Rapid movements of limbs and appendages, faster than those produced by simple muscle contraction alone, are generated through mechanical networks consisting of springs and latches. The latch plays a central role in these spring-loaded mechanisms, but the structural details of the latch are not always known. The mandibles of the trap-jaw ant Odontomachus kuroiwae closes the mandible extremely quickly to capture prey or to perform mandible-powered defensive jumps to avoid potential threats.
View Article and Find Full Text PDFIn temperate zones, seed-dispersal networks by migratory birds are formed on long time scale. In mid-October from 2005 to 2016, to explore the dynamics of the network structures, we examined interannual variability of fruit abundance, bird migration, and seed-dispersal networks in central Japan. For 12 years, the fruit abundance exhibited a remarkable fluctuation across years, with the number of fruiting plants and matured fruits fluctuating repeatedly every other year, leading to the periodic fluctuations.
View Article and Find Full Text PDFMost social Hymenoptera are characterized by simple haploid sex determination and environment-based caste differentiation. This appears to be strikingly different in the queen-polymorphic ant Vollenhovia emeryi. Almost all long- and short-winged queens from a population in Central Japan were homozygous at three microsatellite loci, whereas workers were mostly heterozygous, suggesting either a complex system of genetic caste determination or, more likely, the production of female sexuals from unfertilized eggs by thelytokous parthenogenesis and of workers from fertilized eggs.
View Article and Find Full Text PDFErythronium japonicum (Liliaceae) inhabits deciduous mesic forests of Hokkaido, northern Japan. Myrmecochory of this species was investigated, especially the dispersal frequency, the effect of seed predators and the seed fall pattern. In the quadrat census using marked seeds of E.
View Article and Find Full Text PDFViola is one of the diplochorous plant genera that disperse their seeds in two ways, ballistic and ant dispersal. We compared the seed dispersal of two major Viola species of northern Japan, V. selkirkii and V.
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