Biology subjects

Suryanarayanan, A.

Publications and source records attributed to Suryanarayanan, A..

3 recordsLinked to original sources

bioRxiv2024

Symbiont loss and gain, rather than co-diversification shapes honeybee gut microbiota diversity and function

Studying gut microbiota evolution across animals is crucial for understanding symbiotic interactions but is hampered by the lack of high-resolution genomic data. Honeybees, with their specialized gut microbiota and well-known ecology, offer an ideal system to study this evolution. Using shotgun metagenomics on 200 worker bees from five honeybee species, we recover thousands of metagenome-assembled genomes and identify several novel bacterial species. While microbial communities were mostly host-specific, we found both specialists and generalists, even among closely related bacterial species, with notable variation between honeybee hosts. Some bacterial generalists emerged host-specific only at the strain level, suggesting recent host switches. While we found some signal of co-diversification between hosts and symbionts, this was not more than expected by chance and was much less pronounced than what has been observed for gut bacteria of hominids and small mammals. Instead, symbiont gains, losses, and replacements emerged as the predominant process for honeybees. This highly dynamic evolution of the specialized honey bee gut microbiota has led to taxonomic and functional differences across hosts, such as the ability to degrade pollen-derived pectin. Our results provide new insights into the evolutionary processes govern gut microbiota diversity across closely related hosts and uncover the functional potential of the previously underexplored gut microbiota of these important pollinators.

microbiology↗

bioRxiv2024

Innate floral object identification in the generalist solitary hoverfly pollinator Eristalinus aeneus

All animals must locate and identify food for their survival. Most insects are solitary. Newly emerged solitary insects must therefore employ innate identification of food cues to locate relevant nutritive objects from a distance. Innate preferences for food cues should be both specific enough to allow discrimination between food and non-food objects and general enough to allow for the variety of food objects relevant to each species ecology. How insects with small nervous systems are able to encode these cues innately is an area of intense study for ecologists and neuroscientists alike. Here, we used the solitary generalist pollinator Eristalinus aeneus to understand how the innate search template used to identify multiple floral species can arise through a small number of sensory cues spanning multiple modalities. We found that innate floral choices of the hoverfly E. aeneus are a product of contextual integration of broad, plant-based olfactory cues and visual cues, where a combination of radial symmetry and reflection in the 500-700 nm wavelength range was particularly important. Our study, therefore, shows how tiny brains can efficiently encode multimodal cues to identify multiple relevant objects without prior experience.

animal behavior and cognition↗

bioRxiv2021

Conserved hormonal and molecular mechanisms underlying behavioural maturation in open- and cavity-nesting honey bees

Division of labour in honey bees is based on a process of behavioural development where the worker bee successively performs different tasks at different ages. Workers start with tasks related to brood care and nest maintenance and move on to become foragers. This process of worker behavioural maturation is well studied in Apis mellifera. Juvenile hormone is one of the major drivers of this behavioural maturation, which is also accompanied by changes in brain physiology and anatomy including changes in neuronal gene expression and connections of neurons. Recent studies have identified whole networks of genes associated with specific tasks like nursing, guarding and foraging. Based on this detailed knowledge in A. mellifera, we ask whether major characteristics of the behavioural maturation process and the underlying hormonal and molecular changes are similar or different in two other honey bee species, the phylogenetically ancestral open-nesting A. florea and the more derived cavity-nesting A. cerana. Our behavioural studies show that workers of A. florea exhibit a slower pace of behavioural maturation and on average start foraging at a later age. However, the basic hormonal and molecular changes associated with onset of foraging are similar between both species. Based on our findings, we propose that evolution of accelerated behavioural maturation in cavity-nesting species is likely attributed to changes in the temporal dynamics of juvenile hormone titres.

molecular biology↗