bioRxiv Science⌕ Search

bioRxiv · 10.1101/193714

Fitness effects and transmission of phoretic nematodes of the burying beetle, Nicrophorus vespilloides

Abstract

O_LINicrophorus vespilloides is a cosmopolitan social beetle that rears its offspring on decomposing carrion. Wild beetles are frequently associated with two types of macrobial symbionts, mites and nematodes.\nC_LIO_LIAlthough these organisms are believed to be phoretic commensals that harmlessly use beetles as a means of transfer between carcasses, the role of these symbionts on N. vespilloides fitness is poorly understood. Here we show that nematodes have significant negative effects on beetle fitness across a range of worm densities and also quantify the density-dependent transmission of worms between mating individuals and from parents to offspring.\nC_LIO_LIUsing field-caught beetles, we provide the first report of a new nematode symbiont in N. vespilloides, most closely related to Rhabditoides regina, and show that worm densities are highly variable across individuals isolated from nature but do not differ between males and females. Next, by inoculating mating females with increasing densities of nematodes, we show that worm infections significantly reduce brood size, larval survival and larval mass, and also eliminate the trade-off between brood size and larval mass. Finally, we show that nematodes are efficiently transmitted between mating individuals and from mothers to larvae, directly and indirectly via the carcass, and that worms persist through pupation.\nC_LIO_LIThese results show that the phoretic nematode R. regina can be highly parasitic to burying beetles but can nevertheless persist because of efficient mechanisms of intersexual and intergenerational transmission.\nC_LIO_LIPhoretic species are exceptionally common and may cause significant harm to their hosts, even though they rely on these larger species for transmission to new resources. However, this harm may be inevitable and unavoidable if transmission of phoretic symbionts requires nematode proliferation. It will be important to determine the generality of our result for other phoretic associates of animals.\nC_LI

Explore related subjects

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Wang, Y., Rozen, D.. 2017-09-26. Fitness effects and transmission of phoretic nematodes of the burying beetle, Nicrophorus vespilloides. https://doi.org/10.1101/193714

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related preprints

Particle-based representation of phytoplankton modulates emergent coexistence and biogeography in a model ocean

Phytoplankton communities sustain the marine food web through primary productivity. These communities sustain a high diversity of species, all of which must draw from the same finite nutrient supply. The mechanisms driving phytoplankton biogeography and succession, as well as those enabling high diversity, remain incompletely understood. Here, we compare emerging patterns of biogeography, richness, and diversity in a size-structured phytoplankton community as it is advected and diffused within an idealized North Atlantic double-gyre circulation, using both Eulerian and Lagrangian (particle-based) modeling (PBM) frameworks. When a sufficient number of particles is modeled, the PBM, which resolves mortality at the particle level, produces stronger seasonal variability in biomass in the northern gyre and less stable and higher biomass in the southern gyre, while reproducing large-scale chlorophyll patterns observed by satellite. These contrasting dynamics are accompanied by distinct regional diversity patterns: local richness and diversity are generally higher in the PBM than in the Eulerian model in the northern gyre, with differences depending on the mortality threshold, whereas in the oligotrophic southern gyre, PBM local richness increases with particle number, while Eulerian richness is more sensitive to the mortality threshold. The PBM also produces a dynamic and emergent biogeographical structure that is more robust to the mortality threshold than the Eulerian model. Finally, Lagrangian variability in environmental conditions experienced by particles shows a stronger impact compared to the local Eulerian variability in the Northern gyre and stresses variable sensitivity to environmental histories. Together, these results suggest that the discrete representation of biomass fundamentally alters mortality, biogeography, and emergent coexistence patterns in model plankton ecosystems.

ecology↗

Concrete waste as a source of calcium and alkalinity for coccolithophore cultivation: an experimental test of carbon dioxide removal and sequestration

Cultivation of calcifying microalgae has been proposed as a route to carbon dioxide removal (CDR), but biogenic calcification releases CO2 unless the calcium supplied also adds alkalinity. We used cultures of the coccolithophore Chrysotila sp to test whether hydrated lime (Ca(OH)2), supplied as a reagent or within ground waste concrete, can provide both calcium and alkalinity. In a 26-day factorial batch experiment, we monitored pH, nitrate and dissolved calcium. Calcite was quantified by thermogravimetric analysis. Nitrate concentration decreased and calcite accumulated in all algal treatments, indicating that lime or concrete did not inhibit growth or calcification. Lime and concrete raised culture pH significantly whereas the algal growth rate inferred from nitrate drawdown did not differ among treatments. Calcite production was 3.6-fold higher with lime than in seawater (4.5 vs. 1.2 mg L-1 d-1) and highly variable with concrete; lime and concrete cultures remained supersaturated with respect to calcite ({Omega} {approx} 7-10 vs. 0.2). Carbonate-system calculations indicate that the added alkalinity raises the equilibrium CO2 uptake capacity of the medium by ca. 3.4 mmol kg-1, offsetting CO2 released by calcification. These results provide proof of concept for coupling coccolithophore cultivation with concrete waste reuse for CDR.

ecology↗

Intraspecific trait variation shapes macro-scale patterns ofniche breadth and range size

Morphological variation within species may promote adaptation across ecological and geographic space, perhaps reflecting evolutionary plasticity and adaptability. Based on this concept, species with greater intraspecific variation in morphological traits may be expected to occupy broader ecological niches and larger geographic ranges. However, even in the age of global trait datasets, intraspecific morphological variation remains poorly quantified at broad taxonomic and geographic scales, limiting our understanding of how trait flexibility shapes ecological and biogeographic patterns. Focusing on 161 species of bulbuls, a widespread avian family containing some of the most abundant bird species in the world, along with some of the rarest and most restricted in range, we conducted global-scale sampling of morphological traits. These included beak shape, tarsus length and wing length, associated with dietary niche, foraging strategy and dispersal, respectively. Using phylogenetic models, we tested whether ecological niche breadth and geographical range size are predicted by intraspecific morphological variation quantified from 8,251 museum specimens and 5,627 live captures. Our results demonstrate that morphological trait variation predicts both ecological niche breadth and geographic range size. Furthermore, widespread species exhibit greater morphological variation than restricted-range species even when comparisons are constrained to equivalent geographic extents, consistent with the hypothesis that intraspecific trait variation facilitates range expansion rather than simply accumulating as a consequence of occupying a larger range. These results identify intraspecific morphological variation as a potentially important, yet largely overlooked, predictor of ecological traits and biogeographic distributions in birds.

ecology↗