Concomitancy of Entomophilous and Soil Transmitted Nematodes in Selected Insects

Aim: To determine the occurrence of entomophilous and soil transmitted nematodes of three insect species; Zonocerus variegatus, Gryllotalpa orientalis and Mantis religiosa in Obio Akpor, Local Government Area of Rivers State, Nigeria. Methodology: The insect samples were collected with entomological sweep net as described by Colwell [1] and pitfall traps as described by Davies [2]. Insect samples were dissected using Stubbins’ method [3] while nematodes in the insects were isolated and identified according to Cheesborough, (2005). Results: Two hundred and forty-eight (248) insect specimens comprising; Z. variegatus 193 (77.8%), G. orientalis 42(16.9%) and Mantis religiosa 13(5.2%) were collected from designated ecological settings based on availability and trapping efficiency. Out of the 248 insects sampled; 145 (58.5%) were infected with three genera of nematodes comprising; Ascaris lumbricoides; 17 (7.5%), Mermis Spp., 148 (65.5%) and Trilabiatus lignicolus 61(27.0%). Mermis Spp., an entomophilous nematode occurred in Z. variegatus and Mantis religiosa due to host specific factors. Nematode occurrence in the host did not indicate sex relationship (P>0.05) however, hosts age influenced parasite occurrence as older insects harbored more parasites (P<0.05). Trilabiatus lignicolus; a free-living soil nematode and A. lumbricoides; a soil transmitted helminthes found in the guts of Z. variegatus and G orientalis was attributed to the feeding habits of the insects. Conclusion: The study indicated that Z. variegatus and G. orientalis as veritable vectors of soil transmitted nematodes while Z. variegatus and Mantis religiose are suitable host of the entomophilous nematode Mermis Spp.

An analysis of the horizontal burrow morphology of the oriental mole cricket (Gryllotalpa orientalis) and the distribution pattern of surface vegetation

Food acquisition in animals that construct burrows for foraging is influenced by burrow structure associated with food distribution and searching patterns. The burrowing patterns of the oriental mole cricket ( Gryllotalpa orientalis Brumeister, 1838) (Orthoptera: Gryllotalpidae) were investigated based on analyses of the relation between burrow morphology and plant distribution. To assess differences between horizontal burrows (HB) with and without vertical burrows (VB), the number of branching points, the length of the horizontal parts, the plant ratio of the burrow area, and the burrow fractal dimension were compared. The size of the burrow area was positively related to the degree of branching. Cyperaceae and Gramineae occurred less frequently, whereas Hydrocotyle sibthorpioide Lam. and areas with no plants were more frequent in the burrow area than in the quadrat area. Juncaceae and Persicaria thunbergii (Siebold and Zucc.) H. Gross ex Nakai occurred more frequently and Lindernia crustacea (L.) F. Muell. occurred less frequently in HB without VB than in HB with VB. The ratio of burrow length to the number of branching points was not significantly different between HB with or without VB. HB with VB had a nearly planar structure (higher burrow fractal dimension) than that of HB alone. HB structure and plant composition of the burrow area differed depending on the presence of VB.