (Z)-11-hexadecenal plus various percentages of (Z)-9-hexadecenal.
4.
Receptors that allow such mutual replacement of compounds might permit significant shifts in pheromone systems; a single mutation that drastically alters the female sex pheromone blend could still be carried in a population due to the successful attraction of normal males by mutant females.
... Because PBT and BLT captures evolve differently at low population densities or when mated females are the majority among females, Oloumi-Sadeghi et al. (1975) suggested a competition hypothesis in which the pheromone bait and calling European corn borer females are pheromone sources "competing" for the attraction of males. Studying Heliothis (now Helicoverpa) zea (Boddie), Roach (1975) argues that in high population conditions, pheromone baits are less efÞcient because of a higher probability of males meeting a calling female rather than the trap. This hypothesis has been often cited for European corn borer (Kennedy and Anderson 1980, Fletcher-Howell et al. 1983, Durant et al. 1986, Thompson et al. 1987, Bartels and Hutchison 1998, Bartels et al. 1999. ...
Since the identification of female European corn borer, Ostrinia nubilalis (Hübner) pheromone, pheromone-baited traps have been regarded as a promising tool to monitor populations of this pest. This article reviews the literature produced on this topic since the 1970s. Its aim is to provide extension entomologists and other researchers with all the necessary information to establish an efficient trapping procedure for this moth. The different pheromone races of the European corn borer are described, and research results relating to the optimization of pheromone blend, pheromone bait, trap design, and trap placement are summarized followed by a state-of-the-art summary of data comparing blacklight trap and pheromone-baited trap techniques to monitor European corn borer flight. Finally, we identify the information required to definitively validate/invalidate the pheromone-baited traps as an efficient decision support tool in European corn borer control.
Plum fruit moth (PFM), Grapholita funebrana TreiTschke, 1835, is a destructive pest of Rosaceae species in different parts around the world including Iran. In the current study, population fluctuations of this pest at two major production area of Kohgiluyeh and Boyer- Ahmad province (Dehbar-Aftab and Karyak regions), Iran, was monitored using pheromone traps. Our results revealed that population fluctuations of the PFM have two peaks in Dehbar-Aftab and Karyak regions and hence, this pest has two generations at both site studies. In the first generation, first adult males in Dehbar-Aftab region were captured on April 5. At Karyak region, this event was observed 3 days later (April 8). The peak of captured adults for Dehbar-Aftab and Karyak regions was recorded on April 21 (33.33 male per trap) and April 24 (55.5 male per trap), respectively. Population fluctuations of the second generation of PFM were also revealed that the first male in Dehbar-Aftab and Karyak regions was observed on May 18 and May 19, respectively. Furthermore, the highest population at Dehbar-Aftab and Karyak regions was 27.83 and 30.75 (male per trap) on May 27 and May 29, respectively. In the second generation, population of the PFM in Dehbar-Aftab reaches its peak sooner than Karyak. Duration of time interval between two peaks of the first and second generations was lasted 37 and 36 days at Dehbar-Aftab and Karyak regions, respectively. Although the observed difference was less noticeable, but the higher elevation above sea level at Dehbar-Aftab region could decrease the effective temperature for growth and development of the PFM and subsequently the time interval
between two peaks was prolonged.
Key words: Plum fruit moth, Grapholita funebrana, Population fluctuations, Pheromone
tarp, Kohgiluyeh and Boyer-Ahmad
The development and deployment of crop varieties defended or tolerant against insect attack is a major tactic in pest management. In agricultural terms, plant resistance to insects is a property that enables a plant to avoid, tolerate, or recover from the injurious effects of insect feeding and oviposition. Plants vary considerably in their mechanisms for defense against insects. Defensive strategies range from disruption of insect behavior and development to repair or replacement of organs and tissues damaged through insect attack. The purpose of this chapter is to present research methods and considerations appropriate for: (1) evaluation and development of insect-resistant cultivars, and (2) analysis of plant traits conferring resistance. Additional information of this type is provided by Chesnokov (1962), Dahms (1972), Smith (1978), Tingey and Pillemer (1977), and Maxwell and Jennings (1980).
We evaluated the efficiency of a pheromone trap for monitoring the sorghum plant bug, Stenotus rubrovittatus. The most effective trap position in a paddy field was ≥7 m inside the field's edge. We also evaluated the pheromone trap as an alternative to capture by sweeping. The number of males captured in traps increased before the increase by sweeping three paddy fields. These results suggest that the pheromone trap can be utilized as a tool to support the decision for control or damage estimation of S. rubrovittatus in the early stage of insect invasion into paddy fields.
Adult Helicouerpa zea (Boddie) black light trap and pheromone trap catches were related to oviposition on corn and tomatoes in an attempt to assess the utility of the pheromone trap for making pest management decisions on tomato in western North Carolina. Pheromone trap catches increased during early stages of H. zea night periods, while increases in black light trap catches did not occur until later in the season when populations were at their highest levels as indicated by egg densities. Oviposition on tomato was low until surrounding corn fields became unattractive (i.e., dried silk) to ovipositing females, but once oviposition was initiated on tomato it continued throughout the remainder of the season. Lycopersicon hinmtum Humb. PI 126445, a wild tomato species that is more attractive to ovipositing females than L. esculentum Miller cv. Walter, enabled us to detect the switch from corn to tomato more readily. Correlations between pheromone trap catches and oviposition on tomato were significant only in 1988; but in 1987 and 1989, trap catches were significantly correlated with oviposition on tomato occurring 1 and 2 wk. respectively, prior to pheromone trap catches. Pheromone traps may be most useful for the early detection of H. zea oviposition on tomatoes by providing a means to time egg scouting.
Simple pheromone traps were assessed to identify a suitable trap for use in Tanzania to monitor population size and subsequently forecast outbreaks of Heliothis armigera. The Ukiriguru trap was found to be satisfactory and was therefore adopted. The efficiency of the Ukiriguru pheromone trap relative to a Robinson light trap in monitoring the activity of H. armigera was also assessed over a three year period. Overall, although the light trap caught a proportionately higher number of moths, there was evidence that the pheromone trap could be used reliably to monitor the activity of this insect in Tanzania until a more suitable trap is identified. The relationship between the number of moths caught in the pheromone and light traps was studied. Although the number of females and males caught at the light trap at peak catch were in phase in two out of the three years of study, there was no relationship between the ratio of males to females with the size of female catch. The relationship between the number of moths caught at the pheromone trap and moths caught at the light trap was variable. Similarly, the ratio of males caught in the pheromone trap to the number of females caught in the light trap with the size of the female catch in the light trap was also variable. Thus, further studies on the sexual structure of moth catches at the pheromone and light traps is needed to increase the understanding of how these traps function.
Abstract Electroantennograms were recorded from the antennae of adult male and female corn earworms, Heliothis zea (Boddie). A total of seventeen female moth sex pheromone components from several species were tested. Of these, two components elicited significantly greater responses than the other fifteen. These were (Z)-11-hexadecenal, a conspecific component, and (Z)-9-tetradecenal, a component found in the pheromone blend of a sympatric species H.virescens (F.) that inhibits attraction of H.zea males. The results from dose-response and selective adaptation studies indicate that there are separate populations of receptors for these two chemical signals on the antenna of male H.zea. The more sensitive population is selective for (Z)-11-hexadecenal, while the less sensitive one responds to (Z)-9-tetradecenal. These findings provide a physiological basis by which H.zea males can distinguish the interspecific repellent from the conspecific pheromone blend. It is likely that this discrimination contributes to reproductive isolation between these two species.
1.
The antennal lobes (ALs) in the brain of the corn earworm moth Helicoverpa zea (formerly Heliothis zea; Lepidoptera: Noctuidae) were examined using combined anatomical and electrophysiological methods. Like other moths, male H. zea possess a sex-specific macroglomerular complex (MGC) for processing information about the female sex-pheromone blend. Unlike other moths, however, the MGC in H. zea consists of 3 distinct glomerular structures: two situated dorsally, and a third situated ventrally (Fig. 1).
2.
Intracellular recording and staining revealed a population of projection neurons that link the MGC with the protocerebrum (Figs. 4, 7, and 11). Four physiological classes of MGC neurons were identified based upon their responses to stimulation of the antenna with different components of the pheromonal blends of H. zea and Heliothis virescens (a sympatric species). One class responded selectively to the principal component in both species, Z11 16:AL (Figs. 2 and 3). A second, more broadly tuned class showed strong responses to Z11-16:AL and also to other pheromonal components (Figs. 5 and 6). A third class did not respond to Z11-16:AL but did respond to Z9-14:AL, a substance released by H. virescens females that helps attract conspecific males while it inhibits the attraction of H. zea males (Figs. 8, 9 and 10). Some of these neurons also responded to another pheromonal component required for male attraction in H. zea, Z9-16: AL. A fourth class responded in a unique fashion to a blend of Z11-16: AL and Z9-14:AL(Fig. 12).
3.
Projection neurons that responded to Z11-16:AL had arborizations in all 3 MGC glomeruli (Figs. 4 and 7), whereas neurons that responded to Z9-14:AL from H. virescens had arborizations in just one of the dorsal glomeruli of the MGC (Fig. 11). Thus these two types of neurons with widely different quality-coding functions have overlapping arborizations in one dorsal glomerulus in the MGC, demonstrating that the MGC is not exclusively involved with processing species-specific (pheromonal) information.
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)-11-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.
Responses of single receptor neurons in the antennae of male Helicoverpa zea to sex pheromone components and to behavioral antagonists were recorded using a cut-sensillum extracellular recording technique.
Three types of sensilla were identified from sampling 325 male-specific sensilla trichodea located at the lateral edge of
antennomeres. The majority of these sensilla (71%) contained a receptor neuron tuned to the principal sex pheromone component
(Z)-11-hexadecenal. A second sensillar type (10%) contained a receptor neuron that responded only to (Z)-9-tetradecenal. A third sensillar type (19%) contained a large-spiking neuron tuned to the secondary pheromone component
(Z)-9-hexadecenal, but this neuron also could be stimulated to equivalent spike frequencies by the same emitted amounts of (Z)-9-tetradecenal. A smaller-spiking neuron in this sensillar type responded to two compounds known to act only as behavioral
antagonists, (Z)-11-hexadecen-1-ol and (Z)-11-hexadecenyl acetate, and to (Z)-9-tetradecenal. Cross-adaptation studies confirmed the presence of one large- and one small-spiking neuron in the third
sensillar type. Dose-response studies correlated to collected stimuli amounts showed that the large-spiking neuron in the
third sensillar type was equally tuned to (Z)-9-hexadecenal and (Z)-9-tetradecenal, whereas the smaller-spiking neuron was far more sensitive to (Z)-11-hexadecen-1-ol and to (Z)-11-hexadecenyl acetate than to (Z)-9-tetradecenal.
1.
Responses of single olfactory receptor neurons to pheromones were recorded with tungsten microelectrodes on the antennae of male Helicoverpa (Heliothis) zea. Recordings were obtained from the male specific sensilla trichodea type 1.
2.
More than half (49/91 units) could be classified as olfactory receptor neurons, 35 of which were selective for pheromone components of the heliothine moths H. zea and Heliothis virescens. The majority (31/35) were most responsive to the principal component (Z)-11-hexadecenal (Z11-16AL). The other 4 were tuned to (Z)-9-tetradecenal (Z9-14AL), which is a pheromone component in the sympatric species H. virescens, and also interrupts attraction of H. zea males.
3.
The specificity and sensitivity of these neurons were similar to the corresponding neurons in H. virescens, suggesting homologous populations of neurons in the two species. No other neurons selective for other pheromone compounds were identified.
4.
Receptor neurons of both types (tuned to Z11-16AL and Z9-14AL respectively) showed variations in temporal response characteristics. Some responses showed a pronounced phasic spiking component, a rapid decay, and return to background activity after stimulation. Other responses were more prolonged, far outlasting the stimulation period. Phasic neurons also followed short, rapid stimulus pulses better than tonic neurons, suggesting that they may encode different features of an intermittent pheromone plume.
Evaluations conducted by placingHeliothis virescens (F.) sex pheromone (virelure) dispensers at different distances in the predominant downwind and upwind directions fromHeliothis zea (Boddie) pheromone traps indicated that reductions inH. zea male captures were greatest relative to distance when theH. zea traps were located downwind from the virelure dispensers than when the traps were located upwind. When operating traps for both species at the same site, the influence of virelure dispensers on captures inH. zea pheromone traps would be minimized by placing theH. zea traps upwind of theH. virescens traps and, if wind direction is variable, the traps should be spaced at least 75 m apart.
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