Evolution, Natural Selection, and Behavior
Gail S. Anderson in Biological Influences on Criminal Behavior, 2019
Other forms of rape as an evolutionary reproductive strategy have been proposed by McKibbin and colleagues, including the specialized rapist, the opportunistic rapist, the high-mating-effort rapist, and the partner rapist.29 The specialized rapist is hypothesized to have evolved an ability to be more rapidly aroused and to more rapidly ejaculate than normal, which greatly minimize risk. It has been speculated that premature ejaculation may have increased reproductive success ancestrally to reduce the risk of predation or discovery by potential rivals.29 The opportunistic rapist is hypothesized to normally prefer receptive women but will also engage in rape in situations where there is very little cost,29 which is borne out by the very high numbers of rapes that occur in times of conflict (for example, the more than 1 million rapes by the Red Army after World War II).28 The high-mating-effort rapist is hypothesized to be more sexually experienced than most, with a very high level of self-esteem and self-perceived sexual prowess. He pursues a large number of partners with little investment and resorts to rape when consensual strategies fail. This typology is linked to psychopathy.29 The final hypothesized typology is that of partner rapist, who rapes his partner at times when he believes her to be unfaithful and therefore possibly impregnated by another man. This relates to sperm competition, in which males compete to ensure that their sperm impregnates the female. Although partner rapes are very common and were not even considered illegal in many countries until relatively recently, studies have shown that partner rapes increase during breakups due to concern over infidelity.29
Cellular mechanisms regulating synthetic sex ratio distortion in the Anopheles gambiae germline
Published in Pathogens and Global Health, 2020
Roya Elaine Haghighat-Khah, Atashi Sharma, Mariana Reis Wunderlich, Giulia Morselli, Louise Anna Marston, Christopher Bamikole, Ann Hall, Nace Kranjc, Chrysanthi Taxiarchi, Igor Sharakhov, Roberto Galizi
Previous studies showed that Drosophila melanogaster females mated with males heterozygous for the well-studied killer meiotic driver carry dysfunctional (i.e. dead) sperm [22]. Conversely, in the roundworm Caenorhabditis elegans apoptosis does not occur in response to spermatogenic meiotic defects due to the inability to activate the downstream cytotoxic caspase CED-3 [23]. The postcopulatory transfer of aneuploid sperm, detected from both A. gambiae Ag(PMB)1 and wild-type males, indicates that sperm does not have to be fully functional to be transferred to female mosquitoes after copulation. Also, in some Drosophila species, only long sperm fertilizes the eggs, despite males producing both long and short nucleated mature sperm [24,25], suggesting a possible role of the non-fertilizing mature sperm such as facilitating sperm transportation, nutritional provisions, or preventing receipt and storage of sperm from competing males [26]. Studies in A. gambiae showed that postcopulatory sperm competition may occur between polymorphic sperm of various lengths, where males with short sperm have higher reproductive success [27].
Erectile Dysfunction and Partner-Directed Behaviors in Romantic Relationships: The Mediating Role of Suspicious Jealousy
Published in The Journal of Sex Research, 2022
Gavin Vance, Virgil Zeigler-Hill, Rachel M. James, Todd K. Shackelford
Previous research has documented that greater proportions of men than women are more upset when imagining their partner’s sexual infidelity than when imagining their partner’s emotional infidelity (e.g., D. M. Buss et al., 1992) and that men perform more mate retention behaviors when they are at greater recurrent risk of experiencing sperm competition (due to partner infidelity; V. G. Starratt et al., 2007). Evolutionary theories posit that men perform these behaviors in order to reduce the risk that they will unwittingly invest time and resources in the offspring of other men. This explanation may also be applicable to the relationship between men’s experience with ED and the suspicious jealousy they feel toward their partners. Although men who experience ED are not typically rendered entirely unable to have penile-vaginal intercourse with their partners, their ability to do so is certainly reduced. Any such reduction in a man’s ability to have sex with his partner is a disadvantage in terms of sperm competition because he cannot successfully inseminate his partner with sperm to compete with rival male sperm, and because he also may experience a decline in mate value as a result of his inability to have sex. Mate retention behaviors such as partner-directed violence and insults may be some of the ways in which men manage the perceived increase in the risk of partner infidelity resulting from their experience with ED. A potential alternative explanation is that men feel threatened in their masculinity and relationship stability as a result of their experience with ED, and use mate retention behaviors to partially ameliorate these feelings. The connection between ED and low sexual satisfaction of partners (e.g., Althof, 2002) may explain why men who experience ED report elevated levels of suspicious jealousy and aversive partner-directed behaviors.
Related Knowledge Centers
- Egg Cell
- Fertility
- Sexual Reproduction
- Spermatozoon
- Egg
- Reproductive Success
- Sexual Conflict
- Mating Plug
- Natural Selection
- Anisogamy