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opencc-zeroDec 2015View details →

Data from: Intraguild predation leads to cascading effects on habitat choice, behaviour and reproductive performance

Intraguild predation (IGP) is a commonly recognized mechanism influencing the community structure of predators, but the complex interactions are notoriously difficult to disentangle. The mesopredator suppression hypothesis predicts that a superpredator may either simultaneously repress two mesopredators, restrain the dominant one and thereby release the subdominant mesopredator, or elicit different responses by both mesopredators. We show the outcome arising from such conditions in a three-level predator assemblage (Eurasian eagle owl Bubo bubo L., northern goshawk Accipiter gentilis L. and common buzzard Buteo buteo L.) studied over 25 years. In the second half of the study period, the eagle owl re-colonized the study area, thereby providing a natural experiment of superpredator introduction. We combined this set-up with detailed GIS analysis of habitat use and a field experiment simulating intrusion by the superpredator into territories of the subdominant mesopredator, the buzzard. Although population trends were positive for all three species in the assemblage, the proportion of failed breeding attempts increased significantly in both mesopredators after the superpredator re-colonized the area. We predicted that superpredator-induced niche shifts in the dominant mesopredator may facilitate mesopredator coexistence in superpredator-free refugia. We found significant changes in nesting habitat choice in goshawk, but not in buzzard. Since competition for enemy-free refugia and the rapid increase in population density may have constrained niche shifts of the subdominant mesopredator, we further predicted behavioural changes in response to the superpredator. The field experiment indeed showed a significant increase in aggressive response of buzzards towards eagle owl territory intrusion over the course of 10 years, probably due to phenotypic plasticity in the response towards superpredation risk. Overall, our results show that intraguild predation can be a powerful force of behavioural change, simultaneously influencing habitat use and aggressiveness in predator communities. These changes might help to buffer mesopredator populations against the negative effects of intraguild predation.

opencc-zeroDec 2015View details →

Data from: Local adaptation of reproductive performance during thermal stress

Considerable evidence exists for local adaptation of critical thermal limits in ectotherms following adult temperature stress, but fewer studies have tested for local adaptation of sublethal heat stress effects across life-history stages. In organisms with complex life cycles, such as holometabolous insects, heat stress during juvenile stages may severely impact gametogenesis, having downstream consequences on reproductive performance that may be mediated by local adaptation, although this is rarely studied. Here, we tested how exposure to either benign or heat stress temperature during juvenile and adult stages, either independently or combined, influences egg-to-adult viability, adult sperm motility and fertility in high- and low-latitude populations of Drosophila subobscura. We found both population- and temperature-specific effects on survival and sperm motility; juvenile heat stress decreased survival and subsequent sperm motility and each trait was lower in the northern population. We found an interaction between population and temperature on fertility following application of juvenile heat stress; although fertility was negatively impacted in both populations, the southern population was less affected. When the adult stage was also subject to heat stress, the southern population exhibited positive carry-over effects whereas the northern population's fertility remained low. Thus, the northern population is more susceptible to sublethal reproductive consequences following exposure to juvenile heat stress. This may be common in other organisms with complex life cycles and current models predicting population responses to climate change, which do not take into account the impact of juvenile heat stress on reproductive performance, may be too conservative.

opencc-zeroDec 2016View details →

Data from: Effects of ovarian fluid and genetic differences on sperm performance and fertilization success of alternative reproductive tactics in Chinook salmon

In many species, sperm velocity affects variation in the outcome of male competitive fertilization success. In fishes, ovarian fluid (OF) released with the eggs can increase male sperm velocity and potentially facilitate cryptic female choice for males of specific phenotypes and/or genotypes. Therefore, to investigate the role of OF on fertilization success, we measured sperm velocity and conducted in vitro competitive fertilizations with paired Chinook salmon (Oncorhynchus tshawytscha) males representing two alternative reproductive tactics, jacks (small sneaker males) and hooknoses (large guarding males), in the presence of river water alone and OF mixed with river water. To determine the role of genetic differences on fertilization success, we genotyped fish at neutral (microsatellites) and functional [major histocompatibility complex (MHC) II ß1] markers. We found that when sperm were competed in river water, jacks sired significantly more offspring than hooknoses, however, in OF there was no difference in paternity between the tactics. Sperm velocity was significantly correlated with paternity success in river water but not in ovarian fluid. Paternity success in OF, but not in river water alone, was correlated with genetic relatedness between male and female, where males that were less related to the female attained greater paternity. We found no relationship between MHC II ß1 divergence between mates and paternity success in water or OF. Our results indicate that OF can influence the outcome of sperm competition in Chinook salmon, where OF provides both male tactics with fertilization opportunities, which may in part explain what maintains both tactics in nature.

opencc-zeroDec 2015View details →

Data from: Impact of male condition on his spermatophore and consequences for female reproductive performance in the Glanville fritillary butterfly

In butterflies, male reproductive success is highly related to the quality and the size of the spermatophore transferred to the female. The spermatophore is a capsule produced by the male during copulation, which in many species contains sperm in addition to a nuptial gift, and which is digested by the female after copulation. The nuptial gift may contribute to egg production and offspring quality, and in some cases also to female body maintenance. The production of the spermatophore, however, represents a cost for the male and, in polyandrous species, ejaculates are sometimes allocated adaptively across matings. Nonetheless, although the ecological factors affecting the reproductive success of female butterflies have been the topic of numerous studies, little information exists on the factors affecting males' contribution to reproduction, and the indirect impacts on female fecundity and fitness. We used the Glanville fritillary butterfly, Melitaea cinxia (Linnaeus, 1758) (Nymphalidae), in order to assess variation in male allocation to matings. In this species, smaller males produce smaller spermatophores, but variation in spermatophore size is not correlated with female reproductive success. We show that spermatophore size increases with male age at first mating, decreases with mating frequency and adult food-deprivation, and is not influenced by developmental food-limitation. The length of copulation period does not influence the spermatophore size nor influences the polyandrous mating behavior in this species. Male contribution to his spermatophore size is clearly influenced by his condition and adult-resource at the time of mating. Despite this variation, spermatophore size does not seem to have a direct impact on female reproductive output or mating behavior.

opencc-zeroDec 2017View details →

Data from: Linking oceanographic conditions, migratory schedules and foraging behaviour during the non‐breeding season to reproductive performance in a long‐lived seabird

1. Studies of the mechanisms underlying climate-induced population changes are critically needed to better understand and accurately predict population responses to climate change. Long-lived migratory species might be particularly vulnerable to climate change as they are constrained by different climate conditions and energetic requirements during the breeding and non-breeding seasons. Yet, most studies primarily focus on the breeding season of these species lifecycle. Environmental conditions experienced in the non-breeding season may have downstream effects on the other stages of the annual lifecycle. Not investigating such effects may potentially lead to erroneous inferences about population dynamics. 2. Combining demographic and tracking data collected between 2006 and 2013 at Kerguelen Island on a long-lived migratory seabird, the Black-Browed Albatross (Thalassarche melanophris), we investigated the links between sea surface temperature during the non-breeding season and behavioural and phenological traits (at-sea behaviour and migratory schedules) while accounting for different responses between birds of different sex and reproductive status (previously failed or successful breeders). We then explored if variation in the foraging behaviour and timing of spring migration influenced subsequent reproductive performance. 3. Our results showed that foraging activity and migratory schedules varied by both sex and reproductive status suggesting different energetic requirements and constraints among individuals. Higher sea surface temperatures during late winter, assumed to reflect poor winter conditions, were associated with an earlier departure from the wintering grounds and an extended pre-breeding period. However, an earlier spring migration and an earlier return to Kerguelen grounds were associated with a lower breeding success. 4. Our results highlighted that behaviour during some periods of the non-breeding season, particularly towards the end of the wintering period and the pre-breeding period had a significant effect on the subsequent reproductive success. Therefore, caution needs to be given to all stages of the annual cycle when predicting the influence of climate on population dynamics.

opencc-zeroApr 2022View details →

High MHC diversity confers no advantage for phenotypic quality and reproductive performance in a wild bird

Genes of the major histocompatibility complex (MHC) encode antigen binding molecules and are an integral part of the acquired immune response of vertebrates. In general, high individual MHC diversity is expected to increase fitness by broadening the spectrum of pathogens recognized by the immune system, in accordance with the heterozygote advantage mechanism. On the other hand, the optimality hypothesis assumes that individuals with optimal (intermediate), rather than maximum diversity of the MHC will achieve the highest fitness because of inherent costs associated with expressing diverse MHC alleles. Here, we tested for associations between individual diversity of the MHC class I and class II genes (binding antigens of intra- and extra-cellular pathogens, respectively) and a range of fitness-related traits (condition, ornament expression and reproduction) in an urban population of the Eurasian coot Fulica atra. Contrary to our expectation, we found that high within-individual allelic diversity of MHC genes (both class I and II) was associated with poorer condition (lower blood haemoglobin concentrations), weaker expression of the putative ornament (smaller frontal shield), later onset of breeding and smaller clutches. An analysis of functional MHC allele clusters (supertypes) provided further support for negative associations of MHC diversity with phenotypic quality and reproductive performance, but most of these relationships could not be explained by the presence of specific maladaptive supertypes. Finally, we found little empirical support for the optimality hypothesis in the Eurasian coot. Our results suggest that the costs of high MHC diversity outweighed any benefits associated with broad MHC repertoire, which could be driven by depauperate pathogen diversity in an urban landscape. To the best of our knowledge, this is one of the first studies providing consistent evidence for negative associations of MHC diversity with a range of fitness-related traits in a natural avian population.

Fig. 3 in Effects of Female and Male Density on their Mating Performance and Female Post-Mating Reproductive Fitness in Plagiodera versicolora (Laicharting) (Coleoptera: Chrysomelidae)

Fig. 3. Effect of female and male density on female post-mating fecundity and the egg hatching rate. A–B) Female fecundity, C–D) Egg hatching rate. Different letters indicate significant differences from each other at P <0.05 (n = 29–40). The top and bottom of each box represent the upper and lower Quartiles, respectively; the horizontal line represents the median; the vertical lines extend to the minimum and maximum values within 1.5 times the inter-Quartile range.

Fig. 2 in Effects of Female and Male Density on their Mating Performance and Female Post-Mating Reproductive Fitness in Plagiodera versicolora (Laicharting) (Coleoptera: Chrysomelidae)

Fig. 2. Effect of female and male density on the female post-mating duration of the egg-laying period and longevity. A–B) Female longevity, C–D) Duration of egg laying. Different letters indicate significant differences from each other at P <0.05 (n = 29–40). The top and bottom of each box represent the upper and lower Quartiles, respectively; the horizontal line represents the median; the vertical lines extend to the minimum and maximum values within 1.5 times the inter-quartile range.

Fig. 1 in Effects of Female and Male Density on their Mating Performance and Female Post-Mating Reproductive Fitness in Plagiodera versicolora (Laicharting) (Coleoptera: Chrysomelidae)

Fig. 1. Effect of female and male density on time from pairing to successful mating and mating duration of Plagiodera versicolora. A–B) Time from pairing to successful mating, C–D) Mating duration. Different letters indicate significant differences from each other at P <0.05 (n = 30–41). The top and bottom of each box represent the upper and lower Quartiles, respectively; the horizontal line represents the median; the vertical lines extend to the minimum and maximum values within 1.5 times the inter-Quartile range.

Fig. 4 in Effects of Female and Male Density on their Mating Performance and Female Post-Mating Reproductive Fitness in Plagiodera versicolora (Laicharting) (Coleoptera: Chrysomelidae)

Fig. 4. Effect of female and male density on the female post-mating number of egg clutches and the number of eggs per clutch. A–B) Number of egg clutches, C–D) Number of eggs per clutch. Different letters indicate significant differences from each other at P <0.05 (n = 29–40). The top and bottom of each box represent the upper and lower Quartiles, respectively; the horizontal line represents the median; the vertical lines extend to the minimum and maximum values within 1.5 times the inter-Quartile range.

opencc-by-4.0Aug 2024View details →

Performance-based habitat choice can drive rapid adaptive divergence and reproductive isolation - Data

Data for Performance-based habitat choice can drive rapid adaptive divergence and reproductive isolation

opennotspecifiedFeb 2008View details →

Figure 2 in Reproductive performance of the great cormorant (Phalacrocorax carbo sinensis) in three Greek colonies

Figure 2. Clutch size distribution of the great cormorant in three Greek colonies in 2001 and 2002. See Table 1 for sample sizes.

opencc-zeroOct 2021View details →

Performance tradeoffs and resource availability drive variation in reproductive isolation between sympatrically diverging crossbills

Theoretical models indicate that speciation, especially when the scope for gene flow is great (e.g., sympatric speciation), is most likely when strong performance tradeoffs coincide with reproduction. We tested this classic hypothesis using measures of the strength of three prezygotic reproductive isolating barriers (habitat isolation, reduced immigrant fecundity, and behavioral isolation) between two young (~2,000 yrs) and sympatric red crossbill (Loxia curvirostra) ecotypes. All three isolating barriers increased with increases in performance tradeoffs, with total reproductive isolation varying between 0.72 and 1 (0 represents random mating, 1 represents complete reproductive isolation). Strong tradeoffs led to strong habitat isolation, an inability to breed in the "wrong" habitat, and more assortative flocks, with the latter leading to stronger behavioral isolation. Reproductive isolation decreased as resource availability increased relative to the demands of breeding, with higher resource availabilities eliminating the positive relationship between reproductive isolation and performance tradeoffs. This latter result is consistent with previous work suggesting that increasing resource abundance dampens the effect of strong performance tradeoffs on evolutionary divergence. Because many organisms, with the notable exception of host-specific phytophagous insects, rely on abundant food resources with weak performance tradeoffs while breeding, our results may explain why sympatric speciation is uncommon.

opencc-by-4.0Oct 2023View details →

Extra-pair fertilizations counter the reproductive isolation emerging from performance-based habitat choice Data

Experimental rapid and small-scale ecological population divergence in the absence of current natural selection Data

ClinicalTrials.gov32/100

The Relationship Between Iron Status, Cognitive Performance, Subjective Mood and Fatigue in Women of Reproductive Age.

ClinicalTrials.gov study NCT04257669. IPD Sharing: Not stated. Countries: 1. Publications: 3.

restrictedIPD-UNDECIDEDFeb 2026View details →