| Project/Area Number |
23KF0077
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| Research Category |
Grant-in-Aid for JSPS Fellows
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| Allocation Type | Multi-year Fund |
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| Section | 外国 |
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| Review Section |
Basic Section 45020:Evolutionary biology-related
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| Research Institution | Okinawa Institute of Science and Technology Graduate University |
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Principal Investigator |
ECONOMO Evan 沖縄科学技術大学院大学, 生物多様性・複雑性研究ユニット, 教授 (30648978)
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| Co-Investigator(Kenkyū-buntansha) |
RICHTER ADRIAN 沖縄科学技術大学院大学, 生物多様性・複雑性研究ユニット, 外国人特別研究員
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| Project Period (FY) |
2023-04-25 – 2025-03-31
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| Project Status |
Discontinued (Fiscal Year 2023)
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| Budget Amount *help |
¥2,000,000 (Direct Cost: ¥2,000,000)
Fiscal Year 2024: ¥1,000,000 (Direct Cost: ¥1,000,000)
Fiscal Year 2023: ¥1,000,000 (Direct Cost: ¥1,000,000)
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| Keywords | micro CT scanning / segmentation / convergent evolution / anatomy / Formicidae / feeding system / mouthparts / adaptation |
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| Outline of Research at the Start |
My research consists of three main parts: 1. Documenting the anatomy of the ant digestive system in high detail and for more species than ever before. 2. Reconstructing the evolution of different parts of the digestive system across the ant phylogeny. 3. Relating the anatomical differences in the system to differences in ant ecology and behavior. Depending on results in these main parts, my research may result in two papers. First would be a detailed documentation of digestive system anatomy in a few ant species. The second would test major evolutionary hypotheses related to part 2 and 3.
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| Outline of Annual Research Achievements |
Early in the fiscal year, I worked on a review article on the feeding system and mechanism of ants. This article was published in October 2023 in a special issue of the philosophical transactions of the royal society B. After finishing work on this article, I focused on the mouthparts of ants. These are parts of the feeding system that close off the mouth opening and are used in feeding, but also social functions like cleaning. We discovered that ants have a unique protection mechanism by interlocking mouthparts with each other. This protects the soft mouth ensuring feeding and social functions. Protectiveness level is variable across ants, some having more tightly interlocking mouthparts and others more loose ones. We discovered that this difference is related to the food resource, as predatory ants generally have better protected mouthparts than herbivorous ones. The paper on this project is almost completed and a manuscript will be submitted in the next fiscal year. I presented this project at a conference in Japan and one in the US. Additionally, I generated micro CT scan data of ca. 50 ant species to investigate the rest of their feeding system. I started segmenting this data focusing on the sucking pump and full system in selected species. Finally, I published papers from side projects, one on the evolution of the genitals in the ant subfamily Leptanillinae, one on new fossil species of a group of parasitoid wasps (Megalyridae), and I received a price for Zoological Systematics from the Zoological state collection Munich, Germany, for my research so far.
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| Current Status of Research Progress |
Current Status of Research Progress
2: Research has progressed on the whole more than it was originally planned.
Reason
Early into my project, I already published a review article on my main research topic, the feeding system of ants. A second paper, on the evolution of mouthpart protection in ants, described above, is in a good status of completion. While I initially hoped to finish this project earlier, I found more morphological variation across the ants than I had anticipated. This meant that I needed to learn new phylogenetic comparative methods to analyze this variability and understand the patterns of variation. Learning these tools and applying them to the evolution of the ant feeding system was a main goal of my project, so I feel like I achieved a lot of my initial goal through working on this research question, although it is only a part of my proposed idea and I hoped to finish it sooner. Additionally, I am happy with the data amount that I was able to generate to study the digestive system further. The ant digestive system consists of the buccal cavity, which is the space containing the mouthparts; the sucking pump of the head; the esophagus, a long tube; a crop (social stomach); a proventriculus (valve); the midgut; malpighian tubules; and the hindgut. I already analyzed the sucking pump of 12 species in this fiscal year, and found some interesting patterns, although more analysis will be needed for any evolutionary conclusions. Additionally, I have segmented the full digestive system of 2 species. I think that overall, the progress in the previous fiscal year positions me well to publish significant research in line with my original project ideas and goals.
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| Strategy for Future Research Activity |
I plan to continue analyzing the sucking pump of the head specifically, and the whole digestive system of ants more broadly. My goal is to balance between providing a broader overview of the whole system and studying the evolution of one of its major components in more detail. In providing an overview, my goal will be to segment out the whole digestive system of a few representative ant species (around 10) with different social lifestyles, feeding preferences, and from different evolutionary lineages. I will compare their digestive systems and give a summary of which parts have which function and which parts are different and potentially adapted to enable the different lifestyles across the ants. I aim to present the system and its relevant parts and differences in a way that is easy to understand for a general audience as a reference, not just morphologists or evolutionary biologists. The project on the evolution of the sucking pump will provide a much deeper look and more detailed morphological and evolutionary discussion, in which all the variation of this system occurring across ants will be documented, its evolution reconstructed, and correlations with different lifestyles will be statistically tested, as I already did for the mouthpart closure mechanism. For this, I expect to need roughly 100 species segmented. As the digestive system forms a significant basis for both the feeding and social behavior of ants, I expect my project to have a positive impact on our understanding of ant evolution.
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