0000000000278503
AUTHOR
Satu Paukku
Cost of reproduction in a seed beetle : a quantitative genetic perspective
Lisääntymisestä on kustannuksia, jotka ilmenevät lyhentyneenä elinikänä. Elinikä ja lisääntymisestä aiheutuvat kustannukset ovat geenien määräämiä.- Väitöskirjatyössäni tutkin lisääntymisen kustannuksia koirailla. Tutkimuskohteena käytin Callosobruchus maculatus - jyväkuoriaisia, jotka ovat trooppisia papujen tuholaisia. Kyseinen laji on paljon käytetty evoluutioekologian alan mallilaji. Naarailla on tehty runsaasti lisääntymisen kustannustutkimuksia, mutta koirailla vain muutamia tutkimuksia. Perinteisesti on ajateltu, että koiras panostaa lisääntymiseen lähinnä parittelemalla ja luovuttamalla sukusoluissaan geenejään jälkeläisilleen, Satu Paukku kertoo.Tutkimuksissa ilmeni, että koiraille…
Female Oviposition Decisions and Their Impact on Progeny Life-History Traits
An important factor affecting the life-history of an organism is parental investment in reproduction: reproductive decisions are almost invariably costly. Therefore, reproductive decisions should be beneficial in terms of increased offspring number or fitness. For example, egg laying decisions in many insects can influence resource availability of the offspring through changes in the larval density, and resource availability will have effects on many life-history traits. Here we studied whether female reproductive decisions affect offspring fitness in Callosobruchus maculatus seed beetles. Females laid more eggs on black-eye beans than on mung beans. However, when the difference in the surf…
Cost of reproduction in Callosobruchus maculatus: effects of mating on male longevity and the effect of male mating status on female longevity.
One of the most studied life-history trade-offs is that resulting from the cost of reproduction: a trade-off arises when reproduction diverts limited resources from other life-history traits. We examine the cost of reproduction in male, and the effect of male mating status on female Callosobruchus maculatus seed beetles. Cost of reproduction for male C. maculatus was manifested as reduced longevity. There was also a positive relationship between male body size and male longevity. Females mated to males that had already copulated twice did not live as long as females mated to males that had copulated once or not at all. The third copulation of males also lasted longer than the two previous o…
Female Oviposition Decisions and Their Impact on Progeny Life-History Traits
An important factor affecting the life-history of an organism is parental investment in reproduction: reproductive decisions are almost invariably costly. Therefore, reproductive decisions should be beneficial in terms of increased offspring number or fitness. For example, egg laying decisions in many insects can influence resource availability of the offspring through changes in the larval density, and resource availability will have effects on many life-history traits. Here we studied whether female reproductive decisions affect offspring fitness in Callosobruchus maculatus seed beetles. Females laid more eggs on black-eye beans than on mung beans. However, when the difference in the surf…
Transmission, infectivity and survival of Diplostomum spathaceum cercariae
The transmission dynamics of the cercariae of Diplostomum spathaceum were investigated under laboratory conditions using cercariae collected from naturally infected Lymnaea stagnalis. Cercariae were kept in a constant temperature of 20 °C and the survival and infectivity to naïve young rainbow trout recorded at 3-h intervals until few cercariae were alive. Mortality initially remained constant but increased rapidly after 20 h. While a model of constant mortality fitted the survival data, an age-dependent model provided a better fit and implied that cercariae tended to carry similar quantities of resources and once these were exhausted the cercariae died. Cercarial infectivity also showed an…
Effects of testosterone and β-glucan on immune functions in tench
A hormone manipulation was performed to examine the effects of testosterone on basal and β-glucan-induced immune functions in wild-caught male and female tench Tinca tinca. Testosterone administration elevated testosterone concentration in plasma, but did not suppress lytic activity of plasma or the chemiluminescence response of blood or head kidney phagocytes in any of the three successive samples or in any of the treatment groups. Both testosterone and β-glucan administrations had a negative effect on the relative mass of the spleen, and testosterone-treated fish lost more mass than control fish. Males had a relatively larger spleen than females, but there were no gender differences in im…