scholarly journals Sexual Selection of Male Song in Free-Living Sagebrush Crickets, Cyphoderris Strepitans

Author(s):  
Geoff Ower ◽  
Sandra Steiger ◽  
Kyle Caron ◽  
Scott Sakaluk

Measures of lifetime mating success in the sagebrush cricket, Cyphoderris strepitans, have revealed that most males succeed in obtaining only 1 mating, while many males fail to attract a female at all and a small minority mate 2 to 4 times. Relative to their abundance in the population, virgin males have a greater likelihood of obtaining a mating than non-virgin males have of securing additional matings, a phenomenon known as the virgin male mating advantage. Previous studies of sagebrush crickets have focused primarily on determining the proximate mechanisms responsible for the virgin male mating advantage, but little work has been done to identify the factors that influence male attractiveness in the first place. Because song plays a central role in mate attraction, it’s likely that variability in song parameters among males could account for the observed differences in mating success. Song is an energetically costly signal to produce and could serve as an honest indicator of male quality. Consequently, males that are able to invest greater amounts of energy into singing should be more attractive to females. In a previous field season, we recorded and analyzed the songs of virgin and non-virgin males and indeed found some evidence that females prefer males which invest greater energy into calling. In the present study, we synthesized artificial sagebrush cricket songs and directly measured female song preference with an arena playback experiment. Females were shown to consistently prefer song characteristics that would require greater energy expenditure by males. Males that sing with long pulse duration, long train duration, and at an intermediate dominant frequency were found to be highly attractive to females.

Behaviour ◽  
1999 ◽  
Vol 136 (10-11) ◽  
pp. 1335-1346 ◽  
Author(s):  
Tracie Ivy ◽  
Scott Sakaluk

AbstractFemale sagebrush crickets (Cyphoderris strepitans) feed on males' fleshy hind wings during copulation and ingest haemolymph oozing from the wounds they inflict. The wounds are not fatal and usually only a portion of the hind wings are eaten at any one mating, so that mated males are not precluded from mating again. However, based on their relative abundance in the population, virgin males have a higher mating success than non-virgin males. One explanation for this virgin-male mating advantage is that non-virgin males, having been depleted of their energy reserves through the wing-feeding behaviour of their mates, are unable to sustain the same level of acoustic signalling they produce prior to copulation. Previous assays of male signalling behaviour have provided some support to this hypothesis. However, an alternative explanation is that females actively seek out virgin males as mates because of the greater material resources they offer. If the acoustic structure of males' signals were systematically altered by the loss of hind-wing material underlying the sound-producing tegmina, females could potentially discriminate against mated males through reduced phonotaxis to their calls. We tested this hypothesis by experimentally removing one hind wing from virgin males, thereby simulating the non-virgin condition without the attendant costs of copulation. We compared the mating success of these 'asymmetrical' males with that of sham-operated virgin males when competing under natural conditions. In a companion laboratory study, we used time-lapse video recording to examine the possibility that female preferences are exerted only after pair formation has occurred. There was no significant difference in male mating success across treatments in either study. We conclude, therefore, that the virgin-male mating advantage does not stem from an acoustically mediated, non-independent female mating preference, but rather, from the differential competitiveness of males.


Author(s):  
Scott Sakaluk ◽  
Pamela Brady ◽  
Tracie Ivy ◽  
Marion Sakaluk ◽  
Jennifer Schaus

The sagebrush cricket, Cyphoderris strepitans, is one of only five extant species belonging to an obscure orthopteran lineage, the Haglidae, closely related to the true crickets (Gryllidae) and katydids (Tettigoniidae) (Morris & Gwynne 1978). C. strepitans occurs exclusively in mountainous areas of the western United States, where it is found primarily in high-altitude sagebrush meadow habitat. Adults become sexually active in late spring, shortly after snow melt, and remain active for the following 4-6 weeks. The acoustic signals produced by males function to attract females (Snedden & Irazuzta 1994), thereby enhancing male mating opportunities (Snedden & Sakaluk 1992). Copulation is initiated when a receptive female climbs onto the dorsum of a male, at which time he attempts to transfer a spermatophore. During copulation, the female feeds on the male's fleshy hind wings and bodily fluids leaking from the wounds she inflicts. Previous field studies involving the mark­recapture of a large number of males have shown that once a male has mated, his probability of obtaining an additional copulation is reduced relative to that of a virgin male securing his first mating (Morris et al. 1989). One explanation for the virgin-male mating advantage is that non-virgin males, having lost a substantial portion of their energy reserves through sexual cannibalism by females and the transfer of a large spermatophore, may be unable to sustain the costly acoustical signaling activity required to attract additional females. In support of the "male fatigue" hypothesis, electronic assays of male signaling behavior have shown that virgin male C. strepitans call for significantly longer durations than recently mated males (Sakaluk et al. 1987; Sakaluk & Snedden 1990).


Author(s):  
Scott Sakaluk ◽  
Mark Campbell ◽  
Peter Keorpes ◽  
Andrew Clark

Male sagebrush crickets, Cyphoderris strepitans, offer an unusual nuptial food gift to females during mating: females chew on the ends of the males' fleshy hind wings and ingest hemolymph seeping from the wounds they inflict. Previous studies have shown that once a male had mated, his probability of obtaining an additional copulation is reduced relative to that of a virgin male seeking to secure his first mating, a pattern known as the virgin­male mating advantage. One hypothesis to account for the virgin-male mating advantage is that non­virgin males, having lost a substantial portion of their energy reserves at mating, may be unable to sustain the costly acoustical signaling activity required for the passive attraction of additional females. If the future mating prospects of non-virgin males are diminished because of sexual fatigue, this could stem either from the resources required to manufacture a new spermatophore or through the energy needed to replenish haemolymph lost through female wing­feeding. To distinguish between these two alternatives, we experimentally depleted virgin males of varying amounts haemolymph (0, 5 and 10 ul) in a way that mimicked hemolymph loss of non-virgin males, without the attendant costs of spermatophore production. After they had been treated, males were released in the field and recaptured over the course of the breeding season to monitor their mating success. Control males mated significantly sooner than did males depleted of 5 or 10 ul of hemolymph. We conclude, therefore, that the depletion of hemolymph that occurs through female wing feeding is sufficient by itself to diminish a non-virgin male's ability to secure another mating, acting as a brake on the operation of sexual selection in this species.


Author(s):  
Scott Sakaluk ◽  
W. Snedden

Sagebrush crickets (Cyphoderris strepitans) are primitive acoustic insects which occur only in mountainous areas of Wyoming and Colorado (Morris and Gwynne 1978). In Grand Teton National Park, adults become sexually active in early May and matings subsequently occur over a 3 - 6 week period. Each night of the breeding season, males emerge from the soil litter shortly after sunset, climb into the sagebrush and begin to sing, presumably to attract sexually receptive females. Copulation is initiated when a receptive female climbs onto the dorsum of a male, at which time he attempts to transfer a spermatophore (Dodson et al. 1983, Sakaluk et al. 1987, Morris et al. 1989). During the time that the female is mounted on the male, she feeds on the male's metathoracic wings and ingests any hemolymph oozing from the wounds she inflicts. To deter the female from dismounting before the spermatophore has been transferred, males are equipped with an abdominal pinching organ which functions to secure the female during copulation (Morris 1979, Dodson et al. 1983). Once the spermatophore has disengagement. The bulk of the spermatophore remains attached outside the female's body, who invariably consumes it several hours after mating (present study). A previous field study involving the mark-recapture of a large number of males showed that once a male had mated, his probability of obtaining additional copulations was significantly reduced (Morris et al. 1986). One explanation for this result is that non-virgin males, having lost a substantial portion of available energy reserves at mating, may be unable to sustain calling at pre-mating levels. In support of this hypothesis, electronic assays of male signaling behavior (see Kidder and Sakaluk, in press) have shown that virgin male C. strepitans call for significantly longer durations than recently mated males (Sakaluk et al.1987, Sakaluk and Snedden 1990). Although virgin males call more and have significantly higher mating success than non-virgins, this does not necessarily prove that calling duration and mating success are causally related. In the past, we have experienced two difficulties in establishing a causal basis to this correlation: 1) matings are rarely observed in the field, and we have of necessity relied on wing wounding as an indicator of male mating success (Morris et al. 1989) and 2) we have been unable to demonstrate phonotaxis of females to conspecific song as broadcast either through speakers placed in the field (Sakaluk and Snedden, unpubl. data) or in the laboratory (Morris et al. 1989). To at least partially circumvent these difficulties, we employed time-lapse video photography of mating interactions staged at the UW-NPS Research Station during the 1989 breeding season. The objective of these studies was to determine how mating status, calling time and body size contribute to male mating success, either through their effect on male competitive ability and/or their effect on male attractiveness to females.


Genetics ◽  
1984 ◽  
Vol 107 (4) ◽  
pp. 577-589
Author(s):  
Wyatt W Anderson ◽  
Celeste J Brown

ABSTRACT Recent work has called into question the reality of the rare male mating advantage, pointing out that it could be a statistical artifact of marking flies for behavioral observation or of experimental bias in collecting males. We designed an experiment to test for rare male mating advantage that avoids these sources of bias. Large numbers of males of three Drosophila pseudoobscura karyotypes were allowed to mate with females of one karyotype in population cages. The females were then isolated before multiple mating occurred and their progeny used to diagnose the males that mated them. Populations were studied at five sets of male karyotypic frequencies. The mating success of the male homokaryotypes ST/ST and CH/CH, relative to that of the heterokaryotype ST/CH, was frequency dependent. Both ST/ST and CH/CH males displayed a statistically significant mating advantage at low frequency by comparision with their mating success in the midrange of karyotypic frequencies. Both male homokaryotypes also showed a significantly greater mating success at high homokaryotypic frequency than at intermediate frequencies, which is the same as saying that the heterokaryotype not only failed to show a rare male advantage but actually suffered a mating disadvantage at low frequency. We conclude that rare male mating advantage is not always an experimental or methodological artifact but does occur in laboratory populations of D. pseudoobscura. It may occur for some genotypes and not for others, however, and it may be only one of several forms of frequency-dependent mating behavior operating in a population.


2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Suk-Ling Wee ◽  
Anthony R. Clarke

Abstract Males of certain Dacini fruit flies are strongly attracted to, and feed upon, plant secondary compounds such as methyl eugenol, raspberry ketone and zingerone. The consumed lure is generally found to induce physiological and behavioural changes that enhance the mating performance of lure-fed males. Male Bactrocera jarvisi respond strongly to zingerone from a young age, but only weakly respond to raspberry ketone. We hypothesized that this selective lure-response would be reflected in the physiological importance of the lure to the fly. We found that zingerone feeding by young males resulted in significantly greater mating success in competitive mating trials with lure-deprived flies, but the mating advantage was lost in older males. Lure dosage had a significant effect on the duration of the mating advantage, for example when fed 20 µg of zingerone, the advantage lasted only 1 day post-feeding, but when fed of 50 µg zingerone the advantage lasted 7 days. Raspberry ketone feeding did not confer any mating advantage to males except at one dosage (50 µg) for 1 day after feeding. When given a choice, B. jarvisi females preferred to mate with zingerone-fed versus to raspberry ketone-fed males. This study revealed lure, dosage and age of fly at time of lure administration are all important factors for maximising lure-enhanced fruit fly mating performance. These findings contribute to a better theoretical understanding of the evolution of fruit fly-lure interactions and may help improve fruit fly pest management via the Sterile Insect Technique through semiochemical-mediated enhancement of sterile male mating performance.


1989 ◽  
Vol 2 (2) ◽  
pp. 173-185 ◽  
Author(s):  
Glenn K. Morris ◽  
Darryl T. Gwynne ◽  
Dita E. Klimas ◽  
Scott K. Sakaluk

Author(s):  
W. Snedden ◽  
Michael Greenfield

Female sagebrush crickets, Cyphoderris strepitans, feed on the male's hind wings during copulation. Because removal of hind wing material during mating may alter male acoustic signal characteristics and account for a virgin male mating advantage (Morris et al. 1989; Snedden, in press) we recorded virgin and mated males in the field, and virgins before and after surgical excision of a portion of the hind wings. We found no significant differences in signal spectral characteristics or pulse rate between virgin and mated males following hind­wing excision. However, the signal amplitude of laboratory recorded virgins was greater than that of mated males, and song amplitude was reduced in manipulated males. In contrast, signal amplitude was lower in field recorded virgins than mated males.


Author(s):  
Geoffrey Ower ◽  
Rebecca Smith ◽  
Kyle Caron ◽  
Scott Sakaluk

Male sagebrush crickets exhibit differential mating success based on their previous mating experience: virgin males have a higher probability of obtaining a mating than do non-virgin males. Measures of lifetime mating success in male sagebrush crickets have revealed that the median mating frequency is one, with many males failing to secure a mate at all and a small minority obtaining two to four mates. The purpose of this study was to investigate the acoustic and morphological characteristics that make male sagebrush crickets attractive to females. Male crickets were captured from Deadman’s Bar in Grand Teton National Park and their songs were recorded on subsequent evenings. Five song characteristics were measured including pulse duration, interpulse duration, dominant frequency, train duration, and intertrain duration. Multivariate selection analysis revealed significant linear and nonlinear selection on male song, with each of the five measured song characters contributing to male attractiveness. There was significant directional selection favoring longer pulse durations and shorter interpulse durations, which could be an honest indicator of male quality because these song characters likely impose high energetic costs. Significant stabilizing selection favored males with ~ 13.2 kHz calls and intermediate intertrain durations, which may be imposed by the auditory sensitivity of females.


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