Biology subjects

Raychoudhury, R.

Publications and source records attributed to Raychoudhury, R..

3 recordsLinked to original sources

bioRxiv2021

Bacterial supergroup specific "Cost" of Wolbachia infections in Nasonia vitripennis

The maternally-inherited endosymbiont, Wolbachia, is known to alter the reproductive biology of its arthropod hosts for its benefit and can induce both positive and negative fitness effects in many hosts. Here we describe the effects of the maintenance of two distinct Wolbachia infections, one each from supergroups A and B, on the parasitoid host Nasonia vitripennis. We compare the effect of Wolbachia infections on various traits between the uninfected, single A infected, single B infected, and the double infected strains with their cured versions. Contrary to the previous reports, our results suggest that there is a significant cost associated with the maintenance of Wolbachia infections where traits like family size, fecundity, longevity, and rates of male copulation are compromised in Wolbachia infected strains. The double infected and supergroup B infection strains show higher Wolbachia titer than supergroup A. The double infected Wolbachia strain has the most detrimental impact on the host as compared to single infections. Moreover, there is a supergroup-specific negative impact on these wasps as the supergroup B infections elicit the most pronounced negative effects. These findings raise important questions on the mechanism of survival and maintenance of these reproductive parasites in arthropod hosts.

evolutionary biology↗

bioRxiv2021

The males of the parasitoid wasp, Nasonia vitripennis, can identify which fly hosts contain females.

The reproductive success of a male is limited by the number of females it can mate with. Thus, males deploy elaborate mate-finding strategies to maximize access to females. In the haplodiploid wasp genus, Nasonia, which are parasitoids of cyclorrhaphous flies, mate-finding is restricted to the natal patch, where males compete for access to females. This study investigates whether there are any additional mate finding strategies of males, especially, whether they can identify the presence of adult females which are still inside the fly host. Results reveal that only one out of the four species, N. vitripennis, can distinguish which hosts specifically have adult female wasps indicating a species-specific unique mate-finding capability. Behavioral assays revealed that the cues used by N. vitripennis males are olfactory in nature and not auditory or visual. GC-MS analyses show that these olfactory cues are female-specific cuticular hydrocarbons (CHCs), possibly emanating from within the fly puparium. Further assays indicated that N. vitripennis males can also detect differences in the concentrations of compounds to identify female-specific cues from male-specific ones. This study, therefore, uncovers a previously unknown mate-finding strategy in one of the most widely studied parasitoid wasp.

ecology↗

bioRxiv2021

Pseudomonas can prevent the parasitic fungus, while keeping the crop fungus unaffected, in the gardens of Odontotermes obesus.

Insects that farm monocultures of fungi are canonical examples of nutritional symbiosis as well as independent evolution of agriculture in non-human animals. But just like in human agriculture, these fungal crops face constant threat of invasion by weeds which, if unchecked, takes over the crop fungus. In fungus-growing termites, the crop fungus (Termitomyces) faces such challenges from the parasitic fungus Pseudoxylaria. The mechanism by which Pseudoxylaria is suppressed is not known. However, evidence suggests that some bacterial secondary symbionts can serve as defensive mutualists by preventing the growth of Pseudoxylaria. However, such secondary symbionts must possess the dual, yet contrasting, capabilities of suppressing the weedy fungus while keeping the growth of the crop fungus unaffected. This study describes the isolation, identification and culture-dependent estimation of the roles of several such putative defensive mutualists from the colonies of the wide-spread fungus-growing termite from India, Odontotermes obesus. From the 38 bacterial cultures tested, a strain of Pseudomonas showed significantly greater suppression of the weedy fungus than the crop fungus. Moreover, a 16S rRNA pan-microbiome survey, using the Nanopore platform, revealed Pseudomonas to be a part of the core microbiota of Odontotermes obesus. A meta-analysis of microbiota composition across different species of Odontotermes also confirms the wide-spread prevalence of Pseudomonas within this termite. These evidence indicate that Pseudomonas could be playing the role of defensive mutualist within Odontotermes.

evolutionary biology↗