''Howardula'' is a genus of

nematode The nematodes ( or ; ; ), roundworms or eelworms constitute the phylum Nematoda. Species in the phylum inhabit a broad range of environments. Most species are free-living, feeding on microorganisms, but many are parasitic. Parasitic worms (h ...

that infests the larvae of mushroom-feeding flies, beetles, and other insects. Various ''Howardula'' species and strains infest

mushroom-feeding Drosophila Mushroom-feeding ''Drosophila'' (mycophagous ''Drosophila'') are a subset of ''Drosophila'' flies that have highly specific mushroom-breeding ecologies. Often these flies can tolerate toxic compounds from ''Amanita'' mushrooms. Species groups ...

, including '' Howardula aoronymphium'' and '' Howardula neocosmis''. '' Howardula husseyi'' can infest the mushroom phorid ''

Megaselia halterata The mushroom phorid fly ''(Megaselia halterata)'' is a species of scuttle fly or hump-backed flies in the family Phoridae. "The mushroom phorid" is also used to refer to ''M. halterata''. ''Megaselia halterata'' is a common pest of mushroom cult ...

''.

Life cycle

The life cycle of ''Howardula'' nematodes begins inside the host fly, where infective juvenile nematodes are released by either the fly anus or ovipositor onto mushrooms. There, the juvenile nematodes mature and mate. Mated females will then pierce the cuticle of a fly larva using a specialized stylet, and enter the fly

hemolymph Hemolymph, or haemolymph, is a fluid, similar to the blood in invertebrates, that circulates in the inside of the arthropod's body, remaining in direct contact with the animal's tissues. It is composed of a fluid plasma in which hemolymph c ...

(insect blood) where the nematode resides. Over the course of the fly host's metamorphosis, the female nematode matures into an adult stage called the motherworm. After the adult fly emerges from its

pupa A pupa (; : pupae) is the life stage of some insects undergoing transformation between immature and mature stages. Insects that go through a pupal stage are holometabolous: they go through four distinct stages in their life cycle, the stages th ...

, the motherworm begins releasing juvenile nematodes directly into the

hemocoel In vertebrates, the circulatory system is a organ system, system of organs that includes the heart, blood vessels, and blood which is circulated throughout the body. It includes the cardiovascular system, or vascular system, that consists of ...

, renewing the cycle. Other insect-infecting nematodes such as ''

Steinernema ''Steinernema'' is a genus of nematodes in the family of Steinernematidae. The genus ''Steinernema'' is named after the nematologist Gotthold Steiner. Nematodes of this genus have been shown to be effective as a biological control for agricult ...

'' and '' Heterorhabiditis'' are used as biological control agents, as they efficiently kill their insect prey. However ''Howardula'' species require their hosts to survive into adulthood. As such, while ''Howardula'' infects insects like other nematode parasites, the "goals" of these nematodes differs drastically, leading to distinct host-parasite interactions.

References

{{Taxonbar, from=Q5265307 Tylenchida Secernentea genera

Life cycle

See also

References