Male Crickets Research Articles

Male Field Cricket Songs Are Altered After Aggressive Interactions

To address the hypothesis that male acoustic sexual advertisement signals might be indicators of aggressiveness, in addition to chemical signals, we examined the relationship between levels of aggression/dominance status and acoustic sexual advertisement signals in the field cricket Gryllus integer. Males were paired in aggression trials and recorded the night before and the night after the trial. This allowed us to test whether aggression is inherently linked to song phenotypes, or whether aggressive interactions cause males to alter their songs. We found that dominant (winning) males signaled with higher energy, amplitude and power the night after winning an aggressive encounter, but not before the encounter. Time spent calling and the number of calling bouts were unrelated to aggression, whereas whereas winning males increased their bout lengths after winning, and losing males decreased their bout lengths after losing.

Serotonin Mediates Depression of Aggression After Acute and Chronic Social Defeat Stress in a Model Insect.

In all animals, losers of a conflict against a conspecific exhibit reduced aggressiveness, often coupled with depression-like symptoms, particularly after multiple defeats. While serotonin (5HT) is involved, discovering its natural role in aggression and depression has proven elusive. We show how 5HT influences aggression in male crickets, before, and after single and multiple defeats using serotonergic drugs, at dosages that had no obvious deleterious effect on general motility: the 5HT synthesis inhibitor alpha-methyltryptophan (AMTP), the 5HT2 receptor blocker ketanserin, methiothepin which blocks 5HT receptor subtypes other than 5HT2, 5HT's precursor 5-hydroxytryptophan (5HTP) and re-uptake inhibitor fluoxetine. Contrasting reports for other invertebrates, none of the drugs influenced aggression at the first encounter. However, the recovery of aggression after single defeat, which normally requires 3 h in crickets, was severely affected. Losers that received ketanserin or AMTP regained their aggressiveness sooner, whereas those that received fluoxetine, 5HTP, or methiothepin failed to recover within 3 h. Furthermore, compared to controls, which show long term aggressive depression 24 h after 6 defeats at 1 h intervals, crickets that received AMTP or ketanserin regained their full aggressiveness and were thus more resilient to chronic defeat stress. In contrast, 5HTP and fluoxetine treated crickets showed long term aggressive depression 24 h after only 2 defeats, and were thus more susceptible to defeat stress. We conclude that 5HT acts after social defeat via a 5HT2 like receptor to maintain depressed aggressiveness after defeat, and to promote the susceptibility to and establishment of long-term depression after chronic social defeat. It is known that the decision to flee and establishment of loser depression in crickets is controlled by nitric oxide (NO), whereas dopamine (DA), but not octopamine (OA) is necessary for recovery after defeat. Here we show that blocking NO synthesis, just like ketanserin, affords resilience to multiple defeat stress, whereas blocking DA receptors, but not OA receptors, increases susceptibility, just like fluoxetine. We discuss the possible interplay between 5HT, NO, DA, and OA in controlling aggression after defeat, as well as similarities and differences to findings in mammals and other invertebrate model systems.

Purring Crickets: The Evolution of a Novel Sexual Signal.

Opportunities to observe contemporary signal change are incredibly rare but critical for understanding how diversity is created and maintained. We discovered a population of the Pacific field cricket (Teleogryllus oceanicus) with a newly evolved song (purring), different from any known cricket. Male crickets use song to attract females from afar and to court females once near. Teleogryllus oceanicus is well known for sexual signal evolution, as exemplified by a recent signal loss. In this study, we characterized the new purring sound and investigated the role of the purr in long-distance and short-distance communication. The purring sound differed from typical ancestral calls in peak frequency, amplitude, and bandwidth. Further, the long-distance purring song facilitated mate location, though the role of courtship purring song is less clear. Our discovery of purring male crickets is an unprecedented opportunity to watch the emergence of a newly evolved sexual signal unfold in real time and has potential to illuminate the mechanisms by which evolutionary novelties arise and coevolve between the sexes.

Comparison of biomechanical characteristics between male and female elite fast bowlers

ABSTRACTThis study investigated ball release speed and performance kinematics between elite male and female cricket fast bowlers. Fifty-five kinematic parameters were collected for 20 male and 20 female elite fast bowlers. Group means were analysed statistically using an independent samples approach to identify differences. Significant differences were found between: ball release speed; run-up speed; the kinematics at back foot contact (BFC), front foot contact (FFC), and ball release (BR); and the timings between these key instants. These results indicate that the female bowlers generated less whole body linear momentum during the run-up than the males. The male bowlers also utilised a technique between BFC and FFC which more efficiently maintained linear momentum compared to the females. As a consequence of this difference in linear momentum at FFC, the females typically adopted a technique more akin to throwing where ball release speed was contributed to by both the whole body angular momentum and the large rotator muscles used to rotate the pelvis and torso segments about the longitudinal axis. This knowledge is likely to be useful in the coaching of female fast bowlers although future studies are required to understand the effects of anthropometric and strength constraints on fast bowling performance.

Is it the Song or the Singers? Acoustic and Social Experiences Shape Adult Reproductive Tactics and Condition

When sexual signals are perceived during growth and development they can provide information regarding the social conditions likely to be encountered as an adult. Perception of cues related to the presence and density of future mates and potential competitors can result in altered adult phenotypes. Previous studies have shown that adult male Teleogryllus oceanicus field crickets from a Kauai, Hawaii population reared alone and without hearing conspecific song are more phonotactic than those reared with song. These naive males also reduce investment in body size and immunity. Here we examined whether another source of population density information, the presence of other males, affects behavior, size, and immunity. Specifically, we examined satellite behavior as evidenced by strength of phonotaxis, body condition, and immune response in males reared singly and in groups in the presence and absence of conspecific song. Body condition did not vary with rearing density, and immune response did not vary with either acoustic environment or rearing density. Interestingly, group-housed males were more phonotactic than singly-housed males. This pattern was largely driven by the low levels of phonotaxis exhibited by males that were singly-housed in the presence of conspecific song. These findings suggest that males respond to social cues in addition to conspecific song, but that these cues do not necessarily provide concordant information.

Inhibitory Pathways for Processing the Temporal Structure of Sensory Signals in the Insect Brain.

Insects have acquired excellent sensory information processing abilities in the process of evolution. In addition, insects have developed communication schemes based on the temporal patterns of specific sensory signals. For instance, male moths approach a female by detecting the spatiotemporal pattern of a pheromone plume released by the female. Male crickets attract a conspecific female as a mating partner using calling songs with species-specific temporal patterns. The dance communication of honeybees relies on a unique temporal pattern of vibration caused by wingbeats during the dance. Underlying these behaviors, neural circuits involving inhibitory connections play a critical common role in processing the exact timing of the signals in the primary sensory centers of the brain. Here, we discuss common mechanisms for processing the temporal patterns of sensory signals in the insect brain.

Macronutrients and micronutrients drive trade‐offs between male pre‐ and postmating sexual traits

Abstract Nutrition fundamentally affects life span and reproduction, and identifying how nutrient intakes are linked to the expression of these life‐history traits can advance understanding of the mechanisms underlying life‐history trade‐offs. Males are thought to face trade‐offs between the allocation of resources to premating secondary sexual traits for gaining access to females and allocation to postmating traits such as ejaculate quality that affects their fertility. We used the Geometric Framework for nutrition to examine the effects of macronutrient and micronutrient consumption on life span and the expression of pre‐ and postmating sexual traits in male field crickets Teleogryllus oceanicus. We found that life span was maximized on diets with a low protein‐to‐carbohydrate (P:C) ratio, whereas premating sexual traits (courtship song and cuticular hydrocarbons) were maximized on high P:C ratios. In contrast, sperm viability, a postmating trait, was lowest on high‐P:C‐ratio diets. Higher consumption of micronutrients (minerals and vitamins) was associated with decreased life span and lower relative abundances of longer chained CHCs, but improved the performance of sperm viability and courtship song. We show that different macronutrients are not simply calories to be allocated to different traits, but directly determine the expression of different life‐history traits and mediate their trade‐offs. In this study, we also provide evidence that micronutrients influenced the expression of life‐history traits, emphasizing the value of including micronutrients in experiments using nutritional geometry. A plain language summary is available for this article.

Genotype-by-sex-by-diet interactions for nutritional preference, dietary consumption, and lipid deposition in a field cricket.

Changes in feeding behaviour, especially the overconsumption of calories, has led to a rise in the rates of obesity, diabetes, and other associated disorders in humans and a range of animals inhabiting human-influenced environments. However, understanding the relative contribution of genes, the nutritional environment, and their interaction to dietary intake and lipid deposition in the sexes still remains a major challenge. By combining nutritional geometry with quantitative genetics, we determined the effect of genes, the nutritional environment, and their interaction on the total nutritional preference (TP), total diet eaten (TE), and lipid mass (LM) of male and female black field crickets (Teleogryllus commodus) fed one of four diet pairs (DPs) differing in the ratio of protein to carbohydrate and total nutritional content. We found abundant additive genetic variance for TP, TE, and LM in both sexes and across all four DPs, with significant genetic correlations between TE and TP and between TP and LM in males. We also found significant genotype-by-DP and genotype-by-sex-by-DP interactions for each trait and significant genotype-by-sex interactions for TE and LM. Complex interactions between genes, sex, and the nutritional environment, therefore, play an important role in nutrient regulation and lipid deposition in T. commodus. This finding may also help explain the increasing rate of obesity and the maintenance of sex differences in obesity observed across many animal species, including humans.

Timing of the Onset of Aggressive and Sexual Behaviors in Male Crickets Gryllus bimaculatus and Gryllus locorojo

Timing of the Onset of Aggressive and Sexual Behaviors in Male Crickets Gryllus bimaculatus and Gryllus locorojo

Fight outcome briefly affects the reproductive fitness of male crickets

Sexual selection allows male individuals to adopt different evolutionary strategies in mating system. In this study, we determined whether dominance affected reproductive fitness of male crickets Velarifictorus aspersus during both pre-copulatory and post-copulatory selection when we excluded male–male competition. The results showed that females mated more often with male winners only during the first 2 h after a fight when male winners were more likely to produce courtship songs than losers. However, females did not retain the attached spermatophores of male winners longer than those of male losers, and the fecundity and fertilization success also did not differ significantly between females mated different times with male winners and losers. Instead, the fertilization success was positively correlated with male body weight. These results suggest that a recent wining experience increases reproductive fitness of males during pre-copulatory selection, but females may prefer larger males rather than winners during post-copulatory selection. The incoordination between pre- and post-copulatory selection may allow males to adopt different evolutionary strategies in mating system.

Long Legs And Combat Outcomes Among Male Cave Crickets

Long Legs And Combat Outcomes Among Male Cave Crickets

Sex-based differences in anti-predator response of crickets to chemical cues of a mammalian predator.

Anti-predator behaviors like vigilance or hiding come at the expense of other fitness increasing behaviors such as foraging. To compensate for this trade-off, prey assess predation risk and modify the frequency of anti-predator behaviors according to the likelihood of the threat. In this study, we tested the ability of house crickets (Acheta domesticus) to indirectly assess predation risk via odors from a mammalian predator, Elliot’s short-tailed shrew (Blarina hylophaga). As natural differences in encounter rates and predation risk differs between sexes, we tested if male and female crickets perceive similar rates of predation risk from the presence of shrew odor measured via anti-predator behavioral response. Crickets were placed in enclosed, cardboard-lined chambers either treated with shrew odor or control, along with a food source. Time until foraging was measured for each individual and compared across treatment and sex. We found that in the presence of shrew odor, female crickets delayed foraging while males showed no response. These results suggest adult crickets can use chemical cues to detect mammalian predators. Furthermore, we demonstrate that female crickets associate greater predation risk from shrew predators than do male crickets, which are more stationary yet acoustically conspicuous. As predation risk potentially differs drastically for each sex, changes to the operational sex ratios of wild cricket populations could be influenced by the identity of the predator community.

Effects of core stability training on speed of running in male cricket players

Effects of core stability training on speed of running in male cricket players

Effect of acute augmented feedback on between limb asymmetries and eccentric knee flexor strength during the Nordic hamstring exercise.

BackgroundHamstring strain injuries (HSI) are one of the most prevalent and serious injuries affecting athletes, particularly those in team ball sports or track and field. Recent evidence demonstrates that eccentric knee flexor weakness and between limb asymmetries are possible risk factors for HSIs. While eccentric hamstring resistance training, e.g. the Nordic hamstring exercise (NHE) significantly increases eccentric hamstring strength and reduces HSI risk, little research has examined whether between limb asymmetries can be reduced with training. As augmented feedback (AF) can produce significant acute and chronic increases in muscular strength and reduce injury risk, one way to address the limitation in the eccentric hamstring training literature may be to provide athletes real-time visual AF of their NHE force outputs with the goal to minimise the between limb asymmetry.MethodsUsing a cross over study design, 44 injury free, male cricket players from two skill levels performed two NHE sessions on a testing device. The two NHE sessions were identical with the exception of AF, with the two groups randomised to perform the sessions with and without visual feedback of each limb’s force production in real-time. When performing the NHE with visual AF, the participants were provided with the following instructions to ‘reduce limb asymmetries as much as possible using the real-time visual force outputs displayed in front them’. Between limb asymmetries and mean peak force outputs were compared between the two feedback conditions (FB1 and FB2) using independent t-tests to ensure there was no carryover effect, and to determine any period and treatment effects. The magnitude of the differences in the force outputs were also examined using Cohen d effect size.ResultsThere was a significant increase in mean peak force production when feedback was provided (mean difference, 21.7 N; 95% CI [0.2–42.3 N]; P = 0.048; d = 0.61) and no significant difference in between limb asymmetry for feedback or no feedback (mean difference, 5.7%; 95% CI [−2.8% to 14.3%]; P = 0.184; d = 0.41). Increases in force production under feedback were a result of increased weak limb (mean difference, 15.0 N; 95% CI [1.6–28.5 N]; P = 0.029; d = 0.22) force contribution compared to the strong limb.DiscussionThe results of this study further support the potential utility of AF in improving force production and reducing risk in athletic populations. While there are currently some financial limitations to the application of this training approach, even in high-performance sport, such an approach may improve outcomes for HSI prevention programs. Further research with more homogenous populations over greater periods of time that assess the chronic effect of such training practices on injury risk factors and injury rates are also recommended.

Induced expression of a vestigial sexual signal.

Vestigial morphological traits are common and well known in a variety of taxa. Identification of vestigial genes has illustrated the potential for evolutionary reversals and the re-expression of atavistic traits. Here we induce expression of a behavioural sexual signal, male calling song, in a cricket species, Gryllus ovisopis, which lacks a functional calling song. We successfully used acetylcholine injections in the frontal space of the head of male crickets to activate cerebral command neurons for cricket calling, and we recorded calling songs with a temporal chirp pattern similar to that of G. ovisopis' close evolutionary relatives, G. firmus and G. pennsylvanicus, implying that the neural pattern generators that underlie cricket calling behaviour persist in a vestigial state in G. ovisopis To our knowledge, this is the first demonstration of the induced expression of a vestigial behaviour in any organism. The retention of latent neural capacity to express sexual behaviours could have important implications for rapid evolution, trait re-emergence and reproductive isolation.

How dietary protein and carbohydrate influence field cricket development, size and mate attraction signalling

Researchers examining how nutrition impacts fitness traits usually examine one nutrient at a time, ignoring potential interactions. When researchers simultaneously examine multiple nutrients, their studies often focus on adults, ignoring potential changes in nutritional needs that occur during the transition between juvenile and adult stages. To address these issues, we quantified how dietary nutrient balance (relative amounts of protein and carbohydrate) during development and into adulthood influenced life history and sexually selected traits using male Jamaican field crickets, Gryllus assimilis. Our findings revealed that male crickets developed significantly faster and grew larger when they were reared on a protein-rich diet, but their average daily time spent signalling for mates was significantly higher when they were reared on a carbohydrate-rich diet. Furthermore, while the probability of signalling and daily time spent signalling increased with age, time spent signalling for mates tended to increase at a higher rate with age when males consumed a carbohydrate-rich diet in adulthood. Together our findings suggest that traits may differ in their nutrient requirements, resulting in diet influencing a possible trade-off between traits across different life stages. The ability to locate and consume foods rich in protein during development should impact adult male fitness, as protein availability results in larger males, and larger males typically produce more attractive signals and are preferred by females. Conversely, the ability to locate and consume foods rich in carbohydrate should also impact a male's fitness, as males signal with higher effort when fed carbohydrate-rich diets, and higher signalling effort can directly impact a male's ability to attract a female.

Tibial cartilage volume of the back leg versus the higher loaded front leg in elite male and female English cricket fast bowlers

Tibial cartilage volume of the back leg versus the higher loaded front leg in elite male and female English cricket fast bowlers

The effects of the social environment and physical disturbance on personality traits

The environment can have a considerable impact on behaviour. The social environment is predicted to be a particularly important driver of behavioural variation and evolution through the indirect genetic effects that arise whenever individuals interact with conspecifics. We used male Australian field crickets, Teleogryllus oceanicus, to examine the effects of changes in the social environment (recorded acoustic sexual signals of other males) on the expression and consistency of boldness, activity and exploration, and their between-individual covariation. Switching from a silent environment to being exposed to male acoustic sexual signals resulted in crickets becoming less bold, active and explorative. Switching from an acoustic to a silent environment resulted in increased boldness and activity. We also looked at the effects of changes in the nonsocial environment via a physical disturbance that mimicked the presence of a potential predator (mechanical shaking). The effects of physical disturbance (and changes thereof) on behaviour were far less pronounced than the effects of changes in the social environment. Neither the repeatability of nor correlations between behaviours were affected by changes in physical disturbance. Only the average level of exploration was affected significantly when crickets were moved from an undisturbed to a disturbed environment, with crickets becoming less explorative. Although changes in the social and the nonsocial environment affected the repeatability of and correlations between some of the behaviours measured, changes in the social environment had the greater effect. We discuss the ecological and evolutionary implications of our findings and how they relate to our current understanding of social and nonsocial environmental effects on behaviour.

Stay tuned: Active processes tune tree cricket ears to maintain a match to temperature-dependent song frequency

Tree cricket males produce tonal songs, which are used to attract mates and to interact with other males. In other crickets, the mechanical properties of their peripheral auditory system have evolved to have resonant modes at the communication frequency. The tree cricket auditory system, however, is not passively tuned to song frequency. Tree crickets exploit an active amplification process to tune hearing to song frequency. However, their song frequency increases with temperature, presenting a problem for tuned listeners. We show here that the actively amplified frequency increases with temperature, and shifts mechanical and neuronal auditory tuning to maintain a match with changing song frequency. We also find that in tree crickets active amplification does not provide greater sensitivity or dynamic range than that observed in other crickets that lack active amplification. Thus, the primary adaptive function of active amplification is to ensure that auditory tuning remains matched to conspecific song frequency, despite changing environmental conditions and signal characteristics.

Age-dependent variation in the terminal investment threshold in male crickets.

The terminal investment hypothesis proposes that decreased expectation of future reproduction (e.g., arising from a threat to survival) should precipitate increased investment in current reproduction. The level at which a cue of decreased survival is sufficient to trigger terminal investment (i.e., the terminal investment threshold) may vary according to other factors that influence expectation for future reproduction. We test whether the terminal investment threshold varies with age in male crickets, using heat-killed bacteria to simulate an immune-inducing infection. We measured calling effort (a behavior essential for mating) and hemolymph antimicrobial activity in young and old males across a gradient of increasing infection cue intensity. There was a significant interaction between the infection cue and age in their effect on calling effort, confirming the existence of a dynamic terminal investment threshold: young males reduced effort at all infection levels, whereas old males increased effort at the highest levels relative to naïve individuals. A lack of a corresponding decrease in antibacterial activity suggests that altered reproductive effort is not traded against investment in this component of immunity. Collectively, these results support the existence of a dynamic terminal investment threshold, perhaps accounting for some of the conflicting evidence in support of terminal investment.