Genome Assembly and Annotation of the California Harvester Ant Pogonomyrmex californicus (Buckley, 1867)
The harvester ant genus Pogonomyrmex is endemic to arid and semiarid habitats and deserts of North and South America. The California harvester ant Pogonomyrmex californicus is the most widely distributed Pogonomyrmex species in North America. P. californicus colonies are usually monogynous, i.e. a colony has one queen. However, in a few populations in California, primary polygyny evolved, i.e. several queens cooperate in colony founding after their mating flights and continue to coexist in mature colonies. Here, we present a genome assembly and annotation of P. californicus. The size of the assembly is 241 Mb, which is in agreement with the previously estimated genome size. We were able to annotate 17,889 genes in total, including 15,688 protein-coding ones with BUSCO completeness at a 95% level. The presented P. californicus genome assembly will pave the way for investigations of the genomic underpinnings of social polymorphism in the number of queens, regulation of aggression, and the evolution of adaptations to dry habitats.
Jonas Bohn, Reza Halabian, Lukas Schrader, Victoria Shabardina, Raphael Steffen, Yutaka Suzuki, Ulrich R Ernst, Jürgen Gadau, Wojciech Makałowski "Genome Assembly and Annotation of the California Harvester Ant Pogonomyrmex californicus (Buckley, 1867)" (2020) G3 Genes|Genomes|Genetics
Uli Ernst co-authored a manuscript titled “Beekeepers and Scientists, or Beekeepers vs. Scientists?”. Together with colleagues in Leuven, Belgium, he argues that beekeepers (both, laymen and professional apiculturists) and scientists should work together in researching the biology of the honey bee and best practices in beekeeping.
Ernst UR, Detienne G, Cardoen D. 2020. ‘Beekeepers and Scientists, or Beekeepers vs. Scientists?’ /BeeWorld/ 97, No. 3: 75-77. doi: 10.1080/0005772X.2020.1775540.
Individual learning phenotypes drive collective behavior
Individual differences in learning can influence how animals respond to and communicate about their environment, which may nonlinearly shape how a social group accomplishes a collective task. There are few empirical examples of how differences in collective dynamics emerge from variation among individuals in cognition. Here, we use a naturally variable and heritable learning behavior called latent inhibition (LI) to show that interactions among individuals that differ in this cognitive ability drive collective foraging behavior in honey bee colonies. We artificially selected two distinct phenotypes: high-LI bees that ignore previously familiar stimuli in favor of novel ones and low-LI bees that learn familiar and novel stimuli equally well. We then provided colonies differentially composed of different ratios of these phenotypes with a choice between familiar and novel feeders. Colonies of predominantly high-LI individuals preferred to visit familiar food locations, while low-LI colonies visited novel and familiar food locations equally. Interestingly, in colonies of mixed learning phenotypes, the low-LI individuals showed a preference to visiting familiar feeders, which contrasts with their behavior when in a uniform low-LI group. We show that the shift in feeder preference of low-LI bees is driven by foragers of the high-LI phenotype dancing more intensely and attracting more followers. Our results reveal that cognitive abilities of individuals and their social interactions, which we argue relate to differences in attention, drive emergent collective outcomes.
Chelsea N. Cook, Natalie J. Lemanski, Thiago Mosqueiro, Cahit Ozturk, Jürgen Gadau, Noa Pinter-Wollman, Brian H. Smith
Proceedings of the National Academy of Sciences Jul 2020, 117 (30) 17949-17956; DOI: 10.1073/pnas.1920554117
The Power of Infochemicals in Mediating Individualized Niches
Infochemicals, including hormones, pheromones, and allelochemicals, play a central role in mediating information and shaping interactions within and between individuals. Due to their high plasticity, infochemicals are predestined mediators in facilitating individualized niches of organisms. Only recently it has become clear that individual differences are essential to understand how and why individuals realize a tiny subset of the species' niche. Moreover, individual differences have a central role in both ecological adjustment and evolutionary adaptation in a rapidly changing world. Here we highlight that infochemicals act as key signals or cues and empower the realization of the individualized niche through three proposed processes: niche choice, niche conformance, and niche construction.
Highlights
Individual differences are central in behavior, ecology, and evolution, because they determine which selective factors are relevant for an individual in interaction with its environment; yet ecological niches have rarely been studied on an individual level.
The subset of the species’ niche realized by an individual is called its individualized niche and is implemented by three major processes: choice, conformance, and construction.
Infochemicals can differ between individuals and empower the realization of the individualized niche. Combining hormones and semiochemicals under the term infochemicals highlights their common function in information transfer within or between organisms.
We give several examples how chemical mediators, including hormones, pheromones, and allelochemicals, are essential in the realization of an individualized niche across the animal kingdom.
Caroline Müller, Barbara A. Caspers, Jürgen Gadau and Sylvia Kaiser The Power of Infochemicals in MediatingIndividualized Niches Trends in Ecology & Evolution Volume 35, Issue 11, November 2020, Pages 981-989
Functional insights from the GC-poor genomes of two aphid parasitoids, Aphidius ervi and Lysiphlebus fabarum
Background
Parasitoid wasps have fascinating life cycles and play an important role in trophic networks, yet little is known about their genome content and function. Parasitoids that infect aphids are an important group with the potential for biocontrol. Their success depends on adapting to develop inside aphids and overcoming both host aphid defenses and their protective endosymbionts.
Results
We present the de novo genome assemblies, detailed annotation, and comparative analysis of two closely related parasitoid wasps that target pest aphids: Aphidius ervi and Lysiphlebus fabarum (Hymenoptera: Braconidae: Aphidiinae). The genomes are small (139 and 141 Mbp), highly syntenic, and the most AT-rich reported thus far for any arthropod (GC content: 25.8% and 23.8%). This nucleotide bias is accompanied by skewed codon usage and is stronger in genes with adult-biased expression. AT-richness may be the consequence of reduced genome size, a near absence of DNA methylation, and energy efficiency. We identify missing desaturase genes, whose absence may underlie mimicry in the cuticular hydrocarbon profile of L. fabarum. We also find that absence of some immune genes (Toll and Imd pathways) resembles similar losses in their aphid hosts, highlighting the potential impact of symbiosis on both aphids and their parasitoids.
Conclusions
These findings are of fundamental interest for insect evolution and beyond. This will provide a strong foundation for further functional studies including coevolution with respect to their hosts, the basis of successful infection, and biocontrol. Both genomes are available at https://bipaa.genouest.org.
or genomes of two aphid parasitoids, Aphidius ervi and Lysiphlebus fabarum
Dennis, A.B., Ballesteros, G.I., Robin, S. et al. Functional insights from the GC-poor genomes of two aphid parasitoids, Aphidius ervi and Lysiphlebus fabarum. BMC Genomics 21, 376 (2020).
In this article, Uli Ernst discusses the results of a study by Andrés E. Quiñones and colleagues that appeared in the journal Evolution. Eusociality, i.e. the division of labour between fertile individuals who reproduce and those who do not, is generally quite rare in the animal kingdom. However, it is more common in ants, bees and wasps, i.e. those state-forming insects in which there is a division of labour between queens, which have specialised in reproduction, and infertile workers, who as a rule do not lay eggs but perform all other work. It is striking that ants, bees and wasps all belong to the insect order of hymenopterans, which have a special genetic mechanism for determining the sex of the offspring. Males develop from unfertilized eggs and females hatch from fertilized eggs. It has been discussed for a long time whether this genetic mechanism ("haplodiploidy") could have led to the fact that in the hymenopteran order of insects, state-forming insects developed more frequently than in other insects. In the current study, mathematical models were used to show that there are two factors that initially facilitate the evolution of eusociality. One is an imbalance in the sex ratio between different nests (i.e. that some nests produce mainly males, while others produce mainly females), and the other is that workers within a nest can influence this sex ratio among the offspring by eliminating male offspring. In the long run this leads to different results. On the one hand, it can lead to a mixture of social nests (with female workers) and solitary nests (without female workers). On the other hand, it can also lead to exclusively social nests (with division of labour between infertile workers and fertile queens), where some nests specialise in the production of females, others in the production of males, and others in the production of both females and males.
Ernst, U.R. (2020), Digest: Evolution of eusociality favored by split sex ratios under worker‐control. Evolution, 74: 201-202. doi:10.1111/evo.13890
For the article that is discussed, please click here.
Quiñones, A.E., Henriques, G.J.B. and Pen, I. (2020), Queen–worker conflict can drive the evolution of social polymorphism and split sex ratios in facultatively eusocial life cycles. Evolution, 74: 15-28. doi:10.1111/evo.13844
