China
Africa
Explore chapters and articles related to this topic
Evolution, Natural Selection, and Behavior
Published in Gail S. Anderson, 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].
Nanoparticles as a potential teratogen: a lesson learnt from fruit fly
Published in Nanotoxicology, 2019
Bedanta Kumar Barik, Monalisa Mishra
Cu NPs having myriads of usage (Hajipour et al. 2012; Bondarenko et al. 2013) can induce toxicity in Drosophila (Carmona, Inostroza-Blancheteau et al. 2015). CuO NPs proved to be genotoxic to Drosophila as it causes DNA damage to larval haemocyte. CuO NPs causes mitotic recombination a potential mechanism to cause mutation. Malondialdehyde, a marker for oxidative stress, was found to be increased after CuO NP exposure. The oxidative stress can bring about genotoxicity in Drosophila. CuO NP further causes developmental delay,which is associated either with genotoxicity or with oxidative stress. Han et al. (2014) also reported that Cu NPs causes developmental delay, reduced adult longevity, and sperm competition in Drosophila. CuO NPs resulted reduced larval growth, defective metamorphosis, and delayed pupa to adult stage (Alaraby et al. 2016). The toxicity is due to the copper ions released from the CuO NPs. Genetic markers such as Dual oxidase (Duox), Hemolectin (Hml), Prophenoloxidase 2 (PPO2), and Unpaired 3 (Upd3) in gut cells are downregulated due to the effect of CuO NP. Accumulation of CuO NPs in the gut lumen, gut cells, and haemocytes (after translocation) decreased the microbiota population within the gut.