Effects of Chemical Substances on Rate of Locomotion in the Amoeba Mayorella penardi1

The relationship between the locomotive velocity of amoeba which had not been fed for 24 h and the concentration of the test solutions was examined. With solutions of L-amino acids, protein substances, and alcian blue 8GS, an increase in velocity began at very low concentrations, reaching a maximum at a higher concentration and as the concentration increased further, the velocity fell to zero. In contrast, no increase was observed with D-glutamic acid and β-alanine. Moreover, the velocity of well fed amoebae did not increase significantly even in L-amino acid solution. These results may suggest a correlation between orthokinesis and amoeboid phagocytosis.     

A danaid butterfly, Ideopsis similis, overcomes parasitization by a tachinid fly, Sturmia bella

The danaid butterfly Ideopsis similis, which occurs in the Ryukyu Islands, Japan, is a sedentary and monophagous species, whose larval food plant, Tylophora tanakae (Asclepiadaceae), is shared with the migratory and polyphagous danaid Parantica sita. The tachinid Sturmia bella is known to be a principal parasitoid of larval P. sita, whereas there have been no records of parasitization of I. similis by this tachinid. We conducted laboratory experiments and field surveys at seven sites in the Ryukyu Islands to determine how I. similis evades parasitization by this tachinid. We found eggs of S. bella at four sites and eggs and/or larvae of I. similis on the leaves of T. tanakae at all seven sites in the field survey. Out of 40 I. similis allowed to ingest S. bella eggs, 28 (70%) emerged as normal host adults and nine (22.5%) emerged as host adults with crippled wings. Only three (7.5%) died of parasitization in the pupal stage, whereas 27 (87%) of 31 P. sita given S. bella eggs yielded parasitoid flies and eventually died. Melanized dead larvae of S. bella were found in the abdomens of the I. similes adults that had been parasitized but did not yield parasitoid flies. When I. similis females parasitized by S. bella were released in a greenhouse with males, one of them laid fertile eggs. Out of 125 field‐collected I. similis adults, nine had melanized dipteran larvae within their abdomens, which were considered to be S. bella. These results demonstrate that I. similis has the ability to overcome parasitization by S. bella and develop into a fertile adult. It is possible that I. similis remains sedentary and monophagous because it has a strong defense mechanism against S. bella, whereas P. sita escapes from parasitization using its migratory and polyphagous capability.     

Scanning Electron Microscopy of the Adoral Ciliary Zone of Entodinium Stein (Ciliophora,Entodiniomorphida)1

The adoral ciliary zone of the rumen ciliates, Entodinium spp., was observed topographically in the SEM. The upper side of the anterior end of the body was indented by the vestibulum, which had cilia arranged on its right wall and ribs along the left wall. The adoral ciliary zone could be divided into at least two arrangements. The outer ciliary zone had many membranelle-like structures, which consisted of cilia arranged radially from the body axis. Each membranelle-like structure consisted of two rows of about eight cilia each lining up in a single file. It was, however, different from a typical membranelle, because its cilia were connected with the vestibular cilia and were arranged not spirally but on a plane. These cilia extended toward the outside because of the projecting cytoplasm from which they originated. In contrast, the cilia of the inner ciliary zone were aggregated to form relatively unsystematic bundles. Since the vestibular opening was slanted on the upper side of the body, the ciliary bundles were thick on the lower side and sparse on the upper side of the body. Neither outer nor inner ciliary zones completely surrounded the vestibular opening. The ciliature started from the left side of the vestibular opening, encircled the lower side of the body, and entered the vestibulum from its right side. The functions of these two types of ciliary arrangements are discussed.     

Points of view: Introduction of spawning potential: improvement in the threshold management theory

Reviews in Fish Biology and Fisheries -