Heterotylenchus

Heterotylenchus	Contents	Rev: 02/23/2024
	Classification	Biology and Ecology
	Morphology and Anatomy	Life Cycle
Return to Heterotylenchus Menu		Ecosystem Functions and Services
	Distribution	Management
Return to Parasitylenchidae Menu	Feeding	References
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Rhabditida

Tylenchina/Hexatylina

Sphaerularioidea

Parasitylenchidae

Heterotylenchus Nickle, 1967

Type species of the genus: Heterotylenchus aberrans Bovien, 1937

Synonyms:

Morphology and Anatomy:

Characteristics of Heterotylenchus autumnalis as an example of the genus:

Heterosexual female:

Inhabiting fly ovaries and manure piles.
Stylet well de veloped, with dorsally oblique aperture, without knobs.
DEGO about a stylet-length posterior to the stylet base.
Esophagus with prominent, overlapping glands which extend to mid-body. Median bulb absent.
Intestine degenerate. Anus barely visible.
Gonad typically sphaerulariid, consisting of a two-celled ovary, short, slim oviduct, and a large tubular uterus packed with large, single-celled sperm.
Tail tapers gradually to a rounded point.

Heterosexual male:

Inhabiting insec ovary and manure.
Stylet similar to but not as well developed as in the female.
Esophagus weakly developed. Median bulb absent.; esophageal glands not easily seen but overlap intestine
Gonad single, well developed, not flexed. Sperm larger than most sphaerulariids,
Spicules large, with long shaft and wide scoop-like tip. Gubernaculum absent.
Caudal alae adanal. Tail tip tapers gradually to a rounded tip

Parthenogenic female:

Inhabiting body cavity of insect.
Cuticle thin and smooth. Somatic musculature with prominent nuclei. Lip region slightly offset.
Stylet as in free-living female, without knobs.
Esophagus degenerate, gland orifices as in free-living female. Intestine large, granular in appearance, fills most of body cavity, and probably contains reserve food. Anus not prominent.
Oviparous.
Gonad less well developed than other sphaerulariids. Produces about 24 eggs.
Ovary extends less than half the body length.
Tail tip with characteristic spike

Ref: Nickle, 1967

Heterotylenchus autumnalis. 1: Female lateral view; 2. Membrane-like evagination of excretroy pore; 3.. Male lateral view; 4. Spicules and caudal alae, ventral view. Bar = 50 microns
Drawings from Nickle, 1967

Males:

Body size range for the species of this genus in the database - Click:

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Distribution:

:Heterotylenchus autumnalis is a nematode parasite of the face fly, Musca autumnalis De Geer, which was introduced into North America from Europe. The face fly affects horses and cattle.

The nematode is reported infecting face flies in New York, New Jersey, Missouri, and Nebraska, It causes sterility of the insect female.

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Feeding:

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Life Cycle:

Heterotylenchus is considered a heteromorphic genus, with alternation of gamogenetic and parthenogenetic generations. An infected female face fly may contain adults, ljuveniles and eggs of the nematode.

In the gametogenic phase of the nematode, the ovaries of the female fly become packed with males and unmated females in regions of the gonad usually occupied by eggs. During oviposition behavior, female flies deposit packets of nematodes into manure piles. The males of the "oviposited" nematodes mate and then the male dies; the impregnated young female nematodes enter the body cavity of the fly maggot, apparently through the body wall.

Once inside the maggot, the nematode develops into the adult parasitic stage which lays eggs in the hemolymph. Those eggs develop into parthenogenetic females. The parthenogenetic females lay large numbers of eggs which in turn develop into the small males and females. When they develop to a length of about 1 mm, they penetrate the insect ovaries, completing the life cycle (Nickle, 1967).

For Ecophysiological Parameters for this genus, click