The coexistence of multiple reproductives in eusocial insects is widespread, yet the decisions leading to additional queen acceptance are not well understood. Unlike in vertebrates, acceptance ...decisions are likely controlled by the more numerous helper population rather than the parent reproductive. Yet there are likely to be queen-worker differences in acceptance criteria because workers and queens differ in their relatedness to a secondary queen. We develop a model that examines queen-worker conflict in two scenarios: accepting a queen’s sister or daughter. We additionally ask how the mating frequency and split sex ratios affect the outcomes of these conflicts. Our results reveal that conflict over queen acceptance is highest in monandrous mating systems. We identify a “window of conflict” in which a queen is selected to accept her sister but her workers do not. Our result, that polyandry neutralizes conflict over acceptance thresholds, suggests that conflict suppression may be an additional contributor to the maintenance of polyandrous mating systems.
Emerging infectious disease is a growing threat to global biodiversity. The infectious disease chytridiomycosis, caused by the fungal pathogen Batrachochytrium dendrobatidis (Bd) has led to the ...decline and extinction of hundreds of amphibian species. Severe Bd-caused epizootics have been documented in North, Central and South America-with many of the research focused on anurans. California, where Bd-related epizootics and amphibian declines have been reported, has some of the highest diversity of salamanders. After more than a decade since the first known epizootic in California, little is known about Bd disease dynamics in salamanders. Pacific newts (Genus: Taricha) are ideal study species because of their abundance, wide geographic range, occurrence in both aquatic and terrestrial habitats, and how little is known about Bd infection dynamics for this group. We conducted a retrospective study to determine the relationship between Pacific newts and the fungal pathogen. We tested 1895 specimens collected between 1889-2009 and found no evidence of Bd-infected Pacific newts until the late 1940's. Although we estimate that Bd emerged in this genus and rapidly spread geographically throughout California, we did not find evidence for epizootic dynamics. Bd infection prevalence and intensity, two measures commonly used to estimate dynamics, remained consistently low over time; suggesting Pacific newts may not be highly susceptible. Also, we found the timing of first Bd emergence in Pacific newts predate Bd emergence in other California salamander species. In addition, we found several environmental and anthropogenic factors correlated with Bd prevalence which may help explain Bd disease dynamics in the genus Taricha. Pacific newts may be a reservoir species that signal pathogen invasion into California salamanders, though further studies are needed.
An impressive long-term study of Greater Ani birds reveals fluctuating selection for group size. In wet years, with abundant food, larger groups enjoy greater protection from predators. In dry years, ...however, larger groups suffer greater nestling mortality relative to smaller groups.
An impressive long-term study of Greater Anis birds reveals fluctuating selection for group size. In wet years, with abundant food, larger groups enjoy greater protection from predators. In dry years, however, larger groups suffer greater nestling mortality relative to smaller groups.
Recruitment of beneficial microbes to protect offspring, often reducing the energetic costs of care, is now recognized as an important component of parental care in many animals. Studies on earwigs ...(order Dermaptera) have revealed that removal of females from egg tending increases mortality of eggs due to fungal infections, possibly caused by changes in the bacterial microbiome on the egg surface. We used a controlled female-removal experiment to evaluate whether female nest attendance in the maritime earwig, Anisolabis maritima, influences the bacterial microbiome on the egg surface. Further, we analyzed the microbiomes of mothers and their eggs to determine if there are a core set of bacteria transferred to eggs through female care. Microbiomes were analyzed using 16S rRNA bacterial DNA sequencing, revealing that bacterial operational taxonomic unit (OTU) richness and diversity were both significantly higher for female attended versus unattended eggs. The core microbiome of adult females contained bacteria which have the potential to carry anti-fungal characteristics; these bacteria were found in higher presence and relative abundance on eggs where females were allowed to provide care. These results demonstrate that female egg attendance significantly impacts the bacterial microbiome of A. maritima eggs, and identifies specific bacteria within the egg microbiome that should be investigated further for beneficial anti-fungal properties in this system.
Understanding the spatial structure of populations and communities has been a dominant focus of ecological research, and spatial structure is increasingly seen as critical for understanding ...population dynamics. Habitat (or host) preference is a proximate mechanism that can generate aggregation or overdispersion, lending insight into the ultimate consequences of observed spatial distributions. Publilia concava is a univoltine phloem-feeding insect that forms mutualistic associations with ants, which consume honeydew and protect treehoppers from predation. Treehopper adults and nymphs are aggregated at the scale of goldenrod plant stems, and previous studies have suggested that this aggregation is an adaptive response that increases feeding performance or maximizes benefits of ant-tending. Previous studies have also shown experimentally that individual treehoppers preferentially oviposit on plants with ants present, but a complimentary hypothesis that treehoppers prefer to oviposit near conspecifics (e.g., to take advantage of density-dependent ant attraction) remains untested. We show that, as expected, the probability of treehopper oviposition increases with ant-presence and relative ant abundance. However, we also find that treehopper oviposition decreases with increasing treehopper density. Thus our results are inconsistent with the hypothesis that treehopper aggregation is a socially cooperative strategy to attract ants; we suggest that aggregation is a form of conflict and an unavoidable by-product of individual responses to ant-tending levels.
A multitude of microorganisms live on and within plant and animal hosts, yet the ecology and evolution of these microbial communities remains poorly understood in many taxa. This study examined the ...extent to which environmental factors and host taxonomic identity explain microbiome variation within two salamander genera,
and
, in the family Plethodontidae. In particular, we assessed whether microbiome differentiation paralleled host genetic distance at three levels of taxonomy: genus and high and low clade levels within
. We predicted that more genetically related host populations would have more similar microbiomes than more distantly related host populations. We found that salamander microbiomes possess bacterial species that are most likely acquired from their surrounding soil environment, but the relative representation of those bacterial species is significantly different on the skin of salamanders compared to soil. We found differences in skin microbiome alpha diversity among
higher and lower clade groups, as well as differences between
and
. We also found that relative microbiome composition (beta diversity) did vary between
lower clades, but differences were driven by only a few clades and not correlated to clade genetic distances. We conclude this difference was likely a result of
lower clades being associated with geographic location and habitat type, as salamander identity at higher taxonomic levels (genus and
higher clades) was a weak predictor of microbiome composition. These results lead us to conclude that environmental factors are likely playing a more significant role in salamander cutaneous microbiome assemblages than host-specific traits.
Animals that provide parental care are expected to weigh the value of current offspring against the value of future offspring, such that total investment across all offspring is allocated to maximize ...lifetime fitness. In this study, we characterize the trade-offs associated with maternal care in the maritime earwig, Anisolabis maritima (Dermaptera: Anisolabididae). We measured the benefits of care in terms of hatching success through removal experiments and the costs of care by comparing the future fecundity of caring females to that of removals. We show that the benefits of care greatly outweigh the costs, providing a seven-fold increase in hatching success. Artificially removed females had larger subsequent clutches and shorter internest intervals, but very low hatching success. Naturally abandoning females always cannibalize all their eggs. Partial clutch cannibalism was a ubiquitous feature of maternal care, although rates were variable among individuals. In post hoc tests, we first addressed the ultimate explanation that filial cannibalism is a way for females to facultatively adjust their investment per clutch in order to maximize future reproduction. We then tested two proximate explanations for filial cannibalism: (1) females that lay more eggs for their given body size tend to consume more eggs, reflecting a nutritional deficiency; (2) females prefer to cannibalize the youngest eggs to reduce the overall duration of egg care. In addition, we consider the alternative explanation that females eat unviable eggs for hygienic reasons. Our results provide support for both energy limitation and hygienic maintenance. Higher rates of egg cannibalism near the very end of nesting were also suggestive of nymphal cannibalism, a phenomenon that will be examined in future work.
► We measured the fitness costs and benefits of maternal care in the maritime earwig, Anisolabis maritima. ► Maternal care increased offspring survival seven-fold, but reduced subsequent clutch sizes. ► Females routinely reduced clutch size through filial cannibalism. ► We tested the function of filial cannibalism. ► Filial cannibalism may be a product of energy limitation and hygienic removal of unviable eggs.
When cooperators cheat Zink, Andrew G; Eadie, John M
Nature,
03/2019, Letnik:
567, Številka:
7746
Journal Article
Recenzirano
Odprti dostop
A study of a cuckoo species that usually shows cooperative nesting behaviour, but sometimes cheats at parenthood by laying eggs in others' nests, reveals the benefits that have shaped the evolution ...of this parasitic tactic.
Resident microbial communities living on amphibian skin can have significant effects on host health, yet the basic ecology of the host-microbiome relationship of many amphibian taxa is poorly ...understood. We characterized intraspecific variation in the skin microbiome of the salamander Ensatina eschscholtzii xanthoptica, a sub species composed of four genetically distinct populations distributed throughout the San Francisco Bay Area and the Sierra Nevada mountains in California, USA. We found that salamanders from four geographically and genetically isolated populations harbor similar skin microbial communities, which are dominated by a common core set of bacterial taxa. Additionally, within a population, the skin microbiome does not appear to differ significantly between salamanders of different ages or sexes. In all cases, the salamander skin microbiomes were significantly different from those of the surrounding terrestrial environment. These results suggest that the relationship between E. e. xanthoptica salamanders and their resident skin microbiomes is conserved, possibly indicating a stable mutualism between the host and microbiome.
An elegant study on social parasitism in digger wasps quantifies the costs and benefits of kin recognition and shows that recognizing non-kin comes at a cost. This supports ‘Crozier’s paradox’ of why ...kin recognition genes are unlikely to evolve when rare alleles are selected against.
An elegant study on social parasitism in digger wasps quantifies the costs and benefits of kin recognition and shows that recognizing non-kin comes at a cost. This supports ‘Crozier’s paradox’ of why kin recognition genes are unlikely to evolve when rare alleles are selected against.
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