D.P. Taylor

The Biology of Meloidogyne Naasi

Meloidogyne naasi one-celled eggs required 15-17 days at 22-26°C to develop into second-stage larvae. The first molt occurred inside the egg 8 1 /2-11 days after the first cleavage. Larvae became sedentary in 2-3 days after penetration. Sex differentiation first became apparent on the 12th day, and the second molt was first observed on the 18th day. All three superimposed molts followed each other between the 18th and 24th day. Oviposition started between the 30th and 35th day after penetration of the host plant. At 26° day and 20° night temperature, the life cycle of M. naasi on wheat, var. Pawnee, was completed in 39-51 days.

Biology of Paroigolaimella Bernensis and Fictor Anchicoprophaga (Diplogasterinae) in Laboratory Culture

Members of seventeen of the twenty nematode genera isolated from the waste treatment piant at Urbana, Illinois, could be reared in the laboratory on bacterial-amoebic or nematode cultures. Morphometrics of laboratory populations of Fictor anchicoprophaga and Paroigolaimella bernensis differed considerably from those of populations collected in nature. Eggs of P. bernensis exhibited holoblastic spiral mode of division during development. Generation time varied from 46-48 hours at 30°C to 90-100 hours at 15° for P. bernensis and from 40-44 hours at 35° to 160-178 hours at 15° for F. anchicoprophaga. Maximum populations were reached in shorter times at higher temperatures for these two species and declined sharply after the maximum was reached. Progeny of five females averaged about 18,000 for each species after 10 days at 20°.

Influence of Fungi On Host Preference, Host Suitability, and Morphometrics of Five Mycophagous Nematodes

Influence of ten fungi was studied on host preference, host suitability, and morphometrics of a parthenogenetic and a bisexual isolate of a species of Ditylenchus resembling D. triformis, and one isolate each of Neotylenchus lin f ordi, Aphelenchus avenae, and Paraphelenchus acontioides. Consistent differences in numbers of nematodes recovered from two young fungal colonies located at opposite sides of a dish 18 hours after the nematodes were introduced were too great to be explained as random distribution. None of the fungi tested repulsed any of the nematodes. Five of the fungi tested were rated as excellent hosts for most of the nematodes, two as good hosts, two as poor, and Pythium irregulare as a nonhost. Nematode morphometrics varied considerably within populations reared on a single fungus and between populations reared on different fungi. Position of the vulva varied the least of the five values studied, varying only 1.3% from the mean in N. linfordi. No consistent correlation was found between host preference, host suitability and morphometrics.

Butlerius Micans N. Sp. (Nematoda: Diplogasterinae) From Illinois, With Observations On Its Feeding Habits and a Key To the Species of Butlerius Goodey, 1929

Butlerius micans n. sp. is characterized by the presence of prominent transverse ridges in the lumen of the procorpus and by the short pro-mesorhabdion. This nematode was reared in the laboratory on bacterial-amoebic cultures as well as Aphelenchus avenae. An account of the feeding habits of this predacious nematode is given.

Feeding Mechanisms of Aphelenchoides Bicaudatus On Three Fungi and an Alga

A comparison of the feeding mechanisms of A. bicaudatus was made on the fungi, Pyrenochaeta terrestris, Sporobolomyces sp., Hansenula saturnus, and the alga, Stichococcus bacillaris. The nematode fed briefly and the feeding mechanism, involving an exploration and penetration phase and an ingestion phase, was similar on all four microorganisms. A. bicaudatus removed the host cell contents mechanically and no injection of glandular secretions into the cell by the nematode was observed. The nematode oriented its stylet against the cell wall at a right angle to the cell surface and only a minimal lip contact with the cell surface was necessary for penetration. Metacorporal pulsations were associated with stylet protrusion and resulted from action of its radial muscles. Duration of feeding, number of thrusts required for penetration and rate of metacorporal pulsations varied with the organism used as food. Feeding on P. terrestris, Sporobolomyces sp., H. saturnus and S. bacillaris on an average lasted for 21, 28, 4 and 5 sec, respectively. A recurrent contraction and re-elongation of the tail region caused a back and forth movement of intestinal lumen contents.

Effect of Temperature On the Time Required for Hatching and Duration of Life Cycle of Five Mycophagous Nematodes

The effect of seven temperatures between 10 and 30° C was studied on the shortest time required for hatching, development to egg-laying females, and completion of one generation using Aphelenchus avenae, Neotylenchus lin f ordi, Paraphelenchusacontioides, and two isolates of a species of Ditylenchus. Minimum time required for the first egg to hatch and the first larva to develop to an egg-laying female in any one of the replicates was used as the criterion for assessing the effect of temperature on hatching and duration of life cycle. Time necessary for each process decreased as temperature increased until a minimum was reached above which the time required again increased or the temperature was lethal. The shortest generation times were at 25° for N. linfordi, 30° for the two isolates of Ditylenchus sp., and 35° for A. avenae and P. acontioides. No development occurred at 39° for any species, and although hatching occurred at 10°, in no case was the life cycle completed during the course of the experiment.

Mononchoides Changi N. Sp. and M. Bollingeri N. Sp. (Nematoda: Diplogasterinae), From a Waste Treatment Plant 1 )

Mononchoide.r changi n. sp. is characterized by a curved, doubly notched plate with a singly notched dorsal section, large phasmids in both sexes, gubernaculum narrow with a constriction 2/5 distance from anterior end, and eight or nine pairs of caudal setae on the male. M. bollingeri n. sp. has a doubly notched curved plate with the dorsal section modified to a long tooth, the anterior part of the gubernaculum is short and not set off by a constriction, there are ten pairs of caudal setae on the male, and large phasmids are present in both sexes.

Observations On Molting in Species of Cylindrocorpus

Molting in species of Cylindrocorpus is a stepwise process involving separation of the old lip regions from the rest of the stomal components accompanied by differentiation of the new lip regions, loss of refractivity in the stomal and esophageal regions, further retraction of the head region accompanied by resclerotization of the stomal and esophageal regions and rupturing and casting of the old cuticle with subsequent release of the next developmental stage. The vaginal lining is initially laid down in the pre-adult stage and is not shed with the body cuticle. The cuticular linings of the corpus are defecated.

Emendation of the Genus Demaniella Steiner, 1914 (Nematoda: Diplogasterinae), With Observations On the Biology of D. Basili N. Sp

Structure of the lips, labial papillae, and cheilorhabdions in the genus Demaniella is described and the genus is redefined to include these details. A new species, D. basili, is described which is characterized by the presence of 10 caudal papillae and by the absence of a proximal cap on the gubernaculum. Duration of the life cycle of this nematode in bacterial-amoebic cultures varied from 41/2-5 days at 30°C to 18-20 days at 10°. Populations derived from 5 females and 10 males exceeded 48,000 after 2, 4, and 5 weeks at 30°, 25°, and 20°, respectively.

A Redescription of Aphelenchoides Bicaudatus (Imamura, 1931) Filipjev & Schuurmans Stekhoven, 1941 (Nematoda: Aphelenchoididae), With a Description of the Previously Undescribed Male

Aphelenchoides bicaudatus (Imamura, 1931) Filipjev & Schuurmans Stekhoven, 1941, a mycophagous species, is redescribed. The male is described. Sexual dimorphism is present in the tail shape; the female tail terminus is bifurcated, whereas the male tail terminates in a single mucro. In both A. bicaudatus and A. hainanensis (Rahm, 1938) T. Goodey, 1951 females have a bifurcated tail terminus. However, A. hainanensis is 2-2.5 times longer, fairly slender, relatively shorter in esophageal and tail lengths, and males as well as females have a bifurcated tail tip.