Biology of the white-fringed beetle (naupactus leucoloma boh.) /

In undisturbed annual pasture in a Mediterranean-climate region of Australia adults of the whitefringed weevil, Graphognathus leucoloma (Boheman), were present from summer to early winter (December-June), with upsurge in numbers of first instar larvae only occurring after the rains began in April. The G. leucoloma population was predominantly first instar larvae in high abundance throughout the winter period (May-August). Larval growth, with high mortality, occurred in the spring period (September-January). The survival of eggs during the dry summer when adults were most abundant, although only at times of unseasonal rainfall, indicated that low larval recruitment at that time resulted primarily from the absence of high-quality legume food essential for oogenesis. It was inferred that most larvae arose from heavy oviposition by the few adults present in autumn when rainfall germinated annual legumes. A steady year-round abundance of late-instar larvae indicated that not all individuals completed their development in the one year.

Section: Discussioncontrasting

confidence: 94%

Section: Introductionmentioning

confidence: 99%

Population phenology of whitefringed weevil, Graphognathus leucoloma (Coleoptera: Curculionidae), in pasture in a Mediterranean-climate region of Australia

Matthiessen

1991

“…Matthiessen (1991) in Western Australia has found that these quiescent larvae comprise the bulk of the population for more than half the year. Young et al, (1938) also observed that the first instar larvae could survive for long periods without food. They found that larvae kept in sifted soil began development without food, but we did not.…”

Section: Significance Of the Non-feeding First Instarmentioning

confidence: 85%

“…In 1936 it became a pest in the south-eastern states of the USA (Young & App, 1939; Whitefringed weevil, Graphognathus leucoloma Young et al, 1938;Young etal, 1950) establishing later in (Boheman), is a cosmopolitan, parthenogenetic pest of New Zealand (Todd, 1964), and South Africa (De laeger South American origin. It was first recorded as an exotic et al, 1989).…”

Section: Introductionmentioning

confidence: 98%

Development of larvae of the whitefringed weevil,Graphognathus leucoloma(Coleoptera: Curculionidae), in northern Queensland

Gough

Brown

1991

Growth of larvae of the whitefringed weevil, Graphognathus leucoloma (Boheman), was studied in the laboratory and on various crops in pots in a shadehouse at Kairi, on the Atherton Tableland in north Queensland. In the laboratory at 25.5 ± 1°C there were 11 instars for which head capsule widths and weights were recorded. The first instar weighed 0.14 mg. This was a nonfeeding stage capable of prolonged survival, and after 10 weeks in soil without food 60% survived. When provided with carrot (Daucus carota) larvae grew to 2 or 3 mg after 6 to 7 weeks, then increased rapidly in weight reaching 140 mg after 120 days. At 25.5°C the average time from first instar to adult was 311 days, due in part to a long prepupal period. Larval growth was measured on the roots of peanut (Arachis hypogaea) plants in pots in summer and winter. Under summer conditions (mean soil temperature 23.3°C) larvae reached 140 mg in about 120 days, similar to that in the laboratory on carrot. These fully grown larvae remained in the pots over the mild winter without pupating. Larvae developing in autumn/winter grew more slowly, but the fully grown larvae were then exposed to high spring (early summer) temperatures and soon pupated, the average time from first instar to adult being 273 days. The indications are that temperatures above 25°C quickly precondition mature larvae from Tolga for pupation, thus explaining the broad timing of adult emergence in the field in north Queensland. On different plants common near Tolga, larvae grew most quickly on peanuts and on the pasture legumes dolichos (Lablab purpureus) and stylosanthes (Stylosanthes guianensis). Survival on maize equalled that on peanuts (46.5% in sterilized soil) but growth was less. Larval survival and growth on the grass crowsfoot (Eleusine indica), and (surprisingly) on the pasture legume glycine (Neonotonia wightii) was very poor.

“…Fecundity and longevity are high when adults are fed legumes (East, 1977;Ottens & Todd, 1979), upon which they are easily maintained in the laboratory (Gross & Bartlett, 1972). Although embryonic development can occur under dry conditions (Young & App, 1939), it is optimal at c. 95% rh and 27°C, taking c. 24 days (Gross et al, 1972). Following embryogenesis, the larvae remain within the egg, surviving for eight months or longer if humidity is c. 95% and the temperature c. 18°C (Gross et al, 1972).…”

Section: Introductionmentioning

confidence: 99%

Advantageous attributes of larval whitefringed weevil, Naupactus leucoloma (Coleoptera: Curculionidae) for bioassaying soil fumigants, and responses to pure and plant-derived isothiocyanates

Matthiessen

Shackleton

2000

First instars of the soil-inhabiting whitefringed weevil, Naupactus leucoloma (Boheman), are a particularly good bioassay model for assessing volatile soil fumigants and biofumigants. Eggs are readily obtained and can be stored for long periods with larvae hatched on demand and the first instar is non-feeding, surviving without food or shelter. Longevity varies with temperature, but readily accommodates the period required to conduct bioassays without appreciable mortality of untreated controls. In vitro bioassays of pure methyl isothiocyanate, the active ingredient from metham sodium soil fumigant, and the less volatile 2-phenylethyl isothiocyanate, sensitively detected differences in toxicity and effects of temperature. Bioassay of volatiles emitted from hydrolysed tissue of various isothiocyanate-producing Brassica plants revealed widely varying toxicity effects, indicating that bioassays with N. leucoloma are a sensitive and relevant indicator of the potential of different plants for biofumigation of soil-borne pest organisms.