Ecology of the dorylaimid omnivore genera Aporcelaimellus, Eudorylaimus and Mesodorylaimus

Abstract

Eudorylaimus, Aporcelaimellus and Mesodorylaimus are dominant members of the omnivorous nematode fauna in Florida, USA. Ecological studies that included numerical data on these genera were reviewed to determine key aspects of their ecology and behaviour. These three genera were also the dominant omnivores in many parts of Europe and often occurred together. Multiple species within genera may be present in samples as well. Although results varied with habitat, these omnivores were present in nearly all stages of succession but often reached their greatest numbers in later stages of succession such as old-growth forests. They also showed remarkable adaptation to extreme environments, including Antarctic habitats, dune sands and temperate sites without vegetation. They were found in a variety of soil typés but limited by soil pH < 4.0. Compared with other nematode taxa, they were among the genera most sensitive to moisture levels in sandy soils and to pollution by heavy metals. Some reports also indicated adverse impacts from inorganic fertilisers and other agrichemicals. Much remains unknown about the ecology of these common nematodes, which are widely distributed in soil ecosystems.

Effect of forest and field habitat features on abundance of genera in nematode assemblages

“…Similar results may be expected from the dorylaimid omnivores that are often common in forests (Hanël, 2008;McSorley, 2012) but Fudorylaimus and Mesodorylaimus were more common in grass habitats in the current study. However, some dorylaimid omnivores are colonisers, and occurrences in both early and older successions may result from different species within these genera (Hanël, 2010;McSorley, 2012).…”

“…While data sets at genus or family level provide much information about nematode assemblages, they raise additional questions as well. Multiple species within genera occur in many locations and their ecological behaviour can vary greatly (Bernard, 1992;Hanël, 2010;McSorley, 2012). Additional detail at species level will likely be needed to better interpret "conflicting" behaviour and trends within genera.…”

Stable isotope analysis (δ13C andδ15N) of soil nematodes from four feeding groups

“…Omnivores had a larger SEAc (isotopic niche width) suggesting a wider trophic niche and thus assimilation of a variety of resources, adhering to their definition in nematology as generalist feeders. This reflects the feeding by omnivores reviewed by McSorley (2012) and assumed by Yeates et al (1993) who described omnivores as feeding widely on fungal, deposit, bacterial and predatory reserves from non-nematode and nematode sources. Using the biplot and Convex hull ( Table 3 ) overlaps between omnivores and bacterial feeders, there is a suggestion that omnivores and bacterivores occupy the same trophic level (second highest).…”

Identification and Abundance of Plant-parasitic Nematodes Associated with Amenity Trees in the University of Port Harcourt, Rivers State, Nigeria

“…Also, Aporcelaimus species of the family Aporcelaimidae and Mesodorylaimus species (Dorylaimidae) classified as omnivores and predators (Andrassy, 2000;McSorley, 2012) are just being reported first in the rhizospheres of trees in Nigeria. The presence of these two nematode species has been linked to ecosystems in nearly all stages of succession, but they have their highest population at the later stages of succession especially in soils of old-growth forests (McSorley, 2012). They have strong adaptation to extreme environment, but are limited by soil with low PH, use of inorganic fertilizers and other agrochemicals.…”