Age‐specific mortality and fecundity of a spider mite under diet restriction and delayed mating

Abstract

Numerous experimental life‐history studies on aging are mainly baised on two classical models—fruit fly Drosophila melanogaster (Meigen) and nematode Caenorhabditis elegans (Maupas)—with relatively little attention given to other organisms with different life‐history characters. Two‐spotted spider mite Tetranychus urticae Koch (Acari: Tetranychidae) differs from many other arthropods in that the females continue their growth in the early adult stage and can reproduce sexually and asexually. In this study, the influences of dietary restriction and delayed mating on the aging patterns of the spider mite were examined with the prevailing survival and reproduction trade‐off hypothesis of aging being tested. Significant sex‐specific responses of the spider mites were found. The females showed longevity extension on diet restriction (fasting for 2 days in every 4 days) compared with their counterparts being fed ad libitum, and after delayed mating for 9 days, while the males displayed a decrease in lifespan when experiencing diet restriction but were not significantly influenced by delayed mating. Path analysis was used to investigate the relationship between mite survival and reproduction traits, including longevity, female lifetime reproduction, age at first reproduction, early reproductive efforts and late reproductive efforts, yielding no evidence for trade‐offs between these life‐history traits. The additive effects of dietary restriction and delayed mating in lifespan extension of female spider mites were confirmed, proving that diet restriction is a robust anti‐aging intervention, and that later onset of reproduction can prolong adult lifespan in females.

Diversity, plasticity and asynchrony of actuarial and reproductive senescence in the Collembola Folsomia candida (Willem, 1902)

“…Contrary to what has been observed in Drosophila melanogaster (Partridge et al, 2005) or spider mites for instance (Li and Zhang, 2021), where dietary restriction lowers the risk of death but affects only marginally the rate of ageing itself, dietary restricted Collembola achieved lifespan extension by maintaining a low basal adult mortality rate and by setting back the onset of actuarial senescence and slowing its rate. This plasticity, especially remarkable in one clade (A), enabled the springtails not only to double or almost triple their life expectancy but also to change the qualitative pattern of senescence: a change in diet can trigger a shift from strong negative actuarial senescence to negligible senescence.…”

“…Similarly, some studies have revealed a remarkable qualitative intraspecific variation in the age pattern of reproduction and mortality in species like dogs (Kraus et al, 2013), social insects (Münch et al, 2008), reptiles and amphibians (Cayuela et al, 2020a;Tully et al, 2020;Cayuela et al, 2021) or hexapods (Mallard et al, 2015;Li and Zhang, 2021), while other studies have found similar age-specific mortality patterns across populations of the same species (Reichard, 2016).…”

“…Although many traits can be simultaneously affected by senescence, most studies have focused on describing the effects of age on a single trait in isolation, usually survival rate (Hoekstra et al, 2020). Few longitudinal studies have jointly studied for instance the shape of the age trajectories of mortality and reproduction (Roach and Carey, 2014;Mallard et al, 2015;Tully et al, 2020;Li and Zhang, 2021). A multi-trait approach is, however, required to describe and compare how the effects of age manifest themselves on the different components of fitness.…”

Intraspecific variation for host immune activation by the spider mite Tetranychus evansi

“…The number of surviving females and their eggs were assessed four days after infestation. With these two measures, we calculated fecundity per female assuming linear mortality [ 52 ] by using [total eggs]/[(alive females + total females)/2] and using these numbers as the average per female. This equation accounts for differential female mortality, which is measured at the end of the assay and thus enables a more accurate representation of per capita fecundity.…”

Tomato Defence Suppression is a Common Trait in <em>Tetranychus urticae</em> Collected from Field-Grown Tomatoes

“…Following four days of infestation (day 4), the number of surviving females on the leaflet and the number of eggs laid were counted. With these two measures, we calculated fecundity per female assuming linear mortality (Li & Zhang, 2022) by using: [total eggs] / [(alive females + total females)/2] and using these numbers as the average per female. There were ten to 11 and eight to nine replicates for each population, on WT and def-1, respectively.…”