Detection and monitoring of pink bollworm moths and invasive insects using pheromone traps and encounter rate models

Abstract

Summary1. The pink bollworm moth Pectinophora gossypiella (Saunders) (Lepidoptera: Gelechiidae) is one of the most destructive pests in agriculture. An ongoing eradication program using a combination of sex pheromone monitoring and mating disruption, irradiated sterile moth releases, genetically modified Bt cotton and local insecticide applications have all but exterminated the pink bollworm from the south-western USA and portions of northern Mexico. However, the continued threat of reinvasion from Mexico reinforces the need to improve pheromone-based monitoring. Invasions from other parts of the world such as India, where resistance to single-gene transgenic Bt cotton has evolved, further heightens the need for better monitoring strategies. 2. The mean flight height and standard deviation (SD) of the vertical flight distribution of pink bollworm males were estimated from catches on transparent sticky cylinder traps baited with synthetic pheromone at several heights above-ground. An effective attraction radius (EAR) of a standard pheromone lure was estimated from male moth catches on the pheromone-baited sticky traps and many similar blank traps. The circular EAR c was estimated from the spherical EAR and SD. 3. The EAR of a pheromone lure for pink bollworm was 1Á03 m, and the EAR c was 2Á61 m. The mean flight height of males was 0Á82 m, and the vertical flight distribution SD was 0Á26 m. 4. A computer program simulated male moth movement and capture on various numbers of traps of EAR c distributed over areas of 1-100 km 2 . The simulated catch results were comparable to predictions using the EAR c with modified encounter rate equations of Royama and Rogers. The encounter rate equations were solved for initial populations of male moths in the regions, and Poisson statistics were used to calculate population confidence limits. 5. Synthesis and applications. Encounter rate models and Poisson methods can be used to determine levels of pheromone trap densities that are likely to detect and estimate low population levels of resident or invasive pink bollworms and many other pest insect species.

Sex pheromones as a tool to overcome the Wallacean shortfall in conservation biology: a case of Elater ferrugineus Linnaeus, 1758 (Coleoptera: Elateridae)

“…One of the most effective methods of this kind is the use of pheromones or other semiochemicals as attractants. The method has been for a long time used in detection, monitoring and control of pest insects (Kehat and Dunkelblum 1993;Welter et al 2005;Nadel et al 2012), including introduced invasive species (Crook et al 2008;Byers and Naranjo 2014). As demonstrated in recent studies, species-specific and sensitive pheromone-bait traps can be especially useful to detect low-density populations (e.g.…”

Index of host habitat preference explored by movement‐based simulations and trap captures

“…However, trapping with pheromones in simulations of this type did not yield the appropriate HHP because catches were similar on traps inside and outside the host habitat area, giving HHP equal to zero. The reason catch was similar inside and outside the host habitat was that encounter rate models predict that catch is a function of speed and density (Byers, ; Byers & Naranjo, ; Levi−Zada et al., ). Thus, as speed decreased (smaller steps), a compensatory increase in density occurred as insects remained longer, which caused no differences in catch between the inside and outside areas.…”

“…Movement-based models of habitat choice such as step-selection functions and resource selection functions have been developed for larger vertebrates that can be followed by GPS biotelemetry or by visual observations (Avgar, Potts, Lewis, & Boyce, 2016;Boyce et al, 2016;Gillies & St. Clair, 2010;Mason & Fortin, 2017;Patterson, Thomas, Wilcox, Ovaskainen, & Matthiopoulos, 2007;Thurfjell, Ciuti, & Boyce, 2014). In contrast, insects are small and essentially invisible in flight, thus their relative abundance, movements and spatial distributions can only be readily studied with traps that intercept or attract (Byers, 1999(Byers, , 2012a(Byers, , 2012bByers & Naranjo, 2014;Landolt & Phillips, 1997), or by conventional sampling methods (Kuno, 1991).…”

Agricultural landscapes with prevailing grasslands can mitigate the population densities of a tree-damaging alien species

“…We subsequently counted all adults that emerged until the last individual had emerged. The number of emerged adults was considered an estimate of population density at each site (Mazzi and Dorn, 2012;Byers and Naranjo, 2014) and was controlled by total mining activity in particular sample (Pocock and Evans, 2014).…”