Biology subjects

Buellesbach, J.

Publications and source records attributed to Buellesbach, J..

3 recordsLinked to original sources

bioRxiv2023

The role of cuticular hydrocarbons in intraspecific aggression in the invasive ant Cardiocondyla obscurior

Cuticular hydrocarbons (CHCs) are important cues for nestmate discrimination and intraspecific aggression in ants. In invasive ants, diminished CHC profile diversity is suspected to contribute to the ecological and evolutionary success of populations by reducing intraspecific aggression between colonies. The ant Cardiocondyla obscurior has successfully colonized habitats around the world, reaching high local population densities. However, despite being invasive, colonies still react aggressively against each other, especially in interactions with non-nestmate alate queens. Here, we study whether CHCs are relevant for antagonistic interactions in this species, by combining behavioral experiments with gas-chromatography coupled with mass spectrometry (GC-MS). We show that queen and worker CHC profiles show pronounced quantitative as well as qualitative differences, that queens with depleted CHC profiles receive virtually no aggression from non-nestmates, and that aggression levels are positively correlated with the naturally occurring CHC profile differences between colonies. These findings provide first empirical evidence for a role of CHCs and chemical diversity in antagonistic behaviors against foreign queens in this species. They further suggest that invasive populations of C. obscurior are multicolonial and polydomous.

animal behavior and cognition↗

bioRxiv2023

Decoding the genetic and chemical basis of sexual attractiveness in parasitic wasps

Attracting and securing potential mating partners is of fundamental importance for successfully initiating reproduction and thus assuring the passing of genes to the next generation. Therefore, signaling sexual attractiveness is expected to be tightly coordinated in communication systems synchronizing senders and receivers. Chemical signaling has permeated through all taxa of life as the earliest and most wide-spread form of communication and is particularly prevalent in insects. However, it has been notoriously difficult to decipher how exactly information related to sexual signaling is encoded in complex chemical profiles. Similarly, our knowledge of the genetic basis of sexual signaling is very limited and usually restricted to a few case studies with comparably simple pheromonal communication mechanisms. The present study jointly addresses these two knowledge gaps by characterizing a single gene simultaneously impacting sexual attractiveness and complex chemical surface profiles in parasitic wasps. Knocking down a fatty acid synthase gene in female wasps dramatically reduces their sexual attractiveness coinciding with a drastic decrease in male courtship and copulation behavior. Concordantly, we found a striking shift of methyl-branching patterns in the female surface pheromonal compounds, which we subsequently demonstrate to be the main cause for the greatly reduced male response. Intriguingly, this suggests a potential coding mechanism for sexual attractiveness mediated by specific methyl-branching patterns, whose genetic underpinnings are not well understood despite their high potential for encoding information. Our study sheds light on how biologically relevant information can be encoded in complex chemical profiles and on the genetic basis of sexual attractiveness. Significance StatementUnraveling the genetic basis of chemical signaling is one of the most prevalent yet challenging topics in functional genetics and animal communication studies. Here we present the characterization of a biosynthetic gene in parasitoid wasps that simultaneously impacts sexual attractiveness as well as majorly shifts complex surface pheromone compositions. The shifted pattern primarily constitutes up- and down-regulated methyl-branched compounds with very distinct branching positions. Therefore, these findings immediately suggest a potential coding mechanism for sexual attractiveness in complex chemical profiles. This advances our understanding of how genetic information can be translated into biologically relevant chemical information and reveals that sexual attractiveness can have a comparably simple genetic basis.

genetics↗

bioRxiv2021

Genetic and genomic architecture of species-specific cuticular hydrocarbon variation in parasitoid wasps

Cuticular hydrocarbons (CHCs) serve two fundamental functions in insects: protection against desiccation and chemical signaling. CHC profiles can consist of dozens of different compounds and are considered a prime example for a complex trait. How the interaction of genes shapes CHC profiles, which are essential for insect survival, adaptation, and reproductive success, is still poorly understood. Here we investigate the genetic and genomic basis of CHC biosynthesis and variation in parasitoid wasps of the genus Nasonia. Taking advantage of the wasps haplo-diploid sex determination and cross-species fertility, we mapped 91 quantitative trait loci (QTL) explaining variation of a total of 43 CHCs in F2 hybrid males from interspecific crosses between three Nasonia species. To identify candidate genes, we localized orthologs of CHC biosynthesis-related genes in the Nasonia genomes. By doing so, we discovered multiple genomic regions where the location of QTL coincides with the location of CHC biosynthesis-related candidate genes. Most conspicuously, on a region on chromosome 1 close to the centromere, multiple CHC biosynthesis-related candidate genes co-localize with several QTL explaining variation in methyl-branched alkanes. The genetic underpinnings behind this compound class are not well understood so far, despite their high potential for encoding chemical information as well as their prevalence in both Nasonia CHC profiles and many other Hymenoptera. Our study considerably extends our knowledge on the so far little-known genetic and genomic architecture governing biosynthesis and variation of this fundamental compound class, establishing a model for methyl-branched alkane genetics in the Hymenoptera in general.

genetics↗