Biology subjects

Quintero, E.

Publications and source records attributed to Quintero, E..

3 recordsLinked to original sources

bioRxiv2024

Downscaling mutualistic networks from species to individuals reveals consistent interaction niches and roles within plant populations

Species-level networks emerge as the combination of interactions spanning multiple individuals, and their study has received considerable attention over the past 30 years. However, less is known about the structure of interaction configurations within species, even though individuals are the actual interacting units in nature. We compiled 46 empirical, individual-based, interaction networks on plant-animal seed dispersal mutualisms, comprising 1037 plant individuals across 29 species from various regions. We compared the structure of individual-based networks to that of species-based networks and, by extending the niche concept to interaction assemblages, we explored individual plant specialization. Using a Bayesian framework to account for uncertainty derived from sampling, we examined how plant individuals "explore" the interaction niche of their populations. Both individual-based and species-based networks exhibited high variability in network properties, lacking remarkable structural and topological differences between them. Within populations, frugivores interaction allocation among plant individuals was highly heterogeneous, with one to three frugivore species dominating interactions. Regardless of species or bioregion, plant individuals displayed a variety of interaction profiles across populations, with a consistently small percentage of individuals playing a central role and exhibiting high diversity in their interaction assemblage. Plant populations showed variable mid to low levels of niche specialization; and individuals interaction niche "breadth" accounted for 70% of the population interaction diversity, on average. Our results highlight how downscaling from species to individual-based networks helps understanding the structuring of interactions within ecological communities and provide an empirical basis for the extension of niche theory to complex mutualistic networks. Significance StatementEcological interactions in nature occur between individual partners rather than species, and their outcomes determine fitness variation. By examining among-individual variation in interaction niches, we can bridge evolutionary and ecological perspectives to understand interaction biodiversity. This study investigates individual plant variation in frugivore assemblages worldwide, exploring how plant individuals "build" their interaction profiles with animal frugivores. The structure of networks composed of individuals was surprisingly similar to networks composed of species. Within populations, only a few plants played a key role in attracting a high diversity of frugivores, making them central to the overall network structure. Individuals actually interacted with a substantial diversity of partners, with individual niche "breadth" accounting for up to 70% of total interaction diversity, on average.

ecology↗

bioRxiv2022

Reciprocity and interaction effectiveness in generalised mutualisms among free-living species

Mutualistic interactions among free-living species generally involve weak links and highly asymmetric dependence among partners, yet our understanding of factors beyond their emergence is still limited. Using individual-based interactions of a super-generalist fleshy-fruited plant with its frugivore assemblage we estimate the Resource Provisioning Effectiveness (RPE) and Seed Dispersal Effectiveness (SDE) to assess the balance in the exchange of resources. Plants were highly dependent on a few super-generalist frugivore species, while these interacted with most individual plants, resulting in strong asymmetries in mutual dependence. Both RPE and SDE were mainly driven by interaction frequency. Despite highly asymmetric dependences, the strong reliance on quantity largely determined high reciprocity in rewards between partners (i.e., higher energy provided, more seedlings recruited), not obscured by minor variations in the quality of animal or plant service. We anticipate reciprocity will emerge in low-intimacy mutualisms where the mutualistic outcome largely relies upon interaction frequency.

ecology↗

bioRxiv2021

Differential mechanisms of cold sensitivity in mouse trigeminal and vagal ganglion neurons

Thermal signals are critical elements in the operation of interoceptive and exteroceptive neural circuits, essential for triggering thermally-driven reflexes and conscious behaviors. A fraction of cutaneous and visceral sensory endings are activated by cold temperatures. Compared to somatic (DRG and TG) neurons, little is known about the mechanisms underlying cold sensitivity of visceral vagal neurons. We used molecular, pharmacological and genetic tools for a side-by-side characterization of cold-sensitive (CS) neurons in adult mouse trigeminal (TG) and vagal ganglia (VG). We found that CS neurons are larger in size and more abundant in VG than in TG. In VG, the majority of CS neurons co-express TRPA1 markers and cold-evoked responses are severely blunted in Trpa1 KO mice. Cold sensitivity was evident in neurons with the highest TRPA1 expression. In contrast, TRPM8 deletion or pharmacological TRPM8 blockade had little impact on VG cold sensitivity. Consistent with these findings, in Trpm8eYFP reporter mice we found limited expression of TRPM8 in VG and restricted to the rostral jugular ganglion. In vivo retrograde labelling of airway-innervating vagal neurons demonstrated their enhanced cold sensitivity and a higher expression of TRPA1 compared to neurons innervating the stomach wall. In contrast, the majority of CS TG neurons co-express TRPM8 markers and their cold sensitivity is reduced after TRPM8 deletion or blockade. However, pharmacological or genetic reduction of TRPA1 showed that these channels contribute significantly to high-threshold cold sensitivity in TG, suggestive of a role in noxious cold sensing. In both ganglia, a fraction of CS neurons responded to cooling by a mechanism independent of TRPA1 or TRPM8 yet to be characterized. Finally, in both ganglia, sensitivity to cold varied widely and was enhanced by the potassium channel blocker 4-AP. This effect was independent of the cold sensor expressed by the neuron, suggestive of a common excitability brake mechanism. Significance statementTemperature sensing and its regulation is a critical homeostatic function. Little is known about the molecular mechanism of cold sensing by visceral sensory endings and their relative weight in different visceral organs. This study highlights important differences in thermotransduction mechanisms between somatic (trigeminal) and visceral (vagal) primary sensory neurons, establishing a critical role of TRPA1 channels in visceral cold transduction. The study describes quantitative differences in cold sensitivity of visceral neurons innervating the stomach and the lower airways, suggesting that cold transduction mechanisms may be fine-tuned to the specific needs of different organs. This study significantly advances our understanding of cold sensing in trigeminal and vagal neurons and reveals distinct drug targets for the pharmacological modulation of these thermoreceptors.

neuroscience↗