Chapter 3
Historical Aspects
Abstract
Entomopathogenic nematodes of the genus Steinernema and Heterorhabditis do not have a select shared
ancestry. They independently established relationships with bacteria and insects from disparate, unrelated
ancestors. The diversity and distribution of the families Steinernematidae and Heterorhabditidae entomopathogenic nematodes are widespread in every continent except in Antarctica. In 1923, Steiner described
the first entomopathogenic nematode. All species of Steinernema have mutualistic associations with
Xenorhabdus species and all species of Heterorhabditis have symbiotic associations with Photorhabdus
species. S. glaseri was the first mass produced nematode and used under field conditions for biological
control of an insect pest.
Keywords proto-Rhabditonema, Biogeography, Habitat, Steinernema, Heterorhabditis, Xenorhabdus, Photorhabdus, Systematic
1 Evolution
l
The bio-safe eco-user entomopathogenic nematodes Steinernema and Heterorhabditis are one among the ancient species
which are considered to be evolved 375 million years ago from
a mid-Paleozoic origin.
l
The independent, converging evolution of Steinernema and
Heterorhabditis produces alike morphology and life history
attributes.
l
Based on the similarity between the male tail morphology and
the buccal capsule, it is believed that Steinernema arose from the
“proto-Rhabditonema” ancestor in the terrestrial environment
and Heterorhabditis developed from the “Pellioditis-like” ancestor in the sandy, aquatic environment [3, 4].
l
Steinernema and Heterorhabditis do not have an exclusive shared
ancestry. They independently established relationships with bacteria and insects from disparate, unrelated ancestors [5–8].
S. Sivaramakrishnan and M. Razia, Entomopathogenic Nematodes and Their Symbiotic Bacteria, Springer Protocols Handbooks,
https://doi.org/10.1007/978-1-0716-1445-7_3,
© The Author(s), under exclusive license to Springer Science+Business Media, LLC, part of Springer Nature 2021
7
Historical Aspects
Abstract
Entomopathogenic nematodes of the genus Steinernema and Heterorhabditis do not have a select shared
ancestry. They independently established relationships with bacteria and insects from disparate, unrelated
ancestors. The diversity and distribution of the families Steinernematidae and Heterorhabditidae entomopathogenic nematodes are widespread in every continent except in Antarctica. In 1923, Steiner described
the first entomopathogenic nematode. All species of Steinernema have mutualistic associations with
Xenorhabdus species and all species of Heterorhabditis have symbiotic associations with Photorhabdus
species. S. glaseri was the first mass produced nematode and used under field conditions for biological
control of an insect pest.
Keywords proto-Rhabditonema, Biogeography, Habitat, Steinernema, Heterorhabditis, Xenorhabdus, Photorhabdus, Systematic
1 Evolution
l
The bio-safe eco-user entomopathogenic nematodes Steinernema and Heterorhabditis are one among the ancient species
which are considered to be evolved 375 million years ago from
a mid-Paleozoic origin.
l
The independent, converging evolution of Steinernema and
Heterorhabditis produces alike morphology and life history
attributes.
l
Based on the similarity between the male tail morphology and
the buccal capsule, it is believed that Steinernema arose from the
“proto-Rhabditonema” ancestor in the terrestrial environment
and Heterorhabditis developed from the “Pellioditis-like” ancestor in the sandy, aquatic environment [3, 4].
l
Steinernema and Heterorhabditis do not have an exclusive shared
ancestry. They independently established relationships with bacteria and insects from disparate, unrelated ancestors [5–8].
S. Sivaramakrishnan and M. Razia, Entomopathogenic Nematodes and Their Symbiotic Bacteria, Springer Protocols Handbooks,
https://doi.org/10.1007/978-1-0716-1445-7_3,
© The Author(s), under exclusive license to Springer Science+Business Media, LLC, part of Springer Nature 2021
7