植物化学通讯研究进展

 生物的信息传递是生命科学中引人入胜的研究领域之一,生物种间种内和个体内都存在着物理和化学等各种信息交流方式。植物种间种内是否通过物理信号进行通讯交流还是一个未知数,但邻近的同种或异种植物通过化学物质为媒介的通讯关系确是客观存在的。最近,愈来愈多的研究证明：许多陆生植物种可以合成并释放特定的次生物质,这些次生物质可以通过空气和土壤两种载体进行信息传递,尤其是在植物受到侵袭和寄生条件下。茉莉酮酸甲酯、水杨酸甲酯和乙烯等挥发性次生物质被确证为以空气为媒介进行植物种间和种内通讯的化学信号分子。植物根分泌的黄酮和氢醌等分子也可以经土壤媒介传递信息。由于在自然条件下植物根系分泌物的收集和活性信号分子的俘获及鉴定技术还未能突破,这增加了以土壤为媒介的植物种间和种内化学通讯关系研究的难度。但不论如何,植物的化学通讯是植物种间和种内交流的主要方式,植物间的化学通讯关系的研究还处于突破的前夜,这方面的任一研究成果都会引起世界性的关注。因此,破译植物种间和种内化学通讯密码具有重要的学术价值。     

Morphological and chemical analysis of male scent organs in the butterfly genus Pyrgus (Lepidoptera: Hesperiidae)

Chemical communication in the family Hesperiidae (Lepidoptera) is practically unstudied, even though this group includes approximately 4,000 species and represents a fifth of the world’s butterfly fauna. We present the first comparative morphological and chemical analysis of scent organs for nine species in the genus Pyrgus, the most species-rich hesperiid genus in the Palearctic region. Our results show that the morphology of the two main male scent organs—the costal fold and the tibial tufts—does not differ between species. The chemical analyses detected a total of 125 different compounds exclusively present in these organs. We document great interspecific differences and much narrower intraspecific variability in the chemical profiles. The dynamics of chemical versus genetic distances indicate two different phases: a faster (but more variable) initial chemical divergence at lower genetic divergences (probably related to speciation) and a slower but more constant differentiation (drift). As a result most species can be identified based on their chemical profiles, except for a closely related species pair (P. malvae/P. malvoides) for which hybridisation is common in the contact zone. Our results suggest that the Hesperiidae is a group with great potential for the study of chemical communication that deserves further attention.     

Chemical communication in the lacertid lizard Podarcis muralis: the functional significance of testosterone

Chemical signals are essential for intersexual communication in many animals, including lizards. While faeces have been suggested to contain socially relevant chemical stimuli, epidermal gland secretions are generally believed to be the leading source of chemosignals involved in lizard communication. Early research has shown that sex hormones affect epidermal gland activity, with androgens stimulating gland/pore size and/or gland productivity. However, the functional significance of hormone‐induced glandular activity in lizard chemical communication remains unclear. In this study, we manipulated testosterone (T) concentrations in male Podarcis muralis lizards. While T‐supplementation did not change pore size, it did increase secretion production substantially. Chemosensory tests showed that female conspecifics tongue‐flick at a higher rate and more quickly towards the secretion of males with experimentally increased T levels than towards the secretion of control males, suggesting that females can discriminate between males with dissimilar T levels based on chemical cues of secretion alone. Based on the scent of faeces, however, females were unable to discriminate between males with differential T levels. Also, females reacted more quickly when offered larger amounts of secretion – irrespective of whether secretions were obtained from control or T‐increased males. This result indicates that secretion quantity affects chemosignal detectability in Podarcis muralis.     

Intra- and interspecific aggression do not modulate androgen levels in dusky gregories,yet male aggression is reduced by an androgen blocker

Discussions about social behavior are generally limited to fitness effects of interactions occurring between conspecifics. However, many fitness relevant interactions take place between individuals belonging to different species. Our detailed knowledge about the role of hormones in intraspecific interactions provides a starting point to investigate how far interspecific interactions are governed by the same physiological mechanisms. Here, we carried out standardized resident–intruder (sRI) tests in the laboratory to investigate the relationship between androgens and both intra- and interspecific aggression in a year-round territorial coral reef fish, the dusky gregory, Stegastes nigricans. This damselfish species fiercely defend cultivated algal crops, used as a food source, against a broad array of species, mainly food competitors, and thus represent an ideal model system for comparisons of intra-and interspecific territorial aggression. In a first experiment, resident S. nigricans showed elevated territorial aggression against intra- and interspecific intruders, yet neither elicited a significant increase in androgen levels. However, in a second experiment where we treated residents with flutamide, an androgen receptor blocker, males but not females showed decreased aggression, both towards intra- and interspecific intruders. Thus androgens appear to affect aggression in a broader territorial context where species identity of the intruder appears to play no role. This supports the idea that the same hormonal mechanism may be relevant in intra- and interspecific interactions. We further propose that in such a case, where physiological mechanisms of behavioral responses are found to be context dependent, interspecific territorial aggression should be considered a social behavior.     

Glia as mediators of steroid hormone action on the nervous system: An overview.

This special issue on steroids and glia represents the intersection of two emerging themes in the neurosciences: (a) Glia actively modulate and participate in brain function throughout life, and (b) glia are sensitive to steroid hormones. This overview begins by reviewing some of the basic principles of steroid hormone action on the brain and introducing the various glia that inhabit the peripheral and central nervous system. A prominent theme among the articles that follow is that glia may be direct targets for steroid hormones since they possess steroid receptors and the promoter region of glial-specific genes such as glutamine synthetase contain hormone-responsive elements. The articles in this special issue discuss evidence that glia may mediate steroid action on the nervous system in the context of (a) steroid metabolism, which may control the hormonal microenvironment of neurons both in the normal and injured brain; (b) brain development including sexual differentiation; (c) synaptic plasticity which may underlie the cyclic release of luteinizing hormone releasing hormone in the female rodent brain; (d) neural repair and aging; and (e) brain immune function. Another theme among these articles is that glia influence neurons via specific secreted and cell-surface molecules, and that steroids affect this mode of communication by altering the level of glial production of these signaling molecules and/or the sensitivity of neurons to such signals.     

Ants Use Partner Specific Odors to Learn to Recognize a Mutualistic Partner

Regulation via interspecific communication is an important for the maintenance of many mutualisms. However, mechanisms underlying the evolution of partner communication are poorly understood for many mutualisms. Here we show, in an ant-lycaenid butterfly mutualism, that attendant ants selectively learn to recognize and interact cooperatively with a partner. Workers of the ant Pristomyrmex punctatus learn to associate cuticular hydrocarbons of mutualistic Narathura japonica caterpillars with food rewards and, as a result, are more likely to tend the caterpillars. However, the workers do not learn to associate the cuticular hydrocarbons of caterpillars of a non-ant-associated lycaenid, Lycaena phlaeas, with artificial food rewards. Chemical analysis revealed cuticular hydrocarbon profiles of the mutualistic caterpillars were complex compared with those of non-ant-associated caterpillars. Our results suggest that partner-recognition based on partner-specific chemical signals and cognitive abilities of workers are important mechanisms underlying the evolution and maintenance of mutualism with ants.     

The Macroecology of Chemical Communication in Lizards: Do Climatic Factors Drive the Evolution of Signalling Glands?

Chemical communication plays a pivotal role in shaping sexual and ecological interactions among animals. In lizards, fundamental mechanisms of sexual selection such as female mate choice have rarely been shown to be influenced by quantitative phenotypic traits (e.g., ornaments), while chemical signals have been found to potentially influence multiple forms of sexual and social interactions, including mate choice and territoriality. Chemical signals in lizards are secreted by glands primarily located on the edge of the cloacae (precloacal glands, PG) and thighs (femoral glands), and whose interspecific and interclade number ranges from 0 to >?100. However, elucidating the factors underlying the evolution of such remarkable variation remains an elusive endeavour. Competing hypotheses suggest a dominant role for phylogenetic conservatism (i.e., species within clades share similar numbers of glands) or for natural selection (i.e., their adaptive diversification results in deviating numbers of glands from ancestors). Using the prolific Liolaemus lizard radiation from South America (where PG vary from 0 to 14), we present one of the largest-scale tests of both hypotheses to date. Based on climatic and phylogenetic modelling, we show a clear role for both phylogenetic inertia and adaptation underlying gland variation: (i) solar radiation, net primary productivity, topographic heterogeneity and precipitation range have a significant effect on PG variation, (ii) humid and cold environments tend to concentrate species with a higher number of glands, (iii) there is a strong phylogenetic signal that tends to conserve the number of PG within clades. Collectively, our study confirms that the inertia of niche conservatism can be broken down by the need of species facing different selection regimes to adjust their glands to suit the demands of their specific environments.     

Chemical information transfer in freshwater plankton

The structure of aquatic ecosystems is determined by complex interactions among individual organisms at different trophic levels. Although our basic understanding of how top-down and bottom-up processes interact to determine food-web dynamics has advanced, we still lack insights into how complex interactions and feedbacks affect the dynamics and structure of food webs. It is now becoming increasingly clear that, in addition to energy transfer from one trophic level to the other, there is exchange of information between these levels facilitated by the release of infochemicals by the organisms. There is evidence from recent studies that the exchange of chemical information in freshwater ecosystems is likely to play a decisive role in shaping structure and functioning of these systems. Chemical communication among freshwater organisms mediates many aspects of both predation and interspecific competition, which play key roles in determining community structure and ecosystem functioning. For example, consumer-induced defences in phytoplankton and zooplankton include modifications in the characteristics relating to life history, behaviour, morphology and biochemistry. These inducible defences affect trophic interactions by altering predator feeding rates through changes in attack rate or handling time, or both. Also host-specific fungal parasitism in phytoplankton is probably controlled by infochemicals. The motile fungi recognise their host by host-secreted compounds. Until now models describing the functioning of ecosystems mainly considered flows of biomass and energy. Integration of new knowledge about the role of chemical communication in these models may be one of the aims of ecological informatics. In this chapter I discuss how infochemicals may affect the dynamics and structure of planktonic food webs.     

A LuxS-dependent cell-to-cell language regulates social behavior and development in Bacillus subtilis

Cell-to-cell communication in bacteria is mediated by quorum-sensing systems (QSS) that produce chemical signal molecules called autoinducers (AI). In particular, LuxS/AI-2-dependent QSS has been proposed to act as a universal lexicon that mediates intra- and interspecific bacterial behavior. Here we report that the model organism Bacillus subtilis operates a luxS-dependent QSS that regulates its morphogenesis and social behavior. We demonstrated that B. subtilis luxS is a growth-phase-regulated gene that produces active AI-2 able to mediate the interspecific activation of light production in Vibrio harveyi. We demonstrated that in B. subtilis, luxS expression was under the control of a novel AI-2-dependent negative regulatory feedback loop that indicated an important role for AI-2 as a signaling molecule. Even though luxS did not affect spore development, AI-2 production was negatively regulated by the master regulatory proteins of pluricellular behavior, SinR and Spo0A. Interestingly, wild B. subtilis cells, from the undomesticated and probiotic B. subtilis natto strain, required the LuxS-dependent QSS to form robust and differentiated biofilms and also to swarm on solid surfaces. Furthermore, LuxS activity was required for the formation of sophisticated aerial colonies that behaved as giant fruiting bodies where AI-2 production and spore morphogenesis were spatially regulated at different sites of the developing colony. We proposed that LuxS/AI-2 constitutes a novel form of quorum-sensing regulation where AI-2 behaves as a morphogen-like molecule that coordinates the social and pluricellular behavior of B. subtilis.     

Intracolony chemical communication in social insects

Chemical messengers are the primary mode of intracolony communication in the majority of social insect species. Chemically transmitted information plays a major role in nestmate recognition and kin recognition. Physical and behavioral castes often differ in chemical signature, and queen effects can be significant regulators of behavior and reproduction. Chemical messengers themselves differ in molecular structure, and the effects on behavior and other variables can differ as a consequence of not only molecular structure of the chemical messenger itself but also of its temporal expression, quantity, chemical blends with other compounds, and effects of the environment. The most studied, and probably the most widespread, intracolony chemical messengers are cuticular hydrocarbons (CHCs). CHCs are diverse and have been well studied in social insects with regard to both chemical structure and their role as pheromones. CHCs and other chemical messengers can be distributed among colony members via physical contact, grooming, trophallaxis, and contact with the nesting substrate. Widespread intracolony distribution of chemical messengers gives each colony a specific odor whereby colony members are integrated into the social life of the colony and non-members of the colony are excluded. Colony odor can vary as a function of genetic diversity within the colony, and the odor of a colony can change as a function of colony age and environmental effects. Chemical messengers can disseminate information on the presence of reproductives and fertility of the queen(s) and workers, and queen pheromone can play a significant role in suppressing reproduction by other colony members. New analytical tools and new avenues of investigation can continue to expand knowledge of how individual insects function as members of a society and how the society functions as a collective.     

Selection to attract pollinators and to confuse antagonists specializes fig–pollinator chemical communications

Chemical communication is critical in establishing angiosperm–pollinator mutualisms. However, our understanding of how chemical communication shapes coevolution remains limited. Here, we integrated information theory to model three coevolutionary scenarios (I‒III), where the pollinator fitness is always optimized by the highest certainty of chemical information provided by plants, but plant fitness is determined by (I) the certainty of chemical information attracting pollinators, (II) the uncertainty of chemical information confusing antagonists, or (III) both aspects. We found that the statistical properties of empirical plant volatiles from 45 pairs of fig–pollinator mutualisms were best explained by the selection from both pollinators and antagonists (scenario III). Under this scenario, plant–pollinator mutualisms evolve to be specialized and as few as two volatile chemicals could supply sufficient information for pollinators’ host identification. Our study provides new insights into plant–pollinator coevolution and will facilitate further studies on the evolution and diversification in specialized plant–pollinator–herbivore systems.     

Reverse Chemical Ecology Suggests Putative Primate Pheromones

Pheromonal communication is widespread among living organisms, but in apes and particularly in humans there is currently no strong evidence for such phenomenon. Among primates, lemurs use pheromones to communicate within members of the same species, whereas in some monkeys such capabilities seem to be lost. Chemical communication in humans appears to be impaired by the lack or malfunctioning of biochemical tools and anatomical structures mediating detection of pheromones. Here, we report on a pheromone-carrier protein (SAL) adopting a “reverse chemical ecology” approach to get insights on the structures of potential pheromones in a representative species of lemurs (Microcebus murinus) known to use pheromones, Old-World monkeys (Cercocebus atys) for which chemical communication has been observed, and humans (Homo sapiens), where pheromones and chemical communication are still questioned. We have expressed the SAL orthologous proteins of these primate species, after reconstructing the gene encoding the human SAL, which is disrupted due to a single base mutation preventing its translation into RNA. Ligand-binding experiments with the recombinant SALs revealed macrocyclic ketones and lactones as the best ligands for all three proteins, suggesting cyclopentadecanone, pentadecanolide, and closely related compounds as the best candidates for potential pheromones. Such hypothesis agrees with the presence of a chemical very similar to hexadecanolide in the gland secretions of Mandrillus sphinx, a species closely related to C. atys. Our results indicate that the function of this carrier protein has not changed much during evolution from lemurs to humans, although its physiological role has been certainly impaired in humans.     

Interactions between the immune and neuroendocrine systems: clinical implications

The endocrine and immune systems are interrelated via a bidirectional network in which hormones affect immune function and, in turn, immune responses are reflected in neuroendocrine changes. This bidirectional communication is possible because both systems share a common "chemical language" that results from a sharing of common ligands (hormones and cytokines) and their specific receptors. Cytokines are important partners in this crosstalk. They play a role in modulating the hypothalamo-pituitary-adrenal (HPA) axis responses at all three levels: the hypothalamus, the pituitary gland and the adrenals. Acute effects of cytokines are produced at the central nervous system level, particularly the hypothalamus, whereas pituitary and adrenal actions are slower and are probably involved during prolonged exposure to cytokines such as during chronic inflammation or infection. Several mechanisms have been proposed by which peripheral cytokines may gain access to the brain. They include an active transport through the blood-brain barrier, a passage at the circumventricular organ level, as well as a neuronal pathway through the vagal nerve. The immune-neuroendocrine interactions are involved in numerous physiological and pathophysiological conditions and the interactions with the HPA axis may represent a mechanism through which the immune system, by stimulating the production of glucocorticoids, avoids an overshoot of inflammatory response. They may also be involved in the state of hypogonadism, of hypothyroidism and growth inhibition which can occur during inflammatory and infectious diseases. The crosstalk between the immune and endocrine systems is important to homeostasis, since the interactions can produce various appropriate adaptative responses when homeostasis is threatened.     

EFFECTS OF SUBLETHAL ESERINE ON THE CHEMICAL COMMUNICATION SYSTEM OF ASIAN CORN BORER,OSTRINIA FURNACALIS (GUENEE)*

Abstract Topically applied sublethal doses of eserine may interrupt chemical communication between the two sexes of Asian corn borer, Ostrinia furnacalis (Guenee), by affecting calling and sex pheromone titre released by the females. (1) Studies on the effects of sublethal eserine on the chemical communication system of O. furnacalis indicated that there was a decreasing probability of females calling and sex pheromone titre as the eserine dosage increased from 0.27 to 2 700 ng, with no effect on the periodicity. However, at 2 700 ng, the E/Z ratio of the sex pheromone components was affected. The sexual chemical communication system could not control within narrow level. (2) The recovery test of 27ng‐treated female indicated that the calling percentages of the 1st, 2nd and 4th day post‐treatment were 50%, 78% and 84% respectively. Sex pheromone titre was 40%, 40% and 80% of control female repectively. There was a trend toward recovery. The sexual chemical communication system could control within narrow level from the 2nd day post‐treatment.     

Listening to the brain: microelectrode biosensors for neurochemicals

Chemical signalling underlies every function of the nervous system, from those of which we are unaware, for example, control of the heart, to higher cognitive functions, such as emotions, learning and memory. Neurotransmitters and neuromodulators mediate communication between neurons and between neurons and non-neural cells such as glia and muscle. In the past, the means for studying the production and release of these signalling agents directly has been limited in its temporal and spatial resolution relative to the dynamics of chemical signalling and the structures of interest in the brain. Now microelectrode biosensors are becoming available that give unprecedented spatial and temporal resolution, enabling, for the first time, direct measurement in real time of the chemical conversations between cells in the nervous system.     

Honest signalling through chemicals by elephants with applications for care and conservation

Chemical signals are difficult to fake because they are often directly associated with phenotype and physiological condition, and hence likely to be honest signals for intraspecific communication. Chemical signals may be modified after release by the sender or by the environment. The proximate and ultimate signal meanings are dependent not only on the condition of the sender, but also on the physiological status of the receiver. Understanding the relationships and linkage among signal modality, signal function and receiver response is an essential first step before using natural signals for animal care and conservation. Our studies on chemical communication in Asian and African elephants combine observational and experimental work in captive and wild settings to further this understanding. Recent discoveries of pheromones in Asian elephants and the biochemistry of these compounds provide strong evidence that such chemical signals are honest indicators of reproductive status. Chemically identifying the signals and verifying their functional context with statistically robust behavioural studies are essential aspects for understanding the communication system. Additionally, the investigative process of discovering, identifying and verifying the function of chemical signals among captive elephants offers safe and stimulating enrichments. The knowledge garnered from such studies has potential conservation benefits for managing wild elephant populations. A firm foundation of scientific information is required for successful behavioural investigations and applied conservation and enrichment components.     

Colony-level chemical profiles do not provide reliable information about colony size in the honey bee

1. Chemical communication facilitates colony function across social insects, providing workers with information about individual and colony state. Although workers use chemical cues to detect developmental transitions in individuals, it is unknown whether workers can also use colony-level chemical profiles to detect the developmental state of their colony. Indeed, it is largely unknown how colony-level chemical profiles change as colonies grow and develop. 2. Reproductive onset is a major developmental transition and, in the honey bee, Apis mellifera, colonies must surpass a threshold colony size before workers will invest in reproduction. Given the ubiquity of chemical communication, the present study investigated whether colony-level chemical profiles change with colony size. 3. Chemical compounds deposited by workers of three colony sizes (5000, 10 000, 15 000 workers) collected over a 4-day time-series (0, 12, 24, 48, 72, and 96 h), as well as worker cuticular lipids, were sampled. 4. In total, 26 compounds deposited on nest surfaces and 20 compounds in worker cuticular lipids were identified; it took up to 24 h for sampled nest surfaces to reach saturation in the number and amount of deposited compounds. 5. Among these compounds, no qualitative or quantitative indicators of colony size were found, suggesting that deposited chemical compounds are not semiochemicals in this context. Volatile pheromones have also been shown previously to not play a role in signaling colony size. Therefore, honey bee workers are unlikely to use deposited chemical cues to detect colony size, and must rely instead on other modalities, such as physical cues of worker density.     

Faecal pellets as burrow markers: intra- and interspecific odour recognition by western plethodontid salamanders

Chemical communication is widespread among plethodontid salamanders (Caudata: Plethodontidae), but little information exists on the role of odours in interspecific competition in general and among species in western North America in particular. The present study examined the potential of faecal odours for intra- and interspecific communication among sympatric plethodontids in two-choice tests in the laboratory. In experiment 1, Plethodon vehiculum and Aneides ferrus from Vancouver Island, B.C., Canada, were presented with two burrows marked with (1) a faecal pellet of male P. vehiculum versus a control clay pellet, and (2) a faecal pellet of male A. ferreus versus a control pellet. In experiment 2, responses of P. vehiculum, P. dunni and P. vandykei from Washington, U.S.A., were tested towards faecal pellets of conspecific males and females, and towards pellets of congeneric males. Both P. vehiculum and P. dunni distinguished odours of conspecific males and females, based on their behavioural responses towards faecal and control pellets. Only P. dunni, however, avoided burrows marked with faeces of conspecific individuals. In contrast, neither A. ferreus nor P. vandykei appeared to distinguish faecal odours of conspecific salamanders from control pellets. In tests with odours of heterospecific individuals, P. dunni and P. vehiculum distinguished odours of each other, and P. vandykei distinguished odours of P. vehiculum. The data from these two experiments suggest that P. dunni use faecal pellets as territorial markers both in intraspecific communication and in interspecific encounters with P. vehiculum.     

THE CONTROL OF SEXUAL MORPHOGENESIS IN THE ASCOMYCOTINA

(1) A series of factors controls sexual morphogenesis in the Ascomycotina, a process involving the formation of novel structures such as ascocarps (fruit bodies) and asci (sacs containing spores) during sexual reproduction. (2) Environmental and genetic factors must be correct before Ascomycetes may sexually reproduce. Compatibility in many heterothallic species is under polygenic control, with the mating type loci and also other genetic factors determining the productivity of sexual crosses. (3) Classical genetic studies have shown that sexual morphogenesis involves the expression of a series of developmentally regulated genes, and this has been confirmed by recent molecular studies which have demonstrated changes in patterns of mRNA and protein synthesis during ascocarp formation. (4) Hyphal differentiation leading to the formation of mature fruit bodies occurs in response to a series of signals, which include various physical and chemical factors. (5) Chemical sex factors have been identified which are believed to have important regulatory or nutritional roles in sexual morphogenesis. These include the following. (a) Diffusible sex hormones which may regulate developmental switching between asexual and sexual modes of reproduction, including (i) pheromones involved with the induction of gametangia and gamete attraction, and (ii) sex morphogens involved with triggering particular stages of fruit body formation. (b) Sexual growth substances which are required as nutrients, and may be precursors for the production of sex hormones, or metabolites used in the synthesis of novel sexual structures. Most of these sex factors are lipids. (6) Certain sex morphogens and sexual growth substances have been shown to exhibit activity in a variety of fungal species, suggesting that fungi of related phylogenetic descent may utilize similar metabolites or signalling factors during sexual reproduction. (7) Phenoloxidase enzymes may catalyse hyphal aggregation in developing fruit bodies. (8) Initial stages of ascocarp development may occur independently of the events of the sexual cycle. However, a link(s) with the functional ascogenous hyphae is needed for the formation of morphologically mature ascocarps. (9) Suitable environmental conditions are sufficient to trigger sexual morphogenesis in homothallic Ascomycetes. However, an extra level of control is present in heterothallic species, with a compatible partner required to complete sexual reproduction. This may be partly because novel regulatory products, formed by the combined action of the mating type loci of different partners, are required for further ascocarp development. (10) Further research is required to identify more fungal chemical sex factors and to determine the role of environmental stress in controlling sexual morphogenesis, and how this may be related to temporal patterns in the expression of mating type genes.     

Sublethal effects of permethrin on the chemical communication system of the pink bollworm moth,Pectinophora gossypiella

Topically applied sublethal doses of permethrin can interrupt chemical communication between the sexes of Pectinophora gossypiella by affecting both the signaler and the responder. The probability of calling by females is reduced when they are treated with doses of permethrin which are much less than the LD₅₀. Similarly, key stages in the behavioral response of males to sex pheromone are effectively blocked at these low doses. Males recover from these effects 4 days after treatment, but calling by females is still significantly reduced at this time. Chemical control of P. gossypiella populations with permethrin may not be limited to mortality, and potentially includes effective control of behavioral aspects of chemical communication.