Courtship Responses Research Articles

Determination of Hourly Distribution of Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae) Using Sex Pheromone and Ultraviolet Light Traps in Protected Tomato Crops

Tuta absoluta (Meyrick), a leafminer that damages tomato leaves, terminal buds, flowers, and fruits, is a destructive tomato pest and is responsible for 80–100% of tomato yield losses globally. Different insect species have different courtship responses and phototropic flight rhythms. Improving the trapping effects of the sex pheromone and light traps is important for constructing an IPM system for T. absoluta. The present study explored the hourly distribution of T. absoluta adults caught by the sex pheromone (on the ground) and UV light (380 nm) traps in greenhouses over 24 h. The responses of males to sex pheromone (false female) lures were detected at dawn and early morning. The responses lasted for 3 h, from 05:30 (1 h before sunrise) to 08:30 (2 h after sunrise), and 95.8% of the males were caught during this period. The peak of the male responses to the sex pheromone was detected at 07:30 (from 06:30 to 07:30, 1 h after sunrise), and 80.8% of the males were caught during this period. The flight of male (proportion of 54.3%) and female (45.7%) adults toward the UV light traps occurred from 19:30 (time of sunset) to 06:30 (time of sunrise), lasted for 11 h, and exhibited a scotophase rhythm; 97.4% of the adults were caught during this period. The peak of adults flying toward the UV light traps occurred at 21:30 (from 20:30 to 21:30, 2 h after sunset). The rhythms of males’ responses to the sex pheromone and of the adults’ flight toward the UV lights can help to reveal the mechanisms of chemotactic and phototactic responses and may play a significant role in constructing an IPM system for this pest.

Mistaken identity may explain why male sea snakes (Aipysurus laevis, Elapidae, Hydrophiinae) \u201cattack\u201d scuba divers

Scuba-divers on tropical coral-reefs often report unprovoked “attacks” by highly venomous Olive sea snakes (Aipysurus laevis). Snakes swim directly towards divers, sometimes wrapping coils around the diver’s limbs and biting. Based on a focal animal observation study of free-ranging Olive sea snakes in the southern Great Barrier Reef, we suggest that these “attacks” are misdirected courtship responses. Approaches to divers were most common during the breeding season (winter) and were by males rather than by female snakes. Males also made repeated approaches, spent more time with the diver, and exhibited behaviours (such as coiling around a limb) also seen during courtship. Agitated rapid approaches by males, easily interpreted as “attacks”, often occurred after a courting male lost contact with a female he was pursuing, after interactions between rival males, or when a diver tried to flee from a male. These patterns suggest that “attacks” by sea snakes on humans result from mistaken identity during sexual interactions. Rapid approaches by females occurred when they were being chased by males. Divers that flee from snakes may inadvertently mimic the responses of female snakes to courtship, encouraging males to give chase. To prevent escalation of encounters, divers should keep still and avoid retaliation.

Chemical composition of body extracts from Apriona germari and its function in sexual communication

To elucidate the composition of semiochemicals of Apriona germari and its function in sexual communication, GC-MS was used to detect the composition of semiochemicals of the overall body and the end abdominal tissue extracts in A. germari. Y-tube olfactometer was used to determine the olfactory response of adult female and male to the standard compounds of the five main extracts. The contact reaction test with male and female adults was performed to the eluted adults that smeared tandard compounds. The results showed that the main ingredients of semiochemicals were alkanes and alkenes with more than 10 carbons. Concentration of (Z)-9-Tricosene was the highest, followed by heptacosane, nonacosane, nonadecene, octacosane, 9-Hexylheptadecane, aldehyde, and ester. Results of the olfactory reaction showed that nonacosane had a significant attractivity to both male and female adults, and that heptacosane had a significant attractivity only to female adults. Nonadecene had a extremely significant repellent activity to female adults. 1-docosene and (Z)-9-Tricosene had no evident role to the male and female adults. Results of the contact test showed that male adults had the strongest courtship responses to the eluted adults with 1-docosene, heptacosane and nonacosane. Female adults had the strongest courtship responses to the eluted adults with nonacosane. Our results indicated that 1-docosene, heptacosane, and nonacosane were important component of the sex pheromone of A. germari, which played an important role in the sexual communication.

Male responses suggest both evolutionary conservation and rapid change in chemical cues of female widow spiders

Understanding patterns of diversity in sexual signals can give insight into processes initiating, mediating or following from species diversification. Here we focus on female sex pheromones, which are widespread among animals, where some taxa show phylogenetic patterns of variation, but for others, ecological factors better explain pheromone diversity. Causes of differences in these patterns are unclear, and general insights require studying a broader range of taxa. Here we examined variation in the responses of male redback spiders, Latrodectus hasselti, to sex pheromones produced by three allopatric female congeners with different degrees of phylogenetic relatedness (from the same clade: Latrodectus mirabilis, Latrodectus hesperus; and from a different clade: Latrodectus geometricus) to infer pheromone divergence. We examined variation in male responses to conspecific and heterospecific females’ airborne and contact pheromones, which attract males and elicit courtship behaviour, respectively. We measured male courtship responses to extracted contact pheromones in isolation and male preferences in response to airborne pheromones and combined cues (pheromones, silk) in a two-choice maze. Male responses to airborne chemicals, contact chemicals and combined cues suggested variation in species specificity, with L. hasselti males showing strong discrimination against airborne pheromones of L. hesperus females (same clade), moderate evidence for discrimination based on contact cues of L. geometricus, but only when multiple sources of information were available (different clade), and no discrimination of L. mirabilis females (same clade) relative to conspecifics, regardless of the types of information available. Thus, male responses were not consistent with a phylogenetic pattern. Moreover, airborne pheromones can apparently diverge relatively rapidly, but airborne and contact pheromones may remain similar across long evolutionary timescales. We propose that differential responses to L. hesperus may arise from selection for population-level pheromone divergence within that species and that, in general, pheromones and male responses may be evolutionarily conserved across Latrodectus.

Active and passive sexual roles that arise in Drosophila male-male courtship are modulated by dopamine levels in PPL2ab neurons

The neurology of male sexuality has been poorly studied owing to difficulties in studying brain circuitry in humans. Dopamine (DA) is essential for both physiological and behavioural responses, including the regulation of sexuality. Previous studies have revealed that alterations in DA synthesis in dopaminergic neurons can induce male-male courtship behaviour, while increasing DA levels in the protocerebral posteriolateral dopaminergic cluster neuron 2ab (PPL2ab) may enhance the intensity of male courtship sustainment in Drosophila. Here we report that changes in the ability of the PPL2ab in the central nervous system (CNS) to produce DA strongly impact male-male courtship in D. melanogaster. Intriguingly, the DA-synthesizing abilities of these neurons appear to affect both the courting activities displayed by male flies and the sex appeal of male flies for other male flies. Moreover, the observed male-male courtship is triggered primarily by target motion, yet chemical cues can replace visual input under dark conditions. This is interesting evidence that courtship responses in male individuals are controlled by PPL2ab neurons in the CNS. Our study provides insight for subsequent studies focusing on sexual circuit modulation by PPL2ab neurons.

Gustatory adaptation affects sexual maturation in male German cockroaches, Blattella germanica

AbstractAdaptations to hazardous environmental factors are essential for survival, although they may be maladaptive in conditions where the hazard is absent. In German cockroach (Blattella germanica L.) populations, glucose aversion has evolved rapidly in response to glucose‐containing insecticidal baits, but little is known about the consequences of this behaviour in the absence of bait. In the present study, glucose‐averse (GA) and wild‐type (WT) male German cockroaches are restricted to a range of nutritionally defined diets containing either glucose or fructose as the sole carbohydrate source, and time to first expression of courtship is measured by stimulating the male antennae daily with isolated antennae from receptive, 6‐day‐old females. Glucose‐averse males that are restricted to glucose‐containing diets mature their courtship responses significantly later than GA males restricted to fructose‐containing diets, whereas there is no difference in maturation of courtship responses between GA males restricted to fructose‐containing diets and WT males restricted to diets containing either sugar type. Glucose‐averse males furthermore respond later to GA female antennae than to WT female antennae, all from 6‐day‐old females. This suggests that GA females are less sexually stimulating, and the results are also consistent with earlier findings showing that GA females contain less developed oocytes than WT females at this age. These findings demonstrate that an adaptive gustatory mutation conferring protection from a toxin may have comparatively detrimental effects under conditions where the toxin has vanished, both by delaying female sexual maturation and signalling and by delaying male sexual maturation and courtship under conditions where glucose is a major energy source.

First Quantification of Courtship Behavior in a Silver Fly, Leucopis palumbii (Diptera: Chamaemyiidae): Role of Visual, Olfactory and Tactile Cues

Research on the courtship and mating behavior of insects is the first step toward a full understanding of their behavioral ecology. Investigating mating behavioral sequences could help to unravel mate assessment and mate choice dynamics in entomophagous organisms, adding useful information to develop behavior-based control strategies. In this research, courtship and mating displays, magnitude of male-male sexual interactions and role of female-borne cues evoking male courtship were analyzed in Leucopis palumbii Rondani (Diptera: Chamaemyiidae), a larval predator of aphids. Courtship was initiated by the male and was characterized by three main steps: chasing of the female, wing fanning in her close proximity and tarsal tapping with forelegs on the female’s body. Copulation may follow lasting 765 ± 211.25 s. Same-sex interactions among males (i.e. wing fanning followed by tarsal tapping) were also registered. Male fanning before a successful courtship differed from fanning performed prior to an unsuccessful approach in terms of mean frequency. Female-borne stimuli played a key role in eliciting courtship responses from males. The best male’s response was achieved when physical and chemical cues arising from the female body were contemporarily provided, allowing synergistic visual, olfactory and tactile perception. Results contribute to understanding the role of visual, olfactory and tactile channels among sensory modalities used by aphidophagous Chamaemyiidae during sexual communication.

An eye for beauty: Lateralized visual stimulation of courtship behavior and mate preferences in male zebra finches, Taeniopygia guttata

Research on intersexual selection focuses on traits that have evolved for attracting mates and the consequences of mate choice. However, little is known about the cognitive and neural mechanisms that allow choosers to discriminate among potential mates and express an attraction to specific traits. Preferential use of the right eye during lateral displays in zebra finches, and lateralized expression of intermediate early genes in the left hemisphere during courtship led us to hypothesize that: (1) visual information from each eye differentially mediates courtship responses to potential mates; and (2) the ability to discriminate among mates and prefer certain mates over others is lateralized in the right eye/left hemisphere system of zebra finch brains. First, we exposed male zebra finches to females when using left, right or both eyes. Males courted more when the right eye was available than when only the left eye was used. Secondly, male preference for females – using beak color to indicate female quality – was tested. Right-eyed and binocular males associated with and courted orange-beaked more than gray-beaked females; whereas left-eyed males showed no preference. Lateral displays and eye use in male zebra finches increase their attractiveness and ability to assess female quality, potentially enhancing reproductive success.This article is part of a Special Issue entitled: CO3 2013.

Visual and Olfactory Female-Borne Cues Evoke Male Courtship in the Aphid Parasitoid Aphidius colemani Viereck (Hymenoptera: Braconidae)

We investigated the courtship and mating behavior of the pan-tropical polyphagous endoparasitoid Aphidius colemani Viereck. The courtship and mating displays, the magnitude of male-male sexual approaches and the role of female-borne cues evoking male courtship behavior were quantified. The sequence of events leading to copulation in this parasitoid did not differ from that found for other braconids. Females refused to copulate more than once. Same-sex courtships were observed among males and their possible role in an adaptive context is discussed. Olfactory female-borne cues played a key role in eliciting the courtship responses of males. Males were attracted by freshly dead females, but not by dead females soaked in hexane, nor by visual cues from females alone. Intense male wing fanning behavior was elicited by crushed abdomens of virgin females, suggesting that the female abdomen is the source of a short-distance pheromone crucial in evoking male courtship. Further studies are required to clarify the exact nature of the chemicals involved.

TwoDrosophilaDEG/ENaC Channel Subunits Have Distinct Functions in Gustatory Neurons That Activate Male Courtship

Trimeric sodium channels of the DEG/ENaC family have important roles in neurons, but the specific functions of different subunits present in heteromeric channels are poorly understood. We previously reported that the Drosophila DEG/ENaC subunit Ppk25 is essential in a small subset of gustatory neurons for activation of male courtship behavior, likely through detection of female pheromones. Here we show that, like mutations in ppk25, mutations in another Drosophila DEG/ENaC subunit gene, nope, specifically impair male courtship of females. nope regulatory sequences drive reporter gene expression in gustatory neurons of the labellum wings, and legs, including all gustatory neurons in which ppk25 function is required for male courtship of females. In addition, gustatory-specific knockdown of nope impairs male courtship. Further, the impaired courtship response of nope mutant males to females is rescued by targeted expression of nope in the subset of gustatory neurons in which ppk25 functions. However, nope and ppk25 have nonredundant functions, as targeted expression of ppk25 does not compensate for the lack of nope and vice versa. Moreover, Nope and Ppk25 form specific complexes when coexpressed in cultured cells. Together, these data indicate that the Nope and Ppk25 polypeptides have specific, nonredundant functions in a subset of gustatory neurons required for activation of male courtship in response to females, and suggest the hypothesis that Nope and Ppk25 function as subunits of a heteromeric DEG/ENaC channel required for gustatory detection of female pheromones.

To signal or not to signal? Chemical communication by urine-borne signals mirrors sexual conflict in crayfish

BackgroundSexual selection theory predicts that females, being the limiting sex, invest less in courtship signals than males. However, when chemical signals are involved it is often the female that initiates mating by producing stimuli that inform about sex and/or receptivity. This apparent contradiction has been discussed in the literature as 'the female pheromone fallacy'. Because the release of chemical stimuli may not have evolved to elicit the male's courtship response, whether these female stimuli represent signals remains an open question. Using techniques to visualise and block release of urine, we studied the role of urine signals during fighting and mating interactions of crayfish (Pacifastacus leniusculus). Test individuals were blindfolded to exclude visual disturbance from dye release and artificial urine introduction.ResultsStaged female-male pairings during the reproductive season often resulted in male mating attempts. Blocking female urine release in such pairings prevented any male courtship behaviour. Artificial introduction of female urine re-established male mating attempts. Urine visualisation showed that female urine release coincides with aggressive behaviours but not with female submissive behaviour in reproductive interactions as well as in intersexual and intrasexual fights. In reproductive interactions, females predominately released urine during precopulatory aggression; males subsequently released significantly less urine during mating than in fights.ConclusionsUrine-blocking experiments demonstrate that female urine contains sex-specific components that elicit male mating behaviour. The coincidence of chemical signalling and aggressive behaviour in both females and males suggests that urine release has evolved as an aggressive signal in both sexes of crayfish. By limiting urine release to aggressive behaviours in reproductive interactions females challenge their potential mating partners at the same time as they trigger a sexual response. These double messages should favour stronger males that are able to overcome the resistance of the female. We conclude that the difference between the sexes in disclosing urine-borne information reflects their conflicting interests in reproduction. Males discontinue aggressive urine signalling in order to increase their chances of mating. Females resume urine signalling in connection with aggressive behaviour, potentially repelling low quality or sexually inactive males while favouring reproduction with high quality males.

Jail baits: how and why nymphs mimic adult females of the German cockroach, Blattella germanica

The male German cockroach performs a characteristic courtship behaviour upon contacting a sexually receptive female: he turns away from the female and raises his wings, thereby exposing tergal glands whose reservoirs contain phagostimulatory substances. The female then mounts the male and feeds upon these nuptial secretions; this behaviour places her in the appropriate precopulatory position. The contact sex pheromone on the cuticular surface of the female, responsible for eliciting courtship behaviour in males, consists of a blend of six components that share a common biosynthetic pathway. An excised female antenna can elicit the full courtship display in males. We found that antennae taken from either male or female nymphs of various ages also could elicit the full courtship response in adult males. We extracted lipids from the cuticular surface of nymphs and, guided by behavioural assays, we fractionated the extracts using various chromatography procedures, including flash (column) chromatography, high-performance liquid chromatography and gas chromatography. Mass spectrometry analysis of behaviourally active fractions revealed two classes of courtship-eliciting compounds: all nymphs possessed a novel, still unidentified compound that elicited courtship in adult males. In addition, in last-instar females, we isolated four of the six adult female-specific contact sex pheromone components, consistent with differentiation of the sexes at this stage, and the onset of sexual maturation of the pheromone biosynthetic machinery. Our results support the interpretation that nymphs engage in sexual mimicry to gain access to male-produced nuptial tergal secretions that are exposed and can be secured only during courtship.

SIMULATING RANGE EXPANSION: MALE SPECIES RECOGNITION AND LOSS OF PREMATING ISOLATION IN DAMSELFLIES

Prolonged periods of allopatry might result in loss of the ability to discriminate against other formerly sympatric species, and can lead to heterospecific matings and hybridization upon secondary contact. Loss of premating isolation during prolonged allopatry can operate in the opposite direction of reinforcement, but has until now been little explored. We investigated how premating isolation between two closely related damselfly species, Calopteryx splendens and C. virgo, might be affected by the expected future northward range expansion of C. splendens into the allopatric zone of C. virgo in northern Scandinavia. We simulated the expected secondary contact by presenting C. splendens females to C. virgo males in the northern allopatric populations in Finland. Premating isolation toward C. splendens in northern allopatric populations was compared to sympatric populations in southern Finland and southern Sweden. Male courtship responses of C. virgo toward conspecific females showed limited geographic variation, however, courtship attempts toward heterospecific C. splendens females increased significantly from sympatry to allopatry. Our results suggest that allopatric C. virgo males have partly lost their ability to discriminate against heterospecific females. Reduced premating isolation in allopatry might lead to increased heterospecific matings between taxa that are currently expanding and shifting their ranges in response to climate change.

A Drosophila Protein Family Implicated in Pheromone Perception Is Related to Tay-Sachs GM2-Activator Protein

Low volatility, lipid-like cuticular hydrocarbon pheromones produced by Drosophila melanogaster females play an essential role in triggering and modulating mating behavior, but the chemosensory mechanisms involved remain poorly understood. Recently, we showed that the CheB42a protein, which is expressed in only 10 pheromone-sensing taste hairs on the front legs of males, modulates progression to late stages of male courtship behavior in response to female-specific cuticular hydrocarbons. Here we report that expression of all 12 genes in the CheB gene family is predominantly or exclusively gustatory-specific, and occurs in many different, often non-overlapping patterns. Only the Gr family of gustatory receptor genes displays a comparable variety of gustatory-specific expression patterns. Unlike Grs, however, expression of all but one CheB gene is sexually dimorphic. Like CheB42a, other CheBs may therefore function specifically in gustatory perception of pheromones. We also show that CheBs belong to the ML superfamily of lipid-binding proteins, and are most similar to human GM2-activator protein (GM2-AP). In particular, GM2-AP residues involved in ligand binding are conserved in CheBs but not in other ML proteins. Finally, CheB42a is specifically secreted into the inner lumen of pheromone-sensing taste hairs, where pheromones interact with membrane-bound receptors. We propose that CheB proteins interact directly with lipid-like Drosophila pheromones and modulate their detection by the gustatory signal transduction machinery. Furthermore, as loss of GM2-AP in Tay-Sachs disease prevents degradation of GM2 gangliosides and results in neurodegeneration, the function of CheBs in pheromone response may involve biochemical mechanisms critical for lipid metabolism in human neurons.

Changes in the Intensity of Male Courtship Behavior Following Physical Exposure of Males to Previously Unfamiliar Females in Brown Anoles (Anolis Sagrei)

Male Brown Anoles (Anolis sagrei) have been found in laboratory studies to court unfamiliar females more intensely than familiar females and in choice tests to preferentially court and mate with unfamiliar females. The objective of the present study was to determine how the intensity of male courtship behavior changes following physical exposure of males to previously unfamiliar females. The courtship behavior of males was recorded in 30-min courtship tests with familiar females (pretest), with unfamiliar females (first test), and with previously unfamiliar females after males had been physically exposed to them for two days (retest). When males were first visually exposed to unfamiliar females in the first test, they courted them significantly more intensely than they had courted familiar females in the pretest. Specifically, males gave more bobbing displays with dewlap extensions and spent more time adjacent to the stimulus female in courtship tests with unfamiliar females than in tests with familiar females. However, when males were housed with previously unfamiliar females for two days and then visually exposed to them in the retest, they did not court them significantly differently than they had courted familiar females. These results suggest that the heightened courtship response of males to unfamiliar females disappears relatively quickly after males have had physical exposure to females.

Modulation of Drosophila male behavioral choice.

The reproductive and defensive behaviors that are initiated in response to specific sensory cues can provide insight into how choices are made between different social behaviors. We manipulated both the activity and sex of a subset of neurons and found significant changes in male social behavior. Results from aggression assays indicate that the neuromodulator octopamine (OCT) is necessary for Drosophila males to coordinate sensory cue information presented by a second male and respond with the appropriate behavior: aggression rather than courtship. In competitive male courtship assays, males with no OCT or with low OCT levels do not adapt to changing sensory cues and court both males and females. We identified a small subset of neurons in the suboesophageal ganglion region of the adult male brain that coexpress OCT and male forms of the neural sex determination factor, Fruitless (Fru(M)). A single Fru(M)-positive OCT neuron sends extensive bilateral arborizations to the suboesophageal ganglion, the lateral accessory lobe, and possibly the posterior antennal lobe, suggesting a mechanism for integrating multiple sensory modalities. Furthermore, eliminating the expression of Fru(M) by transformer expression in OCT/tyramine neurons changes the aggression versus courtship response behavior. These results provide insight into how complex social behaviors are coordinated in the nervous system and suggest a role for neuromodulators in the functioning of male-specific circuitry relating to behavioral choice.

A Drosophila DEG/ENaC channel subunit is required for male response to female pheromones

Odorants and pheromones as well as sweet- and bitter-tasting small molecules are perceived through activation of G protein-coupled chemosensory receptors. In contrast, gustatory detection of salty and sour tastes may involve direct gating of sodium channels of the DEG/ENaC family by sodium and hydrogen ions, respectively. We have found that ppk25, a Drosophila melanogaster gene encoding a DEG/ENaC channel subunit, is expressed at highest levels in the male appendages responsible for gustatory and olfactory detection of female pheromones: the legs, wings, and antennae. Mutations in the ppk25 gene reduce or even abolish male courtship response to females in the dark, conditions under which detection of female pheromones is an essential courtship-activating sensory input. In contrast, the same mutations have no effect on other behaviors tested. Importantly, ppk25 mutant males that show no response to females in the dark execute all of the normal steps of courtship behavior in the presence of visible light, suggesting that ppk25 is required for activation of courtship behavior by chemosensory perception of female pheromones. Finally, a ppk25 mutant allele predicted to encode a truncated protein has dominant-negative properties, suggesting that the normal Ppk25 protein acts as part of a multiprotein complex. Together, these results indicate that ppk25 is necessary for response to female pheromones by D. melanogaster males, and suggest that members of the DEG/ENaC family of genes play a wider role in chemical senses than previously suspected.

Female pigeons, Columba livia, respond to multisensory audio/video playbacks of male courtship behaviour

Multiple signals from different sensory channels can enhance, diminish, or have no effect on one another when they are combined into a multisensory signal. Simultaneous auditory and visual signals are known to be important in avian courtship behaviour, but less is known about how the signal components from the two sensory channels interact and which channel is relied upon more. Here we use audio and video playback methods to test the significance of multisensory signals in the pigeon. We used audio- and videotaped male pigeon courtship behaviour as stimuli to assess behavioural reactions of conspecific females to silent video, to audio alone, to the combination of video and audio stimuli, and to a control video of an empty cage. Females responded to the test presentations by watching, circling, tail spreading and cooing. Considered alone, the audio channel elicited higher female response than did the video channel alone, particularly for female cooing responses. Together, however, the multisensory audio/video signal was more effective than either component alone at eliciting typical female courtship responses of circling and tail spreading. Courtship behaviour of these male pigeons is therefore considered an example of multisensory enhancement, in which the combination of signal channels functions to increase the impact of the communication signal.

Vibratory signals of four Neotropical stink bug species

Abstract. The stink bugs Acrosternum impicticorne, Euschistus heros, Piezodorus guildinii and Thyanta perditor (Heteroptera: Pentatomidae) feed and mate on the same host plants and constitute major components of the soybean pest complex in Brazil. During mating, they communicate with species and sex‐specific vibratory signals whose spectral properties are characteristic of the subfamily Pentatominae. Songs differ between species in the time structure and amplitude modulation of their units. The repertoire of A. impicticorne, E. heros and T. perditor fits into the scheme described for most investigated stink bugs: females call with a sequence of pulses that differ between species in their duration and repetition rate, and males respond with courtship songs of species‐specific temporal structure and amplitude modulation of complex pulse trains. Female calling and male courtship songs are the main constituents of vibratory communication between sexes in the mating period. The other vibratory emissions appear to represent either transitional songs, support recognition during close‐range courtship, or are involved in male rivalry. The first recorded vibratory emissions of P. guildinii confirm that the genus Piezodorus represents an exception within the Pentatominae. Irregularly repeated female vibratory signals of P. guildinii do not trigger typical male courtship responses as they would in the small stink bugs Holcostethus strictus and Murgantia histrionica. On the other hand, complex rivalry with extensive frequency modulation of pulses, as also described in Piezodorus lituratus, opens a new insight into the role of vibratory communication in stink bugs.

Changes in response to olfactory cues across the ovulatory cycle in brook sticklebacks, Culaea inconstans

Previous research has shown that female brook stickleback are attracted to the scent from conspecific males. In this paper, I show that a female's response to the male-based cue changes depending upon the stage she has reached in her ovulatory cycle. On the day of ovulation, when the female was ready to spawn, she was strongly attracted to the scent of conspecific males, and even performed the species-specific courtship/receptive display (head-up, sink to the bottom and remain stationary) in response to the cue. Within 24 h of spawning, the female had begun to decrease her courtship response and move away from the cue, and by 48 h she had stopped courting completely and was spending most of her time on the control (water-drip) side of the tank. Upon ovulating a second time, she was again attracted to the scent and began courtship behaviour. This represents the first experimental demonstration of a female teleost showing a change in responsiveness to male-based odours across her ovulatory cycle similar to that displayed by female mammals.