35 research outputs found
Sexual Cannibalism: High Incidence in a Natural Population with Benefits to Females
10 pages, 3 figures.[Background] Sexual cannibalism may be a form of extreme sexual conflict in which females benefit more from feeding on males than mating with them, and males avoid aggressive, cannibalistic females in order to increase net fitness. A thorough understanding of the adaptive significance of sexual cannibalism is hindered by our ignorance of its prevalence in nature. Furthermore, there are serious doubts about the food value of males, probably because most studies that attempt to document benefits of sexual cannibalism to the female have been conducted in the laboratory with non-natural alternative prey. Thus, to understand more fully the ecology and evolution of sexual cannibalism, field experiments are needed to document the prevalence of sexual cannibalism and its benefits to females.[Methodology/Principal Findings] We conducted field experiments with the Mediterranean tarantula (Lycosa tarantula), a burrowing wolf spider, to address these issues. At natural rates of encounter with males, approximately a third of L. tarantula females cannibalized the male. The rate of sexual cannibalism increased with male availability, and females were more likely to kill and consume an approaching male if they had previously mated with another male. We show that females benefit from feeding on a male by breeding earlier, producing 30% more offspring per egg sac, and producing progeny of higher body condition. Offspring of sexually cannibalistic females dispersed earlier and were larger later in the season than spiderlings of non-cannibalistic females.[Conclusions/Significance] In nature a substantial fraction of female L. tarantula kill and consume approaching males instead of mating with them. This behaviour is more likely to occur if the female has mated previously. Cannibalistic females have higher rates of reproduction, and produce higher-quality offspring, than non-cannibalistic females. Our findings further suggest that female L. tarantula are nutrient-limited in nature and that males are high-quality prey. The results of these field experiments support the hypothesis that sexual cannibalism is adaptive to females.This paper has been written under a Ramón y Cajal research contract from the Spanish Ministry of Science and Technology (MCYT) to JML and an I3P-BPD2004-CSIC scholarship to RRB. This work has been funded by MEC grants CGL2004-03153 and CGL2007-60520 to JML, MARG, RRB, CFM and DHW.Peer reviewe
Comparison of in vitro anti-lipase and antioxidant activities, and composition of commercial chokeberry juices
Molecular Quantum Similarity-Based QSARs for Binding Affinities of Several Steroid Sets J. Chem. Inf. Comput. Sci.
Using Molecular Quantum Similarity Measures under Stochastic Transformation To Describe Physical Properties of Molecular Systems
SEOM clinical guidelines for the management of germ cell testicular cancer (2016).
Testicular cancer represents the most common malignancy in males aged 15-34 years and is considered a model of curable neoplasm. Maintaining success, reducing treatment burden, and focusing on survivorship are then key objectives. Inguinal orchiectomy is the first recommended maneuver that has both diagnostic and therapeutic aims. Most patients are diagnosed with stage I disease (confined to the testicle). Close surveillance and selective, short-course adjuvant chemotherapy are accepted alternatives for these cases. In patients with more advanced disease (stages II and III), 3-4 courses of cisplatin-based chemotherapy (according to IGCCCG risk classification) followed by the judicious surgical removal of residual masses represent the cornerstone of therapy. Poor-risk patients and those failing a first-line therapy should be referred to specialized tertiary centers. Paclitaxel-based conventional chemotherapy and high-dose chemotherapy plus autologous hematopoietic support can cure a proportion of patients with relapsing or refractory disease