Host-plant leaf surface compounds influencing oviposition in Delia antiqua

Summary. Delia antiqua (Diptera: Anthomyiidae) females lay eggs between the leaves of onion plants or in the soil around the base of the plants, then the maggots feed on the onion bulb and roots causing rapid secondary infection by fungi and bacteria. It is well known that the first sensory modality used by the onion fly is vision, therefore the shape (vertical narrow cylinders) and colour (yellow) of the plant play a crucial role in the recognition of a potential host plant. In the past it has been shown that n-dipropyl disulfide (Pr₂S₂), a typical component of onion volatiles, is an important chemical host plant cue. We extracted host leaf surface to verify if Pr₂S₂ is the major chemical oviposition stimulant and to determine if other as yet unknown substances may play a role in host-plant selection. We confirmed that the females laid more eggs around onion plants with leaves than when only the onion bulb was present and that the odour of chopped onion stimulates oviposition. Extraction of the surface of onion leaves revealed that only the apolar fraction contained substances that stimulate egg-laying in D. antiqua. GC-EAD analysis indicated that a minor constituent, Pr₂S₂, is perceived by the olfactory receptor on the antennae of the onion fly females. This confirmed the importance of Pr₂S₂ as oviposition stimulant. Contact with the polar fraction did not stimulate egg-laying behaviour in this Delia species. We discuss the oviposition strategy of D. antiqua in comparison with its closely related species, D. radicum, in which the oviposition behaviour is stimulated mainly through contact with the cabbage leaf surface and only partially by the host volatiles.     

The genetic mating system of a sex-role-reversed pipefish (Syngnathus typhle): a molecular inquiry

In the pipefish Syngnathus typhle as in other species of Syngnathidae, developing embryos are reared on the male's ventral surface. Although much laboratory research has been directed toward understanding sexual selection in this sex-role-reversed species, few studies have addressed the mating behavior of S. typhle in the wild, and none has capitalized upon the power of molecular genetic assays. Here we present the first direct assessment of the genetic mating system of S. typhle in nature. Novel microsatellite loci were cloned and characterized from this species, and employed to assay entire broods from 30 pregnant, field-captured males. Genetic analysis of 1340 embryos revealed that 1–6 females (mean = 3.1) contributed to each brooded clutch, the highest rate of multiple maternity yet documented in any pipefish. Evidence of multiple mating by females was also detected. Thus, this population of S. typhle displays a polygynandrous mating system, a finding consistent with previous field and laboratory observations. Our results, considered together with similar studies of other syngnathid species, provide preliminary support for the hypothesis that the genetic mating system is related to the evolution of sexual dimorphism in the fish family Syngnathidae. Received: 19 January 1999 / Received in revised form: 15 April 1999 / Accepted: 9 May 1999     

Effect of sperm depletion and starvation on female mating behavior in the water strider,Aquarius remigis

The resolution of intersexual conflict over mating should be dependent on the current state of each individual. In this study, I used a factorial design to examine the influence of two physiological factors, sperm depletion and food deprivation, on resistance to mating by females of the water strider, Aquarius remigis. Females employ several different mate-resisting tactics during an encounter with a male. Five measures of female resistance to mating were identified: jumping, rolling, dunking, time spent dunking, and struggle duration. Jump, roll, and dunk rates were highly correlated with each other and combined into one metric of resistance to mating (PC1) using principal components analysis. Time per dunk (T/D) and struggle duration were also analyzed. Discrete male behaviors during the struggle could not be identified. Two measures of female resistance, PC1 and T/D, were significantly lower in sperm-depleted females than in sperm-replenished females. Struggle duration did not differ between the two treatments. Starvation had no effect on any of the measures of resistance. Sperm depletion significantly enhanced the probability of mating (54% vs. 24% for replenished females), while starvation had no effect on the probability of mating. I pooled all the females and compared females that mated with those that did not mate. Nonmating females resisted significantly more than mating females in all three measures of resistance. Path analysis indicated that PC1 was the only measure of resistance that was significantly negatively related to the probability of mating. Almost half (46%) of sperm-depleted females showed no resistance to males, while only 3% of sperm-replenished females were nonresistant. When nonresisters were removed from the analysis, sperm depletion had no effect on any of the measures of female resistance to mating and no effect on the probability of mating. In A. remigis, female resistance appears to be a yes/no phenomenon with respect to sperm depletion and not affected directly by starvation. Received: 2 September 1994/Accepted after revision: 9 September 1995     

Mate preferences in <Emphasis Type="Italic">Drosophila</Emphasis> infected with <Emphasis Type="Italic">Wolbachia</Emphasis>?

The maternally inherited bacterium Wolbachia pipientis generates strong reproductive incompatibilities between uninfected females and infected males (cytoplasmic incompatibility), significantly reducing both female and male reproductive success. Such fitness costs are thought to place selective pressure on hosts to evolve pre-copulatory preferences for mating with compatible mates, thereby enabling them to avoid the reproductive incompatibilities associated with Wolbachia. Therefore, uninfected females are predicted to prefer mating with uninfected males, whereas infected males are predicted to prefer mating with infected females. Despite these predictions, previous investigations of pre-copulatory mate preferences in Wolbachia-manipulated Drosophila have not found evidence of female preference for uninfected or compatible males. However, none of these studies utilised a design where focal individuals are provided with a simple choice in a relatively non-competitive situation. We examined both female and male pre-copulatory mate preference based on mate infection status in Drosophila simulans and D. melanogaster using simple choice assays involving between 30–50 replicates per treatment. Although we found no evidence of female pre-copulatory mate preferences in either species, male D. simulans exhibited some preference for mating with females of the same infection status. However, this preference was not evident when we repeated the experiment to confirm this finding. Consequently, we conclude that neither male nor female D. melanogaster and D. simulans exhibit significant Wolbachia-associated pre-copulatory mate preferences.     

Whitefly wax as a cue for phoresy in the broad mite, <Emphasis Type="Italic">Polyphagotarsonemus latus</Emphasis>(Acari: Tarsonemidae)

Summary. Broad mite, Polyphagotarsonemus latus (Acari: Tarsonemidae) exhibits a specific phoretic relationship with whiteflies. Under field conditions most broad mites, caught in sticky traps, are attached to whiteflies. Under laboratory conditions, attachment occurs equally well in the dark and light. Mites do not differentiate between the sexes of their phoretic host Bemisia tabaci. However, mite attachment to B. tabaci is greatly diminished by washing the host with various organic solvents, chloroform in particular. The effect of whitefly waxy particles on broad mite behavior was studied using wax from the whitefly Aleyrodes singularis and from the mealybug Planococcus citri. Broad mites were not only attracted specifically to the A. singularis waxy particles-treated leaf areas but were also attached to leaf trichomes in this area. The results of this study suggests the importance of olfactory cues from the whitefly waxy particles in the recognition process of the phoretic host and/or the induction of the attachment behavior to whitefly legs or leaf trichomes.     

Proximal traits and mechanisms for biasing paternity in the red flour beetle Tribolium castaneum (Coleoptera: Tenebrionidae)

A comprehensive understanding of sexual selection requires knowledge of the traits and mechanisms responsible for increasing a male’s paternity share (proportion of progeny sired) relative to that of other males mating with the same female. In this study we manipulated by starvation the expression of traits that might influence male paternity share in Tribolium castaneum. We then conducted experiments to examine how male starvation affects male performance during sequential episodes of sexual selection from mating to progeny production, and investigated female control over specific stages by using live vs dead females. Comparison of starved vs fed males revealed that T. castaneum females have control over spermatophore transfer during mating, as live females rejected inseminations by starved (“low quality”) males. None of the measured male copulatory behaviors (leg-rubbing frequency, asymmetry, and percent of time spent rubbing) affected the probability of successful insemination, but the last two were positively associated with male paternity share. Spermatophore positioning within the female reproductive tract was not affected by male treatment (starved/fed), by female treatment (live/dead), or by male copulatory behaviors. Starvation, however, had a dramatic effect on male reproductive physiology, decreasing both accessory gland size and total number of sperms transferred (but not sperm viability in seminal vesicles). In addition, females who mated to starved males stored fewer sperms in their spermathecae, which, together with decreased ejaculate size, may explain the reduced paternity share of starved males compared to fed males. This study elucidates some cryptic mechanisms influencing male reproductive success and aids our understanding of trait evolution through sexual selection.     

Storage and display of odour by male Saccopteryx bilineata (Chiroptera, Emballonuridae)

Males of the sac-winged bat, Saccopteryx bilineata, actively fill their propatagial sacs with secretions from the genital region, the gular gland, urine and saliva. From our observations and those of Starck we deduce that propatagial sacs in S. bilineata do not have a glandular function, but are instead organs for the storage and display of odours. In addition to the already known “salting” and hovering behaviour of male S. bilineata, we describe in detail how odour is fanned to roosting individuals during the complex, stereotypic hovering displays. S. bilineata males also coat the fur of their backs with saliva using the wing tip and might scent-mark territory boundaries. “Yawning” may represent a visual as well as an olfactory cue. Odour seems to play an important role in the social communication of S. bilineata and in other emballonurids, as revealed by the broad distribution of wing sacs in this family. S. bilineata males display odour during energetically costly hovering flights in front of females. We demonstrate that the number of hovering displays increases with harem size. The mating effort of S. bilineata males comprises a multimodal signalling behaviour. Although males defend harem territories in which females gather, females seem to be able to choose the father of their progeny freely among the males of a colony. This may have led to the evolution of the complex mating displays by male S. bilineata. Received: 9 December 1998 / Received in revised form: 6 May 1999 / Accepted: 13 June 1999     

Female resistance and male preference in a stream-dwelling isopod: effects of female molt characteristics

In the stream-dwelling isopod, Lirceus fontinalis, mating contests between males and females occur prior to pair formation. We examined the relative contribution of male preference and female resistance to contest outcomes. We first quantified male and female behavior during typical mating interactions and examined the relationship between time until molt (TTM) and mating outcomes. We then examined the role of male preference and female resistance in determining mating outcomes when females differed in molt type (growth, egg deposition) and appeared to differ in TTM (due to hormone applications). Both male preference and female resistance contributed to different components of the mating sequence but female resistance ultimately determined whether or not pair formation occurred. Males expressed a preference for females that appeared to be close to molt, using variation in levels of molt hormone as a cue. However, males did not discriminate between females based on molt type. Received: 5 March 1999 / Received in revised form: 10 August 1999 / Accepted: 16 October 1999     

Prolonged mating in the milkweed leaf beetle Labidomera clivicollis clivicollis (Coleoptera: Chrysomelidae): a test of the “sperm-loading” hypothesis

Summary Female milkweed leaf beetles (Labidomera clivicollis clivicollis) frequently mate with more than one male, and pairs form mating associations which last for up to 42 h in the field. I tested the hypothesis that males remaining with females for long periods of time benefit by numerically overwhelming the sperm of their competitors. Male L.c.clivicollis copulated intermittently with females throughout an 11 hour period in the laboratory. When virgin females were allowed a single copulation, 94.3% of the sperm they received were located in the spermatheca immediately afterward. Males were not sperm-depleted, for they had large numbers of sperm available after one copulation (mean=230,000±43,200); the maximal number of sperm a male transferred to a female in 24 h was 30,500. There was a positive linear relationship between the number of sperm transferred and time up to 24 h after mounting (r ²=0.178, P<0.003). These data suggest that males transfer increasing numbers of sperm throughout a 24-h-period. Mating duration was the most important determinant of paternity when females were placed with one male for 24 h and another male for 6 hours. Females whose first matings were longer showed first male sperm predominance (as determined by starch-gel electrophoresis), while females whose second matings were longer showed last male sperm predominance. In view of these data, it is puzzling that males do not inseminate with large numbers of sperm immediately after mounting the female. It is possible that female refractory behaviors make insemination difficult and favor prolonged mating by male milkweed leaf beetles.     

Mating frequency, colony size, polyethism and sex ratio in fungus-growing ants (Attini)

The mating frequency of queens was estimated for eight attine ant species, Myrmicocrypta ednaella, Apterostigma mayri, Cyphomyrmex costatus, C. rimosus (four lower attines), Trachymyrmex isthmicus, Serico-myrmex amabalis, Acromyrmex octospinosus and Atta colombica (four higher attines), and correlated to colony size, worker polyethism, and sex ratio. Mating frequency was calculated from within-colony relatedness estimated by CAP-PCR DNA fingerprinting. Most queens of lower attines and T. isthmicus mated with only one male, while those of the three higher attines mated with multiple males. Mating frequency was positively correlated with colony size. Polyethism among workers was dependent on worker age in lower attines but on body size in higher attines, suggesting some correlation between mating frequency (i.e., within-colony gene diversity) and caste complexity. The sex ratio was biased toward females in species where the mating frequency equaled one, but toward males in species where the mating frequency was greater than two. Changing in nest site from ground surface to deep underground may have facilitated the evolution of large colony size in Attini, and this may have resulted in the evolution of polyandry (a queen mates with multiple males). With the evolution of polyandry in higher attines, Atta and Acromyrmex in particular have generated high genetic diversity within their colonies and complex social structures. Received: 26 October 1999 / Revised: 25 May 2000 / Accepted: 24 June 2000     

Sperm competition and the level of polyandry in a bushcricket with large nuptial gifts

Variation in paternity due to sperm competition or post-copulatory female choice has a major influence on animal mating system evolution and on the levels of genetic variability in natural populations. However, there are relatively few studies comparing the outcome of sperm-competition experiments in the laboratory with natural variation in polyandry among families from the field. In the bushcricket Ephippiger ephippiger, females mate multiply, and the males provide them with a large, nutritious, and probably expensive, donation at mating. We examined paternity in a series of laboratory matings, where females mated with two males, and amongst a series of families collected from a natural population. In the laboratory, paternity was highly bimodally distributed: 24% of families had offspring fathered by the first male to mate, 68% by the second male (in only 8% was paternity shared). In the field, paternity was more mixed: only 27% of families had a single father, 14% had more than two fathers, whilst 59% had two fathers. While unsuccessful matings may contribute to the highly biased paternity in the laboratory, they cannot fully explain the high incidence of complete P2 families. Nonrandom sperm utilisation is therefore likely. Greater sperm mixing in the field probably results from females mating with more males, but the distribution of paternity also reflects an active process of nonrandom sperm utilisation. Confidence of paternity due to last male advantage may be relatively high in this species, and therefore may have facilitated the evolution of the large spermatophore in E. ephippiger.Communicated by D. Gwynne     

Parental investment, potential reproductive rates, and mating system in the strawberry dart-poison frog, Dendrobates pumilio

We studied the effect of relative parental investment on potential reproductive rates (PRRs) to explain sex differences in selectivity and competition in the dart-poison frog Dendrobates pumilio. We recorded the reproductive behavior of this species in a Costa Rican lowland rainforest for almost 6 months. Females spent more time on parental care than males, and `time out' estimates suggest that PRRs of males are much higher than than those of females, rendering females the limiting sex in the mating process. Males defended territories that provide suitable calling sites, space for courtship and oviposition, and prevent interference by competitors. Male mating success was highly variable, from 0 to 12 matings, and was significantly correlated with calling activity and average perch height, but was independent of body size and weight. Estimates of opportunity for sexual selection and variation in male mating success are given. The mating system is polygamous: males and females mated several times with different mates. Females were more selective than males and may sample males between matings. The discrepancy in PRRs between the sexes due to differences in parental investment and the prolonged breeding season is sufficient to explain the observed mating pattern i.e., selective females, high variance in male mating success, and the considerable opportunity for sexual selection. Received: 9 June 1998 / Received in revised form: 27 March 1999 / Accepted: 3 April 1999     

Mating expenditures reduced via female sex pheromone modulation in the primitively eusocial halictine bee, Lasioglossum (Evylaeus) malachurum (Hymenoptera: Halictidae)

The present paper reports on behavioral experiments and gas chromatographic analysis of chemical communication in the mating biology of the primitively eusocial sweat bee Lasioglossum (Evylaeus) malachurum. In a dual-choice experiment, a female made odorless was significantly less attractive than an untreated one. Attraction in L. (Evylaeus) malachurum is therefore mediated by a female-produced sex pheromone. Further bioassays showed that unmated gynes are more attractive to males than mated ones. Males are able to differentiate between the two groups of females as little as 3 h after mating. Biotests with different samples obtained from attractive gynes showed surface extracts to be most attractive. Behavioral tests with synthetic copies of the compounds identified as cuticular constituents of virgin gynes were highly attractive to males; the volatile bouquets consisting of n-alkanes, n-alkenes and iso- pentenyl esters of unsaturated fatty acids were the most attractive samples. Isopentenyl esters of unsaturated fatty acids were the key compounds in inducing male inspections as well as stimulating pounces and copulatory attempts. Virgin and nesting gynes differed clearly in the relative and absolute amounts of the volatiles on the cuticle. The total amount of volatiles was significantly higher in virgin gynes and decreased in breeding queens. Hydrocarbons were the dominant group of compounds in both groups of females. The relative amounts of the wax-type ester, hexadecyl oleate, iso- pentenyl esters, and a hitherto unidentified steroid were higher in attractive virgin gynes, while the relative proportions of hydrocarbons and lactones dominated in nesting queens. The site of sex pheromone production in attractive young L. (Evylaeus) malachurum gynes remains unknown. Head glands or Dufour's gland secretions may be involved. Another possible source of the `active principle' found among the cuticular lipids could be glandular cells of the epidermis. The significance of modulation of female sex pheromone composition is discussed in terms of a reduction in mating expenditures. Received: 30 April 1998 / Accepted after revision: 24 July 1998     

Interspecific interference competition and mate choice in the soldier beetle,Chauliognathus pennsylvanicus

Summary Interference competition directed at soldier beetles, Chauliognathus pennsylvanicus, by four aggressive wasp species changed the mate choice of females. In the absence of wasps, females mated more frequently with males of greater weight and greater antennal scape diameter. Only in the presence of wasps did females frequently mate when they did not contain mature ova. When wasps were abundant, the proportion of beetles mating was higher. Wasps reacted aggressively toward mating beetles less frequently than toward single beetles. Therefore, females may have fed more efficiently in the presence of wasps when coupled.     

Pheromones inBlattella germanica andBlaberus craniifer (Blaberoidea): Glandular source,morphology and analyses of pheromonally released behaviours

Females ofBlattella germanica andBlaberus craniifer produce a volatile sex pheromone attractive at a distance for conspecific males. During the emission of the pheromone, females ofB. craniifer adopt a typical calling posture; we never observe such a stance inB. germanica females. For both species, the glandular structures responsible for pheromonal production are located on the female pygidium. InB. germanica, the thickness of the glandular epithelium is clearly correlated with the attractiveness of females, being maximum for 13 day old females. The functions of the pygidial glands are discussed in both species.     

Two phylogenetically distinct species of sexually deceptive orchids mimic the sex pheromone of their single common pollinator, the cuckoo bumblebee Bombus vestalis

Sexually deceptive orchids of the genus Ophrys attract male insects for pollination. Pollinator attraction is achieved by mimicking sex pheromones of virgin females of their pollinators, mostly bee species. In earlier investigations, we showed that the phylogenetically distinct Ophrys species O. chestermanii and O. normanii on Sardinia attract their pollinator, males of the cuckoo bumblebee B. vestalis, with the same bouquets of relatively polar volatile compounds. In this investigation, we studied the sex pheromone of virgin females of B. vestalis with the aim of identifying male-attracting compounds and of comparing them with labellum extracts of the two orchids, which were found to release male-attracting compounds in earlier investigations (G?gler et al. 2009). In bioassays, shock-frozen females, cuticle extracts and polar fractions of cuticle extracts of virgin females stimulated mating behaviour in the males. Using gas chromatography coupled with electroantennography (GC-EAD) and gas chromatography coupled with mass spectrometry (GC-MS), we detected in polar fractions of cuticle extracts of B. vestalis females the same electrophysiologically active compounds as in labellum extracts of both orchid species, including aldehydes, esters, fatty acids and alcohols. Since statistical comparisons of the relative proportions of esters showed strong similarities between virgin females and orchids, our results support the hypotheses that this highly specialized Ophrys–pollinator relationship represents another case of chemical mimicry and that esters play a key role in male attraction.     

The cause of size-assortative mating in the leaf beetle Trirhabda canadensis (Coleoptera : Chrysomelidae)

Summary Examples of positive assortative mating by body size are abundant but its causes remain controversial. I show that size-assortative mating occurs in the chrysomelid beetle Trirhabda canadensis and I test a series of alternative hypotheses to explain how this mating pattern comes about. Results suggest that assortative mating in this beetle is due to the greater ease with which size-matched pairs can achieve intromission, and not due to size-biased skews in the availability of mates or mate choice favoring large individuals. There was no correlation between male and female elytron length (a measure of body size) at the initiation of courtship, but pairs assorted positively by size at the onset of intromission. Moreover, in the laboratory, there was a negative correlation between male and female size for pairs engaged in courtship that terminated without mating. Assortative mating was not associated with a large-male mating advantage and there was no evidence of female choice of large males. Nor was there unequivocal evidence for male choice of large females; although mating females were slightly larger and considerably heavier than solitary females, males did not differ in the frequency with which they rejected large and small females. Assortative mating in T. canadensis appeared to be caused by the lower ability of mismatched pairs to achieve intromission after an encounter, both when males were larger and when they were smaller than the female.     

Nutritional phagostimulants function as male courtship pheromone in the German cockroach, <Emphasis Type="Italic">Blattella germanica</Emphasis>

Summary. Males of the German cockroach, Blattella germanica, secrete a pheromonal substance from the abdominal tergal glands, which elicits a feeding response in females during the sequential courtship behavior. The nuptial secretion consists predominantly of a synergistic mixture of sugars and phospholipids. Cholesterol and a series of amino acids, which are also components of the males glandular secretion, significantly enhanced the phagostimulant activity of the sugar components. The nuptial feeding behavior of the female cockroach is therefore elicited by a complex assortment of nutritive components in the male tergal secretion, including sugars, phospholipids, cholesterol, and amino acids. These results indicate that a mixture of primary metabolites, and not of specific secondary metabolites, serves as a pheromonal cue that appeals to the females gustatory sense and effectively brings her to the precopulatory position. Although the male secretion consists of nutrients, we suggest that these compounds probably do not represent a significant nutrient investment in females and their progeny but rather function as a signal in the mating sequence of B. germanica.     

Bacterial colonization of the phyllosphere of nineteen plant species and antimicrobial activity of their leaf secondary metabolites against leaf associated bacteria

Summary. The scope of this work was to examine whether leaf constitutive secondary metabolites play a role in determining bacterial colonization of the phyllosphere. To this aim, we surveyed nineteen native or cultivated plant species that share a common bacterial pool in a North Mediterranean area, and estimated the size of total and ice nucleation active (INA) bacterial populations on their leaves. Large differences in the colonization of their phyllosphere were found; the population size of epiphytic bacteria ranged from 7.5 × 10² to 1 × 10⁶ CFU/g fresh weight, in eucalypt and celery, respectively. Species native in Mediterranean-type climate areas, particularly those belonging to the group of aromatic plants, are characterized by scarce presence of INA bacteria. The antibacterial activity of essential oils, surface phenolics and leaf tissue extracts was also estimated against the INA strains P. syringae and E. herbicola, isolated from two of these plant species. E. herbicola proved more sensitive than P. syringae. Of the species examined, oregano [Origanum vulgare L. subsp. hirtum (Link.) Ietswaart], an aromatic plant, had the highest antimicrobial activity, whereas six species showed no activity at all. Further experiments were performed with oregano and bean (Phaseolus vulgaris L.) that represent two extremes in their secondary metabolite content. Both plants were inoculated with P. syringae. By the end of incubation, the bacterial population on bean plants was about 100 times higher than that on oregano leaves. Scanning electron micrographs showed that bacterial growth on oregano leaves was confined to sites away from glandular hairs. Results from the bacterial colonization survey together with those from the toxicity tests showed that all species rich in antibacterial secondary metabolites harbored low leaf bacterial populations. These results provide substantial evidence that leaf secondary metabolites function as constitutive defense chemicals against microbial invasions. However, the fact that species with non- or moderately active leaf secondary metabolites are not always highly colonized suggests mediation of other unknown factors, the contribution of which requires further investigation.     

Dietary carotenoids and male mating success in the guppy: an environmental component to female choice

Summary This study examined the relationship between dietary carotenoids, female choice, and male mating success in the guppy, Poecilia reticulata. Using a split-brood design, male siblings were either raised on a diet enhanced with astaxanthin and canthaxin or fed a basal diet without carotenoids. Males were photographed, and the location, size, and brightness of their red and orange pigment spots on the body were measured. Courtship behaviors were recorded during visual and mating trials. Males fed the carotenoid-enhanced diet had red and orange spots that averaged 2.5 times brighter, spent significantly more time near the female in visual response trials, were preferred by females in visual choice tests, and had a higher mating success than their siblings raised on the carotenoid-free diet. Diet did not affect male size, location or size of the red and orange pigment spots, or the intensity of courtship behavior. The results of this study show that females respond to environmentally-induced variation in the expression of a secondary sexual trait and that this has important consequences for male mating success.