Biology subjects

Fernandez Otarola, M.

Publications and source records attributed to Fernandez Otarola, M..

3 recordsLinked to original sources

bioRxiv2026

Good parenting of oil-collecting bees: microbial defense in nests of Centris bees?

Microbial symbionts are increasingly recognized as key contributors to bee health, yet their roles in solitary bee brood cells remain largely unexplored. Here, we characterize the bacterial and fungal communities associated with brood cell compartments (cocoon, meconium, and prepupa) of the oil-collecting bee Centris aethyctera, and compare them with gut microbiota from adult Centris species. Using 16S rRNA and ITS amplicon sequencing, we show that microbiota are strongly compartmentalized, with distinct diversity patterns, taxonomic compositions, and inferred functional profiles across brood cell components. Contrary to our initial hypothesis, antibiotic-producing bacteria, particularly Actinomycetia, are most diverse and abundant in the meconium rather than the cocoon. Cocoons are enriched in hydrocarbon-degrading and nitrogen-cycling bacteria, while pre-pupae harbor distinct bacterial and fungal taxa, including genera with potential antimicrobial and symbiotic functions. Fungal communities are likewise structured, with taxa such as Aspergillus and Lecanicillium suggesting possible roles in pathogen defense. Core gut microbiota of adult Centris include acetic acid bacteria shared across species, with partial overlap with brood cell taxa, indicating potential transmission pathways. Together, our results reveal that Centris brood cells form a highly structured, antimicrobial-rich microenvironment likely shaped by maternal provisioning and environmental acquisition. These findings provide the first comprehensive description of microbiota across brood cell compartments in a solitary bee and identify ground-nesting bee systems as promising reservoirs for novel antimicrobial discovery.

ecology↗

bioRxiv2021

Convergent selection on juvenile hormone signaling is associated with the evolution of eusociality in bees

Sweat bees have repeatedly gained and lost eusociality, a transition from individual to group reproduction. Here, we generate chromosome-length genome assemblies for 17 species and identify genomic signatures of evolutionary trade-offs associated with transitions between social and solitary living. Both young genes and regulatory regions show enrichment for these molecular patterns. We also identify loci that show evidence of complementary signals of positive and relaxed selection linked specifically to the convergent gains and losses of eusociality in sweat bees. This includes two proteins that bind and transport juvenile hormone (JH) - a key regulator of insect development and reproduction. We find one of these JH binding proteins is primarily expressed in subperineurial glial cells that form the insect blood-brain barrier and that brain levels of JH vary by sociality. Our findings are consistent with a role of JH in modulating social behavior and suggest eusocial evolution was facilitated by alteration of the proteins that bind and transport JH, revealing how an ancestral, developmental hormone may have been co-opted during one of lifes major transitions. More broadly, our results highlight how trade-offs have structured the molecular basis of eusociality in these bees and demonstrate how both directional selection and release from constraint can shape trait evolution.

evolutionary biology↗

bioRxiv2020

First evidence for an aposematic function of a very common color pattern in small insects.

Many small parasitoid wasps have a black-orange-black (BOB) color pattern, which is usually present in both sexes. A likely function of this widespread pattern is aposematic (warning) coloration, but this has never been investigated. To test this hypothesis, we presented spider predators (Lyssomanes jemineus), both field-captured and lab-reared individuals, to a species with the BOB pattern and a congeneric all-black species in each of four scelionid genera (Baryconus, Chromoteleia, Macroteleia and Scelio). Each spider/wasp trial was filmed for 40 minutes under controlled conditions and three behavioral responses (detect, attack, avoid) were recorded in each of 136 trials, never using the same predator and prey more than once. In order to better understand the results obtained, two additional studies were performed. First, the reflection spectrum of the cuticle of the wasp and a theoretical visual sensibility model of the spider were used to calculate a parameter we called "absorption contrast" that allowed us to compare the perception contrast between black and orange in each wasp genus as viewed by the spider. Second, acute toxicity trials with the water flea, Daphnia magna, were performed to determine toxicity differences between BOB and non-BOB wasps. By combining the results from the three types of experiments, together with a statistical analysis, we confirmed that BOB color pattern plays an aposematic role.

animal behavior and cognition↗