Information use and memory formation during foraging in the parasitoid Nasonia vitripennis

Adapting foraging behavior to variable environments often requires the acquisition, storage and use of information, coming from various sources. By now, behavioral ecologists have developed sophisticated models on how a foraging animal may behave in order to maximize its lifetime fitness gain. While the behavior of many parasitoid species matches the qualitative predictions of those models quite well, the behavior of other parasitoids showed a lack of such a match. Therefore, the role of information use and its possible limitations are of major interest to understand how organisms adjust their behavior in an adaptive way. The present study aimed at investigating aspects of information use during foraging in Nasonia vitripennis in host finding through associative learning and in egg and time allocation decisions under variable habitat qualities

A systematic map of studies testing the relationship between temperature and animal reproduction

Funding: This work was funded by the European Society for Evolution (which funds a Special Topic Network on Evolutionary Ecology of Thermal Fertility Limits to CF, AB, RRS and TARP), the Natural Environment Research Council (NE/P002692/1 to TARP, AB and RRS, NE/X011550/1 to LRD and TARP), the Biotechnology and \Biological Sciences Research Council (BB/W016753/1 to AB, TARP and RRS) and a Heisenberg fellowship from the German Research Foundation (FR 2973/11-1 to CF).1. Exposure to extreme temperatures can negatively affect animal reproduction, by disrupting the ability of individuals to produce any offspring (fertility), or the number of offspring produced by fertile individuals (fecundity). This has important ecological consequences, because reproduction is the ultimate measure of population fitness: a reduction in reproductive output lowers the population growth rate and increases the extinction risk. Despite this importance, there have been no large‐scale summaries of the evidence for effect of temperature on reproduction. 2. We provide a systematic map of studies testing the relationship between temperature and animal reproduction. We systematically searched for published studies that statistically test for a direct link between temperature and animal reproduction, in terms of fertility, fecundity or indirect measures of reproductive potential (gamete and gonad traits). 3. Overall, we collated a large and rich evidence base, with 1654 papers that met our inclusion criteria, encompassing 1191 species. 4. The map revealed several important research gaps. Insects made up almost half of the dataset, but reptiles and amphibians were uncommon, as were non‐arthropod invertebrates. Fecundity was the most common reproductive trait examined, and relatively few studies measured fertility. It was uncommon for experimental studies to test exposure of different life stages, exposure to short‐term heat or cold shock, exposure to temperature fluctuations, or to independently assess male and female effects. Studies were most often published in journals focusing on entomology and pest control, ecology and evolution, aquaculture and fisheries science, and marine biology. Finally, while individuals were sampled from every continent, there was a strong sampling bias towards mid‐latitudes in the Northern Hemisphere, such that the tropics and polar regions are less well sampled. 5. This map reveals a rich literature of studies testing the relationship between temperature and animal reproduction, but also uncovers substantial missing treatment of taxa, traits, and thermal regimes. This database will provide a valuable resource for future quantitative meta‐analyses, and direct future studies aiming to fill identified gaps.Publisher PDFPeer reviewe

Informationsnutzung und Gedächtnisbildung in Bezug auf Habitatparameter bei der parasitischen Wespe Nasonia vitripennis

Adapting foraging behavior to variable environments often requires the acquisition, storage and use of information, coming from various sources. By now, behavioral ecologists have developed sophisticated models on how a foraging animal may behave in order to maximize its lifetime fitness gain. While the behavior of many parasitoid species matches the qualitative predictions of those models quite well, the behavior of other parasitoids showed a lack of such a match. Therefore, the role of information use and its possible limitations are of major interest to understand how organisms adjust their behavior in an adaptive way. The present study aimed at investigating aspects of information use during foraging in Nasonia vitripennis in host finding through associative learning and in egg and time allocation decisions under variable habitat qualities

Data from: Gene expression changes in male accessory glands during ageing are accompanied by reproductive decline in Drosophila melanogaster

Senescence is accompanied by loss of reproductive functions. Here we studied reproductive ageing in Drosophila melanogaster males and asked whether the expected decline in male reproductive success is due to diminished functionality of the male accessory gland. The male accessory gland produces the majority of seminal fluid proteins (SFPs) transferred to the female at mating. SFPs induce female post-mating changes and are key to male reproductive success. We measured age-dependent gene expression changes for five representative SFP genes in males from four different age groups ranging from one to six weeks after eclosion. Simultaneously, we also measured male reproductive success in post-mating traits mediated by transfer of these five SFPs. We found a decrease in male SFP gene expression with advancing age and an accompanying decline in male post-mating success. Hence, male reproductive senescence is associated with a decline in functionality of the male accessory gland. While overall individual SFP genes decrease in expression our results point towards the idea that the composition of an ejaculate might change with male age as the rate of change was variable for those five genes

Cp values from the gene expression assay

Cp values from the gene expression assa

Data on accessory gland protein replenishment

Data on accessory gland protein replenishmen

Data on male reproductive success

Data on male reproductive succes

Increased male investment in sperm competition results in reduced maintenance of gametes

Male animals often show higher mutation rates than their female conspecifics. A hypothesis for this male bias is that competition over fertilization of female gametes leads to increased male investment into reproduction at the expense of maintenance and repair, resulting in a trade-off between male success in sperm competition and offspring quality. Here, we provide evidence for this hypothesis by harnessing the power of experimental evolution to study effects of sexual selection on the male germline in the seed beetle Callosobruchus maculatus. We first show that 50 generations of evolution under strong sexual selection, coupled with experimental removal of natural selection, resulted in males that are more successful in sperm competition. We then show that these males produce progeny of lower quality if engaging in sociosexual interactions prior to being challenged to surveil and repair experimentally induced damage in their germline and that the presence of male competitors alone can be enough to elicit this response. We identify 18 candidate genes that showed differential expression in response to the induced germline damage, with several of these previously implicated in processes associated with DNA repair and cellular maintenance. These genes also showed significant expression changes across sociosexual treatments of fathers and predicted the reduction in quality of their offspring, with expression of one gene also being strongly correlated to male sperm competition success. Sex differences in expression of the same 18 genes indicate a substantially higher female investment in germline maintenance. While more work is needed to detail the exact molecular underpinnings of our results, our findings provide rare experimental evidence for a trade-off between male success in sperm competition and germline maintenance. This suggests that sex differences in the relative strengths of sexual and natural selection are causally linked to male mutation bias. The tenet advocated here, that the allocation decisions of an individual can affect plasticity of its germline and the resulting genetic quality of subsequent generations, has several interesting implications for mate choice processes.Title in the list of papers of Julian Baur's thesis: Increased male investment in sperm competition results in offspring of lower quality</p

Egg laying rather than host quality or host feeding experience drives habitat estimation in the parasitic wasp Nasonia vitripennis

In variable environments, sampling information on habitat quality is essential for making adaptive foraging decisions. In insect parasitoids, females foraging for hosts have repeatedly been shown to employ behavioral strategies that are in line with predictions from optimal foraging models. Yet, which cues exactly are employed to sample information on habitat quality has rarely been investigated. Using the gregarious parasitoid Nasonia vitripennis (Walker; Hymenoptera: Pteromalidae), we provided females with different cues about hosts to elucidate, which of them would change a wasp's posterior behavior suggesting a change in information status. We employed posterior clutch size decisions on a host as proxy for a female's estimation of habitat quality. Taking into account changes in physiological state of the foraging parasitoid, we tested whether different host qualities encountered previously change the subsequent clutch size decision in females. Additionally, we investigated whether other kinds of positive experiences-such as ample time to investigate hosts, host feeding, or egg laying-would increase a wasp's estimated value of habitat quality. Contrary to our expectations, quality differences in previously encountered hosts did not affect clutch size decisions. However, we found that prior egg laying experience changes posterior egg allocation to a host, indicating a change in female information status. Host feeding and the time available for host inspection, though correlated with egg laying experience, did not seem to contribute to this change in information status