Listronotus bonariensis(Coleoptera: Curculionidae) flight in Canterbury, New Zealand

Abstract

Flight by Listronotus bonariensis (Kuschel) in Canterbury, New Zealand varied greatly both within and between seasons; no winter flight was detected between mid-May and mid-August. Predisposing conditions for flight were found to be >19ЊC, rh <81% and windspeed <10.8 km h -1 . Three flight phases with different characteristics were identified when approximately equal numbers of weevils were trapped. These were between mid-August and early December (overwintered weevils), between early December and mid-March (first summer generation weevils) and mid-March and mid-May (first and second generation weevils). The proportion of individuals with developed flight musculature was c. 8% in the first phase and 30% in the last phase; muscle development was delayed in the midphase. First phase weevils with flight muscles were c. 20 times more likely to fly than those in the last. A very weak inverse relationship was observed between developed flight musculature and the presence or absence of eggs. Similarly, there was a very weak inverse relationship between weevil ground densities and the proportion with developed flight muscles. Levels of parasitism by Microctonus hyperodae Loan amongst trapped weevils were far less than that on the ground, indicating that it inhibits flight and may explain the relatively slow dispersal of the parasitoid. It was concluded that the adaptive implications of flight could be linked to escape responses from desiccating microclimates rather than dispersal from crowded habitats.

Caging overrides effects of density in laboratory‐based physiological estimates of reproductivity in Listronotus bonariensis (Coleoptera: Curculionidae)

“…Barker et al (1989a) also reported ASW partitioning of resources between wing muscle and ovarian development. Conversely, this study found no evidence at all of any such allocation, and as such corroborates the Canterbury field observations of Goldson (1981a;Goldson et al 1999) which showed a distinct absence of the flight-oögenesis characteristics that are sometimes observed in other species (e.g. Kennedy 1961;Rankin et al 1986).…”

“…Pottinger 1961;Goldson 1981a,b;Goldson & Emberson 1981;Barker et al 1988;Barker et al 1989b;Goldson et al 1998Goldson et al , 1999Goldson et al , 2011. In brief, in Canterbury, New Zealand, the weevil is bivoltine, with first-generation egg laying in the sheaths of the grass tillers commencing in late September (early spring).…”

Unexpected Listronotus bonariensis (Coleoptera: Curculionidae) mortality in the presence of parasitoids

“…8). It is extremely unlikely that the observed changes in field densities of adult L. bonariensis were related to migratory flight because these are infrequent in autumn and at the same time involve population redistribution rather than net migration in or out of established pastures (Goldson et al, 1999b).…”

Development of probabilistic models for quantitative pathway analysis of plant pest introduction for the EU territory

“…However, in a later study Prestidge and van der Zijpp (1985) reported negligible flight activity amongst 2 generations in central North Island, NZ. Goldson et al (1999a), in studying dispersion of L. bonariensis, found that predisposing conditions for flight were above 19°C, relative humidity below 81% and wind speed below10.8 km per hour, meaning that flight is restricted to the summer months of December to February/March in the north of New Zealand. Barker et al (1989) The present document has been produced and adopted by the bodies identified above as authors.…”

“…The larvae also generally live within the plants on which they feed and are therefore protected from most insecticides (Pottinger et al 1984). The adult weevils' dispersive capability also limits the effectiveness of control using insecticides (Goldson et al, 1999a, b) and their use is not generally economic due to the relatively low returns from growing pasture crops. The use of systemic insecticides, as well as the timing of sowing to ensure that emergence occurs after the start of diapause for the insect, have both been investigated to assess effectiveness in reducing damage to crops (Goldson & Penman, 1979) but have not generally been adopted in pasture crops because of the low cost effectiveness.…”