Biology subjects

Hauber, M.

Publications and source records attributed to Hauber, M..

3 recordsLinked to original sources

bioRxiv2025

Genomic resources for comparative analyses of obligate avian brood parasitism

Examples of convergent evolution, wherein distantly related organisms evolve similar traits, including behaviors, underscore the adaptive power of natural selection. In birds, obligate brood parasitism, and the associated loss of parental care behaviors, has evolved independently in seven different lineages, though little is known about the genetic basis of the complex suite of traits associated with this rare life history strategy. We generated genome assemblies for ten brood parasitic species plus eight species representatives of their parental/nesting outgroups. This includes nine long-read chromosome-level assemblies, with scaffold N50 sizes ranging from 38.1 to 72.6 MB, and gene representation completeness measures >97%. Leveraging this new catalog of avian genomes, we constructed clade-level alignments that reveal variation in chromosomal synteny, provide first-time or improved annotations of protein-coding and non-coding genes, and define cross-species ortholog reference sets. We also refine estimates for the timing of the seven independent origins of brood parasitism, ranging from recent events such as 1.6 to 4.5 million years ago in Molothrus cowbirds to much earlier origins over 30 million years ago in two of the three cuckoo lineages. These genomic resources lay the foundation for investigating the genetic and genomic underpinnings of brood parasitism, including the loss of parental care, shifts in mating systems, perhaps resulting in heightened sperm competition, elevated annual fecundity, improved spatial cognition related to nest-finding, and the diverse adaptations shaped by intense coevolution with host species.

genomics↗

bioRxiv2024

Extreme fatigue-resistance in a brood parasite parallels a war of attrition in begging competition with hosts

Food-solicitation displays are critical to the survival of dependent young. These signals often evolve in extreme ways in response to familial conflict among siblings and between parents and offspring. Avian brood parasites demonstrate how these signals can become exaggerated by engaging in a begging arms race with host offspring. However, despite hypotheses about how begging displays in brood parasites are adapted to support the demands of early parasitic life, we know little about the physiological specializations that support exaggerated parasitic traits. Here, we investigate display performance in the begging competition between brood parasitic brown-headed cowbirds (Molothrus ater) and host prothonotary warblers (Protonotaria citrea). Using in situ muscle stimulation, we test the performance limits of the musculus complexus (MC), which actuates begging displays. Our results show that nestlings of each species initiate their begging display at similar speeds, but cowbirds beg far longer than warblers. We trace these effects to species differences in muscle performance, with the cowbird MC showing dramatically greater fatigue-resistance than warblers, while other facets of muscle performance remained similar between species. Altogether, these findings suggest that intra-brood conflict in host-parasite interactions selects for extreme fatigue-resistance in skeletal muscles to support a "war of attrition" in begging behavior and nestling survival.

animal behavior and cognition↗

bioRxiv2019

Proximate Predictors of Variation in Egg Rejection Behavior by Hosts of Avian Brood Parasites

The rejection of parasitic eggs by hosts of avian brood parasites is one of the most common and effective defenses against parasitism. Despite its adaptive significance, egg rejection often shows substantial intraspecific variation: some individuals are more likely to remove or abandon parasitic eggs than others. Understanding variation in egg rejection requires that we study factors linked to both the ability to perceive parasitic eggs, as well as factors that may influence the rejection of a foreign egg once it has been recognized. Here we asked what cognitive, physiological, and life-history factors explained variation in the rejection of model eggs by American Robin Turdus migratorius females. We found that the probability of egg rejection was related to the clutch size at the time of parasitism: in support of Webers law, females with fewer eggs were more likely to reject the model eggs. In turn, females with greater mass and higher corticosterone levels were less likely to reject eggs, and egg rejection probability was negatively related to incubation progress. Our data thus suggest that proximate predictors of an individuals egg rejection behavior include components of the nests perceptual environment, life-history factors, as well as the physiological state of the animal. However, much of the variation in the responses of robins to the model eggs remained unexplained. Future experiments should aim to understand the causal roles of these and other factors in generating within- and among-individual variation in the rejection of parasitic eggs.

animal behavior and cognition↗