Parasitism-Induced Intersexuality in a Sexually Dimorphic Varunid Crab, (Decapoda: Varunidae).

Although many animals that perform sexual reproduction exhibit sexual dimorphism, individuals with intersex traits between the traits of males and females appear in some species, depending on environmental factors. , a varunid crab, exhibits distinctive sexual dimorphism in the morphology of its abdomen, chelipeds and setal tufts on the chelipeds. In this study, however, we report for the first time that intersex individuals with intermediate characters between those of males and females were occasionally found in wild populations.

Developmental Process of a Heterozooid: Avicularium Formation in a Bryozoan, .

In bryozoans (phylum Bryozoa), representative colonial animals mostly found in marine environments, some species possess different types of individuals (heterozooids) specialized in different functions such as defense or structural support for their colonies. Among them, the best-known heterozooids are the avicularia, known to function as defenders. The differentiation processes of heterozooids, including avicularia, should be important keys to understand the evolutionary significance of bryozoans.

Development of Cerata in the Cladobranchian Sea Slug (Mollusca: Gastropoda: Nudibranchia).

Cladobranchian sea slugs are characterized by a number of dorsal projections, called "cerata," which are presumably involved in such biological functions as kleptocnidal defense, gas exchange, and symbiotic photosynthesis. Here, we investigated the developmental pattern of ceras formation in a cladobranchian, , using field-collected individuals at various postembryonic developmental stages. As the body length increased, the total number of cerata increased in a logistic manner, up to 280 per individual.

Reduction of a nymphal instar in a dampwood termite: heterochronic shift in the caste differentiation pathways.

Background: Generally in termites, alates differentiate through multiple nymphal instars which gradually develop wing buds. However, in a dampwood termite, , alates molt directly from a single nymphal instar with short wing buds. In this study, to examine the mechanism underlying the wing formation during the alate differentiation in , histological and morphological observations were carried out on the developmental process of wing formation during the nymphal instar, in comparison with those in , which has two nymphal instars.

The activin signaling transcription factor Smox is an essential regulator of appendage size during regeneration after autotomy in the crayfish.

Members of the phylum Arthropoda, comprising over 80% of total animal species, have evolved regenerative abilities, but little is known about the molecular mechanisms mediating this process. Transforming growth factor β (TGF-β) signaling mediates a diverse set of essential processes in animals and is a good candidate pathway for regulation of regeneration in arthropods. In this study we investigated the role of activin signaling, a TGF-β superfamily pathway, in limb regeneration in the crayfish.

Dynamics of vitellogenin and vitellogenesis-inhibiting hormone levels in adult and subadult whiteleg shrimp, Litopenaeus vannamei: relation to molting and eyestalk ablation.

Levels of vitellogenin (VG) and vitellogenesis-inhibiting hormone (VIH) in the whiteleg shrimp, Litopenaeus vannamei, were measured by time-resolved fluoroimmunoassay in relation to the molting cycle and ovarian maturation induced by eyestalk ablation. During the molt cycle, VG mRNA expression levels and VG concentrations showed similar patterns of fluctuation. VG levels increased significantly at early intermolt (stage C0) in adults, but not in subadults.

Molecular cloning of prophenoloxidase and the effects of dietary β-glucan and rutin on immune response in hemocytes of the fleshy shrimp, Fenneropenaeus chinensis.

To investigate the effects of dietary β-glucan (0.5 or 1 g kg⁻¹ diet: 0.5-BG, 1-BG) and rutin (0.

Metabolism of amino acids during hyposmotic adaptation in the whiteleg shrimp, Litopenaeus vannamei.

The penaeid prawn, Litopenaeus vannamei, was employed to investigate intracellular isosmotic regulation in situations where invertebrates encounter hyposmosis. Hemolymph osmolality was first analyzed to confirm osmoregulatory conditions in the experimental animals, followed by analysis of amino acids in muscle and hemolymph using high-performance liquid chromatography. Total muscle amino acid levels decreased when hemolymph osmolality was extremely low, whereas glycine and L-serine levels increased in the hemolymph.