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Female Strategies (female + strategy)
Selected AbstractsA novel mating system in a solitary carnivore: the fossaJOURNAL OF ZOOLOGY, Issue 3 2009C. E. Hawkins Abstract The mating strategies of male mammals have long been treated as broadly predictable on the basis of just two factors: the dispersion of females and the benefit of paternal care to male reproductive success. Female strategies and finer scale variations in mating systems remain poorly understood. In the fossa Cryptoprocta ferox, we had the rare opportunity to examine the mating system of a wild solitary carnivore directly, and identified features not classified or predicted by mating system theory. Males competed for mating opportunities at a traditional site monopolized by a female, high in a tree. The female mated with multiple males, repeatedly mated with some individuals and appeared to express mate choice. We observed three females thus, one replacing another on the site after each was seen to mate with four to five males over a period of 1,6 days. Copulations were prolonged (up to 3 h 8 min), involving a weak copulatory tie, and males appeared to guard females briefly after mating. Fossas are at low population density and do not use a den regularly; we suggest that both these factors impede individuals from locating a mate. We hypothesize that the observed mating system reduces this problem for both sexes, and increases the number of mates available to a female while ensuring a low risk of sexual harassment. [source] THE EVOLUTION OF FILIAL CANNIBALISM AND FEMALE MATE CHOICE STRATEGIES AS RESOLUTIONS TO SEXUAL CONFLICT IN FISHESEVOLUTION, Issue 2 2000Kai Lindström Abstract., Filial cannibalism (the consumption of one's own viable offspring) is common among fish with paternal care. In this study, I use a computer simulation to study simultaneous evolution of male filial cannibalism and female mate choice. Under certain conditions, selection on parental males favors filial cannibalism. When filial cannibalism increases a male's probability to raise the current brood successfully, filial cannibalism also benefits the female. However, when egg eating is a male investment into future reproduction, a conflict between female and male interests emerges. Here I investigate how female discrimination against filial cannibals affects evolution of filial cannibalism and how different female choice criteria perform against filial cannibalism. The introduction of discriminating females makes the fixation of filial cannibalism less likely. I introduced three different female choice criteria: (1) females who could discern a male's genotype, that is, whether the male was going to eat eggs as an investment in future reproductive events; (2) energy-choosing females that preferred to mate with males who had enough energy reserves to live through the current brood cycle without consuming eggs; and (3) females that preferred to mate with already mated males, that is, males with eggs in their nest. Genotype choice never coexisted with filial cannibals at fixation and filial cannibals were unable to invade a population with genotype-choosing females. Energy choice was successful only when males had high energy reserves and were less dependent on filial cannibalism as an alternative energy source. The egg choosers frequently coexisted with the cannibals at fixation. When the female strategies were entered simultaneously, the most frequent outcome for low mate sampling costs was that both the cannibals and the egg choice was fixed and all other strategies went extinct. These results suggest that sexual conflicts may not always evolve toward a resolution of the conflict, but sometimes the stable state retains the conflict. In the present case, this was because the egg-preference strategy had a higher fitness than the other female strategies. The outcome of this simulation is similar to empirical findings. In fish with paternal care, male filial cannibalism and female preference for mates with eggs commonly co-occur. [source] Seed weevils living on the edge: pressures and conflicts over body size in the endoparasitic Curculio larvaeECOLOGICAL ENTOMOLOGY, Issue 3 2009RAÚL BONAL Abstract 1.,Body size in parasitic insects can be subjected to contrasting selective pressures, especially if they complete their development within a single host. On the one hand, a larger body size is associated with a higher fitness. On the other hand, the host offers a discrete amount of resources, thus constraining the evolution of a disproportionate body size. 2.,The present study used the weevil Curculio elephas as a study model. Larvae develop within a single acorn, feeding on its cotyledons, and larval body size is strongly related to individual fitness. 3.,The relationship between larval and acorn size was negatively exponential. Larval growth was constrained in small acorns, which did not provide enough food for the weevils to attain their potential size. Larval size increased and levelled off in acorns over a certain size (inflexion point), in which cotyledons were rarely depleted. When there were more than one larva per acorn, a larger acorn was necessary to avoid food depletion. 4.,The results show that C. elephas larvae are sometimes endoparasitic, living on the edge of host holding capacity. If they were smaller they could avoid food depletion more easily, but the fitness benefits linked to a larger size have probably promoted body size increase. The strong negative effects of conspecific competition may have possibly influenced female strategy of laying a single egg per seed. 5.,Being larger and fitter, but always within the limits of the available host sizes, may be one main evolutionary dilemma in endoparasites. [source] | ||||||||||