History of entomopathogenic nematology.

The history of entomopathogenic nematology is briefly reviewed. Topic selections include early descriptions of members of Steinernema and Heterorhabditis, how only morphology was originally used to distinguish between the species; descriptions of the symbiotic bacteria and elucidating their role in the nematode- insect complex, including antibiotic properties, phase variants, and impeding host defense responses. Other topics include early solutions regarding production, storage, field applications and the first commercial sales of entomopathogenic nematodes in North America. Later studies centered on how the nematodes locate insect hosts, their effects on non-target organisms and susceptibility of the infective juveniles to soil microbes. While the goals of early workers was to increase the efficacy of entomopathogenic nematodes for pest control, the increasing use of Heterorhabditis and Photorhabdus as genetic models in molecular biology is noted.

Ultrastructure of 40-million-year-old insect tissue.

Examination of the ultrastructure of preserved tissue in the abdomen of a fossil fly (Mycetophilidae: Diptera) entombed in Baltic amber revealed recognizable cell organelles. Structures that corresponded to muscle fibers, nuclei, ribosomes, lipid droplets, endoplasmic reticulum, and mitochondria were identified with the transmission electron microscope. Preservation was attributed to inert dehydration as well as the presence of compounds in the original sap which functioned as natural fixatives. This evidence of cell organelles in fossilized soft tissues represent an extreme form of mummification since Baltic amber is considered to have formed about 40 million years ago.

Upper eocene gilled mushroom from the dominican republic.

Coprinites dominicana gen.nov., spec.nov. (Coprinaceae) found in amber from the Dominican Republic is the earliest known gilled mushroom, the first fossil fleshy agaric determinable, and the only kiiown fossil "mushroom" (Agaricales) from the tropics. This find is of significance with respect to the evolutionary development of the Basidiomycetes. Because the appearance of this fossil is quite modern, it suggests that mushrooms as a group probably arose much earlier than the early to mid-Tertiary.

An upper eocene frog from the dominican republic and its implication for Caribbean biogeography.

A frog of the leptodactylid genus Eleutherodactylus is reported from Eocene amber found in the Dominican Republic. It is the first described amphibian fossil in amber, and the oldest complete lissamphibian fossil from Mesoamerica (Central America and Mexico). Dating of the amber matrix indicates that by the end of the Eocene a diverse fauna was present in the Antilles, much earlier than has generally been proposed. The presence of this and other amber fossils from this same age suggests that Tertiary patterns of landmass movements were significant in determining the present distribution of species.

Terrestrial soft-bodied protists and other microorganisms in triassic amber.

Protozoa, cyanobacteria, sheathed algae, sheathed fungi, germinating pollen or spores, and fungal spores have been found in amber 220 to 230 million years old. Many of these microorganisms can be assigned to present-day groups. This discovery of terrestrial, soft-bodied protists that can be referred to modern groups indicates that morphological evolution is very gradual in many protists and that both structural and probably functional stasis extend back at least to the Upper Triassic period.

Mermis nigrescens (Mermithidae: Nematoda) recovered from the mouth of a child.

A gravid female Mermis nigrescens Dujardin (Mermithidae: Nematoda) was recovered from the mouth of a 1-month-old infant in Mehama, Oregon. This nematode is a parasite of grasshoppers and deposits its eggs on vegetation. The parasite was probably carried on the hair of the household dog or cat to the vicinity of the patient and was attracted to the moisture in the region of the mouth.

Serratia marcescens as a pathogen of tsetse flies.

When applied to the ears of rabbits used as hosts for tsetse flies, the bacterium Serratia marcescens produced significant mortality in populations of Glossina m. morsitans and G. pallidipes. After being ingested during the blood meal, cells of S. Marcescens multiplied in the intestine of the flies and entered the hemocoel. Using the brush method of applying the bacterium, 100% mortality of both Glossina species occurred within 10 days after application. In newly killed flies, the bacteria could be found free in the hemocoel as well as in the fat body and blood cells. The supernatant of a liquid culture of S. marcescens did not produce fly mortality when applied to rabbit ears. The results indicate that S. marcescens is able to invade the hemocoel of "normal" laboratory-reared tsetse flies.

Laboratory infection of blackflies (Simuliidae) and midges (Chironomidae) by the mosquito mermithid, Romanomermis culicivorax.

Penetrating infective juveniles of Romanomermis culicivorax usually killed first-stage larvae of Chironomus maturus Johann., Chironomus sp., Simulium damnosum Theo., and S. venustum Say. Nematodes were melanized and died after they entered fourth stage larvae of 2 chironomid species, but no host reaction was evident after entry into fourth-stage blackfly larvae. In contrast, the nematodes initiated development in the latter hosts, which died before the nematodes completed their development.

The fine structure of Gastromermis sp. (Nematoda: Mermithidae) sperm.

The development and morphology of the sperm of the mermithid nematode, Gastromermis sp. appears to be different than that reported for any other nematode sperm. The mature sperm of Gastromermis are elongate with membranous organelles surrounding an apical nuclear region. The mitochondria are arranged in parallel rows and form an elongate sheath. Spermatozoa contain dense tubular structures which have not been seen in other nematodes. Spermatids lack fibrous bodies. The pseudopodia of the spermatozoa are filled with microtubules. Centrioles seen throughout sperm development are composed of 9 doublets.

Heydenius dominicus n. sp. (Nematoda: Mermithidae), a Fossil Parasite from the Dominican Republic.

Heydenius dominicus n. sp. is described as a new species of fossil mermithid nematode from Dominican Republic amber. The species is represented by two specimens of parasitic juveniles that left their insect host and became embedded in the resin. The nematodes are associated with an adult male limoniid (Diptera: Limoniidae) and an adult female mosquito (Diptera: Culicidae). The parasites are thought to have emerged from the mosquito host. This is the first report of a fossil mermithid from a Neotropical area.

Praecocilenchus rhaphidophorus n. gen., n. sp. (Nematoda: Aphelenchoidea) Parasitizing Rhynchophorus bilineatus (Montrouzier) (Coleoptera: Curculionidae) in New Britain.

Praecocilenchus rhaphidophorus n. gen., n. sp. is described as a new endoparasitic aphelenchoid nematode parasitizing adults of the palm weevil, Rhynchophorus bilineatus (Montrouzier). P. rhaphidophorus is unusual in that juveniles develop to maturity within the female uterus and thin, needle-shaped crystals form in the intestines of mature parasitic females. Hundreds of parasitic female nematodes were found in the body cavity of infected hosts. The role of this parasite as a biological control agent of Rhynchophorus weevils is discussed.

Hexamermis cathetospiculae n. sp. (Mermithidae: Nematoda), a Parasite of the Rice Stemborer, Tryporyza incertulas (Wlk.) (Pyralidae: Lepidoptera) in Malaysia.

Hexamermis cathetospiculae n. sp. (Mermithidae: Nematoda), a parasite of the rice stemborer, Tryporyza incertulas (Wlk.), is described. This mermithid was observed to control the stemborer in Malaysia. It is distinguished from other members of the genus by the shape of the vagina, the nearly straight spicules, and the form of the amphids.

Drilomermis leioderma n. gen., n. sp. (Mermithidae:Nematoda) parasitizing Cybister fimbriolatus (Say) (Dystiscidae-Coleoptera).

The nematode Drilomermis leioderma n. gen., n. sp. (Merrnithidae) is described from larvae of Cybister fimbriolatus (Say) (Dytiscidae: Coleoptera) in Louisiana. Diagnostic characters of the genus Drilomermis are: medium-sized nematodes with the cuticle appearing smooth (lacking cross fibers) under the light microscope, six cephalic papillae, without mouth papillae, six hypodermal cords at midbody, 2 extremely long spicules (longer than 10 times body width at anus) which are separate and parallel (not twisted), an S-shaped vagina, medium-sized amphids located near head papillae, and postparasitic juvenile with a tail appendage. D. leioderma possesses a ventrally displaced mouth, very long vagina, and male genital papillae arranged in 3 double rows in the vicinity of the cloacal opening. Even when containing multiple parasites, about 40% of the hosts sulwived emergence of the memithids and lived several more days. In nature, some of these hosts may be able to continue their development, which is unusual since most mermithid-parasitized hosts die soon after the nematode emerges.

Rhabditis pellio Schneider (nematoda) from the earthworm, Aporrectodea trapezoides Duges (Annelida).

Studies were conducted on the behavior of the nematode, Rhabditis pellio, in the earthworm, Aporrectodea trapezoides, from southern California. Juvenile and adult nematodes were found in the bladders and tubules of the metanephridia of the host. Similar nematodes that entered the coelom were encapsulated and incorporated into multiple capsules ("brown bodies"). It was demonstrated that this host response is an effective defense reaction since dead and dying nematodes, as well as living forms, were found in the capsules.

Survival and Horizontal Movement of Infective Stage Neoaplectana carpocapsae in the Field.

Infective stage Neoaplectana carpocapsae were applied to a furrow of loam soil in the field. At regular intervals over a 7-week period, soil samples were taken at distances of 0, 10, 20, 30, and 40 cm on either side of the furrow. Live, infective nematodes were recovered from the soil at all sampling dates over the 7-week period, and nematodes slowly spread out from the original line of application, averaging a distance of 4.35 cm/day.

Susceptibility of Neoaplectana spp. and Heterorhabditis heliothidis to the Endoparasitic Fungus Drechmeria coniospora.

Adhesive conidia of the nematophagous fungus, Drechmeria coniospora (Drechsler) W. Gams and Jansson (Moniliales: Deuteromycetes), would occasionally attach but never penetrate the infective stages of insect parasitic Neoaplectana carpocapsae, N. glaseri, N. bibionis, N. intermedia, and Heterorhabditis helfothidis (Rhabditida). However, adult and pre-infective stages of Neoaplectana spp. became infected by the fungus.

Strelkovimermis spiculatus n. sp. (Mermithidae: Nematoda) Parasitizing Aedes albifasciatus Mac. (Culicidae: Diptera) in Argentina.

Strelkovimermis spiculatus n. sp. (Mermithidae: Nematoda), a parasite of the mosquito Aedes albifasciatus Mac. in Argentina, is described. Diagnostic characters of this species include a ventrally shifted mouth opening and spicules fused at the tips. The mermithid has been reared on Culex pipiens L. larvae in the laboratory.

Anatomy of the Pre-Parasitic Stage of Hydromermis conophaga (Mermithidae: Nematoda).

The anatomy of the preparasitic juvenile of Hydromermis conopophaga (Mermithidae: Nematoda) has been examined with the light and electron microscope. The alimentary tract consisted of an onchiostylet, pharyngeal tube, stichosome, and intestine. Paired penetration glands were associated with the anterior half of the stichosome. A total of 16 sensory papillae were found in this stage. Certain features, such as the character of the stylet and the attachment of the pharynx to the intestine, show that the preparasitic juvenile more than any other stage in its life cycle closely resembles a free-living dorylaimoid nematode.