Harvestman: The forest hermit whose appearance changes from place to placeBook Review
Nobuomi Tsurusaki [Author], Tsukiji Shokan, published July 2024, 2,400 yen (excluding tax)
Even among zoologists, how many could form a clear mental image upon hearing the term "harvestman"? A search through the program of last year's 94th Annual Meeting of the Zoological Society of Japan in Yamagata yields only two presentations dealing with harvestmen (one general presentation and one symposium, both by the author of this book). This book is a passionate monograph by an author who has studied such seemingly obscure creatures for over 50 years.
This book consists of seven chapters: "Chapter 1: What are Harvestmen," "Chapter 2: Life History," "Chapter 3: Geographical Variation and Distribution," "Chapter 4: Pioneers of Harvestmen Research in Japan," "Chapter 5: Harvestmen Trivia," "Chapter 6: Collection Methods and Specimen Preparation," and "Chapter 7: Profiles of 30 Japanese Harvestman Species." Between the sections making up the chapters, interesting columns are occasionally included, making for a light and engaging read. By cross-referencing Chapter 7 with the frontispiece featuring clear photographs of the 30 Japanese harvestman species, the book can also be used as a "Harvestman Field Guide."
What kind of strategy did harvestmen—which are small, vulnerable to desiccation, and have such poor dispersal ability that they become geographically isolated simply by being sandwiched between rivers—use to achieve their current speciation? What caught the author's interest the most is that harvestmen;
There are species in which tetraploid males and females stably form populations.
2. There is a species in which gynandromorphs appear at an unusually high rate.
3. There are species in which chromosome number variation within a species (and sometimes within an individual) is frequent due to chromosome nondivision during meiosis, the presence of B chromosomes, etc.
In short, it featured a variety of fascinating phenomena detectable at the chromosome level. Since it is said to be an organism capable of interspecific hybridization, it makes one indulge in wild speculations—such as whether there might even be species that have evolved as allopolyploids originating from two ancestral species, much like the African clawed frog.
Although the book contains a mix of sections requiring some specialized knowledge and parts that are easy for general readers to understand, it can be called a fine work filled with academic stimulation—the kind that might make an undergraduate senior preparing for graduate school suddenly want to pursue harvestman research. General readers will likely find that simply skipping the difficult parts, as the author suggests in the text, is enough to fully immerse themselves in the charm of harvestmen.
There is a reason why the author was drawn to a book about harvestmen. When the author was an elementary school student, the form of a robot spy that appeared in the US animated series "Jonny Quest" (produced by Hanna-Barbera), which was broadcast at the time, modeled that of a harvestman (albeit with some differences). While watching it, the author only thought, "What a strangely shaped robot," but later encountered a harvestman striding across the ground covered in liverwort, and was thrilled, realizing, "Ah, the shape of this creature was the model!!" This childhood experience stayed in the memory, and upon hearing a call for writers to review a book dealing with harvestmen, the author impulsively volunteered. As expected, it was packed with fascinating topics. The author would like to express heartfelt respect and admiration to Mr. Nobuo Tsurusaki, who wrote this book.
Hiromichi Koyama (Visiting Faculty, Faculty of Science, Yokohama City University)
Harvestman: The Forest Hermit Whose Appearance Changes from Place to Place - Book Review (PDF file)
