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Leif Engqvist - One of the best experts on this subject based on the ideXlab platform.
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The evolution of strategic male Mating Effort in an information transfer framework.
Journal of evolutionary biology, 2017Co-Authors: Leif Engqvist, Michael TaborskyAbstract:Sperm competition theory predicts that males should use cues indicating the risk and intensity of sperm competition to tailor their sperm investment accordingly. Rival males are an important source of social information regarding sperm competition risk. However, revealing such information may not be in the rival males' interest. Here, we use a theoretical approach based on informed and uninformed games to investigate when information transfer about sperm competition risk to competitors is beneficial for a male, and when it is not. The results show that signalling to potential future mates that a female has already mated is beneficial when the signalling male has a sperm competition disadvantage, whereas it is unfavourable when the signaller has an advantage. The reason for this counterintuitive result is that the rival males' optimal response is to reduce sperm investment when the signaller has a disadvantage and, conversely, to increase investment when the signaller has an advantage. Furthermore, we analysed scenarios where males use alternative reproductive tactics. In this situation, signalling the awareness of sperm competition risk rarely pays; instead, it is beneficial to maintain an information advantage. Thus, it may be beneficial for bourgeois males to accept cuckoldry instead of revealing their sperm competition awareness to reproductive parasites. These results provide new insight into the evolution of communication between rivals in the context of sperm competition.
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A life-history perspective on strategic Mating Effort in male scorpionflies
Behavioral Ecology, 2002Co-Authors: Leif Engqvist, Klaus Peter SauerAbstract:In species with high male Mating Effort, there is a trade-off between Mating Effort spent in a current Mating and resources left for future Matings. Consequently, to maximize their reproductive success, males have to invest strategically, saving resources in Matings with low reproductive gain for future, more valuable Matings. However, as males age, the expected future reproductive success constantly declines. Thus, the importance of resource rationing may drastically change during a lifetime. Males of the scorpionfly Panorpa cognata offer females a costly nuptial gift before copulation, which functions as male Mating Effort. Resources for the production of these salivary masses are severely limited for males in poor condition. We found that males invested more in copulations with high-quality females than in copulations with low-quality females. However, males ceased to discriminate as they became older. Old males, with a relative small number of expected future Matings, did not invest differentially in copulations with high- versus low-quality females. In copulations with low-quality females, males invested more in late than in initial Matings, whereas in Matings with high-quality females, time of Mating had no influence on Mating Effort. These results imply that males adaptively change their resource allocation strategy during the course of the season. Initial Matings seem to be characterized by male prudence; in later Matings, males seem to adopt a more opportunistic Mating strategy. Copyright 2002.
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Strategic male Mating Effort and cryptic male choice in a scorpionfly
Proceedings. Biological sciences, 2001Co-Authors: Leif Engqvist, Klaus Peter SauerAbstract:In animal species with high male Mating Effort, males often find themselves in a dilemma: by increasing their Mating Effort, the gain from each copulation increases but simultaneously reduces available resources and, thus, the opportunity for future copulations. Therefore, we expect males to spend less reproductive resources on Matings that provide low reproductive potential, thereby saving resources for future copulations, possibly with high–quality females, a sort of cryptic male choice. However, the strength of the trade–off between investment in a current Mating and resources available for future Matings must not be the same for all males. Males with relatively high Mating costs should allocate their limited resources more cautiously than males with more plentiful resources. Here, we examine this prediction in the scorpionfly Panorpa cognata . Prior to copulation, males produce a large salivary mass on which females feed during copulation. We show that the production of larger salivary masses leads to longer copulations. Moreover, the size of the salivary gland and salivary mass increases with increasing male condition. However, males in poor condition make a relatively higher Mating investment than males in good condition. We therefore expect male condition to influence cryptic male choice. In accordance with our hypothesis, only males in poor condition choose cryptically, producing larger salivary masses in copulations with females of high fecundity.
Lukas Schärer - One of the best experts on this subject based on the ideXlab platform.
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Strategic Mating Effort in a simultaneous hermaphrodite
Behavioral Ecology and Sociobiology, 2012Co-Authors: Tim Janicke, Halil Kesselring, Lukas SchärerAbstract:Sexual selection theory for simultaneously hermaphroditic animals predicts an overall preference for inseminating partners that have a relatively higher female fecundity. Previous work on the link between male Mating decisions and female fecundity has primarily focused on the effect of the partners’ body size using existing variation in this trait within a study population. On the assumption that the body size is positively correlated with female fecundity, sperm donors should preferentially inseminate relatively larger individuals to obtain a higher fitness gain through their male sex function. However, empirical evidence for such size-dependent mate choice in simultaneous hermaphrodites is equivocal, possibly because of confounding variables. We studied the Mating behavior of the simultaneously hermaphroditic flatworm Macrostomum lignano and tested for a strategic Mating Effort in response to the feeding status of the partner. We experimentally manipulated the feeding status of potential Mating partners in order to generate variation in female fecundity among them and tested whether this affected the copulation number and the number of sperm that the focal worm managed to store in the partner’s sperm storage organ. We found that the manipulation of the feeding status had a strong effect on the body size of the potential Mating partners and that focal worms copulated more frequently with, and stored more sperm in well-fed partners compared to unfed partners. Our results suggest that M. lignano adjusts its Mating Effort in response to the feeding status of the Mating partner.
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Strategic Mating Effort in a simultaneous hermaphrodite The role of the partner's feeding status
Behavioral Ecology and Sociobiology, 2012Co-Authors: Tim Janicke, Halil Kesselring, Lukas SchärerAbstract:Sexual selection theory for simultaneously hermaphroditic animals predicts an overall preference for inseminating partners that have a relatively higher female fecundity. Previous work on the link between male Mating decisions and female fecundity has primarily focused on the effect of the partners’ body size using existing variation in this trait within a study population. On the assumption that the body size is positively correlated with female fecundity, sperm donors should preferentially inseminate relatively larger individuals to obtain a higher fitness gain through their male sex function. However, empirical evidence for such size-dependent mate choice in simultaneous hermaphrodites is equivocal, possibly because of confounding variables. We studied the Mating behavior of the simultaneously hermaphroditic flatworm Macrostomum lignano and tested for a strategic Mating Effort in response to the feeding status of the partner. We experimentally manipulated the feeding status of potential Mating partners in order to generate variation in female fecundity among them and tested whether this affected the copulation number and the number of sperm that the focal worm managed to store in the partner’s sperm storage organ. We found that the manipulation of the feeding status had a strong effect on the body size of the potential Mating partners and that focal worms copulated more frequently with, and stored more sperm in well-fed partners compared to unfed partners. Our results suggest that M. lignano adjusts its Mating Effort in response to the feeding status of the Mating partner.
Klaus Peter Sauer - One of the best experts on this subject based on the ideXlab platform.
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Mating Effort and cryptic sperm choice in scorpionflies male investment strategy vs female control
Ethology, 2008Co-Authors: Andreas Vermeulen, Sierk Engels, Klaus Peter SauerAbstract:In this study, we examined which sex controls sperm transfer during copulation in scorpionflies. Therefore male scorpionflies were doubly mated to females of high and low fecundity to explore whether they allocate sperm according to female quality. While Mating order had no effect males transferred sperm at higher rates when Mating with low-quality instead of high-quality females. As there is no obvious benefit from providing low-fecundity females with more sperm, we suggest a condition-dependent female ability to counteract sperm transfer. Therefore, we disabled females at the beginning of copulations using the insecticide Propoxur which leads to total paralysis caused by tremors. While the provoked muscle contractions led to significantly smaller numbers of sperm transferred, Propoxur treatment had no effect on males. We suggest female counteracting of sperm transfer to be adaptive by decreasing the relative amount of sperm transferred by low-quality males and increasing the proportion of offspring sired by high-quality males.
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A life-history perspective on strategic Mating Effort in male scorpionflies
Behavioral Ecology, 2002Co-Authors: Leif Engqvist, Klaus Peter SauerAbstract:In species with high male Mating Effort, there is a trade-off between Mating Effort spent in a current Mating and resources left for future Matings. Consequently, to maximize their reproductive success, males have to invest strategically, saving resources in Matings with low reproductive gain for future, more valuable Matings. However, as males age, the expected future reproductive success constantly declines. Thus, the importance of resource rationing may drastically change during a lifetime. Males of the scorpionfly Panorpa cognata offer females a costly nuptial gift before copulation, which functions as male Mating Effort. Resources for the production of these salivary masses are severely limited for males in poor condition. We found that males invested more in copulations with high-quality females than in copulations with low-quality females. However, males ceased to discriminate as they became older. Old males, with a relative small number of expected future Matings, did not invest differentially in copulations with high- versus low-quality females. In copulations with low-quality females, males invested more in late than in initial Matings, whereas in Matings with high-quality females, time of Mating had no influence on Mating Effort. These results imply that males adaptively change their resource allocation strategy during the course of the season. Initial Matings seem to be characterized by male prudence; in later Matings, males seem to adopt a more opportunistic Mating strategy. Copyright 2002.
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Strategic male Mating Effort and cryptic male choice in a scorpionfly
Proceedings. Biological sciences, 2001Co-Authors: Leif Engqvist, Klaus Peter SauerAbstract:In animal species with high male Mating Effort, males often find themselves in a dilemma: by increasing their Mating Effort, the gain from each copulation increases but simultaneously reduces available resources and, thus, the opportunity for future copulations. Therefore, we expect males to spend less reproductive resources on Matings that provide low reproductive potential, thereby saving resources for future copulations, possibly with high–quality females, a sort of cryptic male choice. However, the strength of the trade–off between investment in a current Mating and resources available for future Matings must not be the same for all males. Males with relatively high Mating costs should allocate their limited resources more cautiously than males with more plentiful resources. Here, we examine this prediction in the scorpionfly Panorpa cognata . Prior to copulation, males produce a large salivary mass on which females feed during copulation. We show that the production of larger salivary masses leads to longer copulations. Moreover, the size of the salivary gland and salivary mass increases with increasing male condition. However, males in poor condition make a relatively higher Mating investment than males in good condition. We therefore expect male condition to influence cryptic male choice. In accordance with our hypothesis, only males in poor condition choose cryptically, producing larger salivary masses in copulations with females of high fecundity.
Vincent Egan - One of the best experts on this subject based on the ideXlab platform.
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Untangling the concurrent influences of the Dark Triad, personality and Mating Effort on violence
Personality and Individual Differences, 2015Co-Authors: Jodie Westhead, Vincent EganAbstract:Abstract The Dark Triad (narcissism, Machiavellianism and psychopathy; DT) and Mating Effort are associated with anti-social behaviour, but these associations may build on underlying personality traits not specific to violence. The DT (measured using the SD3), the HEXACO personality scale, and a measure of Mating Effort were regressed onto a measure of self-reported violence as defined by an adapted version of the MacArthur Community Violence Screening Instrument in 305 adults recruited via an online survey. While simple correlation analyses found violence and Mating Effort both systematically associated with most personality and DT measures, regression suggested overall violence was specifically associated with younger age, lower agreeableness, and greater psychopathy (R2 = 0.32, 95% confidence interval = 0.24 to 0.40); unprovoked violence was associated with greater psychopathy. These results suggest that when personality, the DT, and Mating Effort are considered simultaneously, antisocial personality variance falls out of Mating Effort and narcissism constructs, leaving a more parsimonious set of associates for aggression and violence. This study reiterates the importance of concurrently measuring basic disposition when examining factors genuinely underlying violence and aggression, and the centrality of psychopathy and low agreeableness to such behaviour.
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Does Personality, Delinquency, or Mating Effort Necessarily Dictate a Preference for an Aggressive Dog?
Anthrozoös, 2012Co-Authors: Vincent Egan, Jason MackenzieAbstract:ABSTRACTThe current study investigated the relationship between dimensions of personality, self-reports of delinquency, Mating Effort, and the desire to own a dog perceived as aggressive. Seven common breeds of dog were rated by 235 participants living within the UK and North America, using an online survey application. Participants also completed scales measuring personality, earlier delinquency, and Mating Effort. A clear dimension in perceived aggressiveness was found across dog breeds. Persons lower in Agreeableness, higher in Neuroticism and Conscientiousness, and of younger age actively preferred a dog perceived as aggressive. Neither delinquency nor Mating Effort actively predicted this preference for an aggressive dog, although these measures were themselves correlated with Agreeableness; a regression analysis found that low Agreeableness, younger age, and higher Conscientiousness predicted higher ratings on the aggression preference dimension. These findings show that a preference for a more aggr...
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A Case-Control Study of Alcohol-Related Violent Offending among Irish Probation Clients
2012Co-Authors: Janice Kelly, Vincent EganAbstract:Summary: A case–control study examined whether aggressive offenders who had consumed alcohol before offending differed from aggressive offenders who had not consumed alcohol prior to their index offence or non-aggressive control offenders on measures of aggression, criminal cognitions, Mating Effort and personality. We examined whether alcohol-related aggressive offenders could be postdicted by individual difference measures. All 72 participants were on probation and completed the Buss–Perry Aggression Questionnaire; the Psychological Inventory of Criminal Thinking Styles; the Alcohol-Related Aggression Questionnaire; the NEO–Five Factor Inventory–Revised; and the Mating Effort Scale. The study found alcohol-related aggression expectancies predicted by low agreeableness and high neuroticism. Aggressive offenders who had consumed alcohol prior to their index offence were more likely to have higher levels of alcohol-related aggressive expectancies, aggression, callousness, and lower levels of neuroticism and thoughtfulness than non-aggressive offenders.
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Personality, Mating Effort and alcohol-related violence expectancies
Addiction Research & Theory, 2008Co-Authors: Vincent Egan, Edwin HamiltonAbstract:The current study investigated whether scores on the Alcohol Related Aggression Questionnaire (ARAQ) were predictable from the independent influences of personality and intra-sexual competition as measured by the Mating Effort scale (MES) and whether education had a protective factor in any relationship that arose. Ninety-five participants completed personality, MES and ARAQ scales. Hierachical linear regression independently entering MES followed by agreeableness, conscientiousness, age, education and sex found alcohol-aggression expectancies were predicted by higher MES and younger age; alcohol-related trait aggression was predicted by higher MES, lower agreeableness and younger age; alcohol-related sensitivity to pain and anxiety was related to higher MES and younger age; an expectation of drinking cheap but high potency alcoholic beverages was primarily associated with higher MES alone. These results show that Mating Effort has a disproportionate influence upon different facets of alcohol-aggression e...
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Narcissism, vanity, personality and Mating Effort
Personality and Individual Differences, 2007Co-Authors: Vincent Egan, Cara MccorkindaleAbstract:The current study examined the relationship between narcissism and vanity, and the degree these are predicted by the ‘Big Five’ personality traits and Mating Effort (ME) using a sample of 103 females recruited from a large beauty salon. Narcissism correlated with vanity at 0.72 (P < 0.001), and was associated positively with extraversion (E), ME and the subscales of vanity; narcissism was associated negatively with neuroticism (N) and agreeableness (A). Vanity correlated positively with E, conscientiousness, both subscales of narcissism, and ME, and negatively with N and A. A composite narcissism–vanity score was produced using principal components analysis, and used along with scores from the NEO-FFI-R to predict Mating Effort. The narcissism–vanity composite, low A and E significantly and independently predicted Mating Effort (adjusted R 2 = 0.28, F(9.96) = 7.74, P < 0.001). These results show that Mating Effort is additionally
Tim Janicke - One of the best experts on this subject based on the ideXlab platform.
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Strategic Mating Effort in a simultaneous hermaphrodite
Behavioral Ecology and Sociobiology, 2012Co-Authors: Tim Janicke, Halil Kesselring, Lukas SchärerAbstract:Sexual selection theory for simultaneously hermaphroditic animals predicts an overall preference for inseminating partners that have a relatively higher female fecundity. Previous work on the link between male Mating decisions and female fecundity has primarily focused on the effect of the partners’ body size using existing variation in this trait within a study population. On the assumption that the body size is positively correlated with female fecundity, sperm donors should preferentially inseminate relatively larger individuals to obtain a higher fitness gain through their male sex function. However, empirical evidence for such size-dependent mate choice in simultaneous hermaphrodites is equivocal, possibly because of confounding variables. We studied the Mating behavior of the simultaneously hermaphroditic flatworm Macrostomum lignano and tested for a strategic Mating Effort in response to the feeding status of the partner. We experimentally manipulated the feeding status of potential Mating partners in order to generate variation in female fecundity among them and tested whether this affected the copulation number and the number of sperm that the focal worm managed to store in the partner’s sperm storage organ. We found that the manipulation of the feeding status had a strong effect on the body size of the potential Mating partners and that focal worms copulated more frequently with, and stored more sperm in well-fed partners compared to unfed partners. Our results suggest that M. lignano adjusts its Mating Effort in response to the feeding status of the Mating partner.
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Strategic Mating Effort in a simultaneous hermaphrodite The role of the partner's feeding status
Behavioral Ecology and Sociobiology, 2012Co-Authors: Tim Janicke, Halil Kesselring, Lukas SchärerAbstract:Sexual selection theory for simultaneously hermaphroditic animals predicts an overall preference for inseminating partners that have a relatively higher female fecundity. Previous work on the link between male Mating decisions and female fecundity has primarily focused on the effect of the partners’ body size using existing variation in this trait within a study population. On the assumption that the body size is positively correlated with female fecundity, sperm donors should preferentially inseminate relatively larger individuals to obtain a higher fitness gain through their male sex function. However, empirical evidence for such size-dependent mate choice in simultaneous hermaphrodites is equivocal, possibly because of confounding variables. We studied the Mating behavior of the simultaneously hermaphroditic flatworm Macrostomum lignano and tested for a strategic Mating Effort in response to the feeding status of the partner. We experimentally manipulated the feeding status of potential Mating partners in order to generate variation in female fecundity among them and tested whether this affected the copulation number and the number of sperm that the focal worm managed to store in the partner’s sperm storage organ. We found that the manipulation of the feeding status had a strong effect on the body size of the potential Mating partners and that focal worms copulated more frequently with, and stored more sperm in well-fed partners compared to unfed partners. Our results suggest that M. lignano adjusts its Mating Effort in response to the feeding status of the Mating partner.