Wood Baits Research Articles

Resource acquisition by the mycelial-cord-former Stropharia caerulea: effect of resource quantity and quality

Saprotrophic mycelial-cord-forming basidiomycetes, which extend between organic substrata on the forest floor, exhibit remarkable patterns of reallocation of biomass and nutrients when encountering new resources. These have been equated with foraging strategies, and differ between species, resources quality and quantity. Stropharia caerulea occupies more disturbed sites than the fungi previously examined, and the responses of its mycelial foraging systems were investigated non-destructively by image analysis. Resource quantity and quality affected extension rate, extra-resource biomass production and distribution, as quantified by box-count fractal dimension. When mycelia grew from 0.5 cm 3 beech ( Fagus sylvatica) wood inocula across compressed, non-sterile soil to 0.06–4 cm 3 uncolonised sterile beech wood "baits" extension rate fell after contact with large wood baits but biomass production and mycelial distribution was unaffected. In contrast, extension rates of cord systems grown from 0.15 cm 3 U. dioica rhizome inocula to 0.1–1.2 cm 3 rhizome "baits" were unaffected after contact with equal or larger sized baits, but biomass production rates fell and mass fractal dimension increased. Mycelial morphology was affected by inoculum age; systems grown from 84 day old 0.5 cm 3 beech wood inocula took 10 days longer achieving the fractal values of systems developing from 22 day old inocula. Foraging strategies and resource relations of mycelial cord systems are discussed.

The gaseous environment of mound colonies of the subterranean termite Coptotermes lacteus (Isoptera: Rhinotermitidae) before and after feeding on mirex-treated decayed wood bait blocks

AbstractCarbon dioxide, carbon monoxide, chloroform, hydrogen, methane and nitrous oxide emissions were collected from within several mound colonies of the subterranean termite Coptotermes lacteus (Fgottatt) and the surrounding habitat of a dry sclerophyll forest in central Gippsland, Australia, following treatment of the termite mounds with mirex-treated bait blocks. All the mirex-treated colonies died within two weeks of commencing active feeding on the bait blocks. The flux measurements of the gaseous emissions were calculated before, during and after treatment with the mirex-treated decayed wood bait blocks. Carbon dioxide, methane and hydrogen all declined after colony death.

Sequential encounter of wood resources by mycelial cords of Phanerochaete velutina: effect on growth patterns and phosphorus allocation

summaryThe effect of sequential encounter with wood resources (1 cm3 and 2 cm3‘baits’ in various combinations) by mycelial cords of Phanerochaete velutina (DC.: Pers.) Parmasto growing from 1 cm3 wood inocula was investigated in model soil systems in the laboratory. Encountering large wood baits (8 cm3), either next to the inoculum or after encounter of another bait, resulted in cessation of mycelial extension and regression of mycelium from the inoculum and small baits. Small wood baits had no effect on mycelial extension rates, even when encountered in rapid succession. All systems maintained a general polarity when growing out from a bait, but later often curved around the bait, extending over soil which had previously been explored. Allocation of 32P (taken up by the inoculum) between the three resource units (inoculum and two sequentially encountered baits) was investigated; significantly (P≤ 0.05) more 32P was allocated to the large wood baits (whether encountered first or second) than to the other bait; but the inoculum was usually allocated most. Wood inocula decayed more rapidly than baits. The significance of the results is discussed in relation to foraging.

Carbon translocation in mycelial cord systems of Phanerochaete velutina (DC: Pers.) Parmasto

SUMMARYMovement of radiotracer was monitored in mycelial cord systems developed from wood block inocula, pre‐colonized by Phanerochaete velutina (DC: Pers.) Parmasto grown on unsterile soil. In short‐term studies, reproducible but low‐level loading of radiotracer was observed which was independent of the extent of cord systems. Carbon translocation velocities ranged from 132 to 336 cm h‐1, whilst fluxes were estimated to range from 35 to 66 nmol cm‐2 h‐1 (as glucose). When cord systems were supplied with a range of potential carbon resources as baits considerable movement of carbon was detected over 9 wk. More than 80 % of exogenously supplied carbon was retained in resource units rather than being allocated to extra‐resource mycelium. The direction and extent of carbon movement, and partitioning of decay between inocula and baits within cord systems, was dependent upon the type and size of bait and whether or not combinations of baits included wood pre‐colonized by other sapro trophic fungi. There was evidence for coordinated use of resources within cord systems and that carbon movement was not a function of mycelial growth. Respiratory carbon losses were greatest when baits included sterile leaf litter packs and least when sterile wood baits were supplied. The results are discussed in terms of nutrient conservation and cycling in cord systems.

Wood decay, and phosphorus and fungal biomass allocation, in mycelial cord systems

summaryWood block inocula, of different decay states, colonized by Phanerochaete velutina (D.C.: Pers.) Parmasto and Phallus impudicus (L.) Pers., were supplied with [32P]orthophosphate 1 wk after mycelium had made contact with newly supplied sterile wood baits. Inoculum decay state affected the initial pattern of mycelial outgrowth, biomass, phosphorus uptake and subsequent decay rates of newly supplied baits. P. velutina and P. impudicus translocated up to 75 and 13 % respectively of phosphorus accumulated by the inoculum to the new supplied bait, translocation being in proportion to the decay state of the inoculum. On contact with baits, biomass was preferentially allocated to connective rather than non‐connective mycelium. This was accompanied by regression of non‐connective mycelium, which depended on the decay state of the inoculum. Phosphorus movement via connective cords was up to ten times higher in non‐connective cords, maximal rates of 7225 nmol P cm−2 d−1 being recorded for cords from the most decayed P. velutina inocula.

The foraging activity of subterranean termites in the Kuwait Desert

Termite foraging activity was tested in four localities in Kuwait, using wood baits. Psammotermes hybostoma Desneux and Anacanthotermes sp., probably A. vagans (Hagen), were the dominant species. Two activity peaks were recorded, one in February and the other in September. There was a positive correlation between termite activity and soil moisture content. Possible nest sites and frequency of bait infestation were determined. Analysis of the physical and chemical soil properties revealed some relationship between these properties and termite species domination.

Colonization of wood substrates by the aquatic xylophage Xylotopus par (Diptera: Chironomidae) and a description of its life history

Xylotopus par populations were monitored in a central Michigan stream during the summer growth period by sampling two types of indigenous logs and four types of introduced wood block "baits." Populations of larvae in the two indigenous logs were very similar over the course of the study with regard to number of individuals, biomass accumulation, developmental rate, and spatial distribution within colonized areas. Populations of larvae in the wood baits followed trends in density and biomass accumulation that differed between wood types. A positive relationship of the parameters with substrate softness was observed. Populations of larvae in the introduced wood baits developed faster than those in indigenous logs, with portions of the bait-inhabiting populations apparently able to complete development during the summer. Populations in indigenous logs normally require a full year for development and the accelerated growth in the "fresh," introduced substrates indicates a plastic phenology that allows X. par to exploit wood of variable quality. A prerequisite for terrestrial decay in determining wood suitability for X. par is also discussed.

Insecticidal Baits on Field Plot Perimeters Suppress Reticulitermes12

A field trial was conducted in southern Mississippi to determine if placing decayed wood bait blocks impregnated with mirex could suppress termite (Reticulitermes sp.) populations when placed around the perimeter of an area. Bait blocks treated with 10 mg mirex/block were buried at 1.5-m spacing at the perimeter of six 7.5 m-square plots, 3 of which also had treatment along the perimeter of an outer 30-m square. Noninsecticidal bait blocks were used to monitor termite activity within the treatment lines. During a 3.5-yr period, termite activity on the treated plots was suppressed. The efficacy of mirex bait treatment for the protection of man-made structures is disscussed.