Female Chemical Cues Research Articles

Information asymmetry and aggressive behaviour in male house crickets, Acheta domesticus

Aggressive interactions can play an important role in the reproduction of many species. Several factors (e.g. resource value, asymmetries among contestants in fighting ability, and information asymmetry) influence the amount of aggression shown by individuals. In particular, it has been predicted that resident individuals, who presumably have more information about an area than nonresidents, will be more likely to win when the area contains resources of high value. Conversely, invaders, who have incomplete information about an area, should be more likely to win when the resource value is low. Male house crickets, Acheta domesticus, increase their aggressive behaviour in the presence of female chemical cues; thus, we manipulated the amount of chemical cues in a given area and who had information (resident versus invader). Resident males were more aggressive and won more contests when there was a greater amount of female chemical cues. In addition, invader males were more likely to win contests under control conditions with no female cues. Our data suggest that information asymmetry can play an important role in the fighting decisions made by animals. Additionally, our data highlight the multimodal nature of communication in crickets.

Species-Specificity of Chemical Signals: Silk Source Affects Discrimination in a Wolf Spider (Araneae: Lycosidae)

Female spiders deposit chemical cues that elicit male courtship behavior with silk. These cues are often assumed to be species-specific although male spiders may court in response to chemical cues of closely-related species. We used behavioral assays to test the extent of species discrimination of female chemical cues by male Schizocosa ocreata, a wolf spider (Lycosidae). Discrimination, expressed as relative courtship intensity of males, varied significantly with phylogenetic distance. Males did not discriminate between female cues of conspecifics and a sibling species, S. rovneri. Courtship response was intermediate for another species within the ocreata clade and not different from control for spiders outside the clade. These findings support the sibling species status of S. ocreata and S. rovneri, and also suggest the composition of female chemical signals is conserved across closely related wolf spider species.

Population and Species Divergence of Chemical Cues that Influence Male Recognition of Females in Desmognathine Salamanders

AbstractGrowing evidence indicates that males may be more discriminating of mating partners than often has been assumed. In the North American Ocoee dusky salamander, Desmognathus ocoee (Plethodontidae: Desmognathinae), sexual incompatibility among conspecific populations is high in encounters staged in the laboratory, at least in part because males fail to recognize ‘other’ females as appropriate targets for courtship. I used Y‐mazes to test the hypothesis that males of D. ocoee discriminate between substrate‐borne chemical cues produced by ‘own’ (homotypic) and ‘other’ (heterotypic) females. Males of four populations discriminated in favor of substrates soiled by homotypic females over clean (control) substrates (expt 1), suggesting that females produce chemical cues of sociosexual significance to males. Furthermore, males from these populations discriminated in favor of substrates soiled by homotypic females vs. substrates soiled by heterotypic females (expt 2), both conspecific and heterospecific (D. carolinensis and D. orestes). Thus, differences among populations and species in female chemical cues appear to affect the chemotactic responses of males. I suggest that, together with differences in behavioral signals and responses exhibited during courtship, differences in female chemical cues likely contribute to sexual incompatibility among populations and taxa of desmognathine salamanders.

L-DOPA reverses castration-induced disruption of dishabituation responses to female chemical cues in male rats

In the present experiment, habituation/dishabituation behavioral tests were conducted to measure discriminatory olfactory recognition responses to chemical cues among control, castrated, and castrated + l-3,4-dihydroxyphenylalanine ( l-DOPA)-treated males rats. Castration produced a disruption of dishabituation responses to female urine, and this effect was reversed by treatment with l-DOPA. In the posterior olfactory bulb, 3,4,-dihydroxyphenlacetic acid (DOPAC) levels were significantly increased in l-DOPA-treated animals compared with the vehicle-treated control and castrated groups. No significant differences in olfactory bulb norepinephrine or dopamine concentrations among the three treatment groups were obtained. The restoration of behavioral dishabituation responses following l-DOPA treatment suggests that the catecholaminergic system of the olfactory bulb may play a critical role in the recognition and possibly attractions for or preferences to female chemical cues.

Sexual incompatibility and mate-recognition systems: a study of two species of sympatric salamanders (Plethodontidae)

Abstract. In those instances where sexually active individuals of closely related sympatric species encounter one another but fail to mate, one expects to find interspecific differences in some component(s) of their mate-recognition systems. This expectation was tested in a detailed laboratory study of two species of plethedontid salamanders found in sympatry in Virginia. Mountain dusky salamanders, Desmognathus ochrophaeus, and northern dusky salamanders, D. fuscus fuscus, were highly sexually incompatible; none of 60 interspecific encounters resulted in insemination, compared with 32 of 60 intraspecific encounters (experiment 1). Detailed analysis of intraspecific courtship encounters revealed qualitative and quantitative differences between these species in aspects of both the content and overall timing of courtship (experiment 2). However, similarly detailed analysis of interspecific encounters failed to reveal any contemporary role for behavioural differences in the maintenance of sexual incompatibility: males simply ignored heterospecific females (experiment 3). Species differences in female chemical cues may be of importance in this apparent lack of heterospecific recognition. Males of both species discriminated against the chemical cues of heterospecific females in Y-maze tests in which males were presented with substrate-borne conspecific and heterospecific cues simultaneously (experiment 4). These results indicate that attention must be paid to all components of mate-recognition systems if the biological basis of sexual incompatibility is to be understood fully. Had only interspecific differences in courtship behaviour patterns in this study been sought and found, the erroneous conclusion that these differences were responsible for the maintenance of sexual incompatibility might have been reached.