| 1. |
- Baduel, Pierre, et al.
(författare)
-
The “polyploid hop” : shifting challenges and opportunities over the evolutionary lifespan of genome duplications
- 2018
-
Ingår i: Frontiers in Ecology and Evolution. - : Frontiers Media S.A.. - 2296-701X. ; 6:117
-
Tidskriftsartikel (refereegranskat)abstract
- The duplication of an entire genome is no small affair. Whole genome duplication (WGD) is a dramatic mutation with long-lasting effects, yet it occurs repeatedly in all eukaryotic kingdoms. Plants are particularly rich in documented WGDs, with recent and ancient polyploidization events in all major extant lineages. However, challenges immediately following WGD, such as the maintenance of stable chromosome segregation or detrimental ecological interactions with diploid progenitors, commonly do not permit establishment of nascent polyploids. Despite these immediate issues some lineages nevertheless persist and thrive. In fact, ecological modeling commonly supports patterns of adaptive niche differentiation in polyploids, with young polyploids often invading new niches and leaving their diploid progenitors behind. In line with these observations of polyploid evolutionary success, recent work documents instant physiological consequences of WGD associated with increased dehydration stress tolerance in first-generation autotetraploids. Furthermore, population genetic theory predicts both short- and long-term benefits of polyploidy and new empirical data suggests that established polyploids may act as “sponges” accumulating adaptive allelic diversity. In addition to their increased genetic variability, introgression with other tetraploid lineages, diploid progenitors, or even other species, further increases the available pool of genetic variants to polyploids. Despite this, the evolutionary advantages of polyploidy are still questioned, and the debate over the idea of polyploidy as an evolutionary dead-end carries on. Here we broadly synthesize the newest empirical data moving this debate forward. Altogether, evidence suggests that if early barriers are overcome, WGD can offer instantaneous fitness advantages opening the way to a transformed fitness landscape by sampling a higher diversity of alleles, including some already preadapted to their local environment. This occurs in the context of intragenomic, population genomic, and physiological modifications that can, on occasion, offer an evolutionary edge. Yet in the long run, early advantages can turn into long-term hindrances, and without ecological drivers such as novel ecological niche availability or agricultural propagation, a restabilization of the genome via diploidization will begin the cycle anew.
|
|
| 2. |
- Boddum, Tina, et al.
(författare)
-
Host Attraction and Selection in the Swede Midge (Contarinia nasturtii)
- 2018
-
Ingår i: Frontiers in Ecology and Evolution. - : Frontiers Media SA. - 2296-701X. ; 6
-
Tidskriftsartikel (refereegranskat)abstract
- Gall midges (Diptera: Cecidomyiidae) are a speciose family that, as adults, are short lived (lasting only a few days), they use olfactory cues for host and mate localization, and their host plant specificity is a key characteristic of the family. These traits make them good models with which to study the role of olfaction in speciation. The overall objective of this study was to analyze the host selection behavior of the gall midge, Contarinia nasturtii, a crucifer specialist that also is a crucifer pest. Here, we demonstrate that the host specificity of gravid C. nasturtii females was initiated by the olfactory-driven host plant choice during oviposition. Olfactory preference of the female, while narrow, encompassed more plants than were accepted for egg-laying, indicating that other factors following the initial olfactory attraction are involved in ultimate host choice. Similarly, C. nasturtii showed flexibility in host plant choice depending on which plants were available for oviposition. Larvae developed on host plants selected by females for oviposition. This slightly broader range of olfactory preference over acceptance, and the flexibility in host choice, might be the basis for the rapid speciation reported in the gall midge family. Furthermore, we assessed whether ubiquitous and/or family-specific plant odors are involved in the attraction of gravid C. nasturtii to their hosts. For that, we used the crucifer Arabidopsis thaliana, which has a broad range of defined ecotypes and large number of mutants. The attraction of C. nasturtii to two A. thaliana-types were tested; one that does not produce the ubiquitous green leaf volatiles (Columbia, Col-0), and a knock-out mutant which does not produce the crucifer-specific glucosinolates. Surprisingly, C. nasturtii was attracted to both types, indicating that neither of these compounds, nor their breakdown products (e.g., isothiocyanates), are essential for C. nasturtii host attraction.
|
|
| 3. |
- Chizzola, Maddalena, et al.
(författare)
-
Landscape Level Effects of Lion Presence (Panthera leo) on Two Contrasting Prey Species
- 2018
-
Ingår i: Frontiers in Ecology and Evolution. - : Frontiers Media SA. - 2296-701X. ; 6
-
Tidskriftsartikel (refereegranskat)abstract
- Due to the strong individual cost of being predated, potential prey species alter their behavior and physiology in response to predation risk. Such alterations may cause major indirect consequences on prey populations that are additive to the direct demographic effects caused by prey being killed. However, although earlier studies showed strong general effects of the presence of apex predators, recent data suggest that indirect effects may be highly context dependent and not consistently present. We combined behavioral data with data on endocrine stress and stable isotopes to assess landscape level effects of lion (Panthera leo) presence on two prey species in South Africa, impala (Aepyceros melampus) and blue wildebeest (Connochaetes taurinus). We also evaluated if there was any seasonal variation in such effects. In addition, we provide results from a physiological validation for an enzyme-linked immunoassay (EIA) that can be used for non-invasive monitoring of glucocorticoid stress metabolite concentrations in impala from fecal pellets. We did not find any significant differences in vigilance behavior, fecal glucocorticoid metabolite concentrations, delta C-13 values or isotope niche breadth between animals living with and without lions for either species. However, wildebeest living in a reserve with lions spent more time foraging compared to wildebeest in a lion-free environment, but only during the wet season. Values of fecal delta N-15 suggest a shift in habitat use, with impala and wildebeest living with lions potentially feeding in less productive areas compared to animals living without lions. For both species, characteristics of the social groups appeared to be more important than individual characteristics for both foraging and vigilance behavior. Our results highlight that antipredator responses may be highly dynamic and scale-dependent. We urge for further studies that quantify at what temporal and spatial scales predation risk is causing indirect effects on prey populations.
|
|
| 4. |
- Harding, Karin C., 1968, et al.
(författare)
-
Population Wide Decline in Somatic Growth in Harbor Seals—Early Signs of Density Dependence
- 2018
-
Ingår i: Frontiers in Ecology and the Environment. - : Frontiers Media SA. - 1540-9295 .- 1540-9309 .- 2296-701X. ; 6
-
Tidskriftsartikel (refereegranskat)abstract
- The harbor seal populations of Danish and Swedish waters have had turbulent population dynamics during the last century. They were severely depleted by hunting in the beginning of the twentieth century, followed by rapid recovery due to protective measures. They were victims to two mass mortalities caused by Phocine Distemper Virus (PDV) epidemics. Long term monitoring and intensive sampling during the last decades now allow analysis of population level phenomena in response to shifting population size. We compare somatic growth curves from several seal populations including 2,041 specimens with known age, length and population size at birth. Asymptotic body lengths of female harbor seals were 148 cm in all four regions in 1988, when seal abundances had been kept low by hunting for decades. Males were 158 cm, being 10 cm longer. However, in 2002 the asymptotic lengths of seals differed among regions. While seals in the Kattegat showed similar asymptotic lengths as in 1988, seals in the Skagerrak were significantly shorter, where both male and female asymptotic lengths declined by 7 cm. We estimate the area of available feeding grounds in the two sea regions and find the density of seals per square kilometer feeding ground to be three times greater in the Skagerrak compared to the Kattegat. Thus, the shorter body length of seals in the Skagerrak can be an early signal of density dependence. Hampered body growth is known to trigger a suite of changes in life history traits, including delayed age at sexual maturity, higher juvenile mortality and lowered fecundity. These mechanisms all point at a possible “smooth route toward carrying capacity” with gradually reduced population growth rate as the main response to high population density. Recent aerial surveys confirm declining rates of population increase in the Skagerrak.
|
|
| 5. |
|
|
| 6. |
|
|
| 7. |
- Montoro Girona, Miguel
(författare)
-
A Secret Hidden in the Sediments: Lepidoptera Scales
- 2018
-
Ingår i: Frontiers in Ecology and Evolution. - : Frontiers Media SA. - 2296-701X. ; 6
-
Tidskriftsartikel (refereegranskat)abstract
- Natural disturbance is one of the major topics in forest ecology. However, most paleoecological studies have only considered the influence of wildfire as an agent of disturbance, with fire history based primarily on the use of charcoal as a proxy for fire events. The frequency and intensity of insect outbreaks and their effect on the forest landscape have been neglected due to the absence of an effective proxy tool. Finding indicators able to provide insight into the impacts of past insect outbreaks is therefore essential. Fossil moth (Lepidoptera) scales offer a new approach for interpreting past insect-related disturbances and assessing the interactions between climate, fire and insect outbreaks. Paleoindicators must respond to three main criteria: (1) be in high abundance, (2) allow for easy identification and (3) remain well-preserved in sediment records. We demonstrate that wing scales are abundant in the boreal forest during insect outbreak periods. We also show that due to their chitin composition, these scales remain well-preserved throughout a 10,000-year sediment record. Furthermore, they are relatively easy to identify after being recovered from lake sediments. Therefore, we introduce the needs, potential and applications of this paleoindicator in forest ecology, and the main directions for the future research. This new approach offers an important scientific advance in ecology through a much improved, higher resolution reconstruction of an important natural disturbance: insect outbreaks.
|
|
| 8. |
- Morinay, Jennifer, et al.
(författare)
-
Heterospecific nest site copying behavior in a wild bird : assessing the influence of genetics and past experience on a joint breeding phenotype
- 2018
-
Ingår i: Frontiers in Ecology and Evolution. - : Frontiers Media SA. - 2296-701X. ; 5:167
-
Tidskriftsartikel (refereegranskat)abstract
- Breeding site selection is often a joint decision of pair members in species with biparental care and the experience of both pair members may influence the use of information for site selection. Nevertheless, quantitative genetics of joint information use for site selection remains unexplored so far. We used an experimental approach to quantify the relative importance of genetics (heritability) and past experience (age, familiarity with the environment, previous breeding success, previous information use) in heterospecific social information use for nest site selection in wild collared flycatchers (Ficedula albicollis). Flycatchers collect social information from resident tits for nest site selection. We created an apparent preference of tits for a novel nest site feature and recorded choices of flycatchers (copying or rejecting the tit preference). Copying behavior was stronger for naive individuals but also differed between years, which could be explained by contrasting seasonality in the demonstrator species. Past experience as reflected by age affected subsequent use of social information: pairs with a yearling male were more likely to copy the heterospecific preference than pairs with older immigrant males. There was no general pattern in successive individual choices over the years. Accordingly, individual repeatability in copying tit preference was very low. At the pair level, we estimated sex-specific direct and indirect genetic effects on the joint nest site decision and found no sex-specific heritability and no cross-sex genetic correlation. Our results confirm the importance of past experience for social information use and suggest that social information use is highly plastic and most likely not genetically inherited in collared flycatchers. Whether individuals use social information should be related to environmentally-induced changes in the quality of information and thus be context-dependent. Selection may therefore act on the ability to optimally use social information in varying environments and on the processes underlying such adjustment, such as learning, rather than the use of information itself.
|
|
| 9. |
- Puentes, Adriana, et al.
(författare)
-
A Systematic Review on the Effects of Plant-Feeding by Omnivorous Arthropods: Time to Catch-Up With the Mirid-Tomato Bias?
- 2018
-
Ingår i: Frontiers in Ecology and Evolution. - : Frontiers Media SA. - 2296-701X. ; 6
-
Tidskriftsartikel (refereegranskat)abstract
- Zoophytophagous (omnivorous) predators provide valuable pest control services, and offer an advantage over strict carnivores as plant-feeding enables survival during prey shortage. This putative advantage can potentially be their downside, as plant-feeding may entail damage that negatively affects plant growth/yield (i.e., the cost arising from of omnivore plant-feeding). Yet, benefits conferred by predatory services are usually thought to counterbalance any impact of plant damage. In this systematic review, our goal was to determine how often levels of omnivore damage and its consequences for plants (costs) are considered or quantified. We provide a synthesis of publication trends and findings on omnivore plant-feeding levels, plant injury variables, actual (if quantified) and potential effects on growth/yield, the type of study (lab, greenhouse) and the plants/omnivores most often examined. Our search revealed that measures of omnivore plant-feeding are occasionally reported, but seldom are the direct consequences of such damage also considered. Omnivore plant-feeding were reported in 57% of studies (53 of 93 full-text examined); within these, the majority (>80%) indicated moderate to high levels of plant-feeding. However, only 22% of reports (15 of 69) quantified the effects of omnivore-inflicted damage on plant performance. Of these 15 reports, a greater number found negative consequences for plants compared to those showing no effect (8 vs. 4; 3 with both), with consequences for yield relative to growth being more often evaluated (6 vs. 2). Overall, fruit/leaf injuries relative to stem/flower-feeding were most often examined, and lab/greenhouse experiments predominated. Tomatoes (Solanum lycopersicum) and the mirid Nesidiocoris tenuis were the most common species studied (34 and 14 reports, respectively). Our results indicate that costs to plants of omnivore-inflicted damage are often neglected. We argue that predatory benefits need to be simultaneously considered with plant-feeding effects to appropriately evaluate pest control services. Publication trends suggest that more studies are evaluating costs to plants, but a paradigm shift is still needed. Furthermore, we found that our understanding of plant-feeding and its effects is disproportionally based on studies examining tomato plants and its omnivorous biocontrol agents. To confirm the generality of findings thus far, other plant omnivore systems should be further considered.
|
|
| 10. |
- van Toor, Mariëlle L., et al.
(författare)
-
As the Duck Flies-Estimating the Dispersal of Low-Pathogenic Avian Influenza Viruses by Migrating Mallards
- 2018
-
Ingår i: Frontiers in Ecology and Evolution. - : Frontiers Media S.A.. - 2296-701X. ; 6
-
Tidskriftsartikel (refereegranskat)abstract
- Many pathogens rely on the mobility of their hosts for dispersal. In order to understand and predict how a disease can rapidly sweep across entire continents, illuminating the contributions of host movements to disease spread is pivotal. While elegant proposals have been made to elucidate the spread of human infectious diseases, the direct observation of long-distance dispersal events of animal pathogens is challenging. Pathogens like avian influenza A viruses, causing only short disease in their animal hosts, have proven exceptionally hard to study. Here, we integrate comprehensive data on population and disease dynamics for low-pathogenic avian influenza viruses in one of their main hosts, the mallard, with a novel movement model trained from empirical, high-resolution tracks ofmallardmigrations. This allowed us to simulate individualmallard migrations from a key stopover site in the Baltic Sea for the entire population and link these movements to infection simulations. Using this novel approach, we were able to estimate the dispersal of low-pathogenic avian influenza viruses by migrating mallards throughout several autumn migratory seasons and predicted areas that are at risk of importing these viruses. We found that mallards are competent vectors and on average dispersed viruses over distances of 160 km in just 3 h. Surprisingly, our simulations suggest that such dispersal events are rare even throughout the entire autumn migratory season. Our approach directly combines simulated population-level movements with local infection dynamics and offers a potential converging point for movement and disease ecology.
|
|
